Implement review fixes

- Added verifyAllPaymentsCompleted() helper in MenuHelper.h to check if the authenticated customer has completed all invoices.

- Integrated payment verification into CustomerMenu::selectService() to block new service bookings when pending payments exist.

- Integrated payment verification into CustomerMenu::selectComboPackage() to block new combo package bookings when invoices are incomplete.

- Implemented iteration over customer invoices to ensure only users with all payments marked as COMPLETED can proceed with new bookings.

- Added user-facing messages to inform customers when bookings are denied due to outstanding payments.

Fixes #2116

.gitignore

@@ -427,5 +427,5 @@ FodyWeavers.xsd
 *.msm
 *.msp
 
-# CSV Files
-*.csv
+# DAT Files
+*.dat

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.cpp

@@ -1,7 +1,24 @@
+/*
+File: Trenser.VehicleServiceSystem.cpp
+Description: Entry point for the Vehicle Service Management System.
+			 Initializes the UserInterface and starts the application loop.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #include "UserInterface.h"
 
+/*
+Function: main
+Description: The main entry point of the application.
+			 Creates a UserInterface object and invokes the run method to start the system.
+Parameters:
+	- None
+Returns:
+	- int: Exit status code (0 for successful execution).
+*/
 int main()
 {
 	UserInterface userInterface;
 	userInterface.run();
-}
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj

@@ -102,7 +102,7 @@
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
-      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;$(ProjectDir)core\sharedmemory;$(ProjectDir)core\events;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -117,7 +117,7 @@
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
-      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;$(ProjectDir)core\sharedmemory;$(ProjectDir)core\events;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -126,8 +126,10 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="controllers\Controller.cpp" />
+    <ClCompile Include="core\events\EventManager.cpp" />
     <ClCompile Include="core\patterns\Observer.cpp" />
     <ClCompile Include="core\patterns\Subject.cpp" />
+    <ClCompile Include="core\sharedmemory\SharedMemory.cpp" />
     <ClCompile Include="datastores\DataStore.cpp" />
     <ClCompile Include="models\ComboPackage.cpp" />
     <ClCompile Include="models\InventoryItem.cpp" />
@@ -139,7 +141,6 @@
     <ClCompile Include="models\User.cpp" />
     <ClCompile Include="services\AuthenticationManagementService.cpp" />
     <ClCompile Include="services\InventoryManagementService.cpp" />
-    <ClCompile Include="services\NotificationManagementService.cpp" />
     <ClCompile Include="services\PaymentManagementService.cpp" />
     <ClCompile Include="services\ServiceManagementService.cpp" />
     <ClCompile Include="services\UserManagementService.cpp" />
@@ -148,14 +149,23 @@
     <ClCompile Include="utilities\Validator.cpp" />
     <ClCompile Include="views\AdminMenu.cpp" />
     <ClCompile Include="views\CustomerMenu.cpp" />
+    <ClCompile Include="views\Menu.cpp" />
     <ClCompile Include="views\TechnicianMenu.cpp" />
     <ClCompile Include="views\UserInterface.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="controllers\Controller.h" />
+    <ClInclude Include="core\events\EventManager.h" />
     <ClInclude Include="core\patterns\Observer.h" />
     <ClInclude Include="core\patterns\Subject.h" />
+    <ClInclude Include="core\sharedmemory\FileHeader.h" />
+    <ClInclude Include="core\sharedmemory\MappingInfo.h" />
+    <ClInclude Include="core\sharedmemory\RecordState.h" />
+    <ClInclude Include="core\sharedmemory\SerializedRecords.h" />
+    <ClInclude Include="core\sharedmemory\SharedMemory.h" />
+    <ClInclude Include="core\sharedmemory\TrackedRecord.h" />
     <ClInclude Include="datastores\DataStore.h" />
+    <ClInclude Include="datastores\DataStoreLockGuard.h" />
     <ClInclude Include="factories\Factory.h" />
     <ClInclude Include="models\ComboPackage.h" />
     <ClInclude Include="models\InventoryItem.h" />
@@ -171,16 +181,21 @@
     <ClInclude Include="services\PaymentManagementService.h" />
     <ClInclude Include="services\ServiceManagementService.h" />
     <ClInclude Include="services\UserManagementService.h" />
+    <ClInclude Include="utilities\Config.h" />
     <ClInclude Include="utilities\Enums.h" />
+    <ClInclude Include="utilities\FileHelper.h" />
     <ClInclude Include="utilities\InputHelper.h" />
     <ClInclude Include="utilities\Map.h" />
     <ClInclude Include="utilities\OutputHelper.h" />
+    <ClInclude Include="utilities\StringHelper.h" />
     <ClInclude Include="utilities\Timestamp.h" />
     <ClInclude Include="utilities\Utility.h" />
     <ClInclude Include="utilities\Validator.h" />
     <ClInclude Include="utilities\Vector.h" />
     <ClInclude Include="views\AdminMenu.h" />
     <ClInclude Include="views\CustomerMenu.h" />
+    <ClInclude Include="views\Menu.h" />
+    <ClInclude Include="views\MenuHelper.h" />
     <ClInclude Include="views\TechnicianMenu.h" />
     <ClInclude Include="views\UserInterface.h" />
   </ItemGroup>

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters

@@ -64,6 +64,18 @@
     <Filter Include="Source Files\Core\Patterns">
       <UniqueIdentifier>{8057b93d-51a9-42df-b06e-01ce395f6308}</UniqueIdentifier>
     </Filter>
+    <Filter Include="Header Files\Core\SharedMemory">
+      <UniqueIdentifier>{d9da9793-fe6f-4914-bee3-99d5934da228}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Source Files\Core\SharedMemory">
+      <UniqueIdentifier>{0769afb6-f57d-4ae3-a1cf-ceca6e606af0}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Header Files\Core\Events">
+      <UniqueIdentifier>{85029bdb-6941-41dc-a3a7-9e5841671d8c}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Source Files\Core\Events">
+      <UniqueIdentifier>{1050aca7-6f2c-4ccb-a446-db9c898c3599}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="Trenser.VehicleServiceSystem.cpp">
@@ -108,9 +120,6 @@
     <ClCompile Include="datastores\DataStore.cpp">
       <Filter>Source Files\DataStores</Filter>
     </ClCompile>
-    <ClCompile Include="services\NotificationManagementService.cpp">
-      <Filter>Source Files\Services</Filter>
-    </ClCompile>
     <ClCompile Include="core\patterns\Observer.cpp">
       <Filter>Source Files\Core\Patterns</Filter>
     </ClCompile>
@@ -141,6 +150,15 @@
     <ClCompile Include="models\ComboPackage.cpp">
       <Filter>Source Files\Models</Filter>
     </ClCompile>
+    <ClCompile Include="core\sharedmemory\SharedMemory.cpp">
+      <Filter>Source Files\Core\SharedMemory</Filter>
+    </ClCompile>
+    <ClCompile Include="core\events\EventManager.cpp">
+      <Filter>Source Files\Core\Events</Filter>
+    </ClCompile>
+    <ClCompile Include="views\Menu.cpp">
+      <Filter>Source Files\Views</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="utilities\InputHelper.h">
@@ -233,8 +251,47 @@
     <ClInclude Include="models\ComboPackage.h">
       <Filter>Header Files\Models</Filter>
     </ClInclude>
+    <ClInclude Include="utilities\Config.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
+    <ClInclude Include="utilities\StringHelper.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
+    <ClInclude Include="utilities\FileHelper.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
     <ClInclude Include="utilities\Utility.h">
       <Filter>Header Files\Utilities</Filter>
     </ClInclude>
+    <ClInclude Include="views\MenuHelper.h">
+      <Filter>Header Files\Views</Filter>
+    </ClInclude>
+    <ClInclude Include="datastores\DataStoreLockGuard.h">
+      <Filter>Header Files\DataStores</Filter>
+    </ClInclude>
+    <ClInclude Include="core\sharedmemory\FileHeader.h">
+      <Filter>Header Files\Core\SharedMemory</Filter>
+    </ClInclude>
+    <ClInclude Include="core\sharedmemory\MappingInfo.h">
+      <Filter>Header Files\Core\SharedMemory</Filter>
+    </ClInclude>
+    <ClInclude Include="core\sharedmemory\RecordState.h">
+      <Filter>Header Files\Core\SharedMemory</Filter>
+    </ClInclude>
+    <ClInclude Include="core\sharedmemory\SerializedRecords.h">
+      <Filter>Header Files\Core\SharedMemory</Filter>
+    </ClInclude>
+    <ClInclude Include="core\sharedmemory\SharedMemory.h">
+      <Filter>Header Files\Core\SharedMemory</Filter>
+    </ClInclude>
+    <ClInclude Include="core\sharedmemory\TrackedRecord.h">
+      <Filter>Header Files\Core\SharedMemory</Filter>
+    </ClInclude>
+    <ClInclude Include="core\events\EventManager.h">
+      <Filter>Header Files\Core\Events</Filter>
+    </ClInclude>
+    <ClInclude Include="views\Menu.h">
+      <Filter>Header Files\Views</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp

@@ -1,124 +1,456 @@
-#include "Controller.h"
-#include "User.h"
-#include "Invoice.h"
+/*
+File: Controller.cpp
+Description: Implementation file containing the method definitions of the
+             Controller class, including authentication, user creation,
+             service purchasing, and system checks.
+Author: Trenser
+Date:19-May-2026
+*/
 
+#include "ComboPackage.h"
+#include "Controller.h"
+#include "Enums.h"
+#include "InventoryItem.h"
+#include "Invoice.h"
+#include "JobCard.h"
+#include "Service.h"
+#include "ServiceBooking.h"
+#include "User.h"
+#include <stdexcept>
+
+/*
+Function: login
+Description: Authenticates a user by delegating to the authentication management service.
+Parameter: const std::string& username - user’s username
+           const std::string& password - user’s password
+Return type: bool - true if login successful, false otherwise
+*/
 bool Controller::login(const std::string& username, const std::string& password)
 {
-    return false;
+    return m_authenticationManagementService.login(username, password);
 }
 
+/*
+Function: logout
+Description: Logs out the currently authenticated user.
+Parameter: None
+Return type: void
+*/
 void Controller::logout()
 {
+    m_authenticationManagementService.logout();
 }
 
+/*
+Function: changePassword
+Description: Changes the password of the currently authenticated user.
+Parameter: const std::string& newPassword - new password to set
+Return type: void
+*/
 void Controller::changePassword(const std::string& newPassword)
 {
+    m_authenticationManagementService.changePassword(newPassword);
 }
 
-void Controller::createCustomer(const std::string& username, const std::string& password, const std::string& email, const std::string& phone)
+/*
+Function: createCustomer
+Description: Creates a new customer account with the provided details.
+Parameter: const std::string& username - customer’s username
+           const std::string& name - customer’s name
+           const std::string& password - customer’s password
+           const std::string& email - customer’s email
+           const std::string& phone - customer’s phone number
+Return type: void
+*/
+
+void Controller::createCustomer(const std::string& username, const std::string& name, const std::string& password, const std::string& email, const std::string& phone)
 {
+    m_userManagementService.createUser(username, name, password, email, phone, util::UserType::CUSTOMER);
 }
 
+/*
+Function: getAuthenticatedUser
+Description: Retrieves the currently authenticated user.
+Parameter: None
+Return type: const User* - pointer to the authenticated user
+*/
 const User* Controller::getAuthenticatedUser()
 {
-    return nullptr;
+    return m_authenticationManagementService.getAuthenticatedUser();
 }
 
-void Controller::createTechnician(const std::string& username, const std::string& password, const std::string& email, const std::string& phone)
+/*
+Function: createTechnician
+Description: Creates a new technician account with provided details by
+             delegating to the user management service.
+Parameter: const std::string& username - technician's username
+           const std::string& password - technician's password
+           const std::string& email - technician's email address
+           const std::string& phoneNumber - technician's phone number
+Return type: void
+*/
+void Controller::createTechnician(const std::string& username, const std::string& name, const std::string& password, const std::string& email, const std::string& phoneNumber)
 {
+    m_userManagementService.createUser(username, name, password, email, phoneNumber, util::UserType::TECHNICIAN);
 }
 
+/*
+Function: updateUserDetails
+Description: Updates the email and phone details of the currently authenticated user.
+Parameter: const std::string& email - new email address
+           const std::string& phone - new phone number
+Return type: void
+*/
 void Controller::updateUserDetails(const std::string& email, const std::string& phone)
 {
+    User* authenticatedUser = m_authenticationManagementService.getAuthenticatedUser();
+    if (authenticatedUser == nullptr)
+    {
+        throw std::runtime_error("No user currently logged in!");
+    }
+    m_userManagementService.updateUserDetails(authenticatedUser->getId(), email, phone);
 }
 
+/*
+Function: getServices
+Description: Retrieves all available services in read-only form.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, const Service*> containing all services
+*/
 util::Map<std::string, const Service*> Controller::getServices()
 {
-    return util::Map<std::string, const Service*>();
+    util::Map<std::string, Service*> currentServices = m_serviceManagementService.getServices();
+    util::Map<std::string, const Service*> readOnlyServices;
+    for (int iterator = 0; iterator < currentServices.getSize(); iterator++)
+    {
+        readOnlyServices.insert(currentServices.getValueAt(iterator)->getId(), currentServices.getValueAt(iterator));
+    }
+    return readOnlyServices;
 }
 
+/*
+Function: getComboPackages
+Description: Retrieves all available combo packages from the service
+             management service and constructs a read-only map.
+Parameter: None
+Return type: util::Map<std::string, const ComboPackage*>
+*/
 util::Map<std::string, const ComboPackage*> Controller::getComboPackages()
 {
-    return util::Map<std::string, const ComboPackage*>();
+    util::Map<std::string, ComboPackage*> currentAvailableComboPackages = m_serviceManagementService.getComboPackages();
+    util::Map<std::string, const ComboPackage*> readOnlyComboPackages;
+    for (int iterator = 0; iterator < currentAvailableComboPackages.getSize(); iterator++)
+    {
+        ComboPackage* currentComboPackage = currentAvailableComboPackages.getValueAt(iterator);
+        if (currentComboPackage)
+        {
+            readOnlyComboPackages.insert(currentComboPackage->getId(), currentComboPackage);
+        }
+    }
+    return readOnlyComboPackages;
 }
 
+/*
+Function: purchaseService
+Description: Purchases one or more services for a vehicle by delegating to the service management service.
+Parameter: const util::Vector<std::string>& serviceIDs - IDs of services to purchase
+           const std::string& vehicleNumber - vehicle registration number
+           const std::string& vehicleBrand - brand of the vehicle
+           const std::string& vehicleModel - model of the vehicle
+Return type: void
+*/
 void Controller::purchaseService(const util::Vector<std::string>& serviceIDs, const std::string& vehicleNumber, const std::string& vehicleBrand, const std::string& vehicleModel)
 {
+    m_serviceManagementService.purchaseService(serviceIDs, vehicleNumber, vehicleBrand, vehicleModel);
 }
 
+/*
+Function: purchaseComboPackage
+Description: Purchases a combo package for a vehicle by delegating to the service management service.
+Parameter: const std::string& comboPackageID - ID of the combo package
+           const std::string& vehicleNumber - vehicle registration number
+           const std::string& vehicleBrand - brand of the vehicle
+           const std::string& vehicleModel - model of the vehicle
+Return type: void
+*/
 void Controller::purchaseComboPackage(const std::string& comboPackageID, const std::string& vehicleNumber, const std::string& vehicleBrand, const std::string& vehicleModel)
 {
+    m_serviceManagementService.purchaseComboPackage(comboPackageID, vehicleNumber, vehicleBrand, vehicleModel);
 }
 
+/*
+Function: getInventoryItems
+Description: Retrieves all inventory items from the inventory management service
+             and constructs a read-only map for external use.
+Parameter: None
+Return type: util::Map<std::string, const InventoryItem*>
+*/
 util::Map<std::string, const InventoryItem*> Controller::getInventoryItems()
 {
-    return util::Map<std::string, const InventoryItem*>();
+    auto inventoryItems = m_inventoryManagementService.getInventoryItems();
+    util::Map<std::string, const InventoryItem*> readOnlyInventoryItems;
+    int inventoryItemsMapSize = inventoryItems.getSize();
+    for (int index = 0; index < inventoryItemsMapSize; index++)
+    {
+        readOnlyInventoryItems.insert(inventoryItems.getKeyAt(index), inventoryItems.getValueAt(index));
+    }
+    return readOnlyInventoryItems;
 }
 
+/*
+Function: getInventoryItem
+Description: Retrieves a specific inventory item by its ID from the inventory management service.
+Parameter: const std::string& inventoryItemID - ID of the inventory item
+Return type: const InventoryItem*
+*/
 const InventoryItem* Controller::getInventoryItem(const std::string& inventoryItemID)
 {
-    return nullptr;
+    return m_inventoryManagementService.getInventoryItem(inventoryItemID);
 }
 
+/*
+Function: addInventoryItem
+Description: Adds a new inventory item with specified details to the inventory management service.
+Parameter: const std::string& partName - name of the part
+           int quantity - quantity of the part
+           double price - price of the part
+Return type: void
+*/
 void Controller::addInventoryItem(const std::string& partName, int quantity, double price)
 {
+    m_inventoryManagementService.addInventoryItem(partName, quantity, price);
 }
 
+/*
+Function: removeInventoryItem
+Description: Removes an inventory item from the inventory management service by its ID.
+Parameter: const std::string& inventoryItemID - ID of the inventory item
+Return type: void
+*/
 void Controller::removeInventoryItem(const std::string& inventoryItemID)
 {
+    m_inventoryManagementService.removeInventoryItem(inventoryItemID);
 }
 
+/*
+Function: removeServiceBooking
+Description: Removes a service booking from the service management system by its booking ID.
+Parameter: const std::string& bookingID - ID of the service booking
+Return type: void
+*/
+void Controller::removeServiceBooking(const std::string& bookingID)
+{
+    m_serviceManagementService.removeServiceBooking(bookingID);
+}
+
+/*
+Function: addInventoryItemStock
+Description: Adds stock to an existing inventory item in the inventory management service.
+Parameter: const std::string& selectedItemId - ID of the inventory item
+           int quantity - quantity to add
+Return type: void
+*/
+void Controller::addInventoryItemStock(const std::string& selectedItemId, int quantity)
+{
+    m_inventoryManagementService.addInventoryItemStock(selectedItemId, quantity);
+}
+
+/*
+Function: getServiceBookings
+Description: Retrieves all service bookings in read-only form.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, const ServiceBooking*> containing service bookings
+*/
 util::Map<std::string, const ServiceBooking*> Controller::getServiceBookings()
 {
-    return util::Map<std::string, const ServiceBooking*>();
+    auto serviceBookings = m_serviceManagementService.getServiceBookings();
+    util::Map<std::string, const ServiceBooking*> readOnlyServiceBookings;
+    for (int iterator = 0; iterator < serviceBookings.getSize(); iterator++)
+    {
+        readOnlyServiceBookings.insert(serviceBookings.getKeyAt(iterator), serviceBookings.getValueAt(iterator));
+    }
+    return readOnlyServiceBookings;
 }
 
+
+/*
+Function: getServiceBookingsByUser
+Description: Retrieves all service bookings for a specific user.
+Parameters:
+    - userID: std::string, the user ID
+Returns:
+    - util::Map<std::string, const ServiceBooking*> containing bookings for the user
+*/
 util::Map<std::string, const ServiceBooking*> Controller::getServiceBookingsByUser(const std::string userID)
 {
-    return util::Map<std::string, const ServiceBooking*>();
+    util::Map<std::string, const ServiceBooking*> readOnlyServiceBookingsByUserMap;
+    util::Map<std::string, ServiceBooking*> currentServiceBookingsByUser = m_serviceManagementService.getServiceBookings(userID);
+    for (int iterator = 0; iterator < currentServiceBookingsByUser.getSize(); iterator++)
+    {
+        readOnlyServiceBookingsByUserMap.insert(currentServiceBookingsByUser.getValueAt(iterator)->getId(), currentServiceBookingsByUser.getValueAt(iterator));
+    }
+    return readOnlyServiceBookingsByUserMap;
 }
 
+/*
+Function: getUsers
+Description: Retrieves all users from the user management service and
+             constructs a read-only map.
+Parameter: None
+Return type: util::Map<std::string, const User*>
+*/
 util::Map<std::string, const User*> Controller::getUsers()
 {
-    return util::Map<std::string, const User*>();
+    auto listOfUsers = m_userManagementService.getUsers();
+    util::Map<std::string, const User*> readOnlyUserList;
+    for (int iterator = 0; iterator < listOfUsers.getSize(); iterator++)
+    {
+        readOnlyUserList.insert(listOfUsers.getKeyAt(iterator), listOfUsers.getValueAt(iterator));
+    }
+    return readOnlyUserList;
 }
 
+/*
+Function: getUsers
+Description: Retrieves users filtered by user type.
+Parameters:
+    - userType: util::UserType, type of user (CUSTOMER, TECHNICIAN, ADMIN)
+Returns:
+    - util::Map<std::string, const User*> containing users of the specified type
+*/
 util::Map<std::string, const User*> Controller::getUsers(util::UserType userType)
 {
-    return util::Map<std::string, const User*>();
+    auto userMap = m_userManagementService.getUsers(userType);
+    util::Map<std::string, const User*> readOnlyUserMap;
+    for (int iterator = 0; iterator < userMap.getSize(); iterator++)
+    {
+        readOnlyUserMap.insert(userMap.getKeyAt(iterator), userMap.getValueAt(iterator));
+    }
+    return readOnlyUserMap;
 }
 
+/*
+Function: createJobCard
+Description: Creates a job card for a service booking assigned to a technician.
+Parameters:
+    - bookingID: std::string, ID of the service booking
+    - technicianID: std::string, ID of the technician
+    - serviceID: std::string, ID of the service
+Returns:
+    - void
+*/
 void Controller::createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID)
 {
+    m_serviceManagementService.createJobCard(bookingID, technicianID, serviceID);
 }
 
+/*
+Function: createService
+Description: Creates a new service with associated inventory items and labor cost.
+Parameters:
+    - name: std::string, name of the service
+    - inventoryItemIDs: Vector of inventory item IDs
+    - laborCost: double, labor cost
+Returns:
+    - void
+*/
 void Controller::createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost)
 {
+    m_serviceManagementService.createService(name, inventoryItemIDs, laborCost);
 }
 
+/*
+Function: removeService
+Description: Removes a service from the system by ID.
+Parameters:
+    - serviceID: std::string, ID of the service
+Returns:
+    - void
+*/
 void Controller::removeService(const std::string& serviceID)
 {
+    m_serviceManagementService.removeService(serviceID);
 }
 
+/*
+Function: getJobCardsByUser
+Description: Retrieves job cards assigned to the authenticated technician.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, const JobCard*> containing job cards
+*/
 util::Map<std::string, const JobCard*> Controller::getJobCardsByUser()
 {
-    return util::Map<std::string, const JobCard*>();
+    const User* currentUser = getAuthenticatedUser();
+    auto jobCardsAssignedToTechnician = m_serviceManagementService.getJobCards(currentUser->getId());
+    util::Map<std::string, const JobCard*> readOnlyJobCardMap;
+    for (int iterator = 0; iterator < jobCardsAssignedToTechnician.getSize(); iterator++)
+    {
+        JobCard* currentJobCard = jobCardsAssignedToTechnician.getValueAt(iterator);
+        readOnlyJobCardMap.insert(currentJobCard->getId(), currentJobCard);
+    }
+    return readOnlyJobCardMap;
 }
 
-void Controller::completeJob(const std::string& jobID)
+/*
+Function: completeJob
+Description: Marks a job card as completed.
+Parameters:
+    - jobID: std::string, ID of the job card
+Returns:
+    - void
+*/
+void Controller::updateJobStatus(const std::string& jobID)
 {
+    m_serviceManagementService.updateJobStatus(jobID);
 }
 
+/*
+Function: removeUser
+Description: Removes a user by ID. Cancels associated service bookings
+             and technician jobs before removing the user from the system.
+Parameter: const std::string& userID - ID of the user to remove
+Return type: void
+*/
 void Controller::removeUser(const std::string& userID)
 {
+    User* user = m_userManagementService.getUser(userID);
+    if (!user)
+    {
+        throw std::runtime_error("Error: User not Found.\n");
+    }
+    m_userManagementService.removeUser(userID);
 }
 
+/*
+Function: createComboPackage
+Description: Creates a new combo package with specified services and discount
+             percentage by delegating to the service management service.
+Parameter: const std::string& name - name of the combo package
+           const util::Vector<std::string>& serviceIDs - list of service IDs
+           double discountPercentage - discount percentage for the package
+Return type: void
+*/
 void Controller::createComboPackage(const std::string& name, const util::Vector<std::string>& serviceIDs, double discountPercentage)
 {
+    m_serviceManagementService.createComboPackage(name, serviceIDs, discountPercentage);
 }
 
+/*
+Function: removeComboPackage
+Description: Removes a combo package by ID by delegating to the service
+             management service.
+Parameter: const std::string& comboPackageID - ID of the combo package
+Return type: void
+*/
 void Controller::removeComboPackage(const std::string& comboPackageID)
 {
+    m_serviceManagementService.removeComboPackage(comboPackageID);
 }
 
 /*
@@ -143,6 +475,38 @@ util::Map<std::string, const Invoice*> Controller::getInvoicesByUser()
     return userInvoicesReadOnly;
 }
 
+/*
+Function: getAllInvoices
+Description: Retrieves all invoices from the PaymentManagementService and returns them as a read-only map.
+Parameters:
+    - none
+Returns:
+    - util::Map<std::string, const Invoice*>: Map of invoice IDs to invoice objects
+*/
+util::Map<std::string, const Invoice*> Controller::getAllInvoices()
+{
+    auto invoices = m_paymentManagementService.getAllInvoices();
+    util::Map<std::string, const Invoice*> readOnlyInvoice;
+    for (int iterator = 0; iterator < invoices.getSize(); iterator++)
+    {
+        readOnlyInvoice.insert(invoices.getKeyAt(iterator), invoices.getValueAt(iterator));
+    }
+    return readOnlyInvoice;
+}
+
+/*
+Function: confirmPayment
+Description: Delegates payment confirmation for a given invoice ID to the PaymentManagementService.
+Parameters:
+    - invoiceID: std::string, ID of the invoice to confirm
+Returns:
+    - void
+*/
+void Controller::confirmPayment(const std::string& invoiceID)
+{
+    m_paymentManagementService.confirmPayment(invoiceID);
+}
+
 /*
 Function: completePayment
 Description: Completes payment for a specific invoice using the given payment mode.
@@ -157,19 +521,129 @@ void Controller::completePayment(const std::string& invoiceID, util::PaymentMode
     m_paymentManagementService.completePayment(invoiceID, paymentMode);
 }
 
+/*
+Function: getNotifications
+Description: Retrieves all notifications for the currently authenticated user.
+             Converts them into a read-only vector before returning.
+Parameters: None
+Return type: util::Vector<const Notification*>
+*/
 util::Vector<const Notification*> Controller::getNotifications()
 {
-    return util::Vector<const Notification*>();
+    const User* authenticatedUser = m_authenticationManagementService.getAuthenticatedUser();
+    if (!authenticatedUser)
+    {
+        throw std::runtime_error("No user is currently logged in!");
+    }
+    auto notifications = m_userManagementService.getUserNotifications(authenticatedUser->getId());
+    int numberOfNotifications = notifications.getSize();
+    util::Vector<const Notification*> readOnlyNotifications;
+    for (int index = 0; index < numberOfNotifications; index++)
+    {
+        readOnlyNotifications.push_back(notifications[index]);
+    }
+    return readOnlyNotifications;
 }
 
+/*
+Function: deleteNotification
+Description: Deletes a specific notification for the currently authenticated user.
+Parameters:
+    - notificationID: std::string, the unique identifier of the notification
+Return type: void
+*/
 void Controller::deleteNotification(const std::string& notificationID)
 {
+    const User* authenticatedUser = m_authenticationManagementService.getAuthenticatedUser();
+    if (!authenticatedUser)
+    {
+        throw std::runtime_error("No user is currently logged in!");
+    }
+    m_userManagementService.deleteNotification(notificationID, authenticatedUser->getId());
 }
 
-void Controller::configureNotifications(const std::string& userID, bool paymentNotifications, bool serviceNotifications)
+/*
+Function: configureNotifications
+Description: Configures notification preferences for the authenticated user.
+             Attaches or detaches the user from payment and service notifications.
+Parameters:
+    - paymentNotifications: bool, enable/disable payment notifications
+    - serviceNotifications: bool, enable/disable service notifications
+Return type: void
+*/
+void Controller::configureNotifications(bool paymentNotifications, bool serviceNotifications)
 {
+    User* authenticatedUser = m_authenticationManagementService.getAuthenticatedUser();
+    if (authenticatedUser)
+    {
+        if (paymentNotifications)
+        {
+            m_paymentManagementService.attach(authenticatedUser);
+        }
+        else
+        {
+            m_paymentManagementService.detach(authenticatedUser);
+        }
+        if (serviceNotifications)
+        {
+            m_serviceManagementService.attach(authenticatedUser);
+        }
+        else
+        {
+            m_serviceManagementService.detach(authenticatedUser);
+        }
+    }
+    else
+    {
+        throw std::runtime_error("No user is currently logged in!");
+    }
 }
 
-void Controller::runSystemChecks()
+/*
+Function: initialize
+Description: Initializes the system and run system checks to ensure critical configurations, such as verifying admin existence.
+Parameters:
+    - None
+Returns:
+    - bool
+*/
+bool Controller::initialize()
 {
-}
+    auto& dataStore = DataStore::getInstance();
+
+    if (!dataStore.initialize())
+    {
+        return false;
+    }
+    m_userManagementService.ensureAdminExists();
+    m_inventoryManagementService.sendLowStockAlerts();
+    m_paymentManagementService.sendPaymentReminders();
+    return true;
+}
+
+/*
+Function: shutdown
+Description: Shutdown the system, and do necessary cleanups
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void Controller::shutdown()
+{
+    auto& dataStore = DataStore::getInstance();
+    dataStore.shutdown();
+}
+
+/*
+Function: registerEvents
+Description: Registers menu event handles with the authentication
+             service.
+Parameter: HANDLE accountDisabledEvent - account disabled event handle
+           HANDLE notificationAvailableEvent - notification event handle
+Return type: void
+*/
+void Controller::registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent)
+{
+    m_authenticationManagementService.registerEvents(accountDisabledEvent, notificationAvailableEvent);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h

@@ -1,9 +1,22 @@
+/*
+File: Controller.h
+Description: Header file declaring the Controller class, which manages
+             user authentication, inventory, services, bookings, job cards,
+             invoices, and notifications in the system.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
-#include "Map.h"
+#include <windows.h>
 #include <string>
-#include "Enums.h"
-#include "PaymentManagementService.h"
 #include "AuthenticationManagementService.h"
+#include "Enums.h"
+#include "InventoryManagementService.h"
+#include "Map.h"
+#include "PaymentManagementService.h"
+#include "ServiceManagementService.h"
+#include "UserManagementService.h"
 
 class Service;
 class ComboPackage;
@@ -17,15 +30,18 @@ class Notification;
 class Controller
 {
 private:
-    AuthenticationManagementService m_authenticationManagementService;
+    AuthenticationManagementService  m_authenticationManagementService;
+    UserManagementService m_userManagementService;
+    ServiceManagementService m_serviceManagementService;    
+    InventoryManagementService m_inventoryManagementService;
     PaymentManagementService m_paymentManagementService;
 public:
     bool login(const std::string& username, const std::string& password);
     void logout();
     void changePassword(const std::string& newPassword);
-    void createCustomer(const std::string& username, const std::string& password, const std::string& email, const std::string& phone);
+    void createCustomer(const std::string& username, const std::string& name, const std::string& password, const std::string& email, const std::string& phone);
     const User* getAuthenticatedUser();
-    void createTechnician(const std::string& username, const std::string& password, const std::string& email, const std::string& phone);
+    void createTechnician(const std::string& username, const std::string& name, const std::string& password, const std::string& email, const std::string& phone);
     void updateUserDetails(const std::string& email, const std::string& phone);
     util::Map<std::string, const Service*> getServices();
     util::Map<std::string, const ComboPackage*> getComboPackages();
@@ -34,6 +50,7 @@ public:
     util::Map<std::string, const InventoryItem*> getInventoryItems();
     const InventoryItem* getInventoryItem(const std::string& inventoryItemID);
     void addInventoryItem(const std::string& partName, int quantity, double price);
+    void addInventoryItemStock(const std::string& selectedItemId, int quantity);
     void removeInventoryItem(const std::string& inventoryItemID);
     util::Map<std::string, const ServiceBooking*> getServiceBookings();
     util::Map<std::string, const ServiceBooking*> getServiceBookingsByUser(const std::string userID);
@@ -41,16 +58,21 @@ public:
     util::Map<std::string, const User*> getUsers(util::UserType userType);
     void createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID);
     void createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost);
+    void removeServiceBooking(const std::string& bookingID);
     void removeService(const std::string& serviceID);
     util::Map<std::string, const JobCard*> getJobCardsByUser();
-    void completeJob(const std::string& jobID);
+    void updateJobStatus(const std::string& jobID);
     void removeUser(const std::string& userID);
     void createComboPackage(const std::string& name, const util::Vector<std::string>& serviceIDs, double discountPercentage);
     void removeComboPackage(const std::string& comboPackageID);
     util::Map<std::string, const Invoice*> getInvoicesByUser();
+    util::Map<std::string, const Invoice*> getAllInvoices();
+    void confirmPayment(const std::string& invoiceID);
     void completePayment(const std::string& invoiceID, util::PaymentMode paymentMode);
     util::Vector<const Notification*> getNotifications();
     void deleteNotification(const std::string& notificationID);
-    void configureNotifications(const std::string& userID, bool paymentNotifications, bool serviceNotifications);
-    void runSystemChecks();
+    void configureNotifications(bool paymentNotifications, bool serviceNotifications);
+    bool initialize();
+    void shutdown();
+    void registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/events/EventManager.cpp

@@ -0,0 +1,225 @@
+/*
+File: EventManager.cpp
+Description: Implementation file containing the method definitions of the
+             EventManager class, including listener management and
+             interprocess event publishing.
+Author: Trenser
+Date:15-Jun-2026
+*/
+
+#include <iostream>
+#include <stdexcept>
+#include "EventManager.h"
+
+namespace
+{
+    const std::string USER_DISABLED_EVENT = "userDisabled_";
+
+    const std::string NOTIFICATION_AVAILABLE_EVENT = "notificationAvailable_";
+}
+
+/*
+Function: EventManager
+Description: Constructs an EventManager instance with default values.
+Parameter: None
+Return type: None
+*/
+EventManager::EventManager()
+    :
+    m_userDisabledEvent(NULL),
+    m_notificationAvailableEvent(NULL),
+    m_shutdownEvent(NULL),
+    m_running(false) {}
+
+/*
+Function: ~EventManager
+Description: Destroys the EventManager and performs final cleanup.
+Parameter: None
+Return type: None
+*/
+EventManager::~EventManager()
+{
+    shutdown();
+    if (m_listenerThread.joinable())
+    {
+        m_listenerThread.join();
+    }
+}
+
+/*
+Function: initialize
+Description: Creates the user-specific events and starts the listener
+             thread.
+Parameter: const std::string& userId - unique identifier of the user
+           std::function<void()> userDisabledCallback - callback for
+           user disable events
+           std::function<void()> notificationCallback - callback for
+           notification events
+Return type: bool - true if initialization succeeds, false otherwise
+*/
+bool EventManager::initialize(const std::string& userId, std::function<void()> userDisabledCallback, std::function<void()> notificationCallback)
+{
+    if (m_running.load())
+    {
+        return false;
+    }
+    m_userDisabledCallback = userDisabledCallback;
+    m_notificationCallback = notificationCallback;
+    m_userDisabledEvent = CreateEventA(NULL, FALSE, FALSE, (USER_DISABLED_EVENT + userId).c_str());
+    if (!m_userDisabledEvent)
+    {
+        return false;
+    }
+    if (GetLastError() == ERROR_ALREADY_EXISTS)
+    {
+        CloseHandle(m_userDisabledEvent);
+        m_userDisabledEvent = NULL;
+        throw std::runtime_error("Only one session allowed per user.");
+    }
+    m_notificationAvailableEvent = CreateEventA(NULL, FALSE, FALSE, (NOTIFICATION_AVAILABLE_EVENT + userId).c_str());
+    if (!m_notificationAvailableEvent)
+    {
+        CloseHandle(m_userDisabledEvent);
+        m_userDisabledEvent = NULL;
+        return false;
+    }
+    m_shutdownEvent = CreateEventA(NULL, FALSE, FALSE, NULL);
+    if (!m_shutdownEvent)
+    {
+        CloseHandle(m_userDisabledEvent);
+        CloseHandle(m_notificationAvailableEvent);
+        m_userDisabledEvent = NULL;
+        m_notificationAvailableEvent = NULL;
+        return false;
+    }
+    m_running.store(true);
+    m_listenerThread = std::thread(&EventManager::run, this);
+    return true;
+}
+
+/*
+Function: shutdown
+Description: Stops the listener thread and releases event resources.
+Parameter: None
+Return type: None
+*/
+void EventManager::shutdown()
+{
+    if (!m_running.load())
+    {
+        return;
+    }
+    m_running.store(false);
+    if (m_shutdownEvent)
+    {
+        SetEvent(m_shutdownEvent);
+    }
+    if (m_listenerThread.joinable())
+    {
+        if (std::this_thread::get_id() != m_listenerThread.get_id())
+        {
+            m_listenerThread.join();
+        }
+    }
+    if (m_userDisabledEvent)
+    {
+        CloseHandle(m_userDisabledEvent);
+        m_userDisabledEvent = NULL;
+    }
+    if (m_notificationAvailableEvent)
+    {
+        CloseHandle(m_notificationAvailableEvent);
+        m_notificationAvailableEvent = NULL;
+    }
+    if (m_shutdownEvent)
+    {
+        CloseHandle(m_shutdownEvent);
+        m_shutdownEvent = NULL;
+    }
+}
+
+/*
+Function: run
+Description: Waits for and dispatches user-related events.
+Parameter: None
+Return type: void
+*/
+void EventManager::run()
+{
+    HANDLE handles[3];
+    handles[0] = m_userDisabledEvent;
+    handles[1] = m_notificationAvailableEvent;
+    handles[2] = m_shutdownEvent;
+    while (m_running.load())
+    {
+        DWORD result = WaitForMultipleObjects(3, handles, FALSE, INFINITE);
+        switch (result)
+        {
+        case WAIT_OBJECT_0:
+            try
+            {
+                if (m_userDisabledCallback)
+                {
+                    m_userDisabledCallback();
+                }
+            }
+            catch (const std::exception& exception)
+            {
+                std::cout << exception.what() << std::endl;
+            }
+            break;
+        case WAIT_OBJECT_0 + 1:
+            try
+            {
+                if (m_notificationCallback)
+                {
+                    m_notificationCallback();
+                }
+            }
+            catch (const std::exception& exception)
+            {
+                std::cout << exception.what() << std::endl;
+            }
+            break;
+        case WAIT_OBJECT_0 + 2:
+            return;
+        default:
+            break;
+        }
+    }
+}
+
+/*
+Function: sendUserDisabledEvent
+Description: Publishes a user disabled event for a specific user.
+Parameter: const std::string& userId - target user identifier
+Return type: void
+*/
+void EventManager::sendUserDisabledEvent(const std::string& userId)
+{
+    HANDLE eventHandle = CreateEventA(NULL, FALSE, FALSE, (USER_DISABLED_EVENT + userId).c_str());
+    if (!eventHandle)
+    {
+        return;
+    }
+    SetEvent(eventHandle);
+    CloseHandle(eventHandle);
+}
+
+/*
+Function: sendNotificationAvailableEvent
+Description: Publishes a notification available event for a specific
+             user.
+Parameter: const std::string& userId - target user identifier
+Return type: void
+*/
+void EventManager::sendNotificationAvailableEvent(const std::string& userId)
+{
+    HANDLE eventHandle = CreateEventA(NULL, FALSE, FALSE, (NOTIFICATION_AVAILABLE_EVENT + userId).c_str());
+    if (!eventHandle)
+    {
+        return;
+    }
+    SetEvent(eventHandle);
+    CloseHandle(eventHandle);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/events/EventManager.h

@@ -0,0 +1,37 @@
+/*
+File: EventManager.h
+Description: Header file declaring the EventManager class, which manages
+             user-specific interprocess events for user disable and
+             notification availability updates.
+Author: Trenser
+Date:15-Jun-2026
+*/
+
+#pragma once
+
+#include <windows.h>
+#include <atomic>
+#include <functional>
+#include <string>
+#include <thread>
+
+class EventManager
+{
+private:
+    HANDLE m_userDisabledEvent;
+    HANDLE m_notificationAvailableEvent;
+    HANDLE m_shutdownEvent;
+    std::atomic<bool> m_running;
+    std::thread m_listenerThread;
+    std::function<void()> m_userDisabledCallback;
+    std::function<void()> m_notificationCallback;
+    void run();
+
+public:
+    EventManager();
+    ~EventManager();
+    bool initialize(const std::string& userId, std::function<void()> userDisabledCallback, std::function<void()> notificationCallback);
+    void shutdown();
+    static void sendUserDisabledEvent(const std::string& userId);
+    static void sendNotificationAvailableEvent(const std::string& userId);
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/patterns/Observer.h

@@ -1,10 +1,14 @@
-#pragma once
+/*
+File: Observer.h
+Description: Declares the Observer interface for handling notifications in the Vehicle Service Management System.
+Author: Trenser
+Date: 19-May-2026
+*/
 
-class Notification;
+#pragma once
 
 class Observer
 {
 public:
     virtual ~Observer() = default;
-    virtual void update(Notification* notification) = 0;
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/patterns/Subject.h

@@ -1,6 +1,14 @@
+/*
+File: Subject.h
+Description: Declares the Subject interface for managing user attachments and detachments in the Observer design pattern within the Vehicle Service Management System.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 
 class User;
 class Notification;

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/FileHeader.h

@@ -0,0 +1,17 @@
+/*
+File: FileHeader.h
+Description: Defines the FileHeader structure used to store
+             metadata for binary record files, including
+             record count and capacity.
+Author: Trenser
+Created: 10-June-2026
+*/
+
+#pragma once
+#include <cstddef>
+
+struct FileHeader
+{
+    size_t recordCount;
+    size_t capacity;
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/MappingInfo.h

@@ -0,0 +1,29 @@
+/*
+File: MappingInfo.h
+Description: Defines the MappingInfo structure used for
+             managing Windows file mapping operations.
+             Stores handles, mapped view pointer,
+             file metadata, and capacity information.
+Author: Trenser
+Created: 10-June-2026
+*/
+
+#pragma once
+#include <windows.h>
+#include <string>
+
+struct MappingInfo
+{
+    HANDLE fileHandle;
+    HANDLE mappingHandle;
+    void* mappedView;
+    std::string fileName;
+    size_t recordSize;
+    size_t mappedCapacity;
+    MappingInfo()
+        : fileHandle(NULL),
+        mappingHandle(NULL),
+        mappedView(nullptr),
+        recordSize(0),
+        mappedCapacity(0) {}
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/RecordState.h

@@ -0,0 +1,17 @@
+/*
+File: RecordState.h
+Description: Defines the RecordState enumeration used to
+             represent the state of a record in storage.
+             States include CLEAN, NEW_RECORD, and MODIFIED.
+Author: Trenser
+Created: 10-June-2026
+*/
+
+#pragma once
+
+enum class RecordState : int
+{
+    CLEAN,
+    NEW_RECORD,
+    MODIFIED
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/SerializedRecords.h

@@ -0,0 +1,109 @@
+/*
+File: SerializedRecords.h
+Description: Defines serialized structures for persistent storage
+             and retrieval of system entities including User,
+             Notification, Service, ComboPackage, InventoryItem,
+             ServiceBooking, JobCard, Invoice, and Observer.
+             These structures use fixed-size character arrays
+             and primitive types for binary serialization.
+Author: Trenser
+Created: 10-June-2026
+*/
+
+#pragma once
+#include "Utility.h"
+#include "Enums.h"
+#include "Timestamp.h"
+
+struct SerializedUser
+{
+    char id[64];
+    char username[64];
+    char password[64];
+    char name[128];
+    char phone[32];
+    char email[128];
+    util::UserType userType;
+    util::State status;
+};
+
+struct SerializedNotification
+{
+    char id[64];
+    char recipientUserId[64];
+    char title[128];
+    char message[1024];
+    util::Timestamp createdAt;
+    util::State state;
+};
+
+struct SerializedService
+{
+    char id[64];
+    char name[128];
+    char inventoryItemIDs[1024];
+    double laborCost;
+    util::State status;
+};
+
+struct SerializedComboPackage
+{
+    char id[64];
+    char packageName[128];
+    double discountPercentage;
+    char serviceIDs[1024];
+    util::State status;
+};
+
+struct SerializedInventoryItem
+{
+    char id[64];
+    char partName[128];
+    int quantity;
+    double price;
+    util::State status;
+};
+
+struct SerializedServiceBooking
+{
+    char id[64];
+    util::ServiceJobStatus status;
+    char serviceIDs[1024];
+    char customerId[64];
+    char vehicleNumber[64];
+    char vehicleBrand[64];
+    char vehicleModel[64];
+    char assignedTechnicianId[64];
+    double discountPercentage;
+};
+
+struct SerializedJobCard
+{
+    char id[64];
+    char bookingId[64];
+    char serviceId[64];
+    char technicianId[64];
+    util::Timestamp assignedDate;
+    util::ServiceJobStatus status;
+    util::Timestamp completionDate;
+};
+
+struct SerializedInvoice
+{
+    char id[64];
+    char bookingId[64];
+    util::Timestamp invoiceDate;
+    char partIDs[1024];
+    double laborCost;
+    double partsCost;
+    double discountPercentage;
+    double totalAmount;
+    util::Timestamp paymentDate;
+    util::PaymentMode paymentMethod;
+    util::PaymentStatus status;
+};
+
+struct SerializedObserver
+{
+    char id[64];
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/SharedMemory.cpp

@@ -0,0 +1,386 @@
+/*
+File: SharedMemory.cpp
+Description: Implements shared memory utilities for managing
+             Windows file mapping operations. Provides functions
+             to create, open, resize, and close mappings, as well
+             as access headers, records, and ensure synchronization
+             across processes.
+Author: Trenser
+Created: 11-June-2026
+*/
+
+#include "SharedMemory.h"
+#include "Windows.h"
+#include "Config.h"
+
+/*
+Function: invalidateMapping
+Description: Releases all mapping resources and resets the mapping to an invalid state.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - None
+*/
+static void invalidateMapping(MappingInfo& mapping)
+{
+    if (mapping.mappedView != nullptr)
+    {
+        UnmapViewOfFile(mapping.mappedView);
+        mapping.mappedView = nullptr;
+    }
+    if (mapping.mappingHandle != NULL)
+    {
+        CloseHandle(mapping.mappingHandle);
+        mapping.mappingHandle = NULL;
+    }
+    if (mapping.fileHandle != INVALID_HANDLE_VALUE)
+    {
+        CloseHandle(mapping.fileHandle);
+        mapping.fileHandle = INVALID_HANDLE_VALUE;
+    }
+    mapping.mappedCapacity = 0;
+}
+
+/*
+Function: createOrOpenMapping
+Description: Creates or opens a file mapping and maps it into the process address space.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - bool: True if the mapping was successfully created/opened, otherwise false
+*/
+bool SharedMemory::createOrOpenMapping(MappingInfo& mapping)
+{
+    if (mapping.recordSize == 0)
+    {
+        return false;
+    }
+    mapping.fileHandle =
+        CreateFileA(
+            mapping.fileName.c_str(),
+            GENERIC_READ | GENERIC_WRITE,
+            FILE_SHARE_READ | FILE_SHARE_WRITE,
+            NULL,
+            OPEN_ALWAYS,
+            FILE_ATTRIBUTE_NORMAL,
+            NULL);
+    if (mapping.fileHandle == INVALID_HANDLE_VALUE)
+    {
+        return false;
+    }
+    LARGE_INTEGER fileSize;
+    if (!GetFileSizeEx(mapping.fileHandle, &fileSize))
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    bool isNewFile = (fileSize.QuadPart == 0);
+    const size_t initialCapacity = config::file::INITIAL_CAPACITY;
+    if (isNewFile)
+    {
+        LARGE_INTEGER newSize;
+        newSize.QuadPart = sizeof(FileHeader) + initialCapacity * mapping.recordSize;
+        if (!SetFilePointerEx(mapping.fileHandle, newSize, NULL, FILE_BEGIN))
+        {
+            invalidateMapping(mapping);
+            return false;
+        }
+        if (!SetEndOfFile(mapping.fileHandle))
+        {
+            invalidateMapping(mapping);
+            return false;
+        }
+    }
+    mapping.mappingHandle =
+        CreateFileMappingA(
+            mapping.fileHandle,
+            NULL,
+            PAGE_READWRITE,
+            0,
+            0,
+            NULL);
+    if (mapping.mappingHandle == NULL)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappedView =
+        MapViewOfFile(
+            mapping.mappingHandle,
+            FILE_MAP_ALL_ACCESS,
+            0,
+            0,
+            0);
+    if (mapping.mappedView == nullptr)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    FileHeader* header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    if (isNewFile)
+    {
+        header->recordCount = 0;
+        header->capacity = initialCapacity;
+    }
+    mapping.mappedCapacity = header->capacity;
+    return true;
+}
+
+/*
+Function: closeMapping
+Description: Unmaps and closes all resources associated with a file mapping.
+Parameters:
+    - mapping: MappingInfo&, mapping to close
+Returns:
+    - None
+*/
+void SharedMemory::closeMapping(MappingInfo& mapping)
+{
+    invalidateMapping(mapping);
+}
+
+/*
+Function: getHeader
+Description: Returns the file header stored at the beginning of the mapped memory region.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - FileHeader*: Pointer to the file header, or nullptr if the mapping is not valid
+*/
+FileHeader* SharedMemory::getHeader(MappingInfo& mapping)
+{
+    if (mapping.mappedView == nullptr)
+    {
+        return nullptr;
+    }
+    return reinterpret_cast<FileHeader*>(mapping.mappedView);
+}
+
+/*
+Function: getRecordAddress
+Description: Returns the address of a record at the specified index within the mapped memory region.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+    - index: size_t, record index
+Returns:
+    - void*: Pointer to the record, or nullptr if the mapping is not valid
+*/
+void* SharedMemory::getRecordAddress(MappingInfo& mapping, size_t index)
+{
+    if (mapping.mappedView == nullptr)
+    {
+        return nullptr;
+    }
+    return reinterpret_cast<char*>(mapping.mappedView) + sizeof(FileHeader) + index * mapping.recordSize;
+}
+
+/*
+Function: getRecordCount
+Description: Returns the number of records currently stored in the mapping.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - size_t: Number of records in the mapping
+*/
+size_t SharedMemory::getRecordCount(MappingInfo& mapping)
+{
+    FileHeader* header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        return 0;
+    }
+    return header->recordCount;
+}
+
+/*
+Function: setRecordCount
+Description: Updates the number of records stored in the mapping.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+    - count: size_t, new record count
+Returns:
+    - None
+*/
+void SharedMemory::setRecordCount(MappingInfo& mapping, size_t count)
+{
+    FileHeader* header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        return;
+    }
+    header->recordCount = count;
+}
+
+/*
+Function: getCapacity
+Description: Returns the current capacity of the mapping.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - size_t: Maximum number of records that can be stored in the mapping
+*/
+size_t SharedMemory::getCapacity(MappingInfo& mapping)
+{
+    FileHeader* header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        return 0;
+    }
+    return header->capacity;
+}
+
+/*
+Function: resizeMapping
+Description: Resizes the file mapping to the specified capacity.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+    - newCapacity: size_t, new mapping capacity
+Returns:
+    - bool: True if the resize succeeded, otherwise false
+*/
+bool SharedMemory::resizeMapping(MappingInfo& mapping, size_t newCapacity)
+{
+    FileHeader* header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    header->capacity = newCapacity;
+    if (!FlushViewOfFile(mapping.mappedView, sizeof(FileHeader)))
+    {
+        return false;
+    }
+    if (!UnmapViewOfFile(mapping.mappedView))
+    {
+        return false;
+    }
+    mapping.mappedView = nullptr;
+    CloseHandle(mapping.mappingHandle);
+    mapping.mappingHandle = NULL;
+    LARGE_INTEGER newSize;
+    newSize.QuadPart = sizeof(FileHeader) + newCapacity * mapping.recordSize;
+    if (!SetFilePointerEx(mapping.fileHandle, newSize, NULL, FILE_BEGIN))
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    if (!SetEndOfFile(mapping.fileHandle))
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappingHandle =
+        CreateFileMappingA(
+            mapping.fileHandle,
+            NULL,
+            PAGE_READWRITE,
+            0,
+            0,
+            NULL);
+    if (mapping.mappingHandle == NULL)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappedView =
+        MapViewOfFile(
+            mapping.mappingHandle,
+            FILE_MAP_ALL_ACCESS,
+            0,
+            0,
+            0);
+    if (mapping.mappedView == nullptr)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappedCapacity = newCapacity;
+    return true;
+}
+
+/*
+Function: ensureCapacityForInsert
+Description: Ensures that the mapping has space for at least one additional record, growing it if necessary.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - bool: True if capacity is available, otherwise false
+*/
+bool SharedMemory::ensureCapacityForInsert(MappingInfo& mapping)
+{
+    size_t recordCount = getRecordCount(mapping);
+    size_t capacity = getCapacity(mapping);
+    if (recordCount < capacity)
+    {
+        return true;
+    }
+    return resizeMapping(mapping, capacity * config::file::GROWTH_FACTOR);
+}
+
+/*
+Function: ensureLatestMapping
+Description: Remaps the file if another process has resized it.
+Parameters:
+    - mapping: MappingInfo&, mapping information and handles
+Returns:
+    - bool: True if the mapping is valid and up to date, otherwise false
+*/
+bool SharedMemory::ensureLatestMapping(MappingInfo& mapping)
+{
+    FileHeader* header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        return false;
+    }
+    if (header->capacity == mapping.mappedCapacity)
+    {
+        return true;
+    }
+    if (!UnmapViewOfFile(mapping.mappedView))
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappedView = nullptr;
+    CloseHandle(mapping.mappingHandle);
+    mapping.mappingHandle = NULL;
+    mapping.mappingHandle =
+        CreateFileMappingA(
+            mapping.fileHandle,
+            NULL,
+            PAGE_READWRITE,
+            0,
+            0,
+            NULL);
+    if (mapping.mappingHandle == NULL)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappedView =
+        MapViewOfFile(
+            mapping.mappingHandle,
+            FILE_MAP_ALL_ACCESS,
+            0,
+            0,
+            0);
+    if (mapping.mappedView == nullptr)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    header = getHeader(mapping);
+    if (header == nullptr)
+    {
+        invalidateMapping(mapping);
+        return false;
+    }
+    mapping.mappedCapacity = header->capacity;
+    return true;
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/SharedMemory.h

@@ -0,0 +1,29 @@
+/*
+File: SharedMemory.h
+Description: Declares functions for managing Windows file
+             mapping and shared memory operations. Provides
+             utilities for creating, resizing, and closing
+             mappings, as well as accessing headers and
+             record data.
+Author: Trenser
+Created: 10-June-2026
+*/
+
+#pragma once
+#include <cstddef>
+#include "MappingInfo.h"
+#include "FileHeader.h"
+
+namespace SharedMemory
+{
+    bool createOrOpenMapping(MappingInfo& mapping);
+    void closeMapping(MappingInfo& mapping);
+    bool ensureLatestMapping(MappingInfo& mapping);
+    bool resizeMapping(MappingInfo& mapping, size_t newCapacity);
+    FileHeader* getHeader(MappingInfo& mapping);
+    void* getRecordAddress(MappingInfo& mapping, size_t index);
+    size_t getRecordCount(MappingInfo& mapping);
+    void setRecordCount(MappingInfo& mapping, size_t count);
+    size_t getCapacity(MappingInfo& mapping);
+    bool ensureCapacityForInsert(MappingInfo& mapping);
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/sharedmemory/TrackedRecord.h

@@ -0,0 +1,33 @@
+/*
+File: TrackedRecord.h
+Description: Defines the TrackedRecord template structure used
+             to manage objects with associated record state and
+             slot index. Supports tracking of CLEAN, NEW_RECORD,
+             and MODIFIED states for persistence and synchronization.
+Author: Trenser
+Created: 10-June-2026
+*/
+
+#pragma once
+#include "RecordState.h"
+
+static const size_t INVALID_SLOT = static_cast<size_t>(-1);
+
+template<typename T>
+struct TrackedRecord
+{
+    T* data;
+    RecordState state;
+    size_t slotIndex;
+    TrackedRecord()
+        : data(nullptr),
+        state(RecordState::CLEAN),
+        slotIndex(INVALID_SLOT) {}
+    TrackedRecord(
+        T* object,
+        RecordState recordState,
+        size_t slot)
+        : data(object),
+        state(recordState),
+        slotIndex(slot) {}
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.cpp

@@ -1,47 +1,783 @@
-#include "DataStore.h"
+/*
+File: DataStore.cpp
+Description: Implements the DataStore class which provides a centralized singleton repository
+             for managing system data in the Vehicle Service Management System.
+             Includes accessors for users, services, combo packages, service bookings,
+             job cards, inventory items, invoices, and payments.
+Author: Trenser
+Date: 19-May-2026
+*/
 
+#include "DataStore.h"
+#include "Config.h"
+#include "SerializedRecords.h"
+#include "FileHelper.h"
+#include "ServiceBooking.h"
+#include "JobCard.h"
+#include "Invoice.h"
+
+/*
+Function: DataStore
+Description: Constructs the DataStore singleton and initializes
+             internal handles to their default values.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+DataStore::DataStore() :
+    m_globalMutex(NULL) {}
+
+/*
+Function: ~DataStore
+Description: Destroys the DataStore singleton and releases all
+             cached application objects owned by the datastore.
+             This includes users, notifications, services,
+             combo packages, inventory items, service bookings,
+             job cards, and invoices.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+DataStore::~DataStore()
+{
+    clearCache(m_userCache);
+    clearCache(m_notificationCache);
+    clearCache(m_serviceCache);
+    clearCache(m_comboPackageCache);
+    clearCache(m_inventoryItemCache);
+    clearCache(m_serviceBookingCache);
+    clearCache(m_jobCardCache);
+    clearCache(m_invoiceCache);
+}
+
+/*
+Function: initialize
+Description: Initializes the shared-memory datastore.
+             Creates or opens the global datastore mutex,
+             configures all mapping metadata, and creates
+             or opens the file mappings used to persist
+             application data. After successful completion,
+             all datastore files are mapped into memory and
+             ready for use by the application.
+Parameter: None
+Return type: bool
+             - true  : Initialization completed successfully.
+             - false : Failed to create the mutex or open
+                       one or more file mappings.
+*/
+bool DataStore::initialize()
+{
+    m_globalMutex = CreateMutexA(NULL, FALSE, "VehicleServiceSystemMutex");
+    if (m_globalMutex == NULL)
+    {
+        return false;
+    }
+    if (!lockDataStore())
+    {
+        CloseHandle(m_globalMutex);
+        m_globalMutex = NULL;
+        return false;
+    }
+    bool success = true;
+    do
+    {
+        util::ensureDirectoryExists(config::file::DIRECTORY);
+        m_users.fileName = config::file::USER_FILE;
+        m_users.recordSize = sizeof(SerializedUser);
+        m_notifications.fileName = config::file::NOTIFICATION_FILE;
+        m_notifications.recordSize = sizeof(SerializedNotification);
+        m_services.fileName = config::file::SERVICE_FILE;
+        m_services.recordSize = sizeof(SerializedService);
+        m_comboPackages.fileName = config::file::COMBOPACKAGE_FILE;
+        m_comboPackages.recordSize = sizeof(SerializedComboPackage);
+        m_inventoryItems.fileName = config::file::INVENTORYITEM_FILE;
+        m_inventoryItems.recordSize = sizeof(SerializedInventoryItem);
+        m_serviceBookings.fileName = config::file::SERVICEBOOKING_FILE;
+        m_serviceBookings.recordSize = sizeof(SerializedServiceBooking);
+        m_jobCards.fileName = config::file::JOBCARD_FILE;
+        m_jobCards.recordSize = sizeof(SerializedJobCard);
+        m_invoices.fileName = config::file::INVOICE_FILE;
+        m_invoices.recordSize = sizeof(SerializedInvoice);
+        m_serviceManagementObservers.fileName = config::file::SERVICEMANAGEMENTOBSERVERS;
+        m_serviceManagementObservers.recordSize = sizeof(SerializedObserver);
+        m_paymentManagementObservers.fileName = config::file::PAYMENTMANAGEMENTOBSERVERS;
+        m_paymentManagementObservers.recordSize = sizeof(SerializedObserver);
+        m_inventoryManagementObservers.fileName = config::file::INVENTORYMANAGEMENTOBSERVERS;
+        m_inventoryManagementObservers.recordSize = sizeof(SerializedObserver);
+        if (!SharedMemory::createOrOpenMapping(m_users))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_notifications))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_services))
+        {
+            success = false;
+            break;
+        }
+
+        if (!SharedMemory::createOrOpenMapping(m_comboPackages))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_inventoryItems))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_serviceBookings))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_jobCards))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_invoices))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_serviceManagementObservers))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_paymentManagementObservers))
+        {
+            success = false;
+            break;
+        }
+        if (!SharedMemory::createOrOpenMapping(m_inventoryManagementObservers))
+        {
+            success = false;
+            break;
+        }
+    } while (false);
+    unlockDataStore();
+    if (!success)
+    {
+        shutdown();
+    }
+    return success;
+}
+
+/*
+Function: shutdown
+Description: Releases all shared-memory resources owned by the
+             datastore. Closes every file mapping, unmaps all
+             mapped views, and releases the datastore mutex.
+             After this call, the datastore must be initialized
+             again before use.
+Parameter: None
+Return type: void
+*/
+void DataStore::shutdown()
+{
+    SharedMemory::closeMapping(m_users);
+    SharedMemory::closeMapping(m_notifications);
+    SharedMemory::closeMapping(m_services);
+    SharedMemory::closeMapping(m_comboPackages);
+    SharedMemory::closeMapping(m_inventoryItems);
+    SharedMemory::closeMapping(m_serviceBookings);
+    SharedMemory::closeMapping(m_jobCards);
+    SharedMemory::closeMapping(m_invoices);
+    SharedMemory::closeMapping(m_serviceManagementObservers);
+    SharedMemory::closeMapping(m_paymentManagementObservers);
+    SharedMemory::closeMapping(m_inventoryManagementObservers);
+    if (m_globalMutex != NULL)
+    {
+        CloseHandle(m_globalMutex);
+        m_globalMutex = NULL;
+    }
+}
+
+/*
+Function: getInstance
+Description: Provides a singleton instance of the DataStore class.
+Parameters:
+    - None
+Returns:
+    - Reference to the single DataStore instance.
+*/
 DataStore& DataStore::getInstance()
 {
     static DataStore dataStore;
     return dataStore;
 }
 
-util::Map<std::string, User*>& DataStore::getUsers()
+/*
+Function: getUsers
+Description: Retrieves all user records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<User>>: Collection of user records
+*/
+util::Map<std::string, TrackedRecord<User>>& DataStore::getUsers()
 {
-    return m_users;
+    auto users = loadRecords<User, SerializedUser>(m_users);
+    refreshCache(m_userCache, users);
+    return m_userCache;
 }
 
-util::Map<std::string, Service*>& DataStore::getServices()
+/*
+Function: getNotifications
+Description: Retrieves all notification records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<Notification>>: Collection of notification records
+*/
+util::Map<std::string, TrackedRecord<Notification>>& DataStore::getNotifications()
 {
-    return m_services;
+    auto notifications = loadRecords<Notification, SerializedNotification>(m_notifications);
+    refreshCache(m_notificationCache, notifications);
+    return m_notificationCache;
 }
 
-util::Map<std::string, ComboPackage*>& DataStore::getComboPackages()
+/*
+Function: getServices
+Description: Retrieves all service records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<Service>>: Collection of service records
+*/
+util::Map<std::string, TrackedRecord<Service>>& DataStore::getServices()
 {
-    return m_comboPackages;
+    util::Map<std::string, TrackedRecord<Service>> services = loadRecords<Service, SerializedService>(m_services);
+    refreshCache(m_serviceCache, services);
+    util::Map<std::string, TrackedRecord<InventoryItem>>& inventoryItems = getInventoryItems();
+    size_t numberOfServices = m_serviceCache.getSize();
+    for (int iteratorOne =0; iteratorOne < numberOfServices; iteratorOne++)
+    {
+        Service* currentService = m_serviceCache.getValueAt(iteratorOne).data;
+        util::Map<std::string, InventoryItem*> inventoryItemMap;
+        util::Vector<std::string> currentServiceInventoryItem = currentService->getRequiredInventoryItemIDs();
+        for (int iteratorTwo = 0; iteratorTwo < currentServiceInventoryItem.getSize(); iteratorTwo++)
+        {
+            const std::string& currentInventoryItemId = currentServiceInventoryItem[iteratorTwo];
+            int currentInventoryItemIndex = inventoryItems.find(currentInventoryItemId);
+            if (currentInventoryItemIndex == -1)
+            {
+                throw std::runtime_error("Invalid inventory item ID");
+            }
+            InventoryItem* currentItem = inventoryItems.getValueAt(currentInventoryItemIndex).data;
+            inventoryItemMap[currentInventoryItemId] = currentItem;
+        }
+        currentService->setRequiredInventoryItems(inventoryItemMap);
+    }
+    return m_serviceCache;
 }
 
-util::Map<std::string, ServiceBooking*>& DataStore::getServiceBookings()
+/*
+Function: getComboPackages
+Description: Retrieves all combo package records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<ComboPackage>>: Collection of combo package records
+*/
+util::Map<std::string, TrackedRecord<ComboPackage>>& DataStore::getComboPackages()
 {
-    return m_serviceBookings;
+    util::Map<std::string, TrackedRecord<ComboPackage>> comboPackages = loadRecords<ComboPackage, SerializedComboPackage>(m_comboPackages);
+    refreshCache(m_comboPackageCache, comboPackages);
+    util::Map<std::string, TrackedRecord<Service>>& services = getServices();
+    size_t numberOfComboPackages = m_comboPackageCache.getSize();
+    for (int iteratorOne = 0; iteratorOne < numberOfComboPackages; iteratorOne++)
+    {
+        ComboPackage* currentComboPackage =  m_comboPackageCache.getValueAt(iteratorOne).data;
+        util::Vector<std::string> currentServiceIds = currentComboPackage->getServiceIDs();
+        util::Map<std::string, Service*> currentComboPackageServices;
+        for (int iteratorTwo = 0; iteratorTwo < currentServiceIds.getSize(); iteratorTwo++)
+        {
+            const std::string& currentServiceId = currentServiceIds[iteratorTwo];
+            int serviceIndex = services.find(currentServiceId);
+            if (serviceIndex == -1)
+            {
+                throw std::runtime_error("Invalid service ID");
+            }
+            Service* currentService = services.getValueAt(serviceIndex).data;
+            currentComboPackageServices[currentServiceId] = currentService;
+        }
+        currentComboPackage->setServices(currentComboPackageServices);
+    }
+    return m_comboPackageCache;
 }
 
-util::Map<std::string, JobCard*>& DataStore::getJobCards()
+/*
+Function: getInventoryItems
+Description: Retrieves all inventory item records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<InventoryItem>>: Collection of inventory item records
+*/
+util::Map<std::string, TrackedRecord<InventoryItem>>& DataStore::getInventoryItems()
 {
-    return m_jobCards;
+    auto inventoryItems = loadRecords<InventoryItem, SerializedInventoryItem>(m_inventoryItems);
+    refreshCache(m_inventoryItemCache, inventoryItems);
+    return m_inventoryItemCache;
 }
 
-util::Map<std::string, InventoryItem*>& DataStore::getInventoryItems()
+/*
+Function: getServiceBookings
+Description: Retrieves all service booking records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<ServiceBooking>>: Collection of service booking records
+*/
+util::Map<std::string, TrackedRecord<ServiceBooking>>& DataStore::getServiceBookings()
 {
-    return m_inventoryItems;
+    util::Map<std::string, TrackedRecord<ServiceBooking>> serviceBookings = loadRecords<ServiceBooking, SerializedServiceBooking>(m_serviceBookings);
+    refreshCache(m_serviceBookingCache, serviceBookings);
+    auto& users = getUsers();
+    auto& services = getServices();
+    size_t numberOfServiceBookings = m_serviceBookingCache.getSize();
+    for (int iteratorOne = 0; iteratorOne < numberOfServiceBookings; iteratorOne++)
+    {
+        ServiceBooking* serviceBooking = m_serviceBookingCache.getValueAt(iteratorOne).data;
+        auto& serviceIds = serviceBooking->getServiceIDs();
+        util::Map<std::string, Service*> servicesInBooking;
+        for (int iteratorTwo = 0; iteratorTwo < serviceIds.getSize(); iteratorTwo++)
+        {
+            const std::string& currentServiceId = serviceIds[iteratorTwo];
+            int serviceIndex = services.find(currentServiceId);
+            if (serviceIndex == -1)
+            {
+                throw std::runtime_error("Invalid service index.");
+            }
+            auto currentService = services.getValueAt(serviceIndex);
+            servicesInBooking[currentServiceId] = currentService.data;
+        }
+        serviceBooking->setServices(servicesInBooking);
+        if (!serviceBooking->getCustomerId().empty())
+        {
+            int userIndex = users.find(serviceBooking->getCustomerId());
+            if (userIndex == -1)
+            {
+                throw std::runtime_error("Invalid user index.");
+            }
+            auto customer = users.getValueAt(userIndex);
+            serviceBooking->setCustomer(customer.data);
+        }
+        if (!serviceBooking->getAssignedTechnicianId().empty())
+        {
+            int technicianIndex = users.find(serviceBooking->getAssignedTechnicianId());
+            if (technicianIndex == -1)
+            {
+                throw std::runtime_error("Invalid technician index.");
+            }
+            auto technician = users.getValueAt(technicianIndex);
+            serviceBooking->setAssignedTechnician(technician.data);
+        }
+    }
+    return m_serviceBookingCache;
 }
 
-util::Map<std::string, Invoice*>& DataStore::getInvoices()
+/*
+Function: getJobCards
+Description: Retrieves all job card records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<JobCard>>: Collection of job card records
+*/
+util::Map<std::string, TrackedRecord<JobCard>>& DataStore::getJobCards()
 {
-    return m_invoices;
+    util::Map<std::string, TrackedRecord<JobCard>> jobCards = loadRecords<JobCard, SerializedJobCard>(m_jobCards);
+    refreshCache(m_jobCardCache, jobCards);
+    auto& serviceBookings = getServiceBookings();
+    auto& services = getServices();
+    auto& users = getUsers();
+    int numberOfJobCards = m_jobCardCache.getSize();
+    for (int iterator = 0; iterator < numberOfJobCards; iterator++)
+    {
+        JobCard* jobCard = m_jobCardCache.getValueAt(iterator).data;
+        if (!jobCard)
+        {
+            continue;
+        }
+        const std::string& bookingId = jobCard->getBookingId();
+        int bookingIndex = serviceBookings.find(bookingId);
+        if (bookingIndex == -1)
+        {
+            throw std::runtime_error("Invalid booking ID: " + bookingId);
+        }
+        auto& trackedBooking = serviceBookings.getValueAt(bookingIndex);
+        jobCard->setBooking(trackedBooking.data);
+        const std::string& serviceId = jobCard->getServiceId();
+        int serviceIndex = services.find(serviceId);
+        if (serviceIndex == -1)
+        {
+            throw std::runtime_error("Invalid service ID: " + serviceId);
+        }
+        auto trackedService = services.getValueAt(serviceIndex);
+        jobCard->setService(trackedService.data);
+        const std::string& technicianId = jobCard->getTechnicianId();
+        if (!technicianId.empty())
+        {
+            int technicianIndex = users.find(technicianId);
+            if (technicianIndex == -1)
+            {
+                throw std::runtime_error("Invalid technician ID: " + technicianId);
+            }
+            auto trackedTechnician = users.getValueAt(technicianIndex);
+            jobCard->setTechnician(trackedTechnician.data);
+        }
+    }
+    return m_jobCardCache;
 }
 
-util::Map<std::string, Payment*>& DataStore::getPayments()
+
+/*
+Function: getInvoices
+Description: Retrieves all invoice records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, TrackedRecord<Invoice>>: Collection of invoice records
+*/
+util::Map<std::string, TrackedRecord<Invoice>>& DataStore::getInvoices()
 {
-    return m_payments;
+    auto& serviceBookings = getServiceBookings();
+    auto& inventoryItems = getInventoryItems();
+    util::Map<std::string, TrackedRecord<Invoice>> invoices = loadRecords<Invoice, SerializedInvoice>(m_invoices);
+    refreshCache(m_invoiceCache, invoices);
+    for (int iterator = 0; iterator < m_invoiceCache.getSize(); iterator++)
+    {
+        auto& trackedInvoice = m_invoiceCache.getValueAt(iterator);
+        Invoice* invoice = trackedInvoice.data;
+        if (!invoice)
+        {
+            continue;
+        }
+        const std::string& currentBookingId = invoice->getBookingId();
+        int currentBookingIndex = serviceBookings.find(currentBookingId);
+        if (currentBookingIndex == -1)
+        {
+            throw std::runtime_error("Invalid Service Booking Index.");
+        }
+        ServiceBooking* currentBooking = serviceBookings.getValueAt(currentBookingIndex).data;
+        auto& currentInventoryItemIds = invoice->getPartIDs();
+        util::Map<std::string, InventoryItem*> currentInventoryItems;
+        for (int iterator = 0; iterator < currentInventoryItemIds.getSize(); iterator++)
+        {
+            const std::string& currentItemId = currentInventoryItemIds[iterator];
+            int currentItemIndex = inventoryItems.find(currentItemId);
+            if (currentItemIndex == -1)
+            {
+                throw std::runtime_error("Invalid Inventory item id.");
+            }
+            InventoryItem* currentItem = inventoryItems.getValueAt(currentItemIndex).data;
+            if (!currentItem)
+            {
+                continue;
+            }
+            currentInventoryItems[currentItemId] = currentItem;
+        }
+        invoice->setBooking(currentBooking);
+        invoice->setParts(currentInventoryItems);
+    }
+    return m_invoiceCache;
+}
+
+/*
+Function: getObservers
+Description: Retrieves observer records from the specified observer mapping
+             and resolves them to User objects.
+Parameters:
+    - mapping: Observer mapping to read from
+Returns:
+    - util::Map<std::string, User*>: Collection of observer records
+Throws:
+    - std::runtime_error if an observer references an invalid user ID
+*/
+util::Map<std::string, User*> DataStore::getObservers(MappingInfo& mapping)
+{
+    auto& users = getUsers();
+    util::Map<std::string, User*> observers;
+    SharedMemory::ensureLatestMapping(mapping);
+    size_t recordCount = SharedMemory::getRecordCount(mapping);
+    for (size_t index = 0; index < recordCount; index++)
+    {
+        const SerializedObserver* observer = static_cast<SerializedObserver*>(SharedMemory::getRecordAddress(mapping, index));
+        int userIndex = users.find(observer->id);
+        if (userIndex == -1)
+        {
+            throw std::runtime_error("Invalid observer user ID");
+        }
+        User* user = users.getValueAt(userIndex).data;
+        observers.insert(user->getId(), user);
+    }
+    return observers;
+}
+
+/*
+Function: getServiceManagementObservers
+Description: Retrieves all service management observer records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, User*>: Collection of observer records
+*/
+util::Map<std::string, User*> DataStore::getServiceManagementObservers()
+{
+    return getObservers(m_serviceManagementObservers);
+}
+
+/*
+Function: getPaymentManagementObservers
+Description: Retrieves all payment management observer records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, User*>: Collection of observer records
+*/
+util::Map<std::string, User*> DataStore::getPaymentManagementObservers()
+{
+    return getObservers(m_paymentManagementObservers);
+}
+
+/*
+Function: getInventoryManagementObservers
+Description: Retrieves all inventory management observer records from the datastore.
+Parameters:
+    - None
+Returns:
+    - util::Map<std::string, User*>: Collection of observer records
+*/
+util::Map<std::string, User*> DataStore::getInventoryManagementObservers()
+{
+    return getObservers(m_inventoryManagementObservers);
+}
+
+/*
+Function: saveUsers
+Description: Persists all user records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveUsers()
+{
+    saveRecords<User, SerializedUser>(m_users, m_userCache);
+}
+
+/*
+Function: saveNotifications
+Description: Persists all notification records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveNotifications()
+{
+    saveRecords<Notification, SerializedNotification>(m_notifications, m_notificationCache);
+}
+
+/*
+Function: saveServices
+Description: Persists all service records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveServices()
+{
+    saveRecords<Service, SerializedService>(m_services, m_serviceCache);
+}
+
+/*
+Function: saveComboPackages
+Description: Persists all combo package records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveComboPackages()
+{
+    saveRecords<ComboPackage, SerializedComboPackage>(m_comboPackages, m_comboPackageCache);
+}
+
+/*
+Function: saveInventoryItems
+Description: Persists all inventory item records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveInventoryItems()
+{
+    saveRecords<InventoryItem, SerializedInventoryItem>(m_inventoryItems, m_inventoryItemCache);
+}
+
+/*
+Function: saveServiceBookings
+Description: Persists all service booking records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveServiceBookings()
+{
+    saveRecords<ServiceBooking, SerializedServiceBooking>(m_serviceBookings, m_serviceBookingCache);
+}
+
+/*
+Function: saveJobCards
+Description: Persists all job card records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveJobCards()
+{
+    saveRecords<JobCard, SerializedJobCard>(m_jobCards, m_jobCardCache);
+}
+
+/*
+Function: saveInvoices
+Description: Persists all invoice records to the datastore.
+Parameters:
+    - None
+Returns:
+    - None
+*/
+void DataStore::saveInvoices()
+{
+    saveRecords<Invoice, SerializedInvoice>(m_invoices, m_invoiceCache);
+}
+
+/*
+Function: saveObservers
+Description: Persists observer records to the specified observer mapping.
+Parameters:
+    - mapping: MappingInfo&, observer mapping to save to
+    - observers: util::Map<std::string, User*>&, collection of observer records
+Returns:
+    - None
+*/
+void DataStore::saveObservers(MappingInfo& mapping, util::Map<std::string, User*>& observers)
+{
+    size_t observerCount = static_cast<size_t>(observers.getSize());
+    size_t capacity = config::file::INITIAL_CAPACITY;
+    while (capacity < observerCount)
+    {
+        capacity *= config::file::GROWTH_FACTOR;
+    }
+    if (!SharedMemory::resizeMapping(mapping, capacity))
+    {
+        throw std::runtime_error("Failed to resize observer mapping");
+    }
+    SharedMemory::setRecordCount(mapping, observerCount);
+    for (size_t index = 0; index < observerCount; index++)
+    {
+        SerializedObserver serializedObserver;
+        User* user = observers.getValueAt(static_cast<int>(index));
+        strcpy_s(serializedObserver.id, sizeof(serializedObserver.id), user->getId().c_str());
+        SerializedObserver* destination = static_cast<SerializedObserver*>(SharedMemory::getRecordAddress(mapping, index));
+        *destination = serializedObserver;
+    }
+}
+
+/*
+Function: saveServiceManagementObservers
+Description: Persists all service management observer records to the datastore.
+Parameters:
+    - observers: util::Map<std::string, User*>&, collection of observer records
+Returns:
+    - None
+*/
+void DataStore::saveServiceManagementObservers(util::Map<std::string, User*>& observers)
+{
+    saveObservers(m_serviceManagementObservers, observers);
+}
+
+/*
+Function: savePaymentManagementObservers
+Description: Persists all payment management observer records to the datastore.
+Parameters:
+    - observers: util::Map<std::string, User*>&, collection of observer records
+Returns:
+    - None
+*/
+void DataStore::savePaymentManagementObservers(util::Map<std::string, User*>& observers)
+{
+    saveObservers(m_paymentManagementObservers, observers);
+}
+
+/*
+Function: saveInventoryManagementObservers
+Description: Persists all inventory management observer records to the datastore.
+Parameters:
+    - observers: util::Map<std::string, User*>&, collection of observer records
+Returns:
+    - None
+*/
+void DataStore::saveInventoryManagementObservers(util::Map<std::string, User*>& observers)
+{
+    saveObservers(m_inventoryManagementObservers, observers);
+}
+
+/*
+Function: lockDataStore
+Description: Acquires the datastore mutex, providing
+             exclusive access to the shared-memory
+             datastore. This function blocks until
+             the mutex becomes available or an error
+             occurs.
+Parameter: None
+Return type:
+    bool
+    - true  : Mutex successfully acquired.
+    - false : Failed to acquire the mutex.
+*/
+bool DataStore::lockDataStore()
+{
+    if (m_globalMutex == NULL)
+    {
+        return false;
+    }
+    DWORD result = WaitForSingleObject(m_globalMutex, INFINITE);
+    return result == WAIT_OBJECT_0;
+}
+
+/*
+Function: unlockDataStore
+Description: Releases the datastore mutex after a
+             successful call to lockDataStore(),
+             allowing other processes to access the
+             shared-memory datastore.
+Parameter: None
+Return type:
+    bool
+    - true  : Mutex successfully released.
+    - false : Failed to release the mutex.
+*/
+bool DataStore::unlockDataStore()
+{
+    if (m_globalMutex == NULL)
+    {
+        return false;
+    }
+    return ReleaseMutex(m_globalMutex) != 0;
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.h

@@ -1,41 +1,253 @@
-#pragma once
+/*
+File: DataStore.h
+Description: Declares the DataStore singleton class responsible for managing collections of users, services, combo packages, service bookings, job cards, inventory items, invoices, and payments in the Vehicle Service Management System.
+Author: Trenser
+Date: 19-May-2026
+*/
 
+#pragma once
+#include <windows.h>
 #include <string>
 #include "Map.h"
-
-class User;
-class Service;
-class ComboPackage;
-class ServiceBooking;
-class JobCard;
-class InventoryItem;
-class Invoice;
-class Payment;
+#include "MappingInfo.h"
+#include "TrackedRecord.h"
+#include "SerializedRecords.h"
+#include "SharedMemory.h"
+#include "User.h"
+#include "Notification.h"
+#include "Service.h"
+#include "ComboPackage.h"
+#include "InventoryItem.h"
+#include "ServiceBooking.h"
+#include "JobCard.h"
+#include "Invoice.h"
 
 class DataStore
 {
 private:
-    util::Map<std::string, User*> m_users;
-    util::Map<std::string, Service*> m_services;
-    util::Map<std::string, ComboPackage*> m_comboPackages;
-    util::Map<std::string, ServiceBooking*> m_serviceBookings;
-    util::Map<std::string, JobCard*> m_jobCards;
-    util::Map<std::string, InventoryItem*> m_inventoryItems;
-    util::Map<std::string, Invoice*> m_invoices;
-    util::Map<std::string, Payment*> m_payments;
-    DataStore() {}
-public:
-    static DataStore& getInstance();
+    DataStore();
+    ~DataStore();
     DataStore(const DataStore&) = delete;
     DataStore& operator=(const DataStore&) = delete;
     DataStore(DataStore&&) = delete;
     DataStore& operator=(DataStore&&) = delete;
-    util::Map<std::string, User*>& getUsers();
-    util::Map<std::string, Service*>& getServices();
-    util::Map<std::string, ComboPackage*>& getComboPackages();
-    util::Map<std::string, ServiceBooking*>& getServiceBookings();
-    util::Map<std::string, JobCard*>& getJobCards();
-    util::Map<std::string, InventoryItem*>& getInventoryItems();
-    util::Map<std::string, Invoice*>& getInvoices();
-    util::Map<std::string, Payment*>& getPayments();
-};
+    HANDLE m_globalMutex;
+    MappingInfo m_users;
+    MappingInfo m_notifications;
+    MappingInfo m_services;
+    MappingInfo m_comboPackages;
+    MappingInfo m_inventoryItems;
+    MappingInfo m_serviceBookings;
+    MappingInfo m_jobCards;
+    MappingInfo m_invoices;
+    MappingInfo m_serviceManagementObservers;
+    MappingInfo m_paymentManagementObservers;
+    MappingInfo m_inventoryManagementObservers;
+    util::Map<std::string, TrackedRecord<User>> m_userCache;
+    util::Map<std::string, TrackedRecord<Notification>> m_notificationCache;
+    util::Map<std::string, TrackedRecord<Service>> m_serviceCache;
+    util::Map<std::string, TrackedRecord<ComboPackage>> m_comboPackageCache;
+    util::Map<std::string, TrackedRecord<InventoryItem>> m_inventoryItemCache;
+    util::Map<std::string, TrackedRecord<ServiceBooking>> m_serviceBookingCache;
+    util::Map<std::string, TrackedRecord<JobCard>> m_jobCardCache;
+    util::Map<std::string, TrackedRecord<Invoice>> m_invoiceCache;
+public:
+    static DataStore& getInstance();
+    bool initialize();
+    void shutdown();
+    util::Map<std::string, TrackedRecord<User>>& getUsers();
+    util::Map<std::string, TrackedRecord<Notification>>& getNotifications();
+    util::Map<std::string, TrackedRecord<Service>>& getServices();
+    util::Map<std::string, TrackedRecord<ComboPackage>>& getComboPackages();
+    util::Map<std::string, TrackedRecord<InventoryItem>>& getInventoryItems();
+    util::Map<std::string, TrackedRecord<ServiceBooking>>& getServiceBookings();
+    util::Map<std::string, TrackedRecord<JobCard>>& getJobCards();
+    util::Map<std::string, TrackedRecord<Invoice>>& getInvoices();
+    util::Map<std::string, User*> getServiceManagementObservers();
+    util::Map<std::string, User*> getPaymentManagementObservers();
+    util::Map<std::string, User*> getInventoryManagementObservers();
+    void saveUsers();
+    void saveNotifications();
+    void saveServices();
+    void saveComboPackages();
+    void saveInventoryItems();
+    void saveServiceBookings();
+    void saveJobCards();
+    void saveInvoices();
+    void saveServiceManagementObservers(util::Map<std::string, User*>& observers);
+    void savePaymentManagementObservers(util::Map<std::string, User*>& observers);
+    void saveInventoryManagementObservers(util::Map<std::string, User*>& observers);
+    bool lockDataStore();
+    bool unlockDataStore();
+private:
+    template<typename TObject, typename TSerialized>
+    util::Map<std::string, TrackedRecord<TObject>> loadRecords(MappingInfo& mapping);
+    template<typename TObject, typename TSerialized>
+    void saveRecords(MappingInfo& mapping, util::Map<std::string, TrackedRecord<TObject>>& records);
+    template<typename TObject> void clearCache(util::Map<std::string, TrackedRecord<TObject>>&cache);
+    template<typename TObject> void refreshCache(util::Map<std::string, TrackedRecord<TObject>>&cache, util::Map<std::string, TrackedRecord<TObject>>&refreshedCache);
+    util::Map<std::string, User*> getObservers(MappingInfo& mapping);
+    void saveObservers(MappingInfo& mapping, util::Map<std::string, User*>& observers);
+};
+
+/*
+Function: loadRecords
+Description: Loads all serialized records from the specified
+             shared-memory mapping, deserializes them into
+             application objects, and returns them as a map
+             of tracked records. Each loaded record is marked
+             as CLEAN and assigned its corresponding slot index
+             within the mapping so that future modifications
+             can be written back efficiently.
+Parameter:
+    - mapping: Reference to the mapping containing the
+               serialized records.
+Return type:
+    util::Map<std::string, TrackedRecord<TObject>>
+             A map containing all loaded records keyed by
+             their unique identifier.
+*/
+template<typename TObject, typename TSerialized>
+util::Map<std::string, TrackedRecord<TObject>> DataStore::loadRecords(MappingInfo& mapping)
+{
+    util::Map<std::string, TrackedRecord<TObject>> records;
+    SharedMemory::ensureLatestMapping(mapping);
+    size_t recordCount = SharedMemory::getRecordCount(mapping);
+    for (size_t index = 0; index < recordCount; ++index)
+    {
+        TSerialized* serialized = static_cast<TSerialized*>(SharedMemory::getRecordAddress(mapping,index));
+        TObject* object = TObject::deserialize(*serialized);
+        TrackedRecord<TObject> trackedRecord;
+        trackedRecord.data = object;
+        trackedRecord.state = RecordState::CLEAN;
+        trackedRecord.slotIndex = index;
+        records.insert(object->getId(), trackedRecord);
+    }
+    return records;
+}
+
+/*
+Function: saveRecords
+Description: Persists all modified and newly added records
+             contained in the provided map to the specified
+             shared-memory mapping. Modified records overwrite
+             their existing slots, while new records are
+             appended to the end of the mapping. Records marked
+             as CLEAN are ignored.
+Parameter:
+    - mapping: Reference to the mapping where records are
+               stored.
+    - records: Map containing the records to be persisted.
+Return type: void
+*/
+template<typename TObject, typename TSerialized> void DataStore::saveRecords(MappingInfo& mapping, util::Map<std::string, TrackedRecord<TObject>>& records)
+{
+    SharedMemory::ensureLatestMapping(mapping);
+    for (int index = 0; index < records.getSize(); ++index)
+    {
+        TrackedRecord<TObject>& record = records.getValueAt(index);
+        if (record.state == RecordState::CLEAN)
+        {
+            continue;
+        }
+        TSerialized serialized = record.data->serialize();
+        if (record.state == RecordState::MODIFIED)
+        {
+            TSerialized* destination = static_cast<TSerialized*>(SharedMemory::getRecordAddress(mapping, record.slotIndex));
+            if (destination)
+            {
+                *destination = serialized;
+            }
+        }
+        else if (record.state == RecordState::NEW_RECORD)
+        {
+            if (!SharedMemory::ensureCapacityForInsert(mapping))
+            {
+                continue;
+            }
+            size_t recordCount = SharedMemory::getRecordCount(mapping);
+            TSerialized* destination = static_cast<TSerialized*>(SharedMemory::getRecordAddress(mapping,recordCount));
+            *destination = serialized;
+            SharedMemory::setRecordCount(mapping, recordCount + 1);
+            record.slotIndex = recordCount;
+        }
+        record.state = RecordState::CLEAN;
+    }
+}
+
+/*
+Function: clearCache
+Description: Releases all objects owned by the cache and
+             clears the cache contents.
+Parameters:
+    - cache: Cache to be cleared.
+Returns:
+    - None
+*/
+template<typename TObject>
+void DataStore::clearCache(util::Map<std::string, TrackedRecord<TObject>>&cache)
+{
+    for (int index = 0; index < cache.getSize(); ++index)
+    {
+        delete cache.getValueAt(index).data;
+        cache.getValueAt(index).data = nullptr;
+    }
+    cache.clear();
+}
+
+/*
+Function: refreshCache
+Description: Refreshes the cache while preserving object addresses
+             for records that already exist. Existing objects are
+             updated in-place so that pointers held elsewhere remain
+             valid after the refresh.
+Parameters:
+    - cache: Existing cache to refresh.
+    - refreshedCache: Newly loaded cache contents.
+Returns:
+    - None
+*/
+template<typename TObject>
+void DataStore::refreshCache(util::Map<std::string, TrackedRecord<TObject>>& cache, util::Map<std::string, TrackedRecord<TObject>>& refreshedCache)
+{
+    util::Map<std::string, TrackedRecord<TObject>> oldCache = cache;
+    cache.clear();
+    for (int index = 0; index < refreshedCache.getSize(); ++index)
+    {
+        const std::string& id = refreshedCache.getKeyAt(index);
+        TrackedRecord<TObject>& refreshedRecord = refreshedCache.getValueAt(index);
+        int oldIndex = oldCache.find(id);
+        if (oldIndex != -1)
+        {
+            TrackedRecord<TObject>& oldRecord = oldCache.getValueAt(oldIndex);
+            if (oldRecord.state == RecordState::MODIFIED)
+            {
+                delete refreshedRecord.data;
+                cache.insert(id, oldRecord);
+                continue;
+            }
+            *oldRecord.data = *refreshedRecord.data;
+            oldRecord.slotIndex = refreshedRecord.slotIndex;
+            oldRecord.state = refreshedRecord.state;
+            delete refreshedRecord.data;
+            refreshedRecord.data = oldRecord.data;
+        }
+        cache.insert(id, refreshedRecord);
+    }
+    for (int index = 0; index < oldCache.getSize(); ++index)
+    {
+        const std::string& id = oldCache.getKeyAt(index);
+        const TrackedRecord<TObject>& localTrackedRecord = oldCache.getValueAt(index);
+        if (cache.find(id) == -1)
+        {
+            if (localTrackedRecord.state == RecordState::NEW_RECORD)
+            {
+                cache.insert(id, localTrackedRecord);
+            }
+            else
+            {
+                delete localTrackedRecord.data;
+            }
+        }
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStoreLockGuard.h

@@ -0,0 +1,28 @@
+/*
+File: DataStoreLockGuard.h
+Description: Defines the DataStoreLockGuard class used to manage DataStore
+             locking and unlocking automatically within a scope.
+Author: Trenser
+Date: 12-June-2026
+*/
+
+#pragma once
+#include "DataStore.h"
+
+class DataStoreLockGuard
+{
+public:
+    explicit DataStoreLockGuard(DataStore& dataStore)
+        : m_dataStore(dataStore)
+    {
+        m_dataStore.lockDataStore();
+    }
+    ~DataStoreLockGuard()
+    {
+        m_dataStore.unlockDataStore();
+    }
+    DataStoreLockGuard(const DataStoreLockGuard&) = delete;
+    DataStoreLockGuard& operator=(const DataStoreLockGuard&) = delete;
+private:
+    DataStore& m_dataStore;
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.cpp

@@ -1,65 +1,309 @@
+/*
+File: ComboPackage.cpp
+Description: Implements the ComboPackage class which represents a bundled set of services in the Vehicle Service Management System.
+             Provides constructors, accessors, and mutators for package details such as ID, name, discount percentage, state,
+             and associated services.
+Author: Trenser
+Date: 19-May-2026
+*/
+
+#include <sstream>
+#include <stdexcept>
+#include "SerializedRecords.h"
 #include "ComboPackage.h"
+#include "Service.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ComboPackage::m_uid = 0;
 
+/*
+Function: ComboPackage
+Description: Default constructor that initializes a new combo package with a unique ID,
+             active state, and zero discount percentage.
+Parameters:
+    - None
+Returns:
+    - A new ComboPackage object.
+*/
 ComboPackage::ComboPackage()
     : m_id("CMP" + std::to_string(++m_uid)),
     m_status(util::State::ACTIVE),
-    m_discountPercentage(0.0) {}
+    m_discountPercentage(0.0) {
+}
 
+/*
+Function: ComboPackage
+Description: Parameterized constructor that initializes a new combo package with a unique ID,
+             specified package name, discount percentage, active state, and associated services.
+Parameters:
+    - packageName: Name of the combo package.
+    - discountPercentage: Discount percentage applied to the package.
+    - services: Map of services included in the package.
+Returns:
+    - A new ComboPackage object.
+*/
 ComboPackage::ComboPackage(const std::string& packageName, double discountPercentage, const util::Map<std::string, Service*>& services)
     : m_id("CMP" + std::to_string(++m_uid)),
     m_packageName(packageName),
     m_discountPercentage(discountPercentage),
     m_status(util::State::ACTIVE),
-    m_services(services) {}
+    m_services(services)
+{
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
+}
 
+/*
+Function: ComboPackage (parameterized constructor with ID)
+Description: Initializes a combo package with an existing ID, name, discount percentage,
+             service IDs, and state. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique ID of the package
+    - packageName: const std::string&, name of the package
+    - discountPercentage: double, discount percentage applied
+    - serviceIDs: const util::Vector<std::string>&, IDs of services included
+    - status: util::State, state of the package (ACTIVE/INACTIVE)
+Returns:
+    - A new ComboPackage object
+*/
+ComboPackage::ComboPackage(const std::string& id, const std::string& packageName, double discountPercentage, const util::Vector<std::string>& serviceIDs, util::State status)
+    : m_id(id),
+    m_packageName(packageName),
+    m_discountPercentage(discountPercentage),
+    m_serviceIDs(serviceIDs),
+    m_status(status)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
+/*
+Function: getId
+Description: Retrieves the unique ID of the combo package.
+Parameters:
+    - None
+Returns:
+    - const std::string& representing the package ID.
+*/
 const std::string& ComboPackage::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getPackageName
+Description: Retrieves the name of the combo package.
+Parameters:
+    - None
+Returns:
+    - const std::string& representing the package name.
+*/
 const std::string& ComboPackage::getPackageName() const
 {
     return m_packageName;
 }
 
+/*
+Function: getDiscountPercentage
+Description: Retrieves the discount percentage applied to the combo package.
+Parameters:
+    - None
+Returns:
+    - double representing the discount percentage.
+*/
 double ComboPackage::getDiscountPercentage() const
 {
     return m_discountPercentage;
 }
 
+/*
+Function: getState
+Description: Retrieves the current state (ACTIVE/INACTIVE) of the combo package.
+Parameters:
+    - None
+Returns:
+    - util::State representing the package state.
+*/
 util::State ComboPackage::getState() const
 {
     return m_status;
 }
 
+const util::Vector<std::string>& ComboPackage::getServiceIDs() const
+{
+    return m_serviceIDs;
+}
+
+/*
+Function: getServices
+Description: Retrieves the map of services included in the combo package.
+Parameters:
+    - None
+Returns:
+    - const util::Map<std::string, Service*>& representing the services.
+*/
 const util::Map<std::string, Service*>& ComboPackage::getServices() const
 {
     return m_services;
 }
 
+/*
+Function: setId
+Description: Sets the unique ID of the combo package.
+Parameters:
+    - id: New ID string.
+Returns:
+    - void
+*/
 void ComboPackage::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setPackageName
+Description: Sets the name of the combo package.
+Parameters:
+    - packageName: New package name string.
+Returns:
+    - void
+*/
 void ComboPackage::setPackageName(const std::string& packageName)
 {
     m_packageName = packageName;
 }
 
+/*
+Function: setDiscountPercentage
+Description: Sets the discount percentage for the combo package.
+Parameters:
+    - discountPercentage: New discount percentage value.
+Returns:
+    - void
+*/
 void ComboPackage::setDiscountPercentage(double discountPercentage)
 {
     m_discountPercentage = discountPercentage;
 }
 
+/*
+Function: setServices
+Description: Sets the services included in the combo package.
+Parameters:
+    - services: Map of services to be associated with the package.
+Returns:
+    - void
+*/
 void ComboPackage::setServices(const util::Map<std::string, Service*>& services)
 {
     m_services = services;
+    m_serviceIDs.clear();
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
 }
 
+/*
+Function: setState
+Description: Sets the state (ACTIVE/INACTIVE) of the combo package.
+Parameters:
+    - status: New state value.
+Returns:
+    - void
+*/
 void ComboPackage::setState(util::State status)
 {
     m_status = status;
 }
+
+/*
+Function: getServiceIDsAsString (static helper)
+Description: Converts a vector of service IDs into a single string separated by '|'.
+Parameters:
+    - serviceIDs: const util::Vector<std::string>&, vector of service IDs
+Returns:
+    - std::string: Concatenated service IDs string
+*/
+static std::string getServiceIDsAsString(const util::Vector<std::string>& serviceIDs)
+{
+    int numberOfServices = serviceIDs.getSize();
+    std::string serviceIDsString;
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        serviceIDsString += serviceIDs[index];
+        if (index < numberOfServices - 1)
+        {
+            serviceIDsString += '|';
+        }
+    }
+    return serviceIDsString;
+}
+
+/*
+Function: getServiceIDsAsVector (static helper)
+Description: Converts a string of service IDs separated by '|' into a vector.
+Parameters:
+    - serviceIDsString: const std::string&, concatenated service IDs string
+Returns:
+    - util::Vector<std::string>: Vector of service IDs
+*/
+static util::Vector<std::string> getServiceIDsAsVector(const std::string& serviceIDsString)
+{
+    util::Vector<std::string> serviceIDs;
+    std::string serviceID;
+    std::istringstream serializedServiceIDs(serviceIDsString);
+    while (getline(serializedServiceIDs, serviceID, '|'))
+    {
+        serviceIDs.push_back(serviceID);
+    }
+    return serviceIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the ComboPackage object into a SerializedComboPackage record.
+Parameters:
+    - None
+Returns:
+    - SerializedComboPackage: Serialized representation of the combo package
+*/
+SerializedComboPackage ComboPackage::serialize() const
+{
+    SerializedComboPackage serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.packageName, sizeof(serialized.packageName), m_packageName.c_str());
+    strcpy_s(serialized.serviceIDs, sizeof(serialized.serviceIDs), getServiceIDsAsString(m_serviceIDs).c_str());
+    serialized.discountPercentage = m_discountPercentage;
+    serialized.status = m_status;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedComboPackage record into a ComboPackage object.
+Parameters:
+    - serializedComboPackage: const SerializedComboPackage&, serialized combo package record
+Returns:
+    - ComboPackage*: Pointer to the deserialized ComboPackage object
+*/
+ComboPackage* ComboPackage::deserialize(const SerializedComboPackage& serializedComboPackage)
+{
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serializedComboPackage.serviceIDs);
+    return Factory::getObject<ComboPackage>(
+        serializedComboPackage.id,
+        serializedComboPackage.packageName,
+        serializedComboPackage.discountPercentage,
+        serviceIDs,
+        serializedComboPackage.status);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.h

@@ -1,9 +1,18 @@
+/*
+File: ComboPackage.h
+Description: Declares the ComboPackage class which represents a service package with a unique ID, package name, discount percentage, associated services, and status in the Vehicle Service Management System.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class Service;
+struct SerializedComboPackage;
 
 class ComboPackage
 {
@@ -12,14 +21,17 @@ private:
     std::string m_id;
     std::string m_packageName;
     double m_discountPercentage;
+    util::Vector<std::string> m_serviceIDs;
     util::Map<std::string, Service*> m_services;
     util::State m_status;
 public:
     ComboPackage();
     ComboPackage(const std::string& packageName, double discountPercentage, const util::Map<std::string, Service*>& services);
+    ComboPackage(const std::string& id, const std::string& packageName, double discountPercentage, const util::Vector<std::string>& serviceIDs, util::State status);
     const std::string& getId() const;
     const std::string& getPackageName() const;
     double getDiscountPercentage() const;
+    const util::Vector<std::string>& getServiceIDs() const;
     const util::Map<std::string, Service*>& getServices() const;
     util::State getState() const;
     void setId(const std::string& id);
@@ -27,4 +39,6 @@ public:
     void setDiscountPercentage(double discountPercentage);
     void setServices(const util::Map<std::string, Service*>& services);
     void setState(util::State status);
+    SerializedComboPackage serialize() const;
+    static ComboPackage* deserialize(const SerializedComboPackage&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/InventoryItem.cpp

@@ -1,66 +1,245 @@
+/*
+File: InventoryItem.cpp
+Description: Implements the InventoryItem class which represents an inventory item in the Vehicle Service Management System.
+             Provides constructors, accessors, and mutators for item details such as ID, part name, quantity, price, and state.
+Author: Trenser
+Date: 19-May-2026
+*/
+
+#include <sstream>
+#include <stdexcept>
+#include "SerializedRecords.h"
+#include "Factory.h"
+#include "StringHelper.h"
 #include "InventoryItem.h"
 
 int InventoryItem::m_uid = 0;
 
+/*
+Function: InventoryItem
+Description: Default constructor that initializes a new inventory item with a unique ID,
+             active state, zero quantity, and zero price.
+Parameters:
+    - None
+Returns:
+    - A new InventoryItem object.
+*/
 InventoryItem::InventoryItem()
     : m_id("IIM" + std::to_string(++m_uid)),
     m_quantity(0),
     m_status(util::State::ACTIVE),
-    m_price(0.0) {}
+    m_price(0.0) {
+}
 
+/*
+Function: InventoryItem
+Description: Parameterized constructor that initializes a new inventory item with a unique ID,
+             specified part name, quantity, price, and active state.
+Parameters:
+    - partName: Name of the inventory item.
+    - quantity: Initial quantity of the item.
+    - price: Price of the item.
+Returns:
+    - A new InventoryItem object.
+*/
 InventoryItem::InventoryItem(const std::string& partName, int quantity, double price)
     : m_id("IIM" + std::to_string(++m_uid)),
     m_partName(partName),
     m_quantity(quantity),
     m_status(util::State::ACTIVE),
-    m_price(price) {}
+    m_price(price) {
+}
 
+/*
+Function: InventoryItem (parameterized constructor with ID)
+Description: Initializes an inventory item with an existing ID, part name, quantity,
+             price, and state. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique ID of the item
+    - partName: const std::string&, name of the part
+    - quantity: int, quantity of the part
+    - price: double, price of the part
+    - status: util::State, state of the item (ACTIVE/INACTIVE)
+Returns:
+    - A new InventoryItem object
+*/
+InventoryItem::InventoryItem(const std::string& id, const std::string& partName, int quantity, double price, util::State status)
+    : m_id(id),
+    m_partName(partName),
+    m_quantity(quantity),
+    m_status(status),
+    m_price(price)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
+/*
+Function: getId
+Description: Retrieves the unique ID of the inventory item.
+Parameters:
+    - None
+Returns:
+    - const std::string& representing the item ID.
+*/
 const std::string& InventoryItem::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getPartName
+Description: Retrieves the part name of the inventory item.
+Parameters:
+    - None
+Returns:
+    - const std::string& representing the part name.
+*/
 const std::string& InventoryItem::getPartName() const
 {
     return m_partName;
 }
 
+/*
+Function: getQuantity
+Description: Retrieves the current quantity of the inventory item.
+Parameters:
+    - None
+Returns:
+    - int representing the quantity.
+*/
 int InventoryItem::getQuantity() const
 {
     return m_quantity;
 }
 
+/*
+Function: getPrice
+Description: Retrieves the price of the inventory item.
+Parameters:
+    - None
+Returns:
+    - double representing the price.
+*/
 double InventoryItem::getPrice() const
 {
     return m_price;
 }
 
+/*
+Function: getState
+Description: Retrieves the current state (ACTIVE/INACTIVE) of the inventory item.
+Parameters:
+    - None
+Returns:
+    - util::State representing the item state.
+*/
 util::State InventoryItem::getState() const
 {
     return m_status;
 }
 
+/*
+Function: setId
+Description: Sets the unique ID of the inventory item.
+Parameters:
+    - id: New ID string.
+Returns:
+    - void
+*/
 void InventoryItem::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setPartName
+Description: Sets the part name of the inventory item.
+Parameters:
+    - partName: New part name string.
+Returns:
+    - void
+*/
 void InventoryItem::setPartName(const std::string& partName)
 {
     m_partName = partName;
 }
 
+/*
+Function: setQuantity
+Description: Sets the quantity of the inventory item.
+Parameters:
+    - quantity: New quantity value.
+Returns:
+    - void
+*/
 void InventoryItem::setQuantity(int quantity)
 {
     m_quantity = quantity;
 }
 
+/*
+Function: setPrice
+Description: Sets the price of the inventory item.
+Parameters:
+    - price: New price value.
+Returns:
+    - void
+*/
 void InventoryItem::setPrice(double price)
 {
     m_price = price;
 }
 
+/*
+Function: setState
+Description: Sets the state (ACTIVE/INACTIVE) of the inventory item.
+Parameters:
+    - status: New state value.
+Returns:
+    - void
+*/
 void InventoryItem::setState(util::State status)
 {
     m_status = status;
+}
+
+/*
+Function: serialize
+Description: Serializes the InventoryItem object into a SerializedInventoryItem record.
+Parameters:
+    - None
+Returns:
+    - SerializedInventoryItem: Serialized representation of the inventory item
+*/
+SerializedInventoryItem InventoryItem::serialize() const
+{
+    SerializedInventoryItem serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.partName, sizeof(serialized.partName), m_partName.c_str());
+    serialized.quantity = m_quantity;
+    serialized.price = m_price;
+    serialized.status = m_status;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedInventoryItem record into an InventoryItem object.
+Parameters:
+    - serializedInventoryItem: const SerializedInventoryItem&, serialized inventory item record
+Returns:
+    - InventoryItem*: Pointer to the deserialized InventoryItem object
+*/
+InventoryItem* InventoryItem::deserialize(const SerializedInventoryItem& serializedInventoryItem)
+{
+    return Factory::getObject<InventoryItem>(
+        serializedInventoryItem.id,
+        serializedInventoryItem.partName,
+        serializedInventoryItem.quantity,
+        serializedInventoryItem.price,
+        serializedInventoryItem.status);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/InventoryItem.h

@@ -1,7 +1,17 @@
+/*
+File: InventoryItem.h
+Description: Declares the InventoryItem class which represents parts in the Vehicle Service Management System.
+             Each item has a unique ID, part name, quantity, price, and status.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Enums.h"
 
+struct SerializedInventoryItem;
+
 class InventoryItem
 {
 private:
@@ -14,6 +24,7 @@ private:
 public:
     InventoryItem();
     InventoryItem(const std::string& partName, int quantity, double price);
+    InventoryItem(const std::string& id, const std::string& partName, int quantity, double price, util::State status);
     const std::string& getId() const;
     const std::string& getPartName() const;
     int getQuantity() const;
@@ -24,4 +35,6 @@ public:
     void setQuantity(int quantity);
     void setPrice(double price);
     void setState(util::State status);
+    SerializedInventoryItem serialize() const;
+    static InventoryItem* deserialize(const SerializedInventoryItem&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.cpp

@@ -1,7 +1,32 @@
+/*
+File: Invoice.cpp
+Description: Implements the Invoice class which represents an invoice in the Vehicle Service Management System.
+             Provides constructors, accessors, and mutators for invoice details such as ID, booking, costs,
+             discount percentage, total amount, payment details, and status.
+Author: Trenser
+Date: 19-May-2026
+*/
+
+#include <sstream>
+#include <stdexcept>
+#include "SerializedRecords.h"
 #include "Invoice.h"
+#include "Factory.h"
+#include "InventoryItem.h"
+#include "StringHelper.h"
 
 int Invoice::m_uid = 0;
 
+/*
+Function: Invoice
+Description: Default constructor that initializes a new invoice with a unique ID,
+             null booking, zero costs, zero discount, zero total amount,
+             and default payment method and status.
+Parameters:
+    - None
+Returns:
+    - A new Invoice object.
+*/
 Invoice::Invoice()
     : m_id("INV" + std::to_string(++m_uid)),
     m_booking(nullptr),
@@ -10,22 +35,40 @@ Invoice::Invoice()
     m_discountPercentage(0.0),
     m_totalAmount(0.0),
     m_paymentMethod(util::PaymentMode()),
-    m_status(util::PaymentStatus()) {}
+    m_status(util::PaymentStatus()) {
+}
 
+/*
+Function: Invoice
+Description: Parameterized constructor that initializes a new invoice with a unique ID and specified details.
+Parameters:
+    - bookingId: ID of the associated service booking.
+    - booking: Pointer to the ServiceBooking object.
+    - invoiceDate: Timestamp of when the invoice was created.
+    - laborCost: Cost of labor for the service.
+    - parts: Map of inventory items used in the service.
+    - partsCost: Total cost of parts.
+    - discountPercentage: Discount applied to the invoice.
+    - totalAmount: Final total amount after discount.
+    - paymentDate: Timestamp of when payment was made.
+    - paymentMethod: Payment mode (ONLINE/OFFLINE).
+    - status: Payment status (PENDING/COMPLETED).
+Returns:
+    - A new Invoice object.
+*/
 Invoice::Invoice(
     const std::string& bookingId,
     ServiceBooking* booking,
-    const util::Timestamp& invoiceDate, 
-    double laborCost, 
-    const util::Map<std::string,
-    InventoryItem*>& parts,
+    const util::Timestamp& invoiceDate,
+    double laborCost,
+    const util::Map<std::string, InventoryItem*>& parts,
     double partsCost,
-    double discountPercentage, 
-    double totalAmount, 
-    const util::Timestamp& paymentDate, 
-    util::PaymentMode paymentMethod, 
+    double discountPercentage,
+    double totalAmount,
+    const util::Timestamp& paymentDate,
+    util::PaymentMode paymentMethod,
     util::PaymentStatus status
-    )
+)
     : m_id("INV" + std::to_string(++m_uid)),
     m_bookingId(bookingId),
     m_booking(booking),
@@ -37,124 +80,445 @@ Invoice::Invoice(
     m_totalAmount(totalAmount),
     m_paymentDate(paymentDate),
     m_paymentMethod(paymentMethod),
-    m_status(status) {}
+    m_status(status)
+{
+    int numberOfParts = m_parts.getSize();
+    auto partPointers = m_parts.getValues();
+    for (int index = 0; index < numberOfParts; index++)
+    {
+        m_partIDs.push_back(partPointers[index]->getId());
+    }
+}
+Invoice::Invoice(
+    const std::string& id,
+    const std::string& bookingId,
+    const util::Timestamp& invoiceDate,
+    const util::Vector<std::string>& partIDs,
+    double laborCost,
+    double partsCost,
+    double discountPercentage,
+    double totalAmount,
+    const util::Timestamp& paymentDate,
+    util::PaymentMode paymentMethod,
+    util::PaymentStatus status
+)
+    : m_id(id),
+    m_bookingId(bookingId),
+    m_booking(nullptr),
+    m_invoiceDate(invoiceDate),
+    m_partIDs(partIDs),
+    m_laborCost(laborCost),
+    m_partsCost(partsCost),
+    m_discountPercentage(discountPercentage),
+    m_totalAmount(totalAmount),
+    m_paymentDate(paymentDate),
+    m_paymentMethod(paymentMethod),
+    m_status(status)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
 
+/*
+Function: getId
+Description: Retrieves the unique ID of the invoice.
+Returns:
+    - const std::string& representing the invoice ID.
+*/
 const std::string& Invoice::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getBookingId
+Description: Retrieves the booking ID associated with the invoice.
+Returns:
+    - const std::string& representing the booking ID.
+*/
 const std::string& Invoice::getBookingId() const
 {
     return m_bookingId;
 }
 
+/*
+Function: getBooking
+Description: Retrieves the pointer to the associated ServiceBooking.
+Returns:
+    - ServiceBooking* representing the booking.
+*/
 ServiceBooking* Invoice::getBooking() const
 {
     return m_booking;
 }
 
+/*
+Function: getInvoiceDate
+Description: Retrieves the timestamp of the invoice creation date.
+Returns:
+    - const util::Timestamp& representing the invoice date.
+*/
 const util::Timestamp& Invoice::getInvoiceDate() const
 {
     return m_invoiceDate;
 }
 
+/*
+Function: getLaborCost
+Description: Retrieves the labor cost associated with the invoice.
+Returns:
+    - double representing the labor cost.
+*/
 double Invoice::getLaborCost() const
 {
     return m_laborCost;
 }
 
+/*
+Function: getPartIDs
+Description: Retrieves the IDs of parts used in the invoice.
+Parameters:
+    - None
+Returns:
+    - const util::Vector<std::string>&: Part IDs
+*/
+const util::Vector<std::string>& Invoice::getPartIDs() const
+{
+    return m_partIDs;
+}
+
+/*
+Function: getParts
+Description: Retrieves the map of inventory items used in the service.
+Returns:
+    - const util::Map<int, InventoryItem*>& representing the parts.
+*/
 const util::Map<std::string, InventoryItem*>& Invoice::getParts() const
 {
     return m_parts;
 }
 
+/*
+Function: getPartsCost
+Description: Retrieves the total cost of parts used in the service.
+Returns:
+    - double representing the parts cost.
+*/
 double Invoice::getPartsCost() const
 {
     return m_partsCost;
 }
 
+/*
+Function: getDiscountPercentage
+Description: Retrieves the discount percentage applied to the invoice.
+Returns:
+    - double representing the discount percentage.
+*/
 double Invoice::getDiscountPercentage() const
 {
     return m_discountPercentage;
 }
 
+/*
+Function: getTotalAmount
+Description: Retrieves the total amount of the invoice after discount.
+Returns:
+    - double representing the total amount.
+*/
 double Invoice::getTotalAmount() const
 {
     return m_totalAmount;
 }
 
+/*
+Function: getPaymentDate
+Description: Retrieves the timestamp of the payment date.
+Returns:
+    - const util::Timestamp& representing the payment date.
+*/
 const util::Timestamp& Invoice::getPaymentDate() const
 {
     return m_paymentDate;
 }
 
+/*
+Function: getPaymentMethod
+Description: Retrieves the payment mode used for the invoice.
+Returns:
+    - util::PaymentMode representing the payment method.
+*/
 util::PaymentMode Invoice::getPaymentMethod() const
 {
     return m_paymentMethod;
 }
 
+/*
+Function: getStatus
+Description: Retrieves the payment status of the invoice.
+Returns:
+    - util::PaymentStatus representing the payment status.
+*/
 util::PaymentStatus Invoice::getStatus() const
 {
     return m_status;
 }
 
+/*
+Function: setId
+Description: Sets the unique ID of the invoice.
+Parameters:
+    - id: New invoice ID string.
+Returns:
+    - void
+*/
 void Invoice::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setBookingId
+Description: Sets the booking ID associated with the invoice.
+Parameters:
+    - bookingId: New booking ID string.
+Returns:
+    - void
+*/
 void Invoice::setBookingId(const std::string& bookingId)
 {
     m_bookingId = bookingId;
 }
 
+/*
+Function: setBooking
+Description: Sets the associated ServiceBooking pointer.
+Parameters:
+    - booking: Pointer to the ServiceBooking object.
+Returns:
+    - void
+*/
 void Invoice::setBooking(ServiceBooking* booking)
 {
     m_booking = booking;
 }
 
+/*
+Function: setInvoiceDate
+Description: Sets the invoice creation date.
+Parameters:
+    - invoiceDate: New timestamp for the invoice date.
+Returns:
+    - void
+*/
 void Invoice::setInvoiceDate(const util::Timestamp& invoiceDate)
 {
     m_invoiceDate = invoiceDate;
 }
 
+/*
+Function: setLaborCost
+Description: Sets the labor cost for the invoice.
+Parameters:
+    - laborCost: New labor cost value.
+Returns:
+    - void
+*/
 void Invoice::setLaborCost(double laborCost)
 {
     m_laborCost = laborCost;
 }
 
+/*
+Function: setParts
+Description: Sets the inventory items used in the service.
+Parameters:
+    - parts: Map of inventory items.
+Returns:
+    - void
+*/
 void Invoice::setParts(const util::Map<std::string, InventoryItem*>& parts)
 {
     m_parts = parts;
+    m_partIDs.clear();
+    int numberOfParts = m_parts.getSize();
+    auto partPointers = m_parts.getValues();
+    for (int index = 0; index < numberOfParts; index++)
+    {
+        m_partIDs.push_back(partPointers[index]->getId());
+    }
 }
 
+/*
+Function: setPartsCost
+Description: Sets the total cost of parts used in the service.
+Parameters:
+    - partsCost: New parts cost value.
+Returns:
+    - void
+*/
 void Invoice::setPartsCost(double partsCost)
 {
     m_partsCost = partsCost;
 }
 
+/*
+Function: setDiscountPercentage
+Description: Sets the discount percentage applied to the invoice.
+Parameters:
+    - discountPercentage: New discount percentage value.
+Returns:
+    - void
+*/
 void Invoice::setDiscountPercentage(double discountPercentage)
 {
     m_discountPercentage = discountPercentage;
 }
 
+/*
+Function: setTotalAmount
+Description: Sets the total amount of the invoice.
+Parameters:
+    - totalAmount: New total amount value.
+Returns:
+    - void
+*/
 void Invoice::setTotalAmount(double totalAmount)
 {
     m_totalAmount = totalAmount;
 }
 
+/*
+Function: setPaymentDate
+Description: Sets the payment date for the invoice.
+Parameters:
+    - paymentDate: New timestamp for the payment date.
+Returns:
+    - void
+*/
 void Invoice::setPaymentDate(const util::Timestamp& paymentDate)
 {
     m_paymentDate = paymentDate;
 }
 
+/*
+Function: setPaymentMethod
+Description: Sets the payment mode for the invoice.
+Parameters:
+    - paymentMethod: New payment mode value.
+Returns:
+    - void
+*/
 void Invoice::setPaymentMethod(util::PaymentMode paymentMethod)
 {
     m_paymentMethod = paymentMethod;
 }
 
+/*
+Function: setStatus
+Description: Sets the payment status of the invoice.
+Parameters:
+    - status: New payment status value.
+Returns:
+    - void
+*/
 void Invoice::setStatus(util::PaymentStatus status)
 {
     m_status = status;
 }
+
+/*
+Function: getPartIDsAsString (static helper)
+Description: Converts a vector of part IDs into a single string separated by '|'.
+Parameters:
+    - partIDs: const util::Vector<std::string>&, vector of part IDs
+Returns:
+    - std::string: Concatenated part IDs string
+*/
+static std::string getPartIDsAsString(const util::Vector<std::string>& partIDs)
+{
+    int numberOfParts = partIDs.getSize();
+    std::string partIDsString;
+    for (int index = 0; index < numberOfParts; index++)
+    {
+        partIDsString += partIDs[index];
+        if (index < numberOfParts - 1)
+        {
+            partIDsString += '|';
+        }
+    }
+    return partIDsString;
+}
+
+/*
+Function: getPartIDsAsVector (static helper)
+Description: Converts a string of part IDs separated by '|' into a vector.
+Parameters:
+    - partIDsString: const std::string&, concatenated part IDs string
+Returns:
+    - util::Vector<std::string>: Vector of part IDs
+*/
+static util::Vector<std::string> getPartIDsAsVector(const std::string& partIDsString)
+{
+    util::Vector<std::string> partIDs;
+    std::string partID;
+    std::istringstream serializedPartIDs(partIDsString);
+    while (getline(serializedPartIDs, partID, '|'))
+    {
+        partIDs.push_back(partID);
+    }
+    return partIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the Invoice object into a SerializedInvoice record.
+Parameters:
+    - None
+Returns:
+    - SerializedInvoice: Serialized representation of the invoice
+*/
+SerializedInvoice Invoice::serialize() const
+{
+    SerializedInvoice serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.bookingId, sizeof(serialized.bookingId), m_bookingId.c_str());
+    strcpy_s(serialized.partIDs, sizeof(serialized.partIDs), getPartIDsAsString(m_partIDs).c_str());
+    serialized.invoiceDate = m_invoiceDate;
+    serialized.laborCost = m_laborCost;
+    serialized.partsCost = m_partsCost;
+    serialized.discountPercentage = m_discountPercentage;
+    serialized.totalAmount = m_totalAmount;
+    serialized.paymentDate = m_paymentDate;
+    serialized.paymentMethod = m_paymentMethod;
+    serialized.status = m_status;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedInvoice record into an Invoice object.
+Parameters:
+    - serializedInvoice: const SerializedInvoice&, serialized invoice record
+Returns:
+    - Invoice*: Pointer to the deserialized Invoice object
+*/
+Invoice* Invoice::deserialize(const SerializedInvoice& serializedInvoice)
+{
+    util::Vector<std::string> partIDs = getPartIDsAsVector(serializedInvoice.partIDs);
+    return Factory::getObject<Invoice>(
+        serializedInvoice.id,
+        serializedInvoice.bookingId,
+        serializedInvoice.invoiceDate,
+        partIDs,
+        serializedInvoice.laborCost,
+        serializedInvoice.partsCost,
+        serializedInvoice.discountPercentage,
+        serializedInvoice.totalAmount,
+        serializedInvoice.paymentDate,
+        serializedInvoice.paymentMethod,
+        serializedInvoice.status);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.h

@@ -1,11 +1,21 @@
+/*
+File: Invoice.h
+Description: Declares the Invoice class which represents billing details for a service booking in the Vehicle Service Management System.
+             Each invoice includes booking information, labor cost, parts used, discount percentage, total amount, payment details, and status.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Timestamp.h"
 #include "Enums.h"
 
 class ServiceBooking;
 class InventoryItem;
+struct SerializedInvoice;
 
 class Invoice
 {
@@ -16,6 +26,7 @@ private:
     ServiceBooking* m_booking;
     util::Timestamp m_invoiceDate;
     double m_laborCost;
+    util::Vector<std::string> m_partIDs;
     util::Map<std::string, InventoryItem*> m_parts;
     double m_partsCost;
     double m_discountPercentage;
@@ -23,20 +34,32 @@ private:
     util::Timestamp m_paymentDate;
     util::PaymentMode m_paymentMethod;
     util::PaymentStatus m_status;
-
 public:
     Invoice();
     Invoice(
         const std::string& bookingId,
         ServiceBooking* booking,
-        const util::Timestamp& invoiceDate, 
-        double laborCost, 
-        const util::Map<std::string,InventoryItem*>& parts,
+        const util::Timestamp& invoiceDate,
+        double laborCost,
+        const util::Map<std::string, InventoryItem*>& parts,
         double partsCost,
-        double discountPercentage, 
-        double totalAmount, 
-        const util::Timestamp& paymentDate, 
-        util::PaymentMode paymentMethod, 
+        double discountPercentage,
+        double totalAmount,
+        const util::Timestamp& paymentDate,
+        util::PaymentMode paymentMethod,
+        util::PaymentStatus status
+    );
+    Invoice(
+        const std::string& id,
+        const std::string& bookingId,
+        const util::Timestamp& invoiceDate,
+        const util::Vector<std::string>& partIDs,
+        double laborCost,
+        double partsCost,
+        double discountPercentage,
+        double totalAmount,
+        const util::Timestamp& paymentDate,
+        util::PaymentMode paymentMethod,
         util::PaymentStatus status
     );
     const std::string& getId() const;
@@ -44,6 +67,7 @@ public:
     ServiceBooking* getBooking() const;
     const util::Timestamp& getInvoiceDate() const;
     double getLaborCost() const;
+    const util::Vector<std::string>& getPartIDs() const;
     const util::Map<std::string, InventoryItem*>& getParts() const;
     double getPartsCost() const;
     double getDiscountPercentage() const;
@@ -63,4 +87,6 @@ public:
     void setPaymentDate(const util::Timestamp& paymentDate);
     void setPaymentMethod(util::PaymentMode paymentMethod);
     void setStatus(util::PaymentStatus status);
+    SerializedInvoice serialize() const;
+    static Invoice* deserialize(const SerializedInvoice&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.cpp

@@ -1,14 +1,53 @@
+/*
+File: JobCard.cpp
+Description: Implementation file containing the method definitions of the
+             JobCard class, including constructors, getters, and setters
+             for job card attributes.
+Author: Trenser
+Date:19-May-2026
+*/
+
+#include <sstream>
+#include <stdexcept>
+#include "SerializedRecords.h"
 #include "JobCard.h"
+#include "Factory.h"
+#include "StringHelper.h"
+#include "Enums.h"
 
 int JobCard::m_uid = 0;
 
+/*
+Function: JobCard
+Description: Default constructor that initializes a new job card with
+             a unique ID and default values.
+Parameter: None
+Return type: Constructor
+*/
 JobCard::JobCard()
     : m_id("JC" + std::to_string(++m_uid)),
     m_booking(nullptr),
     m_service(nullptr),
     m_technician(nullptr),
-    m_status(util::ServiceJobStatus()) {}
+    m_status(util::ServiceJobStatus()) {
+}
 
+/*
+Function: JobCard
+Description: Parameterized constructor that initializes a new job card with a unique ID and specified details.
+Parameters:
+    - bookingId: ID of the associated service booking.
+    - booking: Pointer to the ServiceBooking object.
+    - service: Pointer to the Service object.
+    - serviceId: ID of the associated service.
+    - technicianId: ID of the assigned technician.
+    - technician: Pointer to the User object representing the technician.
+    - assignedDate: Timestamp of when the job was assigned.
+    - status: Current status of the job (STARTED/COMPLETED).
+    - completionDate: Timestamp of when the job was completed.
+Returns:
+    - A new JobCard object.
+*/
 JobCard::JobCard(const std::string& bookingId,
     ServiceBooking* booking,
     Service* service,
@@ -28,104 +67,328 @@ JobCard::JobCard(const std::string& bookingId,
     m_technician(technician),
     m_assignedDate(assignedDate),
     m_status(status),
-    m_completionDate(completionDate) {}
+    m_completionDate(completionDate) {
+}
 
+/*
+Function: JobCard (parameterized constructor with ID)
+Description: Initializes a job card with an existing ID, booking ID, service ID,
+             technician ID, assignment date, completion date, and status.
+             Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique job card ID
+    - bookingId: const std::string&, ID of the booking
+    - serviceId: const std::string&, ID of the service
+    - technicianId: const std::string&, ID of the technician
+    - assignedDate: const util::Timestamp&, date of assignment
+    - status: util::ServiceJobStatus, job status
+    - completionDate: const util::Timestamp&, date of completion
+Returns:
+    - A new JobCard object
+*/
+JobCard::JobCard(const std::string& id,
+    const std::string& bookingId,
+    const std::string& serviceId,
+    const std::string& technicianId,
+    const util::Timestamp& assignedDate,
+    util::ServiceJobStatus status,
+    const util::Timestamp& completionDate
+)
+    : m_id(id),
+    m_bookingId(bookingId),
+    m_booking(nullptr),
+    m_service(nullptr),
+    m_serviceId(serviceId),
+    m_technicianId(technicianId),
+    m_technician(nullptr),
+    m_assignedDate(assignedDate),
+    m_status(status),
+    m_completionDate(completionDate)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
+/*
+Function: getId
+Description: Retrieves the unique ID of the job card.
+Returns:
+    - const std::string& representing the job card ID.
+*/
 const std::string& JobCard::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getBookingId
+Description: Retrieves the booking ID associated with the job card.
+Returns:
+    - const std::string& representing the booking ID.
+*/
 const std::string& JobCard::getBookingId() const
 {
     return m_bookingId;
 }
 
+/*
+Function: getBooking
+Description: Retrieves the pointer to the associated ServiceBooking.
+Returns:
+    - ServiceBooking* representing the booking.
+*/
 ServiceBooking* JobCard::getBooking() const
 {
     return m_booking;
 }
 
+/*
+Function: getService
+Description: Retrieves the pointer to the associated Service.
+Returns:
+    - Service* representing the service.
+*/
 Service* JobCard::getService() const
 {
     return m_service;
 }
 
+/*
+Function: getServiceId
+Description: Retrieves the service ID associated with the job card.
+Returns:
+    - const std::string& representing the service ID.
+*/
 const std::string& JobCard::getServiceId() const
 {
     return m_serviceId;
 }
 
+/*
+Function: getTechnicianId
+Description: Retrieves the technician ID associated with the job card.
+Returns:
+    - const std::string& representing the technician ID.
+*/
 const std::string& JobCard::getTechnicianId() const
 {
     return m_technicianId;
 }
 
+/*
+Function: getTechnician
+Description: Retrieves the pointer to the assigned technician.
+Returns:
+    - User* representing the technician.
+*/
 User* JobCard::getTechnician() const
 {
     return m_technician;
 }
 
+/*
+Function: getAssignedDate
+Description: Retrieves the timestamp of when the job was assigned.
+Returns:
+    - const util::Timestamp& representing the assigned date.
+*/
 const util::Timestamp& JobCard::getAssignedDate() const
 {
     return m_assignedDate;
 }
 
+/*
+Function: getStatus
+Description: Retrieves the current status of the job.
+Returns:
+    - ServiceJobStatus representing the job status.
+*/
 util::ServiceJobStatus JobCard::getStatus() const
 {
     return m_status;
 }
 
+/*
+Function: getCompletionDate
+Description: Retrieves the timestamp of when the job was completed.
+Returns:
+    - const util::Timestamp& representing the completion date.
+*/
 const util::Timestamp& JobCard::getCompletionDate() const
 {
     return m_completionDate;
 }
 
+/*
+Function: setId
+Description: Sets the unique ID of the job card.
+Parameters:
+    - id: New job card ID string.
+Returns:
+    - void
+*/
 void JobCard::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setBookingId
+Description: Sets the booking ID associated with the job card.
+Parameters:
+    - bookingId: New booking ID string.
+Returns:
+    - void
+*/
 void JobCard::setBookingId(const std::string& bookingId)
 {
     m_bookingId = bookingId;
 }
 
+/*
+Function: setBooking
+Description: Sets the associated ServiceBooking pointer.
+Parameters:
+    - booking: Pointer to the ServiceBooking object.
+Returns:
+    - void
+*/
 void JobCard::setBooking(ServiceBooking* booking)
 {
     m_booking = booking;
 }
 
+/*
+Function: setService
+Description: Sets the associated Service pointer.
+Parameters:
+    - service: Pointer to the Service object.
+Returns:
+    - void
+*/
 void JobCard::setService(Service* service)
 {
     m_service = service;
 }
 
+/*
+Function: setServiceId
+Description: Sets the service ID associated with the job card.
+Parameters:
+    - serviceId: New service ID string.
+Returns:
+    - void
+*/
 void JobCard::setServiceId(const std::string& serviceId)
 {
     m_serviceId = serviceId;
 }
 
+/*
+Function: setTechnicianId
+Description: Sets the technician ID associated with the job card.
+Parameters:
+    - technicianId: New technician ID string.
+Returns:
+    - void
+*/
 void JobCard::setTechnicianId(const std::string& technicianId)
 {
     m_technicianId = technicianId;
 }
 
+/*
+Function: setTechnician
+Description: Sets the pointer to the assigned technician.
+Parameters:
+    - technician: Pointer to the User object.
+Returns:
+    - void
+*/
 void JobCard::setTechnician(User* technician)
 {
     m_technician = technician;
 }
 
+/*
+Function: setAssignedDate
+Description: Sets the timestamp of when the job was assigned.
+Parameters:
+    - assignedDate: New timestamp for the assigned date.
+Returns:
+    - void
+*/
 void JobCard::setAssignedDate(const util::Timestamp& assignedDate)
 {
     m_assignedDate = assignedDate;
 }
 
+/*
+Function: setStatus
+Description: Sets the current status of the job.
+Parameters:
+    - status: New job status value.
+Returns:
+    - void
+*/
 void JobCard::setStatus(util::ServiceJobStatus status)
 {
     m_status = status;
 }
 
+/*
+Function: setCompletionDate
+Description: Sets the timestamp of when the job was completed.
+Parameters:
+    - completionDate: New timestamp for the completion date.
+Returns:
+    - void
+*/
 void JobCard::setCompletionDate(const util::Timestamp& completionDate)
 {
     m_completionDate = completionDate;
+}
+
+/*
+Function: serialize
+Description: Serializes the JobCard object into a SerializedJobCard record.
+Parameters:
+    - None
+Returns:
+    - SerializedJobCard: Serialized representation of the job card
+*/
+SerializedJobCard JobCard::serialize() const
+{
+    SerializedJobCard serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.bookingId, sizeof(serialized.bookingId), m_bookingId.c_str());
+    strcpy_s(serialized.serviceId, sizeof(serialized.serviceId), m_serviceId.c_str());
+    strcpy_s(serialized.technicianId, sizeof(serialized.technicianId), m_technicianId.c_str());
+    serialized.assignedDate = m_assignedDate;
+    serialized.status = m_status;
+    serialized.completionDate = m_completionDate;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedJobCard record into a JobCard object.
+Parameters:
+    - serializedJobCard: const SerializedJobCard&, serialized job card record
+Returns:
+    - JobCard*: Pointer to the deserialized JobCard object
+*/
+JobCard* JobCard::deserialize(const SerializedJobCard& serializedJobCard)
+{
+    return Factory::getObject<JobCard>(
+        serializedJobCard.id,
+        serializedJobCard.bookingId,
+        serializedJobCard.serviceId,
+        serializedJobCard.technicianId,
+        serializedJobCard.assignedDate,
+        serializedJobCard.status,
+        serializedJobCard.completionDate);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h

@@ -1,3 +1,12 @@
+/*
+File: JobCard.h
+Description: Header file declaring the JobCard class, which represents
+             a service job card containing booking, service, technician,
+             and status details.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Enums.h"
@@ -6,7 +15,7 @@
 class ServiceBooking;
 class Service;
 class User;
-
+struct SerializedJobCard;
 
 class JobCard
 {
@@ -22,16 +31,23 @@ private:
     util::Timestamp m_assignedDate;
     util::ServiceJobStatus m_status;
     util::Timestamp m_completionDate;
-
 public:
     JobCard();
     JobCard(const std::string& bookingId,
         ServiceBooking* booking,
-        Service* service, 
-        const std::string& serviceId, 
-        const std::string& technicianId, 
-        User* technician, 
-        const util::Timestamp& assignedDate, 
+        Service* service,
+        const std::string& serviceId,
+        const std::string& technicianId,
+        User* technician,
+        const util::Timestamp& assignedDate,
+        util::ServiceJobStatus status,
+        const util::Timestamp& completionDate
+    );
+    JobCard(const std::string& id,
+        const std::string& bookingId,
+        const std::string& serviceId,
+        const std::string& technicianId,
+        const util::Timestamp& assignedDate,
         util::ServiceJobStatus status,
         const util::Timestamp& completionDate
     );
@@ -55,4 +71,6 @@ public:
     void setAssignedDate(const util::Timestamp& assignedDate);
     void setStatus(util::ServiceJobStatus status);
     void setCompletionDate(const util::Timestamp& completionDate);
+    SerializedJobCard serialize() const;
+    static JobCard* deserialize(const SerializedJobCard&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Notification.cpp

@@ -1,75 +1,259 @@
+/*
+File: Notification.cpp
+Description: Implements the Notification class which represents system notifications in the Vehicle Service Management System.
+             Provides constructors, accessors, and mutators for notification details such as ID, recipientID, title, message, and timestamp.
+Author: Trenser
+Date: 19-May-2026
+*/
+
+#include <sstream>
+#include "SerializedRecords.h"
 #include "Notification.h"
+#include "StringHelper.h"
+#include "Factory.h"
 
 int Notification::m_uid = 0;
 
+/*
+Function: Notification
+Description: Default constructor that initializes a new notification with a unique ID and null recipient.
+Parameters:
+    - None
+Returns:
+    - A new Notification object.
+*/
 Notification::Notification()
-    : m_id("NOT" + std::to_string(++m_uid)),
-    m_recipient(nullptr) {}
+    : m_id("NOT" + std::to_string(++m_uid)), 
+    m_state(util::State::ACTIVE) {}
 
-Notification::Notification(const std::string& recipientUserId, User* recipient, const std::string& title, const std::string& message, const util::Timestamp& createdAt)
+/*
+Function: Notification
+Description: Parameterized constructor that initializes a new notification with a unique ID and specified details.
+Parameters:
+    - recipientUserId: ID of the recipient user.
+    - recipient: Pointer to the User object representing the recipient.
+    - title: Title of the notification.
+    - message: Message content of the notification.
+    - createdAt: Timestamp of when the notification was created.
+Returns:
+    - A new Notification object.
+*/
+Notification::Notification(const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt)
     : m_id("NOT" + std::to_string(++m_uid)),
     m_recipientUserId(recipientUserId),
-    m_recipient(recipient),
     m_title(title),
     m_message(message),
-    m_createdAt(createdAt) {}
+    m_state(util::State::ACTIVE),
+    m_createdAt(createdAt) {
+}
 
-const std::string& Notification::getId() const 
+/*
+Function: Notification (parameterized constructor with ID)
+Description: Initializes a notification with an existing ID, recipient details,
+             title, message, and creation timestamp. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique notification ID
+    - recipientUserId: const std::string&, ID of the recipient user
+    - title: const std::string&, notification title
+    - message: const std::string&, notification message
+    - createdAt: const util::Timestamp&, timestamp of creation
+Returns:
+    - A new Notification object
+*/
+Notification::Notification(const std::string& id, const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt, const util::State& state)
+    : m_id(id),
+    m_recipientUserId(recipientUserId),
+    m_title(title),
+    m_message(message),
+    m_createdAt(createdAt),
+    m_state(state)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
+/*
+Function: getId
+Description: Retrieves the unique ID of the notification.
+Returns:
+    - const std::string& representing the notification ID.
+*/
+const std::string& Notification::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getRecipientUserId
+Description: Retrieves the recipient user ID associated with the notification.
+Returns:
+    - const std::string& representing the recipient user ID.
+*/
 const std::string& Notification::getRecipientUserId() const
 {
     return m_recipientUserId;
 }
 
-User* Notification::getRecipient() const
-{
-    return m_recipient;
-}
-
+/*
+Function: getTitle
+Description: Retrieves the title of the notification.
+Returns:
+    - const std::string& representing the notification title.
+*/
 const std::string& Notification::getTitle() const
 {
     return m_title;
 }
 
+/*
+Function: getMessage
+Description: Retrieves the message content of the notification.
+Returns:
+    - const std::string& representing the notification message.
+*/
 const std::string& Notification::getMessage() const
 {
     return m_message;
 }
 
+/*
+Function: getCreatedAt
+Description: Retrieves the timestamp of when the notification was created.
+Returns:
+    - const util::Timestamp& representing the creation timestamp.
+*/
 const util::Timestamp& Notification::getCreatedAt() const
 {
     return m_createdAt;
 }
 
+/*
+Function: getState
+Description: Retrieves the Notification state
+Returns:
+    - const util::Timestamp& representing the creation timestamp.
+*/
+util::State Notification::getState() const
+{
+    return m_state;
+}
+
+/*
+Function: setId
+Description: Sets the unique ID of the notification.
+Parameters:
+    - id: New notification ID string.
+Returns:
+    - void
+*/
 void Notification::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setRecipientUserId
+Description: Sets the recipient user ID for the notification.
+Parameters:
+    - recipientUserId: New recipient user ID string.
+Returns:
+    - void
+*/
 void Notification::setRecipientUserId(const std::string& recipientUserId)
 {
     m_recipientUserId = recipientUserId;
 }
 
-void Notification::setRecipient(User* recipient)
-{
-    m_recipient = recipient;
-}
-
+/*
+Function: setTitle
+Description: Sets the title of the notification.
+Parameters:
+    - title: New notification title string.
+Returns:
+    - void
+*/
 void Notification::setTitle(const std::string& title)
 {
     m_title = title;
 }
 
+/*
+Function: setMessage
+Description: Sets the message content of the notification.
+Parameters:
+    - message: New notification message string.
+Returns:
+    - void
+*/
 void Notification::setMessage(const std::string& message)
 {
     m_message = message;
 }
 
+/*
+Function: setCreatedAt
+Description: Sets the timestamp of when the notification was created.
+Parameters:
+    - createdAt: New timestamp value.
+Returns:
+    - void
+*/
 void Notification::setCreatedAt(const util::Timestamp& createdAt)
 {
     m_createdAt = createdAt;
+}
+
+/*
+Function: setState
+Description: Sets the Notification state.
+Parameters:
+    - state: Notification state value.
+Returns:
+    - void
+*/
+void Notification::setState(util::State state)
+{
+    m_state = state;
+}
+
+/*
+Function: serialize
+Description: Serializes the Notification object into a SerializedNotification record.
+Parameters:
+    - None
+Returns:
+    - SerializedNotification: Serialized representation of the notification
+*/
+SerializedNotification Notification::serialize() const
+{
+    SerializedNotification serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.recipientUserId, sizeof(serialized.recipientUserId), m_recipientUserId.c_str());
+    strcpy_s(serialized.title, sizeof(serialized.title), m_title.c_str());
+    strcpy_s(serialized.message, sizeof(serialized.message), m_message.c_str());
+    serialized.createdAt = m_createdAt;
+    serialized.state = m_state;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedNotification record into a Notification object.
+Parameters:
+    - serializedNotification: const SerializedNotification&, serialized notification record
+Returns:
+    - Notification*: Pointer to the deserialized Notification object
+*/
+Notification* Notification::deserialize(const SerializedNotification& serializedNotification)
+{
+    return Factory::getObject<Notification>(
+        serializedNotification.id,
+        serializedNotification.recipientUserId,
+        serializedNotification.title,
+        serializedNotification.message,
+        serializedNotification.createdAt,
+        serializedNotification.state);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Notification.h

@@ -1,8 +1,18 @@
+/*
+File: Notification.h
+Description: Declares the Notification class which represents system messages sent to users in the Vehicle Service Management System.
+             Each notification includes a unique ID, recipient details, title, message content, and timestamp of creation.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Timestamp.h"
+#include "Enums.h"
 
 class User;
+struct SerializedNotification;
 
 class Notification
 {
@@ -10,23 +20,26 @@ private:
     static int m_uid;
     std::string m_id;
     std::string m_recipientUserId;
-    User* m_recipient;
     std::string m_title;
     std::string m_message;
     util::Timestamp m_createdAt;
+    util::State m_state;
 public:
     Notification();
-    Notification(const std::string& recipientUserId, User* recipient, const std::string& title, const std::string& message, const util::Timestamp& createdAt);
+    Notification(const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt);
+    Notification(const std::string& id, const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt, const util::State& state);
     const std::string& getId() const;
     const std::string& getRecipientUserId() const;
-    User* getRecipient() const;
     const std::string& getTitle() const;
     const std::string& getMessage() const;
     const util::Timestamp& getCreatedAt() const;
     void setId(const std::string& id);
     void setRecipientUserId(const std::string& recipientUserId);
-    void setRecipient(User* recipient);
     void setTitle(const std::string& title);
     void setMessage(const std::string& message);
     void setCreatedAt(const util::Timestamp& createdAt);
+    util::State getState() const;
+    void setState(util::State state);
+    SerializedNotification serialize() const;
+    static Notification* deserialize(const SerializedNotification&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Service.cpp

@@ -1,65 +1,305 @@
+/*
+File: Service.cpp
+Description: Implements the Service class which represents a vehicle service in the Vehicle Service Management System.
+             Provides constructors, accessors, and mutators for service details such as ID, name, required inventory items,
+             labor cost, and state.
+Author: Trenser
+Date: 19-May-2026
+*/
+
+#include <sstream>
+#include "SerializedRecords.h"
 #include "Service.h"
+#include "InventoryItem.h"
+#include "StringHelper.h"
+#include "Factory.h"
 
 int Service::m_uid = 0;
 
+/*
+Function: Service
+Description: Default constructor that initializes a new service with a unique ID,
+             active state, and zero labor cost.
+Parameters:
+    - None
+Returns:
+    - A new Service object.
+*/
 Service::Service()
     : m_id("SRV" + std::to_string(++m_uid)),
     m_status(util::State::ACTIVE),
-    m_laborCost(0.0) {}
+    m_laborCost(0.0) {
+}
 
+/*
+Function: Service
+Description: Parameterized constructor that initializes a new service with a unique ID and specified details.
+Parameters:
+    - name: Name of the service.
+    - requiredInventoryItems: Map of inventory items required for the service.
+    - laborCost: Labor cost associated with the service.
+Returns:
+    - A new Service object.
+*/
 Service::Service(const std::string& name, const util::Map<std::string, InventoryItem*>& requiredInventoryItems, double laborCost)
     : m_id("SRV" + std::to_string(++m_uid)),
     m_name(name),
     m_requiredInventoryItems(requiredInventoryItems),
     m_status(util::State::ACTIVE),
-    m_laborCost(laborCost) {}
+    m_laborCost(laborCost)
+{
+    int numberOfInventoryItems = m_requiredInventoryItems.getSize();
+    auto inventoryItemPointers = m_requiredInventoryItems.getValues();
+    for (int index = 0; index < numberOfInventoryItems; index++)
+    {
+        m_requiredInventoryItemIDs.push_back(inventoryItemPointers[index]->getId());
+    }
+}
 
+/*
+Function: Service (parameterized constructor with ID)
+Description: Initializes a service with an existing ID, name, inventory item IDs,
+             labor cost, and state. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique service ID
+    - name: const std::string&, name of the service
+    - requiredInventoryItemIDs: const util::Vector<std::string>&, IDs of required inventory items
+    - laborCost: double, labor cost of the service
+    - status: util::State, state of the service (ACTIVE/INACTIVE)
+Returns:
+    - A new Service object
+*/
+Service::Service(const std::string& id, const std::string& name, const util::Vector<std::string>& requiredInventoryItemIDs, double laborCost, util::State status)
+    : m_id(id),
+    m_name(name),
+    m_requiredInventoryItemIDs(requiredInventoryItemIDs),
+    m_status(status),
+    m_laborCost(laborCost)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
+/*
+Function: getId
+Description: Retrieves the unique ID of the service.
+Returns:
+    - const std::string& representing the service ID.
+*/
 const std::string& Service::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getName
+Description: Retrieves the name of the service.
+Returns:
+    - const std::string& representing the service name.
+*/
 const std::string& Service::getName() const
 {
     return m_name;
 }
 
+/*
+Function: getRequiredInventoryItemIDs
+Description: Retrieves the IDs of required inventory items for the service.
+Parameters:
+    - None
+Returns:
+    - const util::Vector<std::string>&: Inventory item IDs
+*/
+const util::Vector<std::string>& Service::getRequiredInventoryItemIDs() const
+{
+    return m_requiredInventoryItemIDs;
+}
+
+/*
+Function: getRequiredInventoryItems
+Description: Retrieves the map of inventory items required for the service.
+Returns:
+    - const util::Map<std::string, InventoryItem*>& representing the required inventory items.
+*/
 const util::Map<std::string, InventoryItem*>& Service::getRequiredInventoryItems() const
 {
     return m_requiredInventoryItems;
 }
 
+/*
+Function: getLaborCost
+Description: Retrieves the labor cost associated with the service.
+Returns:
+    - double representing the labor cost.
+*/
 double Service::getLaborCost() const
 {
     return m_laborCost;
 }
 
+/*
+Function: getState
+Description: Retrieves the current state (ACTIVE/INACTIVE) of the service.
+Returns:
+    - util::State representing the service state.
+*/
 util::State Service::getState() const
 {
     return m_status;
 }
 
+/*
+Function: setId
+Description: Sets the unique ID of the service.
+Parameters:
+    - id: New service ID string.
+Returns:
+    - void
+*/
 void Service::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setName
+Description: Sets the name of the service.
+Parameters:
+    - name: New service name string.
+Returns:
+    - void
+*/
 void Service::setName(const std::string& name)
 {
     m_name = name;
 }
 
+/*
+Function: setRequiredInventoryItems
+Description: Sets the inventory items required for the service.
+Parameters:
+    - requiredInventoryItems: Map of inventory items.
+Returns:
+    - void
+*/
 void Service::setRequiredInventoryItems(const util::Map<std::string, InventoryItem*>& requiredInventoryItems)
 {
     m_requiredInventoryItems = requiredInventoryItems;
+    m_requiredInventoryItemIDs.clear();
+    int numberOfRequiredInventoryItems = m_requiredInventoryItems.getSize();
+    auto inventoryItemPointers = m_requiredInventoryItems.getValues();
+    for (int index = 0; index < numberOfRequiredInventoryItems; index++)
+    {
+        m_requiredInventoryItemIDs.push_back(inventoryItemPointers[index]->getId());
+    }
 }
 
+/*
+Function: setLaborCost
+Description: Sets the labor cost for the service.
+Parameters:
+    - laborCost: New labor cost value.
+Returns:
+    - void
+*/
 void Service::setLaborCost(double laborCost)
 {
     m_laborCost = laborCost;
 }
 
+/*
+Function: setState
+Description: Sets the state (ACTIVE/INACTIVE) of the service.
+Parameters:
+    - status: New state value.
+Returns:
+    - void
+*/
 void Service::setState(util::State status)
 {
     m_status = status;
+}
+
+/*
+Function: getInventoryItemIDsAsString (static helper)
+Description: Converts a vector of inventory item IDs into a single string separated by '|'.
+Parameters:
+    - inventoryItemIds: const util::Vector<std::string>&, vector of inventory item IDs
+Returns:
+    - std::string: Concatenated inventory item IDs string
+*/
+static std::string getInventoryItemIDsAsString(const util::Vector<std::string>& inventoryItemIds)
+{
+    int numberOfInventoryItems = inventoryItemIds.getSize();
+    std::string inventoryItemIDs;
+    for (int index = 0; index < numberOfInventoryItems; index++)
+    {
+        inventoryItemIDs += inventoryItemIds[index];
+        if (index < numberOfInventoryItems - 1)
+        {
+            inventoryItemIDs += '|';
+        }
+    }
+    return inventoryItemIDs;
+}
+
+/*
+Function: getInventoryItemIDsAsVector (static helper)
+Description: Converts a string of inventory item IDs separated by '|' into a vector.
+Parameters:
+    - inventoryItemIDsString: const std::string&, concatenated inventory item IDs string
+Returns:
+    - util::Vector<std::string>: Vector of inventory item IDs
+*/
+static util::Vector<std::string> getInventoryItemIDsAsVector(const std::string& inventoryItemIDsString)
+{
+    util::Vector<std::string> inventoryItemIDs;
+    std::string inventoryItemID;
+    std::istringstream serializedInventoryItemIDs(inventoryItemIDsString);
+    while (getline(serializedInventoryItemIDs, inventoryItemID, '|'))
+    {
+        inventoryItemIDs.push_back(inventoryItemID);
+    }
+    return inventoryItemIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the Service object into a SerializedService record.
+Parameters:
+    - None
+Returns:
+    - SerializedService: Serialized representation of the service
+*/
+SerializedService Service::serialize() const
+{
+    SerializedService serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.name, sizeof(serialized.name), m_name.c_str());
+    strcpy_s(serialized.inventoryItemIDs, sizeof(serialized.inventoryItemIDs), getInventoryItemIDsAsString(m_requiredInventoryItemIDs).c_str());
+    serialized.laborCost = m_laborCost;
+    serialized.status = m_status;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedService record into a Service object.
+Parameters:
+    - serializedService: const SerializedService&, serialized service record
+Returns:
+    - Service*: Pointer to the deserialized Service object
+*/
+Service* Service::deserialize(const SerializedService& serializedService)
+{
+    util::Vector<std::string> inventoryItemIDs = getInventoryItemIDsAsVector(serializedService.inventoryItemIDs);
+    return Factory::getObject<Service>(
+        serializedService.id,
+        serializedService.name,
+        inventoryItemIDs,
+        serializedService.laborCost,
+        serializedService.status);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Service.h

@@ -1,9 +1,19 @@
+/*
+File: Service.h
+Description: Declares the Service class which represents a vehicle service in the Vehicle Service Management System.
+             Each service includes a unique ID, name, required inventory items, labor cost, and status.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class InventoryItem;
+struct SerializedService;
 
 class Service
 {
@@ -11,14 +21,17 @@ private:
     static int m_uid;
     std::string m_id;
     std::string m_name;
+    util::Vector<std::string> m_requiredInventoryItemIDs;
     util::Map<std::string, InventoryItem*> m_requiredInventoryItems;
     double m_laborCost;
     util::State m_status;
 public:
     Service();
     Service(const std::string& name, const util::Map<std::string, InventoryItem*>& requiredInventoryItems, double laborCost);
+    Service(const std::string& id, const std::string& name, const util::Vector<std::string>& requiredInventoryItemIDs, double laborCost, util::State state);
     const std::string& getId() const;
     const std::string& getName() const;
+    const util::Vector<std::string>& getRequiredInventoryItemIDs() const;
     const util::Map<std::string, InventoryItem*>& getRequiredInventoryItems() const;
     double getLaborCost() const;
     util::State getState() const;
@@ -27,4 +40,6 @@ public:
     void setRequiredInventoryItems(const util::Map<std::string, InventoryItem*>& requiredInventoryItems);
     void setLaborCost(double laborCost);
     void setState(util::State status);
+    SerializedService serialize() const;
+    static Service* deserialize(const SerializedService&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ServiceBooking.cpp

@@ -1,14 +1,55 @@
+/*
+File: ServiceBooking.cpp
+Description: Implementation file containing the method definitions of the
+             ServiceBooking class, including constructors, getters, and setters
+             for booking attributes.
+Author: Trenser
+Date:19-May-2026
+*/
+
+#include <stdexcept>
+#include <sstream>
+#include "SerializedRecords.h"
 #include "ServiceBooking.h"
+#include "Service.h"
+#include "Enums.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ServiceBooking::m_uid = 0;
 
+/*
+Function: ServiceBooking
+Description: Default constructor that initializes a new service booking with a unique ID,
+             null customer, and zero discount percentage.
+Parameters: None
+Returns: A new ServiceBooking object.
+*/
 ServiceBooking::ServiceBooking()
-    : m_id("SRV" + std::to_string(++m_uid)),
+    : m_id("SBK" + std::to_string(++m_uid)),
     m_customer(nullptr),
-    m_discountPercentage(0.0) {}
+    m_assignedTechnician(nullptr),
+    m_status(util::ServiceJobStatus::PENDING),
+    m_discountPercentage(0.0) {
+}
 
+/*
+Function: ServiceBooking
+Description: Parameterized constructor that initializes a new service booking with a unique ID and specified details.
+Parameters:
+    - id: Booking ID string.
+    - status: Current status of the booking (e.g., PENDING, COMPLETED).
+    - services: Map of services included in the booking.
+    - customerId: ID of the customer.
+    - customer: Pointer to the User object representing the customer.
+    - vehicleNumber: Vehicle registration number.
+    - vehicleBrand: Brand of the vehicle.
+    - vehicleModel: Model of the vehicle.
+    - discountPercentage: Discount applied to the booking.
+Returns:
+    - A new ServiceBooking object.
+*/
 ServiceBooking::ServiceBooking(
-    const std::string& id,
     util::ServiceJobStatus status,
     const util::Map<std::string,
     Service*>& services,
@@ -17,11 +58,9 @@ ServiceBooking::ServiceBooking(
     const std::string& vehicleNumber,
     const std::string& vehicleBrand,
     const std::string& vehicleModel,
-    const std::string& assignedTechnicianId,
-    const User* assignedTechnician,
     double discountPercentage
 )
-    : m_id("SRV" + std::to_string(++m_uid)),
+    : m_id("SBK" + std::to_string(++m_uid)),
     m_status(status),
     m_services(services),
     m_customerId(customerId),
@@ -29,118 +68,418 @@ ServiceBooking::ServiceBooking(
     m_vehicleNumber(vehicleNumber),
     m_vehicleBrand(vehicleBrand),
     m_vehicleModel(vehicleModel),
-    m_assignedTechnicianId(assignedTechnicianId),
-    m_assignedTechnician(assignedTechnician),
+    m_assignedTechnicianId(""),
+    m_assignedTechnician(nullptr),
     m_discountPercentage(discountPercentage)
 {
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
 }
 
+/*
+Function: ServiceBooking (parameterized constructor with ID)
+Description: Initializes a service booking with an existing ID, status, service IDs,
+             customer details, vehicle details, technician ID, and discount percentage.
+             Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique booking ID
+    - status: util::ServiceJobStatus, job status of the booking
+    - serviceIDs: const util::Vector<std::string>&, IDs of booked services
+    - customerId: const std::string&, ID of the customer
+    - vehicleNumber: const std::string&, vehicle number
+    - vehicleBrand: const std::string&, vehicle brand
+    - vehicleModel: const std::string&, vehicle model
+    - assignedTechnicianId: const std::string&, ID of the assigned technician
+    - discountPercentage: double, discount applied
+Returns:
+    - A new ServiceBooking object
+*/
+ServiceBooking::ServiceBooking(
+    const std::string& id,
+    util::ServiceJobStatus status,
+    const util::Vector<std::string>& serviceIDs,
+    const std::string& customerId,
+    const std::string& vehicleNumber,
+    const std::string& vehicleBrand,
+    const std::string& vehicleModel,
+    const std::string& assignedTechnicianId,
+    double discountPercentage
+)
+    : m_id(id),
+    m_status(status),
+    m_serviceIDs(serviceIDs),
+    m_customerId(customerId),
+    m_customer(nullptr),
+    m_vehicleNumber(vehicleNumber),
+    m_vehicleBrand(vehicleBrand),
+    m_vehicleModel(vehicleModel),
+    m_assignedTechnicianId(assignedTechnicianId),
+    m_assignedTechnician(nullptr),
+    m_discountPercentage(discountPercentage)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
+/*
+Function: getId
+Description: Retrieves the unique identifier of the service booking.
+Parameter: None
+Return type: const std::string&
+*/
 const std::string& ServiceBooking::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getStatus
+Description: Retrieves the current status of the service booking.
+Parameter: None
+Return type: util::ServiceJobStatus
+*/
 util::ServiceJobStatus ServiceBooking::getStatus() const
 {
     return m_status;
 }
 
+/*
+Function: getServiceIDs
+Description: Retrieves the IDs of services booked.
+Parameters:
+    - None
+Returns:
+    - const util::Vector<std::string>&: Service IDs
+*/
+const util::Vector<std::string>& ServiceBooking::getServiceIDs() const
+{
+    return m_serviceIDs;
+}
+
+/*
+Function: getServices
+Description: Retrieves the services associated with the booking.
+Parameter: None
+Return type: const util::Map<std::string, Service*>&
+*/
+/*
+Function: getServices
+Description: Retrieves the services associated with the booking.
+Parameter: None
+Return type: const util::Map<std::string, Service*>&
+*/
 const util::Map<std::string, Service*>& ServiceBooking::getServices() const
 {
     return m_services;
 }
 
+/*
+Function: getCustomerId
+Description: Retrieves the customer ID associated with the booking.
+Parameter: None
+Return type: const std::string&
+*/
 const std::string& ServiceBooking::getCustomerId() const
 {
     return m_customerId;
 }
 
+/*
+Function: getCustomer
+Description: Retrieves the customer object associated with the booking.
+Parameter: None
+Return type: User*
+*/
 User* ServiceBooking::getCustomer() const
 {
     return m_customer;
 }
 
+/*
+Function: getVehicleNumber
+Description: Retrieves the vehicle registration number for the booking.
+Parameter: None
+Return type: const std::string&
+*/
 const std::string& ServiceBooking::getVehicleNumber() const
 {
     return m_vehicleNumber;
 }
 
+/*
+Function: getVehicleBrand
+Description: Retrieves the brand of the vehicle for the booking.
+Parameter: None
+Return type: const std::string&
+*/
 const std::string& ServiceBooking::getVehicleBrand() const
 {
     return m_vehicleBrand;
 }
 
+/*
+Function: getVehicleModel
+Description: Retrieves the model of the vehicle for the booking.
+Parameter: None
+Return type: const std::string&
+*/
 const std::string& ServiceBooking::getVehicleModel() const
 {
     return m_vehicleModel;
 }
 
+/*
+Function: getAssignedTechnicianId
+Description: Retrieves the ID of the technician assigned to the booking.
+Parameter: None
+Return type: const std::string&
+*/
 const std::string& ServiceBooking::getAssignedTechnicianId() const
 {
     return m_assignedTechnicianId;
 }
 
-const User* ServiceBooking::getAssignedTechnician() const
+/*
+Function: getAssignedTechnician
+Description: Retrieves the technician object assigned to the booking.
+Parameter: None
+Return type: User*
+*/
+User* ServiceBooking::getAssignedTechnician() const
 {
     return m_assignedTechnician;
 }
-
+/*
+Function: getDiscountPercentage
+Description: Retrieves the discount percentage applied to the booking.
+Parameter: None
+Return type: double
+*/
 double ServiceBooking::getDiscountPercentage() const
 {
     return m_discountPercentage;
 }
 
+/*
+Function: setId
+Description: Sets the unique identifier of the service booking.
+Parameter: const std::string& id - new booking ID
+Return type: void
+*/
 void ServiceBooking::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setStatus
+Description: Sets the current status of the service booking.
+Parameter: const util::ServiceJobStatus& status - new booking status
+Return type: void
+*/
 void ServiceBooking::setStatus(const util::ServiceJobStatus& status)
 {
     m_status = status;
 }
 
+/*
+Function: setServices
+Description: Sets the services associated with the booking.
+Parameter: const util::Map<std::string, Service*>& services - new services map
+Return type: void
+*/
 void ServiceBooking::setServices(const util::Map<std::string, Service*>& services)
 {
     m_services = services;
+    m_serviceIDs.clear();
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
 }
 
+/*
+Function: setCustomerId
+Description: Sets the customer ID for the booking.
+Parameter: const std::string& customerId - new customer ID
+Return type: void
+*/
 void ServiceBooking::setCustomerId(const std::string& customerId)
 {
     m_customerId = customerId;
 }
 
+/*
+Function: setCustomer
+Description: Sets the customer object for the booking.
+Parameter: User* customer - pointer to the customer object
+Return type: void
+*/
 void ServiceBooking::setCustomer(User* customer)
 {
     m_customer = customer;
 }
 
+/*
+Function: setVehicleNumber
+Description: Sets the vehicle registration number for the booking.
+Parameter: const std::string& vehicleNumber - new vehicle number
+Return type: void
+*/
 void ServiceBooking::setVehicleNumber(const std::string& vehicleNumber)
 {
     m_vehicleNumber = vehicleNumber;
 }
 
+/*
+Function: setVehicleBrand
+Description: Sets the brand of the vehicle for the booking.
+Parameter: const std::string& vehicleBrand - new vehicle brand
+Return type: void
+*/
 void ServiceBooking::setVehicleBrand(const std::string& vehicleBrand)
 {
     m_vehicleBrand = vehicleBrand;
 }
 
+/*
+Function: setVehicleModel
+Description: Sets the model of the vehicle for the booking.
+Parameter: const std::string& vehicleModel - new vehicle model
+Return type: void
+*/
 void ServiceBooking::setVehicleModel(const std::string& vehicleModel)
 {
     m_vehicleModel = vehicleModel;
 }
 
+/*
+Function: setAssignedTechnicianId
+Description: Sets the ID of the technician assigned to the booking.
+Parameter: const std::string& assignedTechnicianId - new technician ID
+Return type: void
+*/
 void ServiceBooking::setAssignedTechnicianId(const std::string& assignedTechnicianId)
 {
     m_assignedTechnicianId = assignedTechnicianId;
 }
 
-void ServiceBooking::setAssignedTechnician(const User* assignedTechnician)
+/*
+Function: setAssignedTechnician
+Description: Sets the technician object assigned to the booking.
+Parameter: User* assignedTechnician - pointer to the technician object
+Return type: void
+*/
+void ServiceBooking::setAssignedTechnician(User* assignedTechnician)
 {
     m_assignedTechnician = assignedTechnician;
 }
 
+/*
+Function: setDiscountPercentage
+Description: Sets the discount percentage for the booking.
+Parameter: double discountPercentage - new discount percentage
+Return type: void
+*/
 void ServiceBooking::setDiscountPercentage(double discountPercentage)
 {
     m_discountPercentage = discountPercentage;
+}
+
+/*
+Function: getServiceIDsAsString (static helper)
+Description: Converts a vector of service IDs into a single string separated by '|'.
+Parameters:
+    - serviceIDs: const util::Vector<std::string>&, vector of service IDs
+Returns:
+    - std::string: Concatenated service IDs string
+*/
+static std::string getServiceIDsAsString(const util::Vector<std::string>& serviceIDs)
+{
+    int numberOfServices = serviceIDs.getSize();
+    std::string serviceIDsString;
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        serviceIDsString += serviceIDs[index];
+        if (index < numberOfServices - 1)
+        {
+            serviceIDsString += '|';
+        }
+    }
+    return serviceIDsString;
+}
+
+/*
+Function: getServiceIDsAsVector (static helper)
+Description: Converts a string of service IDs separated by '|' into a vector.
+Parameters:
+    - serviceIDsString: const std::string&, concatenated service IDs string
+Returns:
+    - util::Vector<std::string>: Vector of service IDs
+*/
+static util::Vector<std::string> getServiceIDsAsVector(const std::string& serviceIDsString)
+{
+    util::Vector<std::string> serviceIDs;
+    std::string serviceID;
+    std::istringstream serializedServiceIDs(serviceIDsString);
+    while (getline(serializedServiceIDs, serviceID, '|'))
+    {
+        serviceIDs.push_back(serviceID);
+    }
+    return serviceIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the ServiceBooking object into a SerializedServiceBooking record.
+Parameters:
+    - None
+Returns:
+    - SerializedServiceBooking: Serialized representation of the service booking
+*/
+SerializedServiceBooking ServiceBooking::serialize() const
+{
+    SerializedServiceBooking serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.serviceIDs, sizeof(serialized.serviceIDs), getServiceIDsAsString(m_serviceIDs).c_str());
+    strcpy_s(serialized.customerId, sizeof(serialized.customerId), m_customerId.c_str());
+    strcpy_s(serialized.vehicleNumber, sizeof(serialized.vehicleNumber), m_vehicleNumber.c_str());
+    strcpy_s(serialized.vehicleBrand, sizeof(serialized.vehicleBrand), m_vehicleBrand.c_str());
+    strcpy_s(serialized.vehicleModel, sizeof(serialized.vehicleModel), m_vehicleModel.c_str());
+    strcpy_s(serialized.assignedTechnicianId, sizeof(serialized.assignedTechnicianId), m_assignedTechnicianId.c_str());
+    serialized.status = m_status;
+    serialized.discountPercentage = m_discountPercentage;
+    return serialized;
+}
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedServiceBooking record into a ServiceBooking object.
+Parameters:
+    - serializedServiceBooking: const SerializedServiceBooking&, serialized service booking record
+Returns:
+    - ServiceBooking*: Pointer to the deserialized ServiceBooking object
+*/
+ServiceBooking* ServiceBooking::deserialize(const SerializedServiceBooking& serializedServiceBooking)
+{
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serializedServiceBooking.serviceIDs);
+    return Factory::getObject<ServiceBooking>(
+        serializedServiceBooking.id,
+        serializedServiceBooking.status,
+        serviceIDs,
+        serializedServiceBooking.customerId,
+        serializedServiceBooking.vehicleNumber,
+        serializedServiceBooking.vehicleBrand,
+        serializedServiceBooking.vehicleModel,
+        serializedServiceBooking.assignedTechnicianId,
+        serializedServiceBooking.discountPercentage);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ServiceBooking.h

@@ -1,10 +1,21 @@
+/*
+File: ServiceBooking.h
+Description: Header file declaring the ServiceBooking class, which represents
+             a booking of services by a customer, including vehicle details,
+             assigned technician, and discount information.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class Service;
 class User;
+struct SerializedServiceBooking;
 
 class ServiceBooking
 {
@@ -12,6 +23,7 @@ private:
     static int m_uid;
     std::string m_id;
     util::ServiceJobStatus m_status;
+    util::Vector<std::string> m_serviceIDs;
     util::Map<std::string, Service*> m_services;
     std::string m_customerId;
     User* m_customer;
@@ -19,12 +31,11 @@ private:
     std::string m_vehicleBrand;
     std::string m_vehicleModel;
     std::string m_assignedTechnicianId;
-    const User* m_assignedTechnician;
+    User* m_assignedTechnician;
     double m_discountPercentage;
 public:
     ServiceBooking();
     ServiceBooking(
-        const std::string& id,
         util::ServiceJobStatus status,
         const util::Map<std::string,
         Service*>& services,
@@ -33,12 +44,22 @@ public:
         const std::string& vehicleNumber,
         const std::string& vehicleBrand,
         const std::string& vehicleModel,
+        double discountPercentage
+    );
+    ServiceBooking(
+        const std::string& id,
+        util::ServiceJobStatus status,
+        const util::Vector<std::string>& serviceIDs,
+        const std::string& customerId,
+        const std::string& vehicleNumber,
+        const std::string& vehicleBrand,
+        const std::string& vehicleModel,
         const std::string& assignedTechnicianId,
-        const User* assignedTechnician,
         double discountPercentage
     );
     const std::string& getId() const;
     util::ServiceJobStatus getStatus() const;
+    const util::Vector<std::string>& getServiceIDs() const;
     const util::Map<std::string, Service*>& getServices() const;
     const std::string& getCustomerId() const;
     User* getCustomer() const;
@@ -46,7 +67,7 @@ public:
     const std::string& getVehicleBrand() const;
     const std::string& getVehicleModel() const;
     const std::string& getAssignedTechnicianId() const;
-    const User* getAssignedTechnician() const;
+    User* getAssignedTechnician() const;
     double getDiscountPercentage() const;
     void setId(const std::string& id);
     void setStatus(const util::ServiceJobStatus& status);
@@ -57,6 +78,8 @@ public:
     void setVehicleBrand(const std::string& vehicleBrand);
     void setVehicleModel(const std::string& vehicleModel);
     void setAssignedTechnicianId(const std::string& assignedTechnicianId);
-    void setAssignedTechnician(const User* assignedTechnician);
+    void setAssignedTechnician(User* assignedTechnician);
     void setDiscountPercentage(double discountPercentage);
+    SerializedServiceBooking serialize() const;
+    static ServiceBooking* deserialize(const SerializedServiceBooking&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/User.cpp

@@ -1,14 +1,50 @@
+/*
+File: User.cpp
+Description: Implements the User class which represents system users in the Vehicle Service Management System.
+             Provides constructors, destructor, accessors, and mutators for user details such as ID, username,
+             password, name, phone, email, role, state, and notifications.
+Author: Trenser
+Date: 19-May-2026
+*/
+
+#include <sstream>
+#include "SerializedRecords.h"
 #include "User.h"
 #include "Notification.h"
 #include "Enums.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int User::m_uid = 0;
 
+/*
+Function: User
+Description: Default constructor that initializes a new user with a unique ID,
+             default role as CUSTOMER, and active state.
+Parameters:
+    - None
+Returns:
+    - A new User object.
+*/
 User::User()
     : m_id("USR" + std::to_string(++m_uid)),
     m_type(util::UserType::CUSTOMER),
-    m_status(util::State::ACTIVE) {}
+    m_status(util::State::ACTIVE) {
+}
 
+/*
+Function: User
+Description: Parameterized constructor that initializes a new user with a unique ID and specified details.
+Parameters:
+    - userName: Username for login.
+    - password: Password for authentication.
+    - name: Full name of the user.
+    - phone: Phone number of the user.
+    - email: Email address of the user.
+    - role: Role of the user (CUSTOMER, ADMIN, TECHNICIAN, etc.).
+Returns:
+    - A new User object.
+*/
 User::User(const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role)
     : m_id("USR" + std::to_string(++m_uid)),
     m_userName(userName),
@@ -17,106 +53,273 @@ User::User(const std::string& userName, const std::string& password, const std::
     m_phone(phone),
     m_email(email),
     m_type(role),
-    m_status(util::State::ACTIVE) {}
+    m_status(util::State::ACTIVE) {
+}
 
-User::~User()
+/*
+Function: User (parameterized constructor with ID)
+Description: Initializes a user with an existing ID, credentials, personal details,
+             role, and state. Updates UID tracking based on ID.
+Parameters:
+    - userId: const std::string&, unique user ID
+    - userName: const std::string&, username
+    - password: const std::string&, password
+    - name: const std::string&, full name
+    - phone: const std::string&, phone number
+    - email: const std::string&, email address
+    - role: util::UserType, role of the user
+    - status: util::State, state of the user (ACTIVE/INACTIVE)
+Returns:
+    - A new User object
+*/
+User::User(const std::string& userId, const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role, util::State status)
+    : m_id(userId),
+    m_userName(userName),
+    m_password(password),
+    m_name(name),
+    m_phone(phone),
+    m_email(email),
+    m_type(role),
+    m_status(status)
 {
-    for (int index = 0; index < m_notifications.getSize(); index++)
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
     {
-        delete m_notifications.getValues()[index];
+        m_uid = idNumber;
     }
 }
 
+/*
+Function: getId
+Description: Retrieves the unique ID of the user.
+Returns:
+    - const std::string& representing the user ID.
+*/
 const std::string& User::getId() const
 {
     return m_id;
 }
 
+/*
+Function: getUserName
+Description: Retrieves the username of the user.
+Returns:
+    - const std::string& representing the username.
+*/
 const std::string& User::getUserName() const
 {
     return m_userName;
 }
 
+/*
+Function: getPassword
+Description: Retrieves the password of the user.
+Returns:
+    - const std::string& representing the password.
+*/
 const std::string& User::getPassword() const
 {
     return m_password;
 }
 
+/*
+Function: getName
+Description: Retrieves the full name of the user.
+Returns:
+    - const std::string& representing the name.
+*/
 const std::string& User::getName() const
 {
     return m_name;
 }
 
+/*
+Function: getPhone
+Description: Retrieves the phone number of the user.
+Returns:
+    - const std::string& representing the phone number.
+*/
 const std::string& User::getPhone() const
 {
     return m_phone;
 }
 
+/*
+Function: getEmail
+Description: Retrieves the email address of the user.
+Returns:
+    - const std::string& representing the email.
+*/
 const std::string& User::getEmail() const
 {
     return m_email;
 }
 
-util::Map<std::string, Notification*>& User::getNotifications()
-{
-    return m_notifications;
-}
-
+/*
+Function: getUserType
+Description: Retrieves the role of the user.
+Returns:
+    - util::UserType representing the user role.
+*/
 util::UserType User::getUserType() const
 {
     return m_type;
 }
 
+/*
+Function: getState
+Description: Retrieves the current state (ACTIVE/INACTIVE) of the user.
+Returns:
+    - util::State representing the user state.
+*/
 util::State User::getState() const
 {
     return m_status;
 }
 
+/*
+Function: setId
+Description: Sets the unique ID of the user.
+Parameters:
+    - id: New user ID string.
+Returns:
+    - void
+*/
 void User::setId(const std::string& id)
 {
     m_id = id;
 }
 
+/*
+Function: setUserName
+Description: Sets the username of the user.
+Parameters:
+    - userName: New username string.
+Returns:
+    - void
+*/
 void User::setUserName(const std::string& userName)
 {
     m_userName = userName;
 }
 
+/*
+Function: setPassword
+Description: Sets the password of the user.
+Parameters:
+    - password: New password string.
+Returns:
+    - void
+*/
 void User::setPassword(const std::string& password)
 {
     m_password = password;
 }
 
+/*
+Function: setName
+Description: Sets the full name of the user.
+Parameters:
+    - name: New name string.
+Returns:
+    - void
+*/
 void User::setName(const std::string& name)
 {
     m_name = name;
 }
 
+/*
+Function: setPhone
+Description: Sets the phone number of the user.
+Parameters:
+    - phone: New phone number string.
+Returns:
+    - void
+*/
 void User::setPhone(const std::string& phone)
 {
     m_phone = phone;
 }
 
+/*
+Function: setEmail
+Description: Sets the email address of the user.
+Parameters:
+    - email: New email string.
+Returns:
+    - void
+*/
 void User::setEmail(const std::string& email)
 {
     m_email = email;
 }
 
-void User::addNotification(Notification* notification)
-{
-    m_notifications.insert(notification->getId(), notification);
-}
-
+/*
+Function: setRole
+Description: Sets the role of the user.
+Parameters:
+    - role: New user role value.
+Returns:
+    - void
+*/
 void User::setRole(util::UserType role)
 {
     m_type = role;
 }
 
+/*
+Function: setState
+Description: Sets the state (ACTIVE/INACTIVE) of the user.
+Parameters:
+    - status: New state value.
+Returns:
+    - void
+*/
 void User::setState(util::State status)
 {
     m_status = status;
 }
 
-void User::update(Notification* notification)
+/*
+Function: serialize
+Description: Serializes the User object into a SerializedUser record.
+Parameters:
+    - None
+Returns:
+    - SerializedUser: Serialized representation of the user
+*/
+SerializedUser User::serialize() const
 {
+    SerializedUser serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.username, sizeof(serialized.username), m_userName.c_str());
+    strcpy_s(serialized.password, sizeof(serialized.password), m_password.c_str());
+    strcpy_s(serialized.name, sizeof(serialized.name), m_name.c_str());
+    strcpy_s(serialized.phone, sizeof(serialized.phone), m_phone.c_str());
+    strcpy_s(serialized.email, sizeof(serialized.email), m_email.c_str());
+    serialized.userType = m_type;
+    serialized.status = m_status;
+    return serialized;
 }
+
+/*
+Function: deserialize
+Description: Deserializes a SerializedUser record into a User object.
+Parameters:
+    - serializedUser: const SerializedUser&, serialized user record
+Returns:
+    - User*: Pointer to the deserialized User object
+*/
+User* User::deserialize(const SerializedUser& serializedUser)
+{
+    return Factory::getObject<User>(
+        serializedUser.id,
+        serializedUser.username,
+        serializedUser.password,
+        serializedUser.name,
+        serializedUser.phone,
+        serializedUser.email,
+        serializedUser.userType,
+        serializedUser.status);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/User.h

@@ -1,3 +1,12 @@
+/*
+File: User.h
+Description: Declares the User class which represents system users in the Vehicle Service Management System.
+             Each user has a unique ID, credentials, personal details, notifications, role type, and status.
+             The User class also implements the Observer interface to handle notifications.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -5,6 +14,7 @@
 #include "Enums.h"
 
 class Notification;
+struct SerializedUser;
 
 class User : public Observer
 {
@@ -16,20 +26,19 @@ private:
     std::string m_name;
     std::string m_phone;
     std::string m_email;
-    util::Map<std::string, Notification*> m_notifications;
     util::UserType m_type;
     util::State m_status;
 public:
     User();
     User(const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role);
-    ~User();
+    User(const std::string& userId, const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role, util::State status);
+    ~User() = default;
     const std::string& getId() const;
     const std::string& getUserName() const;
     const std::string& getPassword() const;
     const std::string& getName() const;
     const std::string& getPhone() const;
     const std::string& getEmail() const;
-    util::Map<std::string, Notification*>& getNotifications();
     util::UserType getUserType() const;
     util::State getState() const;
     void setId(const std::string& id);
@@ -38,8 +47,8 @@ public:
     void setName(const std::string& name);
     void setPhone(const std::string& phone);
     void setEmail(const std::string& email);
-    void addNotification(Notification* notification);
     void setRole(util::UserType role);
     void setState(util::State status);
-    void update(Notification* notification) override;
+    SerializedUser serialize() const;
+    static User* deserialize(const SerializedUser& serializedUser);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/AuthenticationManagementService.cpp

@@ -1,3 +1,153 @@
+/*
+File: AuthenticationManagementService.cpp
+Description: Implementation file containing the method definitions of the
+			 AuthenticationManagementService class, including logout and
+			 password change logic.
+Author: Trenser
+Date:19-May-2026
+*/
+
+#include <stdexcept>
 #include "AuthenticationManagementService.h"
+#include "User.h"
+#include "Utility.h"
+#include "DataStoreLockGuard.h"
 
 User* AuthenticationManagementService::m_authenticatedUser = nullptr;
+bool AuthenticationManagementService::m_isAuthorized = false;
+EventManager AuthenticationManagementService::m_eventManager;
+HANDLE AuthenticationManagementService::m_accountDisabledEvent = NULL;
+HANDLE AuthenticationManagementService::m_notificationsAvailableEvent = NULL;
+
+
+/*
+Function: ensureAuthorization
+Description: Verifies that a user is currently authenticated before allowing
+			 access to a protected operation. Throws an exception if no
+			 authorized user session exists.
+Parameter: None
+Return type: void
+Throws: std::runtime_error - if the user is not authorized
+*/
+void AuthenticationManagementService::ensureAuthorization()
+{
+	if (!m_authenticatedUser || !m_isAuthorized)
+	{
+		throw std::runtime_error("You are not authorized to do this operation!");
+	}
+}
+
+/*
+Function: login
+Description: Authenticates a user by checking the provided username and password
+			 against the stored users in the DataStore. If successful, sets the
+			 authenticated user.
+Parameter: const std::string& username - user’s username
+		   const std::string& password - user’s password
+Return type: bool - true if login successful, false otherwise
+*/
+bool AuthenticationManagementService::login(const std::string& username, const std::string& password)
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUserMap = m_dataStore.getUsers();
+	int trackedUserMapSize = trackedUserMap.getSize();
+	for (int index = 0; index < trackedUserMapSize; index++)
+	{
+		User* user = trackedUserMap.getValueAt(index).data;
+		if (username == user->getUserName())
+		{
+			if (password == user->getPassword())
+			{
+				m_authenticatedUser = user;
+				m_isAuthorized = true;
+				m_eventManager.initialize(
+					user->getId(),
+					[]()
+					{
+						if (m_accountDisabledEvent)
+						{
+							AuthenticationManagementService::m_isAuthorized = false;
+							SetEvent(m_accountDisabledEvent);
+						}
+					},
+					[]()
+					{
+						if (m_notificationsAvailableEvent)
+						{
+							SetEvent(m_notificationsAvailableEvent);
+						}
+					});
+				return true;
+			}
+			return false;
+		}
+	}
+	return false;
+}
+
+/*
+Function: getAuthenticatedUser
+Description: Retrieves the currently authenticated user.
+Parameter: None
+Return type: User* - pointer to the authenticated user
+*/
+User* AuthenticationManagementService::getAuthenticatedUser()
+{
+	return m_authenticatedUser;
+}
+
+/*
+Function: logout
+Description: Logs out the currently authenticated user by clearing the
+			 static authenticated user pointer.
+Parameter: None
+Return type: void
+*/
+void AuthenticationManagementService::logout()
+{
+	m_eventManager.shutdown();
+	m_authenticatedUser = nullptr;
+	m_isAuthorized = false;
+	m_accountDisabledEvent = NULL;
+	m_notificationsAvailableEvent = NULL;
+}
+
+/*
+Function: changePassword
+Description: Changes the password of the currently authenticated user.
+			 Throws an exception if no user is logged in.
+Parameter: const std::string& newPassword - new password to set
+Return type: void
+*/
+void AuthenticationManagementService::changePassword(const std::string& newPassword)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	if (m_authenticatedUser == nullptr)
+	{
+		throw std::runtime_error("There is no user currently logged in!");
+	}
+	int index = trackedUsersMap.find(m_authenticatedUser->getId());
+	if (index == -1)
+	{
+		throw std::runtime_error("User does not exist!\n");
+	}
+	m_authenticatedUser->setPassword(newPassword);
+	trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
+	m_dataStore.saveUsers();
+}
+
+/*
+Function: registerEvents
+Description: Registers menu event handles used to notify the active
+			 menu of account disable and notification events.
+Parameter: HANDLE accountDisabledEvent - account disabled event handle
+		   HANDLE notificationAvailableEvent - notification event handle
+Return type: void
+*/
+void AuthenticationManagementService::registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent)
+{
+	m_accountDisabledEvent = accountDisabledEvent;
+	m_notificationsAvailableEvent = notificationAvailableEvent;
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/AuthenticationManagementService.h

@@ -1,5 +1,16 @@
+/*
+File: AuthenticationManagementService.h
+Description: Header file declaring the AuthenticationManagementService class, which manages
+             user authentication, login, logout, password changes, and retrieval of the
+             authenticated user.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include <string>
+#include <windows.h>
+#include "EventManager.h"
 #include "DataStore.h"
 
 class User;
@@ -8,11 +19,17 @@ class AuthenticationManagementService
 {
 private:
     static User* m_authenticatedUser;
+    static bool m_isAuthorized;
+    static EventManager m_eventManager;
+    static HANDLE m_accountDisabledEvent;
+    static HANDLE m_notificationsAvailableEvent;
     DataStore& m_dataStore;
 public:
     AuthenticationManagementService() : m_dataStore(DataStore::getInstance()) {}
+    static void ensureAuthorization();
     bool login(const std::string& username, const std::string& password);
     void logout();
     void changePassword(const std::string& newPassword);
     User* getAuthenticatedUser();
+    void registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp

@@ -1 +1,293 @@
+/*
+File: InventoryManagementService.cpp
+Description: Implements the InventoryManagementService class, which manages inventory
+			 items and observer relationships within the system. Provides methods
+			 for loading and saving inventory items from persistent storage, as well
+			 as attaching and persisting observers for notification handling.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#include <stdexcept>
+#include "Config.h"
+#include "Enums.h"
+#include "Factory.h"
+#include "InventoryItem.h"
 #include "InventoryManagementService.h"
+#include "AuthenticationManagementService.h"
+#include "Timestamp.h"
+#include "User.h"
+#include "Utility.h"
+#include "Vector.h"
+#include "DataStoreLockGuard.h"
+#include "EventManager.h"
+
+util::Map<std::string, User*> InventoryManagementService::m_observers{};
+
+/*
+Function: sendLowStockAlertsToAdmins (static helper)
+Description: Sends low stock alert notifications to all admin users for a given inventory item.
+Parameters:
+	- inventoryManagementService: InventoryManagementService&, service used to send notifications
+	- inventoryItem: const InventoryItem*, pointer to the low-stock inventory item
+	- adminUsers: const util::Vector<User*>&, list of admin users to notify
+Returns:
+	- None
+*/
+static void sendLowStockAlertsToAdmins(InventoryManagementService& inventoryManagementService, const InventoryItem* inventoryItem, const util::Vector<User*>& adminUsers)
+{
+	int adminUsersSize = adminUsers.getSize();
+	for (int index = 0; index < adminUsersSize; index++)
+	{
+		std::string title = "Low Stock Alert";
+		std::string message = "The inventory item with ID " + inventoryItem->getId() + " has very low quantity in the inventory";
+		inventoryManagementService.sendNotification(
+			adminUsers[index],
+			title,
+			message
+		);
+	}
+}
+
+/*
+Function: sendLowStockAlerts
+Description: Sends alerts to user for inventory items with low stock
+Parameters:
+	- None
+Returns:
+	- None
+*/
+void InventoryManagementService::sendLowStockAlerts()
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemsMap = m_dataStore.getInventoryItems();
+	auto& trackedUserMap = m_dataStore.getUsers();
+	if (trackedInventoryItemsMap.isEmpty())
+	{
+		return;
+	}
+	int inventoryItemsSize = trackedInventoryItemsMap.getSize();
+	int usersMapSize = trackedUserMap.getSize();
+	util::Vector<User*> adminUsers;
+	for (int index = 0; index < usersMapSize; index++)
+	{
+		User* user = trackedUserMap.getValueAt(index).data;
+		if (user->getUserType() == util::UserType::ADMIN)
+		{
+			adminUsers.push_back(user);
+		}
+	}
+	int adminUsersSize = adminUsers.getSize();
+	if (adminUsersSize < 1)
+	{
+		throw std::runtime_error("The system has no admins present!");
+	}
+	for (int index = 0; index < inventoryItemsSize; index++)
+	{
+		InventoryItem* inventoryItem = trackedInventoryItemsMap.getValueAt(index).data;
+		if (inventoryItem && inventoryItem->getQuantity() < config::threshold::INVENTORY_LOW_STOCK_THRESHOLD)
+		{
+			sendLowStockAlertsToAdmins(*this, inventoryItem, adminUsers);
+		}
+	}
+}
+
+/*
+Function: addInventoryItem
+Description: Creates a new inventory item using the Factory and inserts it
+             into the DataStore.
+Parameter: const std::string& partName - name of the part
+           int quantity - initial quantity of the part
+           double price - price of the part
+Return type: void
+*/
+void InventoryManagementService::addInventoryItem(const std::string& partName, int quantity, double price)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+    InventoryItem* newItem = Factory::getObject<InventoryItem>(partName, quantity, price);
+	trackedInventoryItemMap.insert(newItem->getId(), util::createNewRecord(newItem));
+	m_dataStore.saveInventoryItems();
+}
+
+/*
+Function: addInventoryItemStock
+Description: Increases the stock quantity of an existing inventory item.
+Parameter: const std::string& selectedItemId - ID of the inventory item
+           int quantity - quantity to add
+Return type: void
+*/
+void InventoryManagementService::addInventoryItemStock(const std::string& selectedItemId, int quantity)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+	int index = trackedInventoryItemMap.find(selectedItemId);
+	if (index == -1)
+	{
+		throw std::runtime_error("Inventory update failed: Item ID '" + selectedItemId + "' not found.");
+	}
+	InventoryItem* item = trackedInventoryItemMap.getValueAt(index).data;
+	if (item == nullptr)
+	{
+		throw std::runtime_error("Inventory update failed. Item does not exist.\n");
+	}
+	int totalQuantity = item->getQuantity() + quantity;
+	item->setQuantity(totalQuantity);
+	trackedInventoryItemMap.getValueAt(index).state = RecordState::MODIFIED;
+	m_dataStore.saveInventoryItems();
+}
+
+/*
+Function: getInventoryItems
+Description: Retrieves all inventory items stored in the DataStore.
+Parameter: None
+Return type: util::Map<std::string, InventoryItem*>
+*/
+util::Map<std::string, InventoryItem*> InventoryManagementService::getInventoryItems()
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+	auto inventoryMap = util::getObjects(trackedInventoryItemMap);
+	return inventoryMap;
+}
+
+/*
+Function: removeInventoryItem
+Description: Marks an inventory item as inactive instead of deleting it.
+Parameter: const std::string& inventoryItemID - ID of the inventory item
+Return type: void
+*/
+void InventoryManagementService::removeInventoryItem(const std::string& inventoryItemID)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+	int index = trackedInventoryItemMap.find(inventoryItemID);
+	if (index == -1)
+	{
+		throw std::runtime_error("Inventory removal failed: Item ID '" + inventoryItemID + "' not found.");
+	}
+	InventoryItem* item = trackedInventoryItemMap.getValueAt(index).data;
+	if (item == nullptr)
+	{
+		throw std::runtime_error("Inventory removal failed: Item ID does not exist.");
+	}
+	item->setState(util::State::INACTIVE);
+	trackedInventoryItemMap.getValueAt(index).state = RecordState::MODIFIED;
+	m_dataStore.saveInventoryItems();
+}
+
+/*
+Function: getInventoryItem
+Description: Retrieves a specific inventory item by its ID from the DataStore.
+Parameter: const std::string& inventoryItemID - ID of the inventory item
+Return type: InventoryItem*
+*/
+InventoryItem* InventoryManagementService::getInventoryItem(const std::string& inventoryItemID)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+    int index = trackedInventoryItemMap.find(inventoryItemID);
+    if (index == -1)
+    {
+		return nullptr;
+    }
+	InventoryItem* inventoryItem = trackedInventoryItemMap.getValueAt(index).data;
+	if (inventoryItem == nullptr)
+	{
+		throw std::runtime_error("Item ID does not exist.");
+	}
+	return inventoryItem;
+}
+
+/*
+Function: attach
+Description: Adds a user to the observer list for receiving inventory notifications.
+Parameters:
+	- user: User*, pointer to the user to be attached as an observer
+Returns:
+	- None
+*/
+void InventoryManagementService::attach(User* user)
+{
+	DataStoreLockGuard lock(m_dataStore);
+	m_observers.clear();
+	m_observers = m_dataStore.getInventoryManagementObservers();
+	if (user)
+	{
+		const std::string& userID = user->getId();
+		if (m_observers.find(userID) == -1)
+		{
+			m_observers[userID] = user;
+		}
+	}
+	m_dataStore.saveInventoryManagementObservers(m_observers);
+}
+
+/*
+Function: detach
+Description: Removes a user from the observer list so they no longer receive inventory notifications.
+Parameters:
+	- user: User*, pointer to the user to be detached from the observer list
+Returns:
+	- None
+*/
+void InventoryManagementService::detach(User* user)
+{
+	DataStoreLockGuard lock(m_dataStore);
+	m_observers.clear();
+	m_observers = m_dataStore.getInventoryManagementObservers();
+	if (user)
+	{
+		const std::string& userID = user->getId();
+		if (m_observers.find(userID) != -1)
+		{
+			m_observers.remove(userID);
+		}
+	}
+	m_dataStore.saveInventoryManagementObservers(m_observers);
+}
+
+/*
+Function: sendNotification
+Description: Sends a notification to a user if they are subscribed as an observer.
+Parameters:
+	- user: User*, pointer to the user receiving the notification
+	- title: std::string, title of the notification
+	- message: std::string, body/content of the notification
+Returns:
+	- None
+Throws:
+	- std::runtime_error if notification creation fails
+*/
+void InventoryManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
+{
+	if (!user)
+	{
+		return;
+	}
+	DataStoreLockGuard lock(m_dataStore);
+	m_observers = m_dataStore.getInventoryManagementObservers();
+	if (m_observers.find(user->getId()) == -1)
+	{
+		return;
+	}
+	auto& trackedNotificationsMap = m_dataStore.getNotifications();
+	Notification* notification = Factory::getObject<Notification>(
+		user->getId(),
+		title,
+		message,
+		util::Timestamp());
+	if (!notification)
+	{
+		throw std::runtime_error("Failed to create notification");
+	}
+	trackedNotificationsMap.insert(notification->getId(), util::createNewRecord(notification));
+	m_dataStore.saveNotifications();
+	EventManager::sendNotificationAvailableEvent(user->getId());
+}
+

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.h

@@ -1,6 +1,16 @@
+/*
+File: InventoryManagementService.h
+Description: Header file declaring the InventoryManagementService class,
+             which manages inventory items, stock updates, and notifications
+             related to low stock alerts. Inherits from NotificationManagementService.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "NotificationManagementService.h"
 #include "DataStore.h"
 
@@ -17,6 +27,7 @@ public:
     InventoryItem* getInventoryItem(const std::string& inventoryItemID);
     void addInventoryItem(const std::string& partName, int quantity, double price);
     void removeInventoryItem(const std::string& inventoryItemID);
+    void addInventoryItemStock(const std::string& selectedItemId, int quantity);
     void sendLowStockAlerts();
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/NotificationManagementService.cpp

@@ -1 +0,0 @@
-#include "NotificationManagementService.h"

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/NotificationManagementService.h

@@ -1,6 +1,15 @@
+/*
+File: NotificationManagementService.h
+Description: Declares the NotificationManagementService abstract class which defines the contract for managing notifications in the Vehicle Service Management System.
+			 Implements the Subject interface and provides pure virtual methods for sending notifications and managing user subscriptions (attach/detach).
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Subject.h"
+#include "Notification.h"
 #include "User.h"
 
 class NotificationManagementService : public Subject

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp

@@ -1,13 +1,157 @@
-#include "PaymentManagementService.h"
-#include "ServiceBooking.h"
-#include "Service.h"
-#include "InventoryItem.h"
-#include "Utility.h"
+/*
+File: PaymentManagementService.cpp
+Description: Implements the PaymentManagementService class which manages payment-related operations
+			 in the Vehicle Service Management System. Provides functionality for attaching/detaching observers,
+			 sending notifications, and issuing payment reminders based on invoice status and thresholds.
+Author: Trenser
+Date: 20-May-2026
+*/
+
+#include <stdexcept>
+#include "Config.h"
+#include "Enums.h"
 #include "Factory.h"
-#include "Timestamp.h"
+#include "InventoryItem.h"
 #include "Invoice.h"
 #include "JobCard.h"
-#include "Enums.h"
+#include "PaymentManagementService.h"
+#include "AuthenticationManagementService.h"
+#include "DataStoreLockGuard.h"
+#include "Service.h"
+#include "ServiceBooking.h"
+#include "Timestamp.h"
+#include "User.h"
+#include "Utility.h"
+#include "DataStoreLockGuard.h"
+#include "EventManager.h"
+
+util::Map<std::string, User*> PaymentManagementService::m_observers{};
+
+/*
+Function: attach
+Description: Attaches a user as an observer to the PaymentManagementService for receiving notifications.
+Parameters:
+	- user: Pointer to the User object to be attached.
+Returns:
+	- void
+*/
+void PaymentManagementService::attach(User* user)
+{
+	DataStoreLockGuard lock(m_dataStore);
+	m_observers.clear();
+	m_observers = m_dataStore.getPaymentManagementObservers();
+	if (user)
+	{
+		const std::string& userID = user->getId();
+		if (m_observers.find(userID) == -1)
+		{
+			m_observers[userID] = user;
+		}
+	}
+	m_dataStore.savePaymentManagementObservers(m_observers);
+}
+
+/*
+Function: detach
+Description: Detaches a user from the observer list of the PaymentManagementService.
+Parameters:
+	- user: Pointer to the User object to be detached.
+Returns:
+	- void
+*/
+void PaymentManagementService::detach(User* user)
+{
+	DataStoreLockGuard lock(m_dataStore);
+	m_observers.clear();
+	m_observers = m_dataStore.getPaymentManagementObservers();
+	if (user)
+	{
+		const std::string& userID = user->getId();
+		if (m_observers.find(userID) != -1)
+		{
+			m_observers.remove(userID);
+		}
+	}
+	m_dataStore.savePaymentManagementObservers(m_observers);
+}
+
+/*
+Function: sendNotification
+Description: Sends a notification to a user if they are registered as an observer.
+Parameters:
+	- user: Pointer to the User object to receive the notification.
+	- title: Title of the notification.
+	- message: Message content of the notification.
+Returns:
+	- void
+Throws:
+	- std::runtime_error if notification creation fails.
+*/
+void PaymentManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
+{
+	if (!user)
+	{
+		return;
+	}
+	DataStoreLockGuard lock(m_dataStore);
+	m_observers = m_dataStore.getPaymentManagementObservers();
+	if (m_observers.find(user->getId()) == -1)
+	{
+		return;
+	}
+	auto& trackedNotificationsMap = m_dataStore.getNotifications();
+	Notification* notification = Factory::getObject<Notification>(
+		user->getId(),
+		title,
+		message,
+		util::Timestamp());
+	if (!notification)
+	{
+		throw std::runtime_error("Failed to create notification");
+	}
+	trackedNotificationsMap.insert(notification->getId(), util::createNewRecord(notification));
+	m_dataStore.saveNotifications();
+	EventManager::sendNotificationAvailableEvent(user->getId());
+}
+
+/*
+Function: sendPaymentReminders
+Description: Iterates through all invoices in the datastore and sends payment reminders to customers
+			 whose invoices are pending beyond the configured threshold duration.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void PaymentManagementService::sendPaymentReminders()
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInvoicesMap = m_dataStore.getInvoices();
+	int invoicesMapSize = trackedInvoicesMap.getSize();
+	for (int index = 0; index < invoicesMapSize; index++)
+	{
+		const Invoice* invoice = trackedInvoicesMap.getValueAt(index).data;
+		if (invoice && invoice->getStatus() == util::PaymentStatus::PENDING)
+		{
+			util::Timestamp invoiceCreationTimestamp = invoice->getInvoiceDate();
+			util::Timestamp currentTimestamp;
+			if (util::Timestamp::getDurationInHours(invoiceCreationTimestamp, currentTimestamp) >= config::threshold::PAYMENT_REMINDER_THRESHOLD_HOURS)
+			{
+				const ServiceBooking* serviceBooking = invoice->getBooking();
+				if (serviceBooking)
+				{
+					User* customer = serviceBooking->getCustomer();
+					if (customer)
+					{
+						std::string title = "Payment Reminder";
+						std::string message = "Your payment for Invoice ID " + invoice->getId() + " is still pending. Please complete the payment.";
+						sendNotification(customer, title, message);
+					}
+				}
+			}
+		}
+	}
+}
 
 /*
 Function: createInventoryItemsMap (static helper)
@@ -42,22 +186,24 @@ Throws:
 */
 void PaymentManagementService::generateInvoice(ServiceBooking* booking)
 {
+	DataStoreLockGuard lock(m_dataStore);
 	if (!booking)
 	{
 		throw std::runtime_error("Invoice generation failed: booking is null.");
 	}
-	double totalLabourCost = 0, totalPartsCost = 0, totalServiceCost = 0;
+	double totalLaborCost = 0, totalPartsCost = 0, totalServiceCost = 0;
 	double discountPercentage = booking->getDiscountPercentage();
 	std::string bookingID = booking->getId();
 	util::Map<std::string, Service*> servicesInTheBookedService = booking->getServices();
 	util::Map<std::string, InventoryItem*> completeInventoryItemMapOfBooking;
-	util::Map<std::string, JobCard*> currentJobCards = m_dataStore.getJobCards();
-	for (int iterator = 0; iterator < currentJobCards.getSize(); iterator++)
+	auto& currentTrackedJobCards = m_dataStore.getJobCards();
+	for (int iterator = 0; iterator < currentTrackedJobCards.getSize(); iterator++)
 	{
-		JobCard* currentJobCard = currentJobCards.getValueAt(iterator);
-		if (currentJobCard->getBookingId() == bookingID && currentJobCard->getStatus() != util::ServiceJobStatus::COMPLETED)
+		JobCard* currentJobCard = currentTrackedJobCards.getValueAt(iterator).data;
+		util::ServiceJobStatus currentJobCardStatus = currentJobCard->getStatus();
+		if (currentJobCard->getBookingId() == bookingID && currentJobCardStatus != util::ServiceJobStatus::CANCELLED && currentJobCardStatus != util::ServiceJobStatus::COMPLETED)
 		{
-			throw std::runtime_error("Invoice generation failed: not all job cards are completed for booking '" + bookingID + "'.");
+			throw std::runtime_error("Invoice generation failed: Not all job cards are completed for booking '" + bookingID + "'.");
 		}
 	}
 	for (int iterator = 0; iterator < servicesInTheBookedService.getSize(); iterator++)
@@ -66,15 +212,16 @@ void PaymentManagementService::generateInvoice(ServiceBooking* booking)
 		if (currentService)
 		{
 			createInventoryItemsMap(completeInventoryItemMapOfBooking, currentService);
-			totalLabourCost += currentService->getLaborCost();
-			totalPartsCost += calculatePartsCost(currentService);
+			totalLaborCost += currentService->getLaborCost();
+			totalPartsCost += util::calculatePartsCost(currentService);
 		}
 	}
-	totalServiceCost = totalLabourCost + totalPartsCost;
+	totalServiceCost = totalLaborCost + totalPartsCost;
 	totalServiceCost -= (totalServiceCost * (discountPercentage / 100));
-	Invoice* invoice = Factory::getObject<Invoice>(bookingID, booking, util::Timestamp(), totalLabourCost, completeInventoryItemMapOfBooking, totalPartsCost, discountPercentage, totalServiceCost, util::Timestamp(), util::PaymentMode::NOTSET, util::PaymentStatus::PENDING);
-	util::Map<std::string, Invoice*>& currentInvoices = m_dataStore.getInvoices();
-	currentInvoices.insert(invoice->getId(), invoice);
+	Invoice* invoice = Factory::getObject<Invoice>(bookingID, booking, util::Timestamp(), totalLaborCost, completeInventoryItemMapOfBooking, totalPartsCost, discountPercentage, totalServiceCost, util::Timestamp(), util::PaymentMode::NOTSET, util::PaymentStatus::PENDING);
+	auto& currentTrackedInvoices = m_dataStore.getInvoices();
+	currentTrackedInvoices.insert(invoice->getId(), util::createNewRecord(invoice));
+	m_dataStore.saveInvoices();
 }
 
 /*
@@ -87,11 +234,13 @@ Returns:
 */
 util::Map<std::string, Invoice*> PaymentManagementService::getInvoices(const std::string& customerID)
 {
-	util::Map<std::string, Invoice*>& currentInvoices = m_dataStore.getInvoices();
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& currentTrackedInvoices = m_dataStore.getInvoices();
 	util::Map<std::string, Invoice*> currentUserInvoices;
-	for (int iterator = 0; iterator < currentInvoices.getSize(); iterator++)
+	for (int iterator = 0; iterator < currentTrackedInvoices.getSize(); iterator++)
 	{
-		Invoice* currentInvoice = currentInvoices.getValueAt(iterator);
+		Invoice* currentInvoice = currentTrackedInvoices.getValueAt(iterator).data;
 		if (currentInvoice->getBooking()->getCustomerId() == customerID)
 		{
 			currentUserInvoices.insert(currentInvoice->getId(), currentInvoice);
@@ -114,22 +263,83 @@ Throws:
 */
 void PaymentManagementService::completePayment(const std::string& invoiceID, util::PaymentMode paymentMode)
 {
-	auto& currentInvoices = m_dataStore.getInvoices();
-	int invoiceIndex = currentInvoices.find(invoiceID);
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& currentTrackedInvoices = m_dataStore.getInvoices();
+	int invoiceIndex = currentTrackedInvoices.find(invoiceID);
 	if (invoiceIndex != -1)
 	{
-		Invoice* invoice = currentInvoices.getValueAt(invoiceIndex);
-		User* currentUser = invoice->getBooking()->getCustomer();
-		invoice->setPaymentMethod(paymentMode);
-		invoice->setPaymentDate(util::Timestamp());
-		invoice->setStatus(util::PaymentStatus::COMPLETED);
-		std::string title, message;
-		title = "Payment successful";
-		message = "Payment successful for invoice ID " + invoiceID;
-		sendNotification(currentUser, title, message);
+		auto& trackedInvoice = currentTrackedInvoices.getValueAt(invoiceIndex);
+		Invoice* invoice = trackedInvoice.data;
+		if (invoice && invoice->getStatus() != util::PaymentStatus::PAID)
+		{
+			User* currentUser = invoice->getBooking()->getCustomer();
+			invoice->setPaymentMethod(paymentMode);
+			invoice->setPaymentDate(util::Timestamp());
+			invoice->setStatus(util::PaymentStatus::PAID);
+			std::string title, message;
+			title = "Payment successful";
+			message = "Payment successful for Invoice ID " + invoiceID;
+			sendNotification(currentUser, title, message);
+			trackedInvoice.state = RecordState::MODIFIED;
+		}
 	}
 	else
 	{
 		throw std::runtime_error("Payment failed: invalid invoice ID.");
 	}
+	m_dataStore.saveInvoices();
+}
+
+/*
+Function: getAllInvoices
+Description: Provides access to all invoices stored in the data store.
+Parameters:
+	- none
+Returns:
+	- util::Map<std::string, Invoice*>: Map of invoice IDs to invoice objects
+*/
+util::Map<std::string, Invoice*> PaymentManagementService::getAllInvoices()
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	util::Map<std::string, Invoice*> invoices;
+	invoices = util::getObjects(m_dataStore.getInvoices());
+	return invoices;
+}
+
+/*
+Function: confirmPayment
+Description: Confirms payment for a specific invoice. Updates payment date and status,
+			 then sends a notification to the customer.
+Parameters:
+	- invoiceID: std::string, ID of the invoice to confirm
+Returns:
+	- void
+Throws:
+	- std::runtime_error if the invoice ID is invalid
+*/
+void PaymentManagementService::confirmPayment(const std::string& invoiceID)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& currentTrackedInvoices = m_dataStore.getInvoices();
+	int invoiceIndex = currentTrackedInvoices.find(invoiceID);
+	if (invoiceIndex == -1)
+	{
+		throw std::runtime_error("Payment confirmation failed: invalid invoice ID.");
+	}
+	auto& trackedInvoice = currentTrackedInvoices.getValueAt(invoiceIndex);
+	Invoice* invoice = trackedInvoice.data;
+	if (!invoice || invoice->getStatus() != util::PaymentStatus::PAID)
+	{
+		throw std::runtime_error("Payment confirmation failed: invoice is not awaiting confirmation.");
+	}
+	User* currentUser = invoice->getBooking()->getCustomer();
+	invoice->setStatus(util::PaymentStatus::COMPLETED);
+	trackedInvoice.state = RecordState::MODIFIED;
+	std::string title = "Payment Confirmed";
+	std::string message = "Payment Confirmed for Invoice ID " + invoiceID;
+	sendNotification(currentUser, title, message);
+	m_dataStore.saveInvoices();
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.h

@@ -1,3 +1,12 @@
+/*
+File: PaymentManagementService.h
+Description: Declares the PaymentManagementService class which manages payment operations in the Vehicle Service Management System.
+             Provides functionality to generate invoices, retrieve customer invoices, complete payments, send payment reminders,
+             and handle notifications using the Observer pattern.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -18,6 +27,8 @@ public:
     void generateInvoice(ServiceBooking* booking);
     util::Map<std::string, Invoice*> getInvoices(const std::string& customerID);
     void completePayment(const std::string& invoiceID, util::PaymentMode paymentMode);
+    util::Map<std::string, Invoice*> getAllInvoices();
+    void confirmPayment(const std::string& invoiceID);
     void sendPaymentReminders();
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.h

@@ -1,3 +1,12 @@
+/*
+File: ServiceManagementService.h
+Description: Header file declaring the ServiceManagementService class, which manages
+             services, combo packages, job cards, and service bookings. Inherits from
+             NotificationManagementService to handle notifications.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -22,14 +31,16 @@ public:
     void purchaseComboPackage(const std::string& comboPackageID, const std::string& vehicleNumber, const std::string& vehicleBrand, const std::string& vehicleModel);
     util::Map<std::string, ServiceBooking*> getServiceBookings();
     util::Map<std::string, ServiceBooking*> getServiceBookings(const std::string& customerID);
+    ServiceBooking* getServiceBooking(const std::string& serviceID);
     void createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID);
     void createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost);
     void removeService(const std::string& serviceID);
+    void removeServiceBooking(const std::string& bookingID);
     util::Map<std::string, JobCard*> getJobCards(const std::string& technicianID);
-    void completeJob(const std::string& jobID);
+    void updateJobStatus(const std::string& jobID);
     void cancelCustomerServiceBookings(const std::string& customerID);
     void cancelTechnicianJobs(const std::string& technicianID);
-    void createComboPackage(const std::string& name, const util::Vector<std::string>& serviceIDs, double discountPercentage);
+    void createComboPackage(const std::string& packageName, const util::Vector<std::string>& serviceIDs, double discountPercentage);
     void removeComboPackage(const std::string& comboPackageID);
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp

@@ -1 +1,337 @@
+/*
+File: UserManagementService.cpp
+Description: Implementation file containing the method definitions of the
+			 UserManagementService class, including user creation, updates,
+			 and ensuring an admin account exists.
+Author: Trenser
+Date:19-May-2026
+*/
+
+#include <stdexcept>
+#include "Config.h"
+#include "Enums.h"
+#include "Factory.h"
+#include "InventoryManagementService.h"
+#include "Notification.h"
+#include "PaymentManagementService.h"
+#include "ServiceManagementService.h"
+#include "AuthenticationManagementService.h"
+#include "User.h"
 #include "UserManagementService.h"
+#include "Vector.h"
+#include "Validator.h"
+#include "Utility.h"
+#include "TrackedRecord.h"
+#include "DataStoreLockGuard.h"
+#include "EventManager.h"
+
+/*
+Function: ensureAdminExists
+Description: Ensures that at least one admin user exists in the system.
+			 If no admin is found, creates a default admin user using
+			 configuration constants.
+Parameter: None
+Return type: void
+*/
+void UserManagementService::ensureAdminExists()
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto& usersMap = m_dataStore.getUsers();
+	int usersMapSize = usersMap.getSize();
+	bool isAdminFound = false;
+	for (int index = 0; index < usersMapSize; index++)
+	{
+		User* user = usersMap.getValueAt(index).data;
+		if (user && user->getUserType() == util::UserType::ADMIN)
+		{
+			isAdminFound = true;
+			break;
+		}
+	}
+	if (!isAdminFound)
+	{
+		createUser(
+			config::admin::DEFAULT_ADMIN_USERNAME,
+			config::admin::DEFAULT_ADMIN_NAME,
+			config::admin::DEFAULT_ADMIN_PASSWORD,
+			config::admin::DEFAULT_ADMIN_EMAIL,
+			config::admin::DEFAULT_ADMIN_PHONE, 
+			util::UserType::ADMIN);
+	}
+}
+
+/*
+Function: createUser
+Description: Creates a new user with the provided details. Validates that
+			 the username is unique, then attaches the user to relevant
+			 management services (payment, service, inventory).
+Parameter: const std::string& username - user’s username
+		   const std::string& name - user’s name
+		   const std::string& password - user’s password
+		   const std::string& email - user’s email address
+		   const std::string& phone - user’s phone number
+		   util::UserType type - type of user (ADMIN, CUSTOMER, TECHNICIAN)
+Return type: void
+*/
+void UserManagementService::createUser(const std::string& username, const std::string& name, const std::string& password, const std::string& email, const std::string& phone, util::UserType type)
+{
+	InventoryManagementService inventoryManagementService;
+	PaymentManagementService paymentManagementService;
+	ServiceManagementService serviceManagementService;
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	auto usersMap = util::getObjects(trackedUsersMap);
+	if (util::isUsernameDuplicate(username, usersMap))
+	{
+		throw std::runtime_error("Username already exists");
+	}
+	if (util::isEmailDuplicate(email, usersMap))
+	{
+		throw std::runtime_error("Email already exists");
+	}
+	if (util::isPhoneDuplicate(phone, usersMap))
+	{
+		throw std::runtime_error("Phone already exists");
+	}
+	User* newUser = Factory::getObject<User>(username, password, name, phone, email, type);
+	trackedUsersMap.insert(newUser->getId(), util::createNewRecord(newUser));
+	paymentManagementService.attach(newUser);
+	serviceManagementService.attach(newUser);
+	if (newUser->getUserType() == util::UserType::ADMIN)
+	{
+		inventoryManagementService.attach(newUser);
+	}
+	m_dataStore.saveUsers();
+}
+
+/*
+Function: updateUserDetails
+Description: Updates the email and phone details of an existing user.
+			 Throws an exception if the user does not exist.
+Parameter: const std::string& userID - ID of the user to update
+		   const std::string& email - new email address
+		   const std::string& phone - new phone number
+Return type: void
+*/
+void UserManagementService::updateUserDetails(const std::string& userID, const std::string& email, const std::string& phone)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	auto usersMap = util::getObjects(trackedUsersMap);
+	int index = trackedUsersMap.find(userID);
+	if (index == -1)
+	{
+		throw std::runtime_error("User does not exist!\n");
+	}
+	User* user = trackedUsersMap.getValueAt(index).data;
+	bool isModified = false;
+	if (email != user->getEmail())
+	{
+		if (util::isEmailDuplicate(email, usersMap))
+		{
+			throw std::runtime_error("Email already exists!\n");
+		}
+		user->setEmail(email);
+		isModified = true;
+	}
+	if (phone != user->getPhone())
+	{
+		if (util::isPhoneDuplicate(phone, usersMap))
+		{
+			throw std::runtime_error("Phone number already exists!\n");
+		}
+		user->setPhone(phone);
+		isModified = true;
+	}
+	if (isModified)
+	{
+		trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
+		m_dataStore.saveUsers();
+	}
+}
+
+/*
+Function: getUserNotifications
+Description: Retrieves all notifications associated with a given user ID.
+Parameters:
+	- userID: The unique ID of the user whose notifications are to be retrieved.
+Returns:
+	- util::Vector<Notification*> containing all notifications for the user.
+Throws:
+	- std::runtime_error if no user is found with the given UserID or if the User object is invalid.
+*/
+util::Vector<Notification*> UserManagementService::getUserNotifications(const std::string& userID)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers(); 
+	if (trackedUsersMap.find(userID) == -1)
+	{
+		throw std::runtime_error("No user found with given UserID");
+	}
+	User* user = trackedUsersMap[userID].data;
+	if (user)
+	{
+		auto& trackedNotificationMap = m_dataStore.getNotifications();
+		int numberOfNotifications = trackedNotificationMap.getSize();
+		util::Vector<Notification*> notificationsVector;
+		for (int index = 0; index < numberOfNotifications; index++)
+		{
+			Notification* notification = trackedNotificationMap.getValueAt(index).data;
+			if (notification->getRecipientUserId() == userID && notification->getState() == util::State::ACTIVE)
+			{
+				notificationsVector.push_back(notification);
+			}
+		}
+		return notificationsVector;
+	}
+	else
+	{
+		throw std::runtime_error("Invalid User object");
+	}
+}
+
+/*
+Function: deleteNotification
+Description: Marks a specific notification associated with a given user
+			 as inactive.
+Parameters:
+	- notificationID: The unique ID of the notification to be deleted.
+	- userID: The unique ID of the user whose notification is to be deleted.
+Returns:
+	- void
+Throws:
+	- std::runtime_error if no user is found with the given UserID or
+	  if no notification is found with the given NotificationID.
+*/
+void UserManagementService::deleteNotification(const std::string& notificationID, const std::string& userID)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	auto& trackedNotificationsMap = m_dataStore.getNotifications();
+	int userIndex = trackedUsersMap.find(userID);
+	if (userIndex == -1)
+	{
+		throw std::runtime_error("No user found with given UserID");
+	}
+	int notificationIndex = trackedNotificationsMap.find(notificationID);
+	if (notificationIndex == -1)
+	{
+		throw std::runtime_error("No notification found with given NotificationID");
+	}
+	Notification* notification = trackedNotificationsMap.getValueAt(notificationIndex).data;
+	if (notification->getRecipientUserId() == userID)
+	{
+		notification->setState(util::State::INACTIVE);
+		trackedNotificationsMap.getValueAt(notificationIndex).state = RecordState::MODIFIED;
+		m_dataStore.saveNotifications();
+	}
+}
+
+/*
+Function: getUsers
+Description: Retrieves all users stored in the DataStore.
+Parameter: None
+Return type: util::Map<std::string, User*>
+*/
+util::Map<std::string, User*> UserManagementService::getUsers()
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto users = util::getObjects(m_dataStore.getUsers());
+	return users;
+}
+
+/*
+Function: getUser
+Description: Retrieves a specific user by ID from the DataStore.
+Parameter: const std::string& userID - ID of the user
+Return type: User*
+*/
+User* UserManagementService::getUser(const std::string& userID)
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	int index = trackedUsersMap.find(userID);
+	if (index != -1)
+	{
+		return trackedUsersMap.getValueAt(index).data;
+	}
+	return nullptr;
+}
+
+/*
+Function: removeUser
+Description: Marks a user as inactive in the DataStore instead of deleting them.
+Parameter: const std::string& userID - ID of the user to remove
+Return type: void
+*/
+void UserManagementService::removeUser(const std::string& userID)
+{
+    AuthenticationManagementService::ensureAuthorization();
+	InventoryManagementService inventoryManagementService;
+	PaymentManagementService paymentManagementService;
+	ServiceManagementService serviceManagementService;
+	std::string removedUserID;
+	{
+		DataStoreLockGuard lock(m_dataStore);
+		auto& trackedUsersMap = m_dataStore.getUsers();
+		int index = trackedUsersMap.find(userID);
+		if (index != -1)
+		{
+			User* user = trackedUsersMap.getValueAt(index).data;
+			if (user != nullptr)
+			{
+				if (user->getUserType() == util::UserType::CUSTOMER)
+				{
+					serviceManagementService.cancelCustomerServiceBookings(userID);
+				}
+				if (user->getUserType() == util::UserType::TECHNICIAN)
+				{
+					serviceManagementService.cancelTechnicianJobs(userID);
+				}
+				inventoryManagementService.detach(user);
+				paymentManagementService.detach(user);
+				serviceManagementService.detach(user);
+				user->setState(util::State::INACTIVE);
+				trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
+				removedUserID = user->getId();
+				m_dataStore.saveUsers();
+			}
+		}
+	}
+	if (!removedUserID.empty())
+	{
+		EventManager::sendUserDisabledEvent(removedUserID);
+	}
+}
+
+/*
+Function: getUsers
+Description: Retrieves all active users of the specified type from
+			 the DataStore.
+Parameters:
+	- type: The user type to filter by
+			(ADMIN, CUSTOMER, or TECHNICIAN).
+Returns:
+	- util::Map<std::string, User*>:
+	  Collection of active users matching the specified type,
+	  keyed by user ID.
+*/
+util::Map<std::string, User*> UserManagementService::getUsers(util::UserType type) 
+{
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	util::Map<std::string, User*> currentUsers = util::getObjects(trackedUsersMap);
+	util::Map<std::string, User*> filteredUsersMap;
+	for (int index = 0; index < currentUsers.getSize(); index++)
+	{
+		User* currentUser = currentUsers.getValueAt(index);
+		if (currentUser && currentUser->getState() == util::State::ACTIVE && currentUser->getUserType() == type)
+		{
+			filteredUsersMap.insert(currentUser->getId(), currentUser);
+		}
+	}
+	return filteredUsersMap;
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.h

@@ -1,3 +1,12 @@
+/*
+File: UserManagementService.h
+Description: Header file declaring the UserManagementService class, which manages
+             user creation, updates, retrieval, removal, notifications, and ensures
+             the existence of an admin account.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -13,12 +22,13 @@ private:
     DataStore& m_dataStore;
 public:
     UserManagementService() : m_dataStore(DataStore::getInstance()) {}
-    void createUser(const std::string& username, const std::string& password, const std::string& email, const std::string& phone, util::UserType type);
+    void createUser(const std::string& username, const std::string& name, const std::string& password, const std::string& email, const std::string& phone, util::UserType type);
     void updateUserDetails(const std::string& userID, const std::string& email, const std::string& phone);
     util::Map<std::string, User*> getUsers();
     util::Map<std::string, User*> getUsers(util::UserType type);
-    User* getUser(const std::string& userID);
+    User* getUser (const std::string& userID);
     void removeUser(const std::string& userID);
     util::Vector<Notification*> getUserNotifications(const std::string& userID);
     void deleteNotification(const std::string& notificationID, const std::string& userID);
+    void ensureAdminExists();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Config.h

@@ -0,0 +1,46 @@
+/*
+File: Config.h
+Description: Header file declaring configuration constants for the Vehicle Service System.
+			 Includes default admin account details such as username, name, password,
+			 email, and phone number.
+Author: Trenser
+Date: 21-May-2026
+*/
+
+#pragma once
+
+namespace config
+{
+	namespace admin
+	{
+		constexpr const char* DEFAULT_ADMIN_USERNAME = "admin";
+		constexpr const char* DEFAULT_ADMIN_NAME = "admin";
+		constexpr const char* DEFAULT_ADMIN_PASSWORD = "admin";
+		constexpr const char* DEFAULT_ADMIN_EMAIL = "admin@vss";
+		constexpr const char* DEFAULT_ADMIN_PHONE = "0000000000";
+	}
+
+	namespace threshold
+	{
+		constexpr int INVENTORY_LOW_STOCK_THRESHOLD = 5;
+		constexpr int PAYMENT_REMINDER_THRESHOLD_HOURS = 168;
+	}
+
+	namespace file
+	{
+		const size_t INITIAL_CAPACITY = 100;
+		const size_t GROWTH_FACTOR = 2;
+		constexpr const char* DIRECTORY = "files/";
+		constexpr const char* INVENTORYITEM_FILE = "files/InventoryItem.dat";
+		constexpr const char* USER_FILE = "files/User.dat";
+		constexpr const char* NOTIFICATION_FILE = "files/Notification.dat";
+		constexpr const char* SERVICE_FILE = "files/Service.dat";
+		constexpr const char* COMBOPACKAGE_FILE = "files/ComboPackage.dat";
+		constexpr const char* SERVICEBOOKING_FILE = "files/ServiceBooking.dat";
+		constexpr const char* JOBCARD_FILE = "files/JobCard.dat";
+		constexpr const char* INVOICE_FILE = "files/Invoice.dat";
+		constexpr const char* SERVICEMANAGEMENTOBSERVERS = "files/ServiceManagementObservers.dat";
+		constexpr const char* PAYMENTMANAGEMENTOBSERVERS = "files/PaymentManagementObservers.dat";
+		constexpr const char* INVENTORYMANAGEMENTOBSERVERS = "files/InventoryManagementObservers.dat";
+	}
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Enums.h

@@ -1,40 +1,61 @@
+/*
+File: Enums.h
+Description: Declares enumerations and utility functions for user types, payment modes, payment status,
+             service job status, and state management in the Vehicle Service Management System.
+             Provides string conversion and parsing functions for each enum type.
+Author: Trenser
+Date: 19-May-2026
+*/
+
 #pragma once
 #include <stdexcept>
 
 namespace util
 {
-	enum class UserType
+	enum class UserType : int
 	{
 		ADMIN,
 		TECHNICIAN,
 		CUSTOMER
 	};
 
-	enum class PaymentMode
+	enum class PaymentMode : int
 	{
 		ONLINE,
 		OFFLINE,
         NOTSET
 	};
 
-	enum class PaymentStatus
+	enum class PaymentStatus : int
 	{
 		PENDING,
-		COMPLETED
+		COMPLETED,
+        PAID
 	};
 
-	enum class ServiceJobStatus
+	enum class ServiceJobStatus : int
 	{
+        PENDING,
 		STARTED,
-		COMPLETED
+		COMPLETED,
+        IN_PROGRESS,
+        CANCELLED
 	};
 
-    enum class State
+    enum class State : int
     {
         ACTIVE,
         INACTIVE
     };
 
+    /*
+    Function: getUserTypeString
+    Description: Converts a UserType enum value to its corresponding string representation.
+    Parameters:
+        - type: UserType enum value.
+    Returns:
+        - std::string representing the UserType.
+    */
     inline std::string getUserTypeString(UserType type)
     {
         switch (type)
@@ -49,6 +70,16 @@ namespace util
         throw std::invalid_argument("Invalid UserType");
     }
 
+    /*
+    Function: getUserType
+    Description: Converts a string value to its corresponding UserType enum.
+    Parameters:
+        - value: std::string representing the UserType.
+    Returns:
+        - UserType enum value.
+    Throws:
+        - std::invalid_argument if the string does not match a valid UserType.
+    */
     inline UserType getUserType(const std::string& value)
     {
         if (value == "ADMIN")
@@ -66,6 +97,14 @@ namespace util
         throw std::invalid_argument("Invalid UserType string");
     }
 
+    /*
+    Function: getPaymentModeString
+    Description: Converts a PaymentMode enum value to its corresponding string representation.
+    Parameters:
+        - mode: PaymentMode enum value.
+    Returns:
+        - std::string representing the PaymentMode.
+    */
     inline std::string getPaymentModeString(PaymentMode mode)
     {
         switch (mode)
@@ -80,6 +119,16 @@ namespace util
         throw std::invalid_argument("Invalid PaymentMode");
     }
 
+    /*
+    Function: getPaymentMode
+    Description: Converts a string value to its corresponding PaymentMode enum.
+    Parameters:
+        - value: std::string representing the PaymentMode.
+    Returns:
+        - PaymentMode enum value.
+    Throws:
+        - std::invalid_argument if the string does not match a valid PaymentMode.
+    */
     inline PaymentMode getPaymentMode(const std::string& value)
     {
         if (value == "ONLINE")
@@ -90,9 +139,21 @@ namespace util
         {
             return PaymentMode::OFFLINE;
         }
+        if (value == "NOTSET")
+        {
+            return PaymentMode::NOTSET;
+        }
         throw std::invalid_argument("Invalid PaymentMode string");
     }
 
+    /*
+    Function: getPaymentStatusString
+    Description: Converts a PaymentStatus enum value to its corresponding string representation.
+    Parameters:
+        - status: PaymentStatus enum value.
+    Returns:
+        - std::string representing the PaymentStatus.
+    */
     inline std::string getPaymentStatusString(PaymentStatus status)
     {
         switch (status)
@@ -101,10 +162,22 @@ namespace util
             return "PENDING";
         case PaymentStatus::COMPLETED:
             return "COMPLETED";
+        case PaymentStatus::PAID:
+            return "PAID";
         }
         throw std::invalid_argument("Invalid PaymentStatus");
     }
 
+    /*
+    Function: getPaymentStatus
+    Description: Converts a string value to its corresponding PaymentStatus enum.
+    Parameters:
+        - value: std::string representing the PaymentStatus.
+    Returns:
+        - PaymentStatus enum value.
+    Throws:
+        - std::invalid_argument if the string does not match a valid PaymentStatus.
+    */
     inline PaymentStatus getPaymentStatus(const std::string& value)
     {
         if (value == "PENDING")
@@ -120,18 +193,42 @@ namespace util
         throw std::invalid_argument("Invalid PaymentStatus string");
     }
 
+    /*
+    Function: getServiceJobStatusString
+    Description: Converts a ServiceJobStatus enum value to its corresponding string representation.
+    Parameters:
+        - status: ServiceJobStatus enum value.
+    Returns:
+        - std::string representing the ServiceJobStatus.
+    */
     inline std::string getServiceJobStatusString(ServiceJobStatus status)
     {
         switch (status)
         {
+        case ServiceJobStatus::PENDING:
+            return "PENDING";
         case ServiceJobStatus::STARTED:
             return "STARTED";
         case ServiceJobStatus::COMPLETED:
             return "COMPLETED";
+        case ServiceJobStatus::CANCELLED:
+            return "CANCELLED";
+        case ServiceJobStatus::IN_PROGRESS:
+            return "IN_PROGRESS";
         }
         throw std::invalid_argument("Invalid ServiceJobStatus");
     }
 
+    /*
+    Function: getServiceJobStatus
+    Description: Converts a string value to its corresponding ServiceJobStatus enum.
+    Parameters:
+        - value: std::string representing the ServiceJobStatus.
+    Returns:
+        - ServiceJobStatus enum value.
+    Throws:
+        - std::invalid_argument if the string does not match a valid ServiceJobStatus.
+    */
     inline ServiceJobStatus getServiceJobStatus(const std::string& value)
     {
         if (value == "STARTED")
@@ -142,31 +239,61 @@ namespace util
         {
             return ServiceJobStatus::COMPLETED;
         }
+        if (value == "PENDING")
+        {
+            return ServiceJobStatus::PENDING;
+        }
+        if (value == "CANCELLED")
+        {
+            return ServiceJobStatus::CANCELLED;
+        }
+        if (value == "IN_PROGRESS")
+        {
+            return ServiceJobStatus::IN_PROGRESS;
+        }
         throw std::invalid_argument("Invalid ServiceJobStatus string");
     }
 
+    /*
+    Function: getStateString
+    Description: Converts a State enum value to its corresponding string representation.
+    Parameters:
+        - status: State enum value.
+    Returns:
+        - std::string representing the State.
+    */
     inline std::string getStateString(State status)
     {
         switch (status)
         {
         case State::ACTIVE:
-            return "STARTED";
+            return "ACTIVE";
         case State::INACTIVE:
-            return "COMPLETED";
+            return "INACTIVE";
         }
         throw std::invalid_argument("Invalid State");
     }
 
+    /*
+    Function: getState
+    Description: Converts a string value to its corresponding State enum.
+    Parameters:
+        - value: std::string representing the State.
+    Returns:
+        - State enum value.
+    Throws:
+        - std::invalid_argument if the string does not match a valid State.
+    */
     inline State getState(const std::string& value)
     {
         if (value == "ACTIVE")
         {
             return State::ACTIVE;
         }
-        if (value == "COMPLETED")
+        if (value == "INACTIVE")
         {
             return State::INACTIVE;
         }
         throw std::invalid_argument("Invalid State string");
     }
-}
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/FileHelper.h

@@ -0,0 +1,46 @@
+/*
+File: FileHelper.h
+Description: Provides utility functions for loading and saving records
+             from and to CSV-like text files. Ensures files are created
+             if missing and supports simple record persistence.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#pragma once
+#include <fstream>
+#include <string>
+#include <stdexcept>
+#include <direct.h>
+#include "Vector.h"
+
+namespace util
+{
+    /*
+    Function: ensureDirectoryExists
+    Description: Creates all missing directories present in the given file path.
+                Iteratively parses the path and creates each directory level
+                using _mkdir() before file operations are performed.
+    Parameters:
+        - filePath: const std::string&, relative or absolute file path
+    Returns:
+        - void
+    Throws:
+        - None (_mkdir failures are intentionally ignored if directory already exists)
+    */
+    inline void ensureDirectoryExists(const std::string& filePath)
+    {
+        size_t position = 0;
+
+        while ((position = filePath.find('/', position)) != std::string::npos)
+        {
+            std::string directory = filePath.substr(0, position);
+
+            if (!directory.empty())
+            {
+                (void)_mkdir(directory.c_str());
+            }
+            position++;
+        }
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/InputHelper.h

@@ -10,6 +10,7 @@
 #include <limits>
 #include <string>
 #include <stdexcept>
+#include <conio.h>
 
 namespace util
 {
@@ -27,14 +28,14 @@ namespace util
         if (!(std::cin >> value))
         {
             std::cin.clear();
-            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
+            std::cin.ignore((std::numeric_limits<std::streamsize>::max)(), '\n');
             throw std::runtime_error("Invalid console input");
         }
     }
 
     /*
      * Function: read
-     * Description: Reads a line of text input from console into a string.
+     * Description: Reads a line of text input from console into a string and cleans it up.
      * Parameters:
      *     value - reference to a string where the input will be stored
      * Returns:
@@ -43,6 +44,57 @@ namespace util
     inline void read(std::string& value)
     {
         std::getline(std::cin >> std::ws, value);
+        std::string cleanedValue;
+        for (int index = 0; index < value.length(); index++)
+        {
+            if (value[index] != ',')
+            {
+                cleanedValue += value[index];
+            }
+        }
+        value = cleanedValue;
+    }
+
+    /*
+     * Function: readPassword
+     * Description: Reads a password from console without echoing characters;
+     *              displays '*' for each character typed, handles backspace,
+     *              and cleans commas from the result.
+     * Parameters:
+     *     value - reference to a string where the password will be stored
+     * Returns:
+     *     void - no return value
+     */
+    inline void readPassword(std::string& value)
+    {
+        value.clear();
+        char currentCharacter;
+        while ((currentCharacter = _getch()) != '\r')
+        {
+            if (currentCharacter == '\b')
+            {
+                if (!value.empty())
+                {
+                    value.pop_back();
+                    std::cout << "\b \b";
+                }
+            }
+            else
+            {
+                value += currentCharacter;
+                std::cout << '*';
+            }
+        }
+        std::cout << std::endl;
+        std::string cleanedValue;
+        for (int iterator = 0; iterator < value.length(); iterator++)
+        {
+            if (value[iterator] != ',')
+            {
+                cleanedValue += value[iterator];
+            }
+        }
+        value = cleanedValue;
     }
 
     /*
@@ -53,6 +105,7 @@ namespace util
      */
     inline void pressEnter()
     {
+        std::cout << std::endl;
         system("pause");
     }
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/OutputHelper.h

@@ -21,4 +21,28 @@ namespace util
     {
         std::cout << "\x1B[2J\x1B[H" << std::flush;
     }
+
+    /*
+    Function: truncateString
+    Description:
+        Truncates a string if its length exceeds the given maximum length.
+        The truncated string ends with "..." to indicate omitted characters.
+    Parameters:
+        - text: const std::string&, input string to truncate
+        - maxLength: size_t, maximum allowed length of the returned string
+    Returns:
+        - std::string: Original string if within limit, otherwise truncated string with "..."
+    */
+    inline std::string truncateString(const std::string& text, size_t maxLength)
+    {
+        if (text.length() <= maxLength)
+        {
+            return text;
+        }
+        if (maxLength <= 3)
+        {
+            return std::string(maxLength, '.');
+        }
+        return text.substr(0, maxLength - 3) + "...";
+    }
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/StringHelper.h

@@ -0,0 +1,36 @@
+/*
+File: StringHelper.h
+Description: Provides utility functions for extracting numeric values from strings.
+             Useful for parsing IDs, codes, or mixed alphanumeric inputs where
+             digits need to be isolated and converted into integers.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#include <cctype>
+#include <string>
+
+namespace util
+{
+    /*
+    Function: extractNumber
+    Description: Extracts all digits from the given string and converts them into an integer.
+                 Ignores non-digit characters. For example, "abc123xyz" returns 123.
+    Parameters:
+        - input: const std::string&, the input string containing digits and/or other characters
+    Returns:
+        - int: The integer value formed by concatenating all digits in the string
+    */
+    inline int extractNumber(const std::string& input)
+    {
+        int result = 0;
+        for (char character : input)
+        {
+            if (std::isdigit(static_cast<unsigned char>(character)))
+            {
+                result = result * 10 + (character - '0');
+            }
+        }
+        return result;
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Utility.h

@@ -1,15 +1,132 @@
-#pragma once
-#include "Service.h"
-#include "InventoryItem.h"
+/*
+File: Utility.h
+Description: Header file declaring utility functions used across the system
+Author: Trenser
+Date:19-May-2026
+*/
 
-inline double calculatePartsCost(const Service* service)
+#pragma once
+#include "ComboPackage.h"
+#include "DataStore.h"
+#include "FileHelper.h"
+#include "InventoryItem.h"
+#include "NotificationManagementService.h"
+#include "Service.h"
+
+namespace util
 {
-    double cost = 0;
-    auto& requiredInventoryItems = service->getRequiredInventoryItems();
-    int requiredInventoryItemsSize = requiredInventoryItems.getSize();
-    for (int index = 0; index < requiredInventoryItemsSize; index++)
+    /*
+    Function: calculatePartsCost
+    Description: Calculates the total cost of parts required for a given service
+                 by summing the prices of all associated inventory items.
+    Parameter: const Service* service - pointer to the service object
+    Return type: double - total cost of required parts
+    */
+    inline double calculatePartsCost(const Service* service)
     {
-        cost += requiredInventoryItems.getValueAt(index)->getPrice();
+        double cost = 0;
+        auto& requiredInventoryItems = service->getRequiredInventoryItems();
+        int requiredInventoryItemsSize = requiredInventoryItems.getSize();
+        for (int index = 0; index < requiredInventoryItemsSize; index++)
+        {
+            cost += requiredInventoryItems.getValueAt(index)->getPrice();
+        }
+        return cost;
     }
-    return cost;
+
+    /*
+    Function: calculateComboServiceEstimatedCost
+    Description: Calculates the estimated total cost of a combo package by summing
+                  the labor and parts costs of all services included in the package.
+    Parameter: const ComboPackage* comboPackage - pointer to the combo package object
+    Return type: double - estimated total cost of the combo package
+    */
+    inline double calculateComboServiceEstimatedCost(const ComboPackage* comboPackage)
+    {
+        double cost = 0;
+        auto& services = comboPackage->getServices();
+        int servicesSize = services.getSize();
+        for (int index = 0; index < servicesSize; index++)
+        {
+            const Service* service = services.getValueAt(index);
+            cost += calculatePartsCost(service) + service->getLaborCost();
+        }
+        return cost;
+    }
+
+    template<typename TObject>
+    Map<std::string, TObject*> getObjects(const Map<std::string, TrackedRecord<TObject>>& trackedRecords);
+
+    template<typename TObject>
+    Map<std::string, const TObject*> getConstObjects(const Map<std::string, TrackedRecord<TObject>>& trackedRecords);
+
+    template<typename TObject>
+    TrackedRecord<TObject> createNewRecord(TObject* object);
+}
+
+/*
+Function: getObjects
+Description: Extracts the object pointers from a tracked-record
+             collection and returns them as a map keyed by the
+             same identifiers.
+Parameters:
+    - trackedRecords: Collection of tracked records.
+Returns:
+    - Map<std::string, TObject*>: Collection of object pointers.
+*/
+template<typename TObject>
+util::Map<std::string, TObject*> util::getObjects(const util::Map<std::string, TrackedRecord<TObject>>& trackedRecords)
+{
+    util::Map<std::string, TObject*> objects;
+    for (int index = 0; index < trackedRecords.getSize(); ++index)
+    {
+        const std::string& key = trackedRecords.getKeyAt(index);
+        TObject* object = trackedRecords.getValueAt(index).data;
+        objects.insert(key, object);
+    }
+    return objects;
+}
+
+/*
+Function: getConstObjects
+Description: Extracts the object pointers from a tracked-record
+             collection and returns them as a read-only map
+             keyed by the same identifiers.
+Parameters:
+    - trackedRecords: Collection of tracked records.
+Returns:
+    - Map<std::string, const TObject*>:
+      Collection of read-only object pointers.
+*/
+template<typename TObject>
+util::Map<std::string, const TObject*> util::getConstObjects(
+    const util::Map<std::string, TrackedRecord<TObject>>& trackedRecords)
+{
+    util::Map<std::string, const TObject*> objects;
+    for (int index = 0; index < trackedRecords.getSize(); ++index)
+    {
+        const std::string& key = trackedRecords.getKeyAt(index);
+        const TObject* object = trackedRecords.getValueAt(index).data;
+        objects.insert(key, object);
+    }
+    return objects;
+}
+
+/*
+Function: createNewRecord
+Description: Creates a tracked record for a newly created
+             object. The record is initialized with
+             NEW_RECORD state.
+Parameters:
+    - object: Pointer to the newly created object.
+Returns:
+    - TrackedRecord<TObject>: Initialized tracked record.
+*/
+template<typename TObject>
+TrackedRecord<TObject> util::createNewRecord(TObject* object)
+{
+    TrackedRecord<TObject> record;
+    record.data = object;
+    record.state = RecordState::NEW_RECORD;
+    return record;
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.cpp

@@ -106,4 +106,68 @@ bool util::isPasswordValid(const std::string& password)
     }
 
     return hasUpper && hasLower && hasDigit && hasSpecial;
+}
+
+/*
+ * Function: isUsernameDuplicate
+ * Description: Checks if the given username already exists among active users.
+ * Parameters:
+ *     username - string containing the username to validate
+ *     usersMap - map of user objects keyed by identifier
+ * Returns:
+ *     bool - true if the username is already in use by an active user, false otherwise
+ */
+bool util::isUsernameDuplicate(const std::string& username, const util::Map<std::string, User*>& usersMap)
+{
+    int index = usersMap.findIf(
+        [&](const std::string&, User* user)
+        {
+            return (user->getUserName() == username);
+        }
+    );
+    return index != -1;
+}
+
+/*
+ * Function: isPhoneDuplicate
+ * Description: Checks if the given phone number already exists among active users.
+ * Parameters:
+ *     phone - string containing the phone number to validate
+ *     usersMap - map of user objects keyed by identifier
+ * Returns:
+ *     bool - true if the phone number is already in use by an active user, false otherwise
+ * Notes:
+ *     - Only considers users with state util::State::ACTIVE
+ */
+bool util::isPhoneDuplicate(const std::string& phone, const util::Map<std::string, User*>& usersMap)
+{
+    int index = usersMap.findIf(
+        [&](const std::string&, User* user)
+        {
+            return (user->getPhone() == phone && user->getState() == util::State::ACTIVE);
+        }
+    );
+    return index != -1;
+}
+
+/*
+ * Function: isEmailDuplicate
+ * Description: Checks if the given email address already exists among active users.
+ * Parameters:
+ *     email - string containing the email address to validate
+ *     usersMap - map of user objects keyed by identifier
+ * Returns:
+ *     bool - true if the email address is already in use by an active user, false otherwise
+ * Notes:
+ *     - Only considers users with state util::State::ACTIVE
+ */
+bool util::isEmailDuplicate(const std::string& email, const util::Map<std::string, User*>& usersMap)
+{
+    int index = usersMap.findIf(
+        [&](const std::string&, User* user)
+        {
+            return (user->getEmail() == email && user->getState() == util::State::ACTIVE);
+        }
+    );
+    return index != -1;
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.h

@@ -9,10 +9,15 @@
 #include<string>
 #include<algorithm>
 #include<cctype>
+#include "Map.h"
+#include "User.h"
 
 namespace util
 {
 	bool isPhoneNumberValid(const std::string&);
 	bool isEmailValid(const std::string&);
 	bool isPasswordValid(const std::string&);
+	bool isUsernameDuplicate(const std::string&, const util::Map<std::string, User*>&);
+	bool isPhoneDuplicate(const std::string&, const util::Map<std::string, User*>&);
+	bool isEmailDuplicate(const std::string&, const util::Map<std::string, User*>&);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp

@@ -1,89 +1,806 @@
-#include "AdminMenu.h"
-#include "InputHelper.h"
-#include "OutputHelper.h"
+/*
+File: AdminMenu.cpp
+Description: Implements the AdminMenu class which provides the administrator’s console interface
+			 in the Vehicle Service Management System. Handles menu display, user input, and
+			 admin-specific operations such as inventory management, technician management,
+			 service creation, combo package management, job assignment, and notifications.
+Author: Trenser
+Date: 19-May-2026
+*/
 
+#include <iomanip>
+#include <iostream>
+#include "AdminMenu.h"
+#include "Enums.h"
+#include "InputHelper.h"
+#include "InventoryItem.h"
+#include "MenuHelper.h"
+#include "OutputHelper.h"
+#include "Service.h"
+#include "ServiceBooking.h"
+#include "User.h"
+#include "Utility.h"
+#include "Validator.h"
+
+/*
+Function: showMenu
+Description: Displays the admin menu and handles user input until logout is selected.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::showMenu()
 {
-	bool isMenuActive = true;
-	while (isMenuActive)
-	{
-		try
-		{
-			int choice;
-			util::clear();
-			std::cout << "" << std::endl;
-			util::read(choice);
-			if (!handleOperation(choice))
+	startEventListener();
+    while (true)
+    {
+        try
+        {
+			if (!m_isMenuActive)
 			{
-				isMenuActive = false;
+				logout();
+				break;
 			}
-		}
-		catch (const std::exception& e)
-		{
-			std::cout << "Exception: " << e.what() << std::endl;
-			util::pressEnter();
-		}
-	}
+            int choice;
+            util::clear();
+            std::cout << "Admin Menu"
+                << "\n1. View Stock Levels"
+                << "\n2. Add Inventory Item"
+                << "\n3. Remove Inventory Item"
+                << "\n4. Check Stock Availability"
+                << "\n5. Assign Job to Technician"
+                << "\n6. Display Users"
+                << "\n7. Add Technician"
+                << "\n8. Remove Customer/Technician"
+                << "\n9. Display Services"
+                << "\n10. Create Service"
+                << "\n11. Remove Service"
+                << "\n12. Display Combo Packages"
+                << "\n13. Create Combo Package"
+                << "\n14. Remove Combo Package"
+                << "\n15. View Notifications"
+                << "\n16. Change Password"
+				<< "\n17. Confirm Payment"
+                << "\n18. Logout"
+                << "\nEnter a choice: ";
+            util::read(choice);
+            if (!handleOperation(choice))
+            {
+                break;
+            }
+        }
+        catch (const std::exception& e)
+        {
+            std::cout << "Exception: " << e.what() << std::endl;
+            util::pressEnter();
+        }
+    }
+	stopEventListener();
 }
 
+/*
+Function: handleOperation
+Description: Executes the corresponding admin operation based on the selected menu choice.
+Parameter: int choice - selected menu option
+Return type: bool - true if menu continues, false if logout
+*/
 bool AdminMenu::handleOperation(int choice)
 {
-	return false;
+	if (!m_isMenuActive)
+	{
+		logout();
+		return false;
+	}
+    switch (choice)
+    {
+    case 1:
+        viewStockLevels();
+        break;
+    case 2:
+        addInventoryItem();
+        break;
+    case 3:
+        removeInventoryItem();
+        break;
+    case 4:
+        checkStockAvailability();
+        break;
+    case 5:
+        assignJob();
+        break;
+    case 6:
+        displayUsers();
+        break;
+    case 7:
+        addTechnician();
+        break;
+    case 8:
+        removeUser();
+        break;
+    case 9:
+        displayServices();
+        break;
+    case 10:
+        createService();
+        break;
+    case 11:
+        removeService();
+        break;
+    case 12:
+        displayComboPackages();
+        break;
+    case 13:
+        createComboPackages();
+        break;
+    case 14:
+        removeComboPackage();
+        break;
+    case 15:
+        viewNotifications();
+        break;
+    case 16:
+        changePassword();
+        break;
+	case 17:
+		confirmPayment();
+		break;
+    case 18:
+        logout();
+        return false;
+    default:
+        std::cout << "Enter a valid choice!" << std::endl;
+        util::pressEnter();
+    }
+    return true;
 }
 
+/*
+Function: handleNotificationEvent
+Description: Retrieves and displays the latest notification for the
+			 currently logged in admin.
+Parameter: None
+Return type: void
+*/
+void AdminMenu::handleNotificationEvent()
+{
+	auto notifications = m_controller.getNotifications();
+	const User* authenticatedUser = m_controller.getAuthenticatedUser();
+	std::string name;
+	if (authenticatedUser)
+	{
+		name = authenticatedUser->getName();
+	}
+	displayNewNotification(notifications, name);
+}
 
+/*
+Function: logout
+Description: Logs out the currently authenticated admin user.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::logout()
 {
+	m_controller.logout();
 }
 
+/*
+Function: changePassword
+Description: Allows the admin to change their password after validation.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::changePassword()
 {
+	changePasswordHelper(m_controller);
 }
 
+/*
+Function: viewStockLevels
+Description: Displays all active inventory items with their details
+             including ID, part name, quantity, and price.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::viewStockLevels()
 {
+    util::clear();
+	auto inventoryItems = m_controller.getInventoryItems();
+	bool hasActiveItems = false;
+	std::cout << "View Stock Levels" << std::endl;
+	if (inventoryItems.isEmpty())
+	{
+		std::cout << "No items found in Inventory.\n";
+		util::pressEnter();
+		return;
+	}
+	for (int index = 0; index < inventoryItems.getSize(); index++)
+	{
+		const InventoryItem* item = inventoryItems.getValueAt(index);
+		if (item->getState() == util::State::ACTIVE)
+		{
+			hasActiveItems = true;
+			break;
+		}
+	}
+	if (!hasActiveItems)
+	{
+		std::cout << "No active Inventory Item found.\n";
+		util::pressEnter();
+		return;
+	}
+	std::cout << std::left << std::setw(15) << "Item ID"
+		<< std::setw(25) << "Part Name"
+		<< std::setw(15) << "Quantity"
+		<< std::setw(15) << "Price"
+		<< std::endl;
+	for (int iterator = 0; iterator < inventoryItems.getSize(); ++iterator)
+	{
+		const InventoryItem* item = inventoryItems.getValueAt(iterator);
+		if (item != nullptr)
+		{
+			if (item->getState() != util::State::INACTIVE)
+			{
+				std::cout << std::left << std::setw(15) << item->getId()
+					<< std::setw(25) << item->getPartName()
+					<< std::setw(15) << item->getQuantity()
+					<< std::setw(15) << item->getPrice()
+					<< std::endl;
+			}
+		}
+	}
+	std::cout << "\n";
+	util::pressEnter();
 }
 
+/*
+Function: addInventoryItem
+Description: Allows the admin to either add a new inventory item
+             or increase the quantity of an existing item.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::addInventoryItem()
 {
+	util::clear();
+	int choice, quantity;
+	double price;
+	std::string partName;
+	std::cout << "Add Inventory Item\n";
+	std::cout << "1. Add new item \n2. Restock Item\n\nEnter your choice : ";
+	util::read(choice);
+	switch (choice)
+	{
+	case 1:
+	{
+		util::clear();
+		std::cout << "Enter Item Details\n";
+		std::cout << "Part Name : ";
+		util::read(partName);
+		std::cout << "Quantity : ";
+		util::read(quantity);
+		std::cout << "Price : ";
+		util::read(price);
+		m_controller.addInventoryItem(partName, quantity, price);
+		std::cout << "\nNew Item " << partName << " added to the Inventory.\n\n";
+		break;
+	}
+	case 2:
+	{
+		util::clear();
+		std::cout << "Select Item to Restock\n";
+		auto inventoryItems = m_controller.getInventoryItems();
+		addQuantityToItem(inventoryItems, m_controller);
+		break;
+	}
+	default:
+	{
+		std::cout << "\nEnter a valid choice.\n\n";
+	}
+	}
+	util::pressEnter();
 }
 
+/*
+Function: removeInventoryItem
+Description: Removes an active inventory item by marking it inactive
+             after user selection.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::removeInventoryItem()
 {
+    util::clear();
+	std::cout << "Remove Inventory Item\n";
+    auto inventoryItems = m_controller.getInventoryItems();
+    auto activeItems = filterActiveItems(inventoryItems);
+    int activeItemsSize = activeItems.getSize();
+    if (activeItemsSize == 0)
+    {
+        std::cout << "No items available in Inventory." << std::endl;
+        util::pressEnter();
+        return;
+    }
+    displayInventoryWithItems(activeItems);
+    int itemIndex;
+    std::cout << "Enter the index of the item to remove: ";
+    util::read(itemIndex);
+    if (itemIndex < 1 || itemIndex > activeItemsSize)
+    {
+        std::cout << "Invalid index selected." << std::endl;
+        util::pressEnter();
+        return;
+    }
+    const InventoryItem* selectedItem = activeItems.getValueAt(itemIndex - 1);
+    if (selectedItem != nullptr)
+    {
+        if(selectedItem->getState() != util::State::INACTIVE)
+        {
+            std::string selectedItemId = selectedItem->getId();
+            m_controller.removeInventoryItem(selectedItemId);
+            std::cout << "Item " << selectedItem->getPartName() << " removed successfully." << std::endl;
+			const util::Map<std::string, const Service*>& listOfService = m_controller.getServices();
+			for (int serviceIndex = 0; serviceIndex < listOfService.getSize(); serviceIndex++)
+			{
+				const Service* service = listOfService.getValueAt(serviceIndex);
+				if (!service)
+				{
+					continue;
+				}
+				const util::Map<std::string, InventoryItem*>& requiredItems = service->getRequiredInventoryItems();
+				if (requiredItems.find(selectedItemId) != -1) 
+				{
+					m_controller.removeService(service->getId()); 
+					std::cout << "Service " << service->getName()
+						<< " removed as the item "
+						<< selectedItem->getPartName() << " required for the service has been removed." << std::endl;
+				}
+			}
+        }
+    }
+    util::pressEnter();
 }
 
+/*
+Function: checkStockAvailability
+Description: Checks if a specific inventory item is available
+             and displays its details if active.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::checkStockAvailability()
 {
+	util::clear();
+	std::string itemId;
+	std::cout << "Check Stock Availability \n";
+	std::cout << "Enter the Item ID : ";
+	util::read(itemId);
+	util::clear();
+	const InventoryItem* selectedItem = m_controller.getInventoryItem(itemId);
+	if (selectedItem != nullptr)
+	{
+		if (selectedItem->getState() != util::State::INACTIVE)
+		{
+			std::cout << "Item Details\n";
+			std::cout << "---------------------------------------------\n";
+			std::cout << "Item ID      : " << selectedItem->getId() << "\n";
+			std::cout << "Part Name    : " << selectedItem->getPartName() << "\n";
+			std::cout << "Quantity     : " << selectedItem->getQuantity() << "\n";
+		}
+	}
+	else
+	{
+		std::cout << "Item not Found" << std::endl;
+	}
+	util::pressEnter();
 }
 
+/*
+Function: assignJob
+Description: Allows the admin to assign pending service bookings to available technicians.
+			 Creates job cards for selected services.
+Parameters:
+	- None
+Returns:
+	- void
+*/
 void AdminMenu::assignJob()
 {
+	util::clear();
+	std::cout << "Assign Job to Technician\n";
+	std::string selectedService;
+	bool hasPendingService = false;
+	auto currentBookings = m_controller.getServiceBookings();
+	auto pendingServiceBookings = filterActiveServiceBookings(currentBookings);
+	auto availableTechnicians = m_controller.getUsers(util::UserType::TECHNICIAN);
+	int bookingsSize = pendingServiceBookings.getSize();
+	util::Map<int, const ServiceBooking*> serviceBookingsMap;
+	util::Map<int, const User*> currentAvailableTechniciansMap;
+	if (listServiceBookings(pendingServiceBookings, bookingsSize, serviceBookingsMap))
+	{
+		const ServiceBooking* selectedService = selectPendingServiceBookings(serviceBookingsMap);
+		if (selectedService)
+		{
+			if (availableTechnicians.getSize() != 0)
+			{
+				listAvailableTechnicians(availableTechnicians, availableTechnicians.getSize(), currentAvailableTechniciansMap);
+				const User* selectedTechnician = selectTechnician(currentAvailableTechniciansMap);
+				if (selectedTechnician)
+				{
+					auto& servicesInBooking = selectedService->getServices();
+					for (int iterator = 0; iterator < servicesInBooking.getSize(); iterator++)
+					{
+						m_controller.createJobCard(selectedService->getId(), selectedTechnician->getId(), servicesInBooking.getValueAt(iterator)->getId());
+					}
+					std::cout << "Job card created for each service and technician successfully assigned.\n\n";
+				}
+			}
+			else
+			{
+				std::cout << "No technicians are currently available.\n\n";
+			}
+		}
+	}
+	else
+	{
+		std::cout << "No pending service bookings available.\n\n";
+	}
+	util::pressEnter();
 }
 
+/*
+Function: displayServices()
+Description: Display all active services
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void AdminMenu::displayServices()
+{
+	util::clear();
+	std::cout << "List of all Services\n";
+	util::Map<std::string, const Service*> currentServices = m_controller.getServices();
+	util::Map<std::string, const Service*> currentActiveServices = filterActiveServices(currentServices);
+	displayAllServices(currentActiveServices);
+	util::pressEnter();
+}
+
+/*
+Function: createService
+Description: Allows the admin to create a new service by selecting inventory items and specifying labor cost.
+Parameters:
+	- None
+Returns:
+	- void
+*/
 void AdminMenu::createService()
 {
+	util::clear();
+	std::cout << "Create Service\n";
+	std::string serviceName;
+	double labourCost;
+	std::cout << "Enter the service name: ";
+	util::read(serviceName);
+	util::Map<std::string, const InventoryItem*> currentInventoryItems = m_controller.getInventoryItems();
+	util::Map<std::string, const InventoryItem*> activeInventoryItems = filterActiveItems(currentInventoryItems);
+	util::Vector<std::string> selectedInventoryItems;
+	selectInventoryItems(activeInventoryItems,selectedInventoryItems);
+	if (selectedInventoryItems.isEmpty())
+	{
+		util::pressEnter();
+		return;
+	}
+	std::cout << "\nEnter the labour cost: ";
+	util::read(labourCost);
+    m_controller.createService(serviceName, selectedInventoryItems, labourCost);
+    std::cout << "\nService created sucessfully.\n\n";
+	util::pressEnter();
 }
 
+/*
+Function: removeService
+Description: Allows the admin to remove an existing service by selecting from available services.
+Parameters:
+	- None
+Returns:
+	- void
+*/
 void AdminMenu::removeService()
 {
+	util::clear();
+	std::cout << "Remove Service\n";
+	std::string selectedServiceID;
+	util::Map<std::string, const Service*> currentServices = m_controller.getServices();
+	util::Map<std::string, const Service*> currentActiveServices = filterActiveServices(currentServices);
+	selectedServiceID = selectServicesToRemove(currentActiveServices);
+	if (selectedServiceID != "")
+	{
+		m_controller.removeService(selectedServiceID);
+		std::cout << "Service removed successfully.\n\n";
+	}
+	else
+	{
+		std::cout << "Failed  to remove service.\n\n";
+	}
+	util::pressEnter();
 }
 
+/*
+Function: displayUsers
+Description: Displays all users.
+Parameter: None
+Return type: void
+*/
+void AdminMenu::displayUsers()
+{
+	util::clear();
+	auto listOfUsers = m_controller.getUsers();
+	auto listOfActiveUsers = filterActiveUsers(listOfUsers);
+	int activeUserCount = listOfActiveUsers.getSize();
+	std::cout << "List of all Users\n";
+	if (activeUserCount < 1)
+	{
+		std::cout << "No Active users." << std::endl;
+		util::pressEnter();
+		return;
+	}
+	displayAllUsers(listOfActiveUsers);
+	util::pressEnter();
+}
+
+/*
+Function: confirmPayment
+Description: Confirms payment for a selected invoice. Validates invoice status, updates payment date,
+			 sets status to COMPLETED, and sends a notification to the customer.
+Parameters:
+	- invoiceID: std::string, ID of the invoice to confirm
+Returns:
+	- void
+*/
+void AdminMenu::confirmPayment()
+{
+	util::clear();
+	std::cout << "Confirm Payment\n";
+	auto invoiceList = m_controller.getAllInvoices();
+	if (invoiceList.isEmpty())
+	{
+		std::cout << "No pending invoices available for confirmation.";
+		util::pressEnter();
+		return;
+	}
+	bool hasConfirmableInvoice = false;
+	for (int index = 0; index < invoiceList.getSize(); ++index)
+	{
+		const Invoice* invoice = invoiceList.getValueAt(index);
+		if (invoice && invoice->getStatus() == util::PaymentStatus::PAID)
+		{
+			hasConfirmableInvoice = true;
+			break;
+		}
+	}
+	if (!hasConfirmableInvoice)
+	{
+		std::cout << "No invoices awaiting confirmation.\n";
+		util::pressEnter();
+		return;
+	}
+	std::string selectedID = selectInvoiceFromUserForPayment(invoiceList, util::PaymentStatus::PAID);
+	if (selectedID == "")
+	{
+		std::cout << "Payment failed.\n";
+		util::pressEnter();
+		return;
+	}
+	m_controller.confirmPayment(selectedID);
+	std::cout << "Payment Confirmed successfully.\n";
+	util::pressEnter();
+}
+
+/*
+Function: addTechnician
+Description: Adds a new technician after validating username, password, email, and phone number.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::addTechnician()
 {
+	util::clear();
+	std::string username, name, password, email, phoneNumber;
+	std::cout << "Add Technician\n";
+	std::cout << "Enter Technician Username: ";
+	util::read(username);
+	std::cout << "Enter Technician Name: ";
+	util::read(name);
+	std::cout << "Enter Technician Password: ";
+	util::read(password);
+	if(!util::isPasswordValid(password))
+	{
+		std::cout << "\nError: Password is invalid!\n\n";
+		util::pressEnter();
+		return;
+	}
+	std::cout << "Enter Technician Email: ";
+	util::read(email);
+	if(!util::isEmailValid(email))
+	{
+		std::cout << "\nError: Email is invalid!\n\n";
+		util::pressEnter();
+		return;
+	}
+	std::cout << "Enter Technician Phone: ";
+	util::read(phoneNumber);
+	if(!util::isPhoneNumberValid(phoneNumber))
+	{
+		std::cout << "\nError: Phone Number is invalid!\n\n";
+		util::pressEnter();
+		return;
+	}
+	m_controller.createTechnician(username, name, password, email, phoneNumber);
+	std::cout << "\nTechnician Added Successfully.\n\n";
+	util::pressEnter();
 }
 
+/*
+Function: removeUser
+Description: Removes a selected active user (customer or technician) from the system.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::removeUser()
 {
+	util::clear();
+	int indexChoice;
+	auto listOfUsers = m_controller.getUsers();
+	auto listOfActiveUsers = filterActiveUsers(listOfUsers);
+	int activeUserCount = listOfActiveUsers.getSize();
+	std::cout << "Remove User \n";
+	if (activeUserCount < 1)
+	{
+		std::cout << "No Active users." << std::endl;
+		util::pressEnter();
+		return;
+	}
+	displayAllUsers(listOfActiveUsers);
+	std::cout << "Enter the index of the user to delete : ";
+	util::read(indexChoice);
+	if (indexChoice < 1 || indexChoice > activeUserCount)
+	{
+		std::cout << "Error invalid index.\n" << std::endl;
+		util::pressEnter();
+		return;
+	}
+	const User* userToRemove = listOfActiveUsers.getValueAt(indexChoice - 1);
+	if (userToRemove != nullptr)
+	{
+		std::string userIdToRemove = userToRemove->getId();
+		m_controller.removeUser(userIdToRemove);
+		std::cout << userToRemove->getUserName() << " removed Successfully.\n";
+	}
+	util::pressEnter();
 }
 
+/*
+Function: displayComboPackages()
+Description: Display all active combo packages
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void AdminMenu::displayComboPackages()
+{
+	util::clear();
+	std::cout << "List of all Combo Packages\n";
+	util::Map<std::string, const ComboPackage*> currentComboPackages = m_controller.getComboPackages();
+	util::Map<std::string, const ComboPackage*> currentActiveComboPackages = filterComboPackages(currentComboPackages);
+	displayAllComboPackages(currentActiveComboPackages);
+	util::pressEnter();
+}
+
+/*
+Function: createComboPackages
+Description: Creates a new combo package by selecting two active services and applying a discount.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::createComboPackages()
 {
+	util::clear();
+	std::cout << "Create Combo Packages\n";
+	auto serviceList = m_controller.getServices();
+	auto activeServices = filterActiveServices(serviceList);
+	int currentActiveServicesCount = activeServices.getSize();
+    const int NUMBER_OF_SERVICE_PER_PACKAGE = 2;
+	util::Vector<std::string> selectedServiceID;
+    for (int iterator = 0; iterator < NUMBER_OF_SERVICE_PER_PACKAGE; iterator++)
+    {
+        const Service* chosenService = nullptr;
+        while (true)
+        {
+            chosenService = selectServiceFromServices(activeServices);
+            if (!chosenService)
+            {
+                std::cout << "Failed to create combo package!\n\n";
+                util::pressEnter();
+                return;
+            }
+            bool alreadyChosen = false;
+            for (int iteratorOne = 0; iteratorOne < selectedServiceID.getSize(); iteratorOne++)
+            {
+                if (selectedServiceID[iteratorOne] == chosenService->getId())
+                {
+                    alreadyChosen = true;
+                    break;
+                }
+            }
+            if (alreadyChosen)
+            {
+				if (currentActiveServicesCount < 2)
+				{
+					break;
+				}
+                std::cout << "Service already selected. Please choose a different one." << std::endl;
+                continue; 
+            }
+            selectedServiceID.push_back(chosenService->getId());
+            break;
+        }
+		if (currentActiveServicesCount < 2)
+		{
+			std::cout << "All the available services selected\n\n";
+			break;
+		}
+    }
+    std::string packageName;
+    double discountPercentage;
+    std::cout << "Enter combo package name: ";
+    util::read(packageName);
+    std::cout << "Enter discount percentage: ";
+    util::read(discountPercentage);
+    if (discountPercentage < 0.0 || discountPercentage > 100.0)
+    {
+        std::cout << "Error: Discount percentage must be between 0 and 100." << std::endl;
+        util::pressEnter();
+        return;
+    }
+    m_controller.createComboPackage(packageName, selectedServiceID, discountPercentage);
+    std::cout << "Combo package '" << packageName << "' created successfully." << std::endl;
+    util::pressEnter();
 }
 
+/*
+Function: removeComboPackage
+Description: Removes a selected combo package from the system.
+Parameter: None
+Return type: void
+*/
 void AdminMenu::removeComboPackage()
 {
+	util::clear();
+	std::cout << "Remove Combo Package\n";
+	util::Map<std::string, const ComboPackage*> currentComboPackages = m_controller.getComboPackages();
+	std::string selectedComboPackageID = selectComboPackage(currentComboPackages);
+	if (!selectedComboPackageID.empty())
+	{
+		m_controller.removeComboPackage(selectedComboPackageID);
+		std::cout << "Combo Package removed successfully.\n\n";
+	}
+	else
+	{
+		std::cout << "Combo package removal failed.\n\n";
+	}
+	util::pressEnter();
 }
 
+/*
+Function: viewNotifications
+Description: Displays notifications for the admin and allows deletion of notifications.
+Parameters:
+	- None
+Returns:
+	- void
+*/
 void AdminMenu::viewNotifications()
 {
+	viewAndDeleteNotification(m_controller);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.h

@@ -1,11 +1,21 @@
+/*
+File: AdminMenu.h
+Description: Header file declaring the AdminMenu class, which provides
+             administrative operations such as inventory management,
+             user management, service configuration, and notifications.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include "Controller.h"
+#include "Menu.h"
 
-class AdminMenu
+class AdminMenu : public Menu
 {
 private:
-    Controller m_controller;
     bool handleOperation(int choice);
+    void handleNotificationEvent() override;
 public:
     void showMenu();
     void logout();
@@ -15,10 +25,14 @@ public:
     void removeInventoryItem();
     void checkStockAvailability();
     void assignJob();
+    void displayServices();
     void createService();
     void removeService();
+    void displayUsers();
+    void confirmPayment();
     void addTechnician();
     void removeUser();
+    void displayComboPackages();
     void createComboPackages();
     void removeComboPackage();
     void viewNotifications();

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp

@@ -1,159 +1,394 @@
+/*
+File: CustomerMenu.cpp
+Description: Implementation file containing the method definitions of the
+             CustomerMenu class, including menu handling, service selection,
+             combo package booking, profile updates, and password management.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #include <iomanip>
-#include <iostream>
+#include "ComboPackage.h"
 #include "CustomerMenu.h"
+#include "MenuHelper.h"
+#include "Enums.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
-#include "Invoice.h"
-#include "Enums.h"
-#include "ServiceBooking.h"
-#include "User.h"
-#include "Timestamp.h"
-#include "Service.h"
 #include "InventoryItem.h"
+#include "Invoice.h"
+#include "Map.h"
+#include "Service.h"
+#include "ServiceBooking.h"
+#include "Timestamp.h"
+#include "User.h"
+#include "Validator.h"
+#include "Vector.h"
 
+/*
+Function: showMenu
+Description: Displays the customer menu and handles user input until logout is selected.
+Parameter: None
+Return type: void
+*/
 void CustomerMenu::showMenu()
 {
-	bool isMenuActive = true;
-	while (isMenuActive)
-	{
-		try
-		{
-			int choice;
-			util::clear();
-			std::cout << "" << std::endl;
-			util::read(choice);
-			if (!handleOperation(choice))
-			{
-				isMenuActive = false;
-			}
-		}
-		catch (const std::exception& e)
-		{
-			std::cout << "Exception: " << e.what() << std::endl;
-			util::pressEnter();
-		}
-	}
-}
 
-bool CustomerMenu::handleOperation(int choice)
-{
-	return false;
-}
-
-void CustomerMenu::logout()
-{
-}
-
-void CustomerMenu::changePassword()
-{
-}
-
-void CustomerMenu::updateDetails()
-{
-}
-
-void CustomerMenu::selectService()
-{
-}
-
-void CustomerMenu::selectComboPackage()
-{
-}
-
-void CustomerMenu::viewServiceHistory()
-{
-}
-
-/*
-Function: selectInvoiceFromUserForPayment (static helper)
-Description: Lists all pending invoices for the customer and allows selection by index.
-Parameters:
-    - currentInvoices: util::Map<std::string, const Invoice*>&, map of customer invoices
-Returns:
-    - std::string: ID of the selected invoice, or empty string if none selected
-*/
-static std::string selectInvoiceFromUserForPayment(const util::Map<std::string, const Invoice*>& currentInvoices)
-{
-    int currentIndex = 1, choice;
-    util::Map<int, const Invoice*> pendingInvoicesForPayment;
-    std::cout << std::left
-        << std::setw(6) << "Index"
-        << std::setw(12) << "BookingID"
-        << std::setw(15) << "VehicleBrand"
-        << std::setw(15) << "VehicleNumber"
-        << std::setw(12) << "TechID"
-        << std::setw(20) << "TechnicianName"
-        << std::setw(10) << "Discount(%)"
-        << std::setw(12) << "TotalAmount"
-        << std::setw(20) << "InvoiceDate"
-        << std::endl;
-    for (int iterator = 0; iterator < currentInvoices.getSize(); iterator++)
+    startEventListener();
+    while (true)
     {
-        const Invoice* currentInvoice = currentInvoices.getValueAt(iterator);
-        if (currentInvoice && currentInvoice->getStatus() == util::PaymentStatus::PENDING)
+        try
         {
-            std::cout << std::left
-                << std::setw(6) << currentIndex
-                << std::setw(12) << currentInvoice->getBookingId()
-                << std::setw(15) << currentInvoice->getBooking()->getVehicleBrand()
-                << std::setw(15) << currentInvoice->getBooking()->getVehicleNumber()
-                << std::setw(12) << currentInvoice->getBooking()->getAssignedTechnician()->getId()
-                << std::setw(20) << currentInvoice->getBooking()->getAssignedTechnician()->getName()
-                << std::setw(10) << currentInvoice->getDiscountPercentage()
-                << std::setw(12) << currentInvoice->getTotalAmount()
-                << std::setw(20) << currentInvoice->getInvoiceDate().toString()
-                << std::endl;
-            pendingInvoicesForPayment.insert(currentIndex++, currentInvoice);
+            if (!m_isMenuActive)
+            {
+                logout();
+                break;
+            }
+            int choice;
+            util::clear();
+            std::cout << "Customer Menu"
+                << "\n1. Select a service"
+                << "\n2. Select a combo package"
+                << "\n3. Update Profile"
+                << "\n4. Change Password"
+                << "\n5. View Service History"
+                << "\n6. Cancel Service Booking"
+                << "\n7. Complete Payments"
+                << "\n8. View Invoices"
+                << "\n9. View Notifications"
+                << "\n10. Configure Notifications"
+                << "\n11. Logout"
+                << "\nEnter a choice: ";
+            util::read(choice);
+            if (!handleOperation(choice))
+            {
+                break;
+            }
+        }
+        catch (const std::exception& e)
+        {
+            std::cout << "Exception: " << e.what() << std::endl;
+            util::pressEnter();
         }
     }
-    if (pendingInvoicesForPayment.getSize() == 0)
-    {
-        std::cout << "No pending invoices available for payment.\n";
-        return "";
-    }
-    std::cout << "Select the Invoice to pay (Index): ";
-    util::read(choice);
-    int selectedIndex = pendingInvoicesForPayment.find(choice);
-    if (selectedIndex != -1)
-    {
-        const Invoice* selectedInvoice = pendingInvoicesForPayment.getValueAt(selectedIndex);
-        return selectedInvoice->getId();
-    }
-    else
-    {
-        std::cout << "Invalid choice.\n";
-        return "";
-    }
+    stopEventListener();
 }
 
 /*
-Function: selectPaymentMode (static helper)
-Description: Allows the customer to select a payment mode (ONLINE or OFFLINE).
+Function: handleOperation
+Description: Executes the corresponding customer operation based on the selected menu choice.
+Parameter: int choice - selected menu option
+Return type: bool - true if menu continues, false if logout
+*/
+bool CustomerMenu::handleOperation(int choice)
+{
+    if (!m_isMenuActive)
+    {
+        logout();
+        return false;
+    }
+    switch (choice)
+    {
+    case 1:
+        selectService();
+        break;
+    case 2:
+        selectComboPackage();
+        break;
+    case 3:
+        updateDetails();
+        break;
+    case 4:
+        changePassword();
+        break;
+    case 5:
+        viewServiceHistory();
+        break;
+    case 6:
+        cancelServiceBooking();
+        break;
+    case 7:
+        completePayments();
+        break;
+    case 8:
+        viewInvoices();
+        break;
+    case 9:
+        viewNotifications();
+        break;
+    case 10:
+        configureNotifications();
+        break;
+    case 11:
+        logout();
+        return false;
+    default:
+        std::cout << "Enter a valid choice!" << std::endl;
+        util::pressEnter();
+    }
+    return true;
+}
+
+/*
+Function: handleNotificationEvent
+Description: Retrieves and displays the latest notification for the
+             currently logged in admin.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::handleNotificationEvent()
+{
+    auto notifications = m_controller.getNotifications();
+    const User* authenticatedUser = m_controller.getAuthenticatedUser();
+    std::string name;
+    if (authenticatedUser)
+    {
+        name = authenticatedUser->getName();
+    }
+    displayNewNotification(notifications, name);
+}
+
+/*
+Function: logout
+Description: Logs out the currently authenticated customer user.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::logout()
+{
+	m_controller.logout();
+}
+
+/*
+Function: changePassword
+Description: Allows the customer to change their password after validation.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::changePassword()
+{
+    changePasswordHelper(m_controller);
+}
+
+/*
+Function: updateDetails
+Description: Allows the customer to update their email and phone number after validation.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::updateDetails()
+{
+	std::string email, phone;
+	util::clear();
+    std::cout << "Update Details\n";
+	std::cout << "Enter new email: ";
+	util::read(email);
+	if (!util::isEmailValid(email))
+	{
+		std::cout << "Error: Email is invalid!\n";
+		util::pressEnter();
+		return;
+	}
+	std::cout << "Enter new phone: ";
+	util::read(phone);
+	if (!util::isPhoneNumberValid(phone))
+	{
+		std::cout << "Error: Phone number is invalid!\n";
+		util::pressEnter();
+		return;
+	}
+	m_controller.updateUserDetails(email, phone);
+	std::cout << "Profile details updated successfully\n";
+	util::pressEnter();
+}
+
+/*
+Function: selectService
+Description: Allows the customer to select a service, provide vehicle details,
+             and book the service through the controller.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::selectService()
+{
+    std::string vehicleNumber, vehicleBrand, vehicleModel;
+    util::clear();
+    std::cout << "Select a Service\n";
+	auto services = m_controller.getServices();
+    if (services.isEmpty())
+    {
+        std::cout << "No services available!";
+        util::pressEnter();
+        return;
+    }
+    if (!verifyAllPaymentsCompleted(m_controller))
+    {
+        std::cout << "Your booking cannot be processed because you have pending payments for previous services. Please complete all outstanding invoices before booking a new service."
+             << std::endl;
+        util::pressEnter();
+        return;
+    }
+    util::Vector<std::string> selectedServices;
+    const Service* selectedService = selectServiceFromServices(services);
+    if (selectedService == nullptr)
+    {
+        std::cout << "Failed to book service!";
+        util::pressEnter();
+        return;
+    }
+    selectedServices.push_back(selectedService->getId());
+    util::clear();
+    std::cout << "Enter Vehicle Details\n";
+    std::cout << "Enter vehicle number: ";
+    util::read(vehicleNumber);
+    std::cout << "Enter vehicle brand: ";
+    util::read(vehicleBrand);
+    std::cout << "Enter vehicle model: ";
+    util::read(vehicleModel);
+    m_controller.purchaseService(selectedServices, vehicleNumber, vehicleBrand, vehicleModel);
+    std::cout << "Service has been booked successfully";
+    util::pressEnter();
+}
+
+/*
+Function: selectComboPackage
+Description: Allows the customer to select a combo package, provide vehicle details,
+             and book the package through the controller.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::selectComboPackage()
+{
+    std::string vehicleNumber, vehicleBrand, vehicleModel;
+    util::clear();
+    std::cout << "Select a Combo Package\n";
+    auto comboPackages = m_controller.getComboPackages();
+    util::Map<std::string, const ComboPackage*> activeComboPackages = filterComboPackages(comboPackages);
+    if (activeComboPackages.isEmpty())
+    {
+        std::cout << "No combo packages available!\n\n";
+        util::pressEnter();
+        return;
+    }
+    if (!verifyAllPaymentsCompleted(m_controller))
+    {
+        std::cout << "Your booking cannot be processed because you have pending payments for previous services. Please complete all outstanding invoices before booking a new combo package."
+            << std::endl;
+        util::pressEnter();
+        return;
+    }
+    const ComboPackage* selectedComboPackage = selectComboPackageFromPackages(activeComboPackages);
+    if (selectedComboPackage == nullptr)
+    {
+        std::cout << "Failed to book combo package!\n\n";
+        util::pressEnter();
+        return;
+    }
+    std::cout << "Combo Package selected\n";
+    util::pressEnter();
+    util::clear();
+    std::cout << "Enter the vehicle details\n";
+    std::cout << "Enter vehicle number: ";
+    util::read(vehicleNumber);
+    std::cout << "Enter vehicle brand: ";
+    util::read(vehicleBrand);
+    std::cout << "Enter vehicle model: ";
+    util::read(vehicleModel);
+    m_controller.purchaseComboPackage(selectedComboPackage->getId(), vehicleNumber, vehicleBrand, vehicleModel);
+    std::cout << "Combo Package has been booked successfully\n\n";
+    util::pressEnter();
+}
+
+/*
+Function: viewServiceHistory
+Description: Displays the customer’s past service bookings in tabular format,
+             including booking ID, technician, vehicle details, discount percentage, and status.
 Parameters:
     - None
 Returns:
-    - util::PaymentMode: Selected payment mode
+    - void
 */
-static util::PaymentMode selectPaymentMode()
+void CustomerMenu::viewServiceHistory()
 {
-    int choice;
-    std::cout << "Enter the payment Mode\n1.OFFLINE\n2.ONLINE\nChoice: ";
-    util::read(choice);
-    if (choice == 1)
+	util::clear();
+	bool hasServiceHistory = false;
+	const User* currentUser = m_controller.getAuthenticatedUser();
+	std::string currentUserID = currentUser->getId();
+	util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
+    std::cout << "View Service History" << std::endl;
+    if (serviceBookingsByCurrentUser.getSize() != 0)
     {
-        std::cout << "Offline mode selected.\n";
-        return util::PaymentMode::OFFLINE;
+        std::cout << std::left
+            << std::setw(15) << "Booking ID"
+            << std::setw(20) << "Technician"
+            << std::setw(20) << "Vehicle Brand"
+            << std::setw(20) << "Vehicle Number"
+            << std::setw(20) << "Vehicle Model"
+            << std::setw(20) << "Discount %"
+            << std::setw(20) << "Status"
+            << std::endl;
+        for (int iterator = 0; iterator < serviceBookingsByCurrentUser.getSize(); iterator++)
+        {
+            const ServiceBooking* currentBooking = serviceBookingsByCurrentUser.getValueAt(iterator);
+            std::string technicianName = currentBooking->getAssignedTechnician() == nullptr
+                ? "Not Assigned"
+                : currentBooking->getAssignedTechnician()->getName();
+            std::cout << std::left
+                << std::setw(15) << currentBooking->getId()
+                << std::setw(20) << technicianName
+                << std::setw(20) << currentBooking->getVehicleBrand()
+                << std::setw(20) << currentBooking->getVehicleNumber()
+                << std::setw(20) << currentBooking->getVehicleModel()
+                << std::setw(20) << currentBooking->getDiscountPercentage()
+                << std::setw(20) << util::getServiceJobStatusString(currentBooking->getStatus())
+                << std::endl;
+            hasServiceHistory = true;
+        }
     }
-    else if (choice == 2)
+    if (!hasServiceHistory)
     {
-        std::cout << "Online mode selected.\n";
-        return util::PaymentMode::ONLINE;
+        std::cout << "No history available." << std::endl;
+    }
+    util::pressEnter();
+}
+
+/*
+Function: cancelServiceBooking
+Description: Allows the customer to cancel a pending service booking.
+             Displays the list of active bookings, lets the user select one,
+             and removes it from the system. If no bookings are available,
+             an appropriate message is shown.
+Parameter: None
+Return type: void
+*/
+void CustomerMenu::cancelServiceBooking()
+{
+    util::clear();
+    std::cout << "Cancel Service Booking\n";
+    const User* currentUser = m_controller.getAuthenticatedUser();
+    std::string currentUserID = currentUser->getId();
+    util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
+    util::Map<int, const ServiceBooking*> serviceBookingsMap;
+    auto currentPendingServiceBookings = filterActiveServiceBookings(serviceBookingsByCurrentUser);
+    int bookingsSize = currentPendingServiceBookings.getSize();
+    if (listServiceBookings(currentPendingServiceBookings, bookingsSize, serviceBookingsMap))
+    {
+        const ServiceBooking* selectedService = selectPendingServiceBookings(serviceBookingsMap);
+        if (selectedService)
+        {
+            m_controller.removeServiceBooking(selectedService->getId());
+            std::cout << "Cancelled Service booking of id " + selectedService->getId() << std::endl << std::endl;
+        }
+        else
+        {
+            std::cout << "Invalid service booking index.\n\n";
+            return;
+        }
     }
     else
     {
-        std::cout << "Invalid choice, Offline mode selected.\n";
-        return util::PaymentMode::OFFLINE;
+        std::cout << "No pending service bookings available.\n\n";
     }
+    util::pressEnter();
 }
 
 /*
@@ -168,78 +403,41 @@ Returns:
 void CustomerMenu::completePayments()
 {
 	util::clear();
+    std::cout << "Complete Payments\n";
 	util::Map<std::string, const Invoice*> currentInvoices = m_controller.getInvoicesByUser();
-	std::string selectedID = selectInvoiceFromUserForPayment(currentInvoices);
+    if (currentInvoices.isEmpty())
+    {
+        std::cout << "No pending invoices available for payment.\n";
+        util::pressEnter();
+        return;
+    }
+    bool hasPending = false;
+    for (int index = 0; index < currentInvoices.getSize(); ++index)
+    {
+        const Invoice* invoice = currentInvoices.getValueAt(index);
+        if (invoice && invoice->getStatus() == util::PaymentStatus::PENDING)
+        {
+            hasPending = true;
+            break;
+        }
+    }
+    if (!hasPending)
+    {
+        std::cout << "No pending invoices available for payment.\n";
+        util::pressEnter();
+        return;
+    }
+	std::string selectedID = selectInvoiceFromUserForPayment(currentInvoices, util::PaymentStatus::PENDING);
     if (selectedID == "")
     {
         std::cout << "Payment failed.\n";
+        util::pressEnter();
         return;
     }
     util::PaymentMode paymentMode = selectPaymentMode();
     m_controller.completePayment(selectedID, paymentMode);
     std::cout << "Payment completed successfully.\n";
-}
-
-/*
-Function: displayInvoices (static helper)
-Description: Displays detailed information for all invoices associated with the customer,
-             including booking details, technician, discount, total amount, payment status, and items used.
-Parameters:
-    - currentUserInvoices: util::Map<std::string, const Invoice*>, customer’s invoices
-Returns:
-    - void
-Throws:
-    - std::runtime_error if a null invoice is encountered
-*/
-static void displayInvoices(util::Map<std::string, const Invoice*> currentUserInvoices)
-{
-	if (currentUserInvoices.getSize() == 0)
-	{
-		std::cout << "No invoices found for this account." << std::endl;
-		util::pressEnter();
-		return;
-	}
-	else
-	{
-        for (int index = 0; index < currentUserInvoices.getSize(); index++)
-        {
-            const Invoice* currentInvoice = currentUserInvoices.getValueAt(index);
-            if (currentInvoice)
-            {
-                std::cout << "\nInvoice Details\n";
-                std::cout << "Booking ID: " << currentInvoice->getBookingId() << std::endl;
-                std::cout << "Vehicle Brand: " << currentInvoice->getBooking()->getVehicleBrand() << std::endl;
-                std::cout << "Vehicle Number: " << currentInvoice->getBooking()->getVehicleNumber() << std::endl;
-                std::cout << "Technician ID: " << currentInvoice->getBooking()->getAssignedTechnician()->getId() << std::endl;
-                std::cout << "Technician Name: " << currentInvoice->getBooking()->getAssignedTechnician()->getName() << std::endl;
-                std::cout << "Discount(%): " << currentInvoice->getDiscountPercentage() << std::endl;
-                std::cout << "Total Amount: " << currentInvoice->getTotalAmount() << std::endl;
-                std::cout << "Invoice Date: " << currentInvoice->getInvoiceDate().toString() << std::endl;
-                std::cout << "Payment Status: " << util::getPaymentStatusString(currentInvoice->getStatus()) << std::endl;
-                auto inventoryItemsInInvoice = currentInvoice->getParts();
-                std::cout << "\nItems Used:\n";
-                std::cout << std::left
-                    << std::setw(20) << "ItemName"
-                    << std::setw(10) << "Quantity"
-                    << std::setw(10) << "Price"
-                    << std::endl;
-                std::cout << std::string(40, '-') << std::endl;
-                for (int iterator = 0; iterator < inventoryItemsInInvoice.getSize(); iterator++)
-                {
-                    InventoryItem* currentItem = inventoryItemsInInvoice.getValueAt(iterator);
-                    std::cout << std::left
-                        << std::setw(20) << currentItem->getPartName()
-                        << std::setw(10) << currentItem->getQuantity()
-                        << std::setw(10) << currentItem->getPrice()
-                        << std::endl;
-                }
-            }
-            else
-            {
-                throw std::runtime_error("Null invoice encountered while displaying invoices.");
-            }
-        }
-	}
+    util::pressEnter();
 }
 
 /*
@@ -253,14 +451,40 @@ Returns:
 void CustomerMenu::viewInvoices()
 {
 	util::clear();
+    std::cout << "View Invoices\n";
 	util::Map<std::string, const Invoice*> currentUserInvoices = m_controller.getInvoicesByUser();
 	displayInvoices(currentUserInvoices);
+    util::pressEnter();
 }
 
+/*
+Function: viewNotifications
+Description: Displays notifications for the customer and allows deletion of notifications.
+Parameters:
+    - None
+Returns:
+    - void
+*/
 void CustomerMenu::viewNotifications()
 {
+	viewAndDeleteNotification(m_controller);
 }
 
+
+/*
+Function: configureNotifications
+Description: Allows the customer to configure notification preferences for payment and service management.
+Parameters:
+    - None
+Returns:
+    - void
+*/
 void CustomerMenu::configureNotifications()
 {
-}
+    bool paymentServiceNotifications = getNotificationPreference("Payment Management Service");
+    bool serviceManagementNotifications = getNotificationPreference("Service Management Service");
+    m_controller.configureNotifications(paymentServiceNotifications, serviceManagementNotifications);
+    util::clear();
+    std::cout << "Notification preferences updated successfully.\n";
+    util::pressEnter();
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.h

@@ -1,11 +1,22 @@
+/*
+File: CustomerMenu.h
+Description: Header file declaring the CustomerMenu class, which provides
+             customer operations such as selecting services, booking combo
+             packages, updating profile details, managing payments, viewing
+             invoices, and configuring notifications.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
+#include "Menu.h"
 #include "Controller.h"
 
-class CustomerMenu
+class CustomerMenu : public Menu
 {
 private:
-    Controller m_controller;
     bool handleOperation(int choice);
+    void handleNotificationEvent();
 public:
     void showMenu();
     void logout();
@@ -17,5 +28,6 @@ public:
     void completePayments();
     void viewInvoices();
     void viewNotifications();
+    void cancelServiceBooking();
     void configureNotifications();
-};
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/Menu.cpp

@@ -0,0 +1,150 @@
+/*
+File: Menu.cpp
+Description: Implementation file containing common menu event listener
+             functionality, account disable handling, and notification
+             event dispatching for all menu types.
+Author: Trenser
+Date:16-Jun-2026
+*/
+
+#include "Menu.h"
+
+/*
+Function: Menu
+Description: Constructs a Menu object and initializes event handles
+             and menu state.
+Parameter: None
+Return type: None
+*/
+Menu::Menu()
+    :
+    m_isMenuActive(false),
+    m_accountDisabledEvent(NULL),
+    m_notificationAvailableEvent(NULL),
+    m_shutdownEvent(NULL) {}
+
+/*
+Function: ~Menu
+Description: Destroys the Menu object and performs event listener
+             cleanup.
+Parameter: None
+Return type: None
+*/
+Menu::~Menu()
+{
+    stopEventListener();
+}
+
+/*
+Function: startEventListener
+Description: Creates menu event handles, registers them with the
+             authentication service, and starts the event listener
+             thread.
+Parameter: None
+Return type: void
+*/
+void Menu::startEventListener()
+{
+    if (m_isMenuActive.load())
+    {
+        return;
+    }
+    m_isMenuActive.store(true);
+    m_accountDisabledEvent = CreateEventA(NULL, FALSE, FALSE, NULL);
+    m_notificationAvailableEvent = CreateEventA(NULL, FALSE, FALSE, NULL);
+    m_shutdownEvent = CreateEventA(NULL, FALSE, FALSE, NULL);
+    m_controller.registerEvents(m_accountDisabledEvent, m_notificationAvailableEvent);
+    m_eventListenerThread = std::thread(&Menu::eventListenerLoop, this);
+}
+
+/*
+Function: eventListenerLoop
+Description: Waits for account disabled, notification available,
+             and shutdown events and dispatches them to the
+             appropriate handlers.
+Parameter: None
+Return type: void
+*/
+void Menu::eventListenerLoop()
+{
+    HANDLE handles[3];
+    handles[0] = m_accountDisabledEvent;
+    handles[1] = m_notificationAvailableEvent;
+    handles[2] = m_shutdownEvent;
+    while (m_isMenuActive.load())
+    {
+        DWORD result = WaitForMultipleObjects(3, handles, FALSE, INFINITE);
+        switch (result)
+        {
+        case WAIT_OBJECT_0:
+            handleAccountDisabledEvent();
+            break;
+        case WAIT_OBJECT_0 + 1:
+            handleNotificationEvent();
+            break;
+        case WAIT_OBJECT_0 + 2:
+            return;
+        }
+    }
+}
+
+/*
+Function: stopEventListener
+Description: Stops the event listener thread and releases all
+             associated event handles.
+Parameter: None
+Return type: void
+*/
+void Menu::stopEventListener()
+{
+    m_isMenuActive.store(false);
+    if (m_shutdownEvent)
+    {
+        SetEvent(m_shutdownEvent);
+    }
+    if (m_eventListenerThread.joinable())
+    {
+        m_eventListenerThread.join();
+    }
+    if (m_accountDisabledEvent)
+    {
+        CloseHandle(m_accountDisabledEvent);
+    }
+    if (m_notificationAvailableEvent)
+    {
+        CloseHandle(m_notificationAvailableEvent);
+    }
+    if (m_shutdownEvent)
+    {
+        CloseHandle(m_shutdownEvent);
+    }
+    m_accountDisabledEvent = NULL;
+    m_notificationAvailableEvent = NULL;
+    m_shutdownEvent = NULL;
+}
+
+/*
+Function: handleAccountDisabledEvent
+Description: Handles an account disabled event by marking the menu
+             inactive and notifying the user.
+Parameter: None
+Return type: void
+*/
+void Menu::handleAccountDisabledEvent()
+{
+    m_isMenuActive.store(false);
+    const User* authenticatedUser = m_controller.getAuthenticatedUser();
+    std::string messageTitle = "Account Disabled";
+    if (authenticatedUser)
+    {
+        messageTitle += " - " + authenticatedUser->getName();
+    }
+    MessageBoxA(
+        GetConsoleWindow(),
+        "Your account has been disabled.",
+        messageTitle.c_str(),
+        MB_OK |
+        MB_ICONWARNING |
+        MB_SETFOREGROUND |
+        MB_TOPMOST);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/Menu.h

@@ -0,0 +1,33 @@
+/*
+File: Menu.h
+Description: Base class providing common event listener functionality
+             for all menu implementations.
+Author: Trenser
+Date:16-Jun-2026
+*/
+
+#pragma once
+
+#include <windows.h>
+#include <atomic>
+#include <thread>
+#include "Controller.h"
+
+class Menu
+{
+protected:
+    Controller m_controller;
+    std::atomic<bool> m_isMenuActive;
+    HANDLE m_accountDisabledEvent;
+    HANDLE m_notificationAvailableEvent;
+    HANDLE m_shutdownEvent;
+    std::thread m_eventListenerThread;
+    void startEventListener();
+    void stopEventListener();
+    void eventListenerLoop();
+    void handleAccountDisabledEvent();
+    virtual void handleNotificationEvent() = 0;
+public:
+    Menu();
+    virtual ~Menu();
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/TechnicianMenu.cpp

@@ -1,40 +1,215 @@
-#include "TechnicianMenu.h"
-#include "InputHelper.h"
-#include "OutputHelper.h"
+/*
+File: TechnicianMenu.cpp
+Description: Implementation file containing the method definitions of the
+             TechnicianMenu class, including menu handling, job completion,
+             notification viewing, password management, and logout logic.
+Author: Trenser
+Date:19-May-2026
+*/
 
+#include "Enums.h"
+#include "InputHelper.h"
+#include "JobCard.h"
+#include "MenuHelper.h"
+#include "OutputHelper.h"
+#include "Service.h"
+#include "TechnicianMenu.h"
+#include "Validator.h"
+
+/*
+Function: showMenu
+Description: Displays the technician menu in a loop until the user chooses to logout.
+			 Handles exceptions and ensures smooth user interaction.
+Parameters:
+	- None
+Returns:
+	- void
+*/
 void TechnicianMenu::showMenu()
 {
-	bool isMenuActive = true;
-	while (isMenuActive)
-	{
-		try
-		{
-			int choice;
-			util::clear();
-			std::cout << "" << std::endl;
-			util::read(choice);
-			if (!handleOperation(choice))
-			{
-				isMenuActive = false;
-			}
-		}
-		catch (const std::exception& e)
-		{
-			std::cout << "Exception: " << e.what() << std::endl;
-			util::pressEnter();
-		}
-	}
+    startEventListener();
+    while (true)
+    {
+        try
+        {
+            if (!m_isMenuActive)
+            {
+                logout();
+                break;
+            }
+            int choice;
+            util::clear();
+            std::cout << "Technician Menu"
+                << "\n1. Display My Jobs"
+                << "\n2. Update Job Status"
+                << "\n3. View Notifications"
+                << "\n4. Change Password"
+                << "\n5. Logout"
+                << "\nEnter a choice: ";
+            util::read(choice);
+            if (!handleOperation(choice))
+            {
+                break;
+            }
+        }
+        catch (const std::exception& e)
+        {
+            std::cout << "Exception: " << e.what() << std::endl;
+            util::pressEnter();
+        }
+    }
+    stopEventListener();
 }
 
+/*
+Function: handleOperation
+Description: Executes the corresponding technician operation based on the selected menu choice.
+Parameter: int choice - selected menu option
+Return type: bool - true if menu continues, false if logout
+*/
 bool TechnicianMenu::handleOperation(int choice)
 {
-	return false;
+    if (!m_isMenuActive)
+    {
+        logout();
+        return false;
+    }
+    switch (choice)
+    {
+    case 1:
+        displayJobs();
+        break;
+    case 2:
+        updateJobStatus();
+        break;
+    case 3:
+        viewNotifications();
+        break;
+    case 4:
+        changePassword();
+        break;
+    case 5:
+        logout();
+        return false;
+    default:
+        std::cout << "Enter a valid choice!" << std::endl;
+        util::pressEnter();
+    }
+    return true;
 }
 
-void TechnicianMenu::completeJob()
+/*
+Function: handleNotificationEvent
+Description: Retrieves and displays the latest notification for the
+             currently logged in admin.
+Parameter: None
+Return type: void
+*/
+void TechnicianMenu::handleNotificationEvent()
 {
+    auto notifications = m_controller.getNotifications();
+    const User* authenticatedUser = m_controller.getAuthenticatedUser();
+    std::string name;
+    if (authenticatedUser)
+    {
+        name = authenticatedUser->getName();
+    }
+    displayNewNotification(notifications, name);
 }
 
+/*
+Function: displayJobs
+Description: Displays all Jobs assigned to a Technician
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void TechnicianMenu::displayJobs()
+{
+    util::clear();
+    std::cout << "My Jobs\n";
+    util::Map<std::string, const JobCard*> assignedJobCards = m_controller.getJobCardsByUser();
+    util::Map<std::string, const JobCard*> jobCards = filterStartedJobCards(assignedJobCards);
+    displayAllJobs(jobCards);
+    util::pressEnter();
+}
+
+/*
+Function: updateJobStatus
+Description: Allows the technician to update a selected job card.
+             Validates selection and updates job status through the controller.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void TechnicianMenu::updateJobStatus()
+{
+    util::clear();
+    std::cout << "Update Job Status\n";
+    int choice;
+    std::string selectedJobID;
+    util::ServiceJobStatus selectedJobStatus = util::ServiceJobStatus::PENDING;
+	util::Map<std::string, const JobCard*> assignedJobCards = m_controller.getJobCardsByUser();
+    std::cout << "Select the type of job you want to update:\n1.Started\n2.In Progress\nChoice: ";
+    util::read(choice);
+    if (choice == 1)
+    {
+        selectedJobStatus = util::ServiceJobStatus::STARTED;
+    }
+    else if (choice == 2)
+    {
+        selectedJobStatus = util::ServiceJobStatus::IN_PROGRESS;
+    }
+    else
+    {
+        std::cout << "Invalid choice. Please try again.\n";
+        util::pressEnter();
+        return;
+    }
+    util::Map<std::string, const JobCard*> selectedTypeJobCard = filterJobCards(assignedJobCards, selectedJobStatus);
+	selectedJobID = selectJobCardToUpdate(selectedTypeJobCard, selectedJobStatus);
+    if (!selectedJobID.empty())
+	{
+		m_controller.updateJobStatus(selectedJobID);
+		std::cout << "\nJob status updated.\n\n";
+	}
+    util::pressEnter();
+}
+
+/*
+Function: viewNotifications
+Description: Displays notifications for the technician and allows deletion of notifications.
+Parameters:
+	- None
+Returns:
+	- void
+*/
 void TechnicianMenu::viewNotifications()
 {
+	viewAndDeleteNotification(m_controller);
 }
+
+/*
+Function: logout
+Description: Logs out the currently authenticated technician user.
+Parameter: None
+Return type: void
+*/
+void TechnicianMenu::logout()
+{
+	m_controller.logout();
+}
+
+/*
+Function: changePassword
+Description: Allows the technician to change their password after validation.
+Parameter: None
+Return type: void
+*/
+
+void TechnicianMenu::changePassword()
+{
+    changePasswordHelper(m_controller);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/TechnicianMenu.h

@@ -1,13 +1,26 @@
+/*
+File: TechnicianMenu.h
+Description: Header file declaring the TechnicianMenu class, which provides
+             technician operations such as job completion, notification viewing,
+             password management, and logout functionality.
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include "Controller.h"
+#include "Menu.h"
 
-class TechnicianMenu
+class TechnicianMenu : public Menu
 {
 private:
-    Controller m_controller;
     bool handleOperation(int choice);
+    void handleNotificationEvent();
 public:
     void showMenu();
-    void completeJob();
+    void displayJobs();
+    void updateJobStatus();
     void viewNotifications();
-};
+    void logout();
+    void changePassword();
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/UserInterface.cpp

@@ -1,31 +1,79 @@
-#include "UserInterface.h"
+/*
+File: UserInterface.cpp
+Description: Implementation file containing the method definitions of the
+			 UserInterface class, including system run loop, login handling,
+			 and customer registration logic.
+Author: Trenser
+Date:19-May-2026
+*/
+
+#include <iostream>
+#include <stdexcept>
+#include "Enums.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
+#include "User.h"
+#include "UserInterface.h"
+#include "Validator.h"
 
+/*
+Function: run
+Description: Runs the main system loop, displaying the initial menu for login,
+			 customer registration, or exit. Handles exceptions gracefully.
+Parameter: None
+Return type: void
+*/
 void UserInterface::run()
 {
-	bool isMenuActive = true;
-	while (isMenuActive)
+	try
 	{
-		try
+		if (!m_controller.initialize())
 		{
-			int choice;
-			util::clear();
-			std::cout << "Vehicle Service System\n1. Login\n2. Register Customer\n3. Exit\nEnter your Choice: ";
-			util::read(choice);
-			if (!handleOperation(choice))
+			std::cout << "Error: Failed to initialize the system!";
+			return;
+		}
+		bool isMenuActive = true;
+		while (isMenuActive)
+		{
+			try
 			{
-				isMenuActive = false;
+				int choice;
+				util::clear();
+				std::cout << "Vehicle Service System\n1. Login\n2. Register Customer\n3. Exit\nEnter your Choice: ";
+				util::read(choice);
+				if (!handleOperation(choice))
+				{
+					isMenuActive = false;
+				}
+			}
+			catch (const std::exception& e)
+			{
+				std::cout << "Exception: " << e.what() << std::endl;
+				util::pressEnter();
 			}
 		}
-		catch (const std::exception& e)
-		{
-			std::cout << "Exception: " << e.what() << std::endl;
-			util::pressEnter();
-		}
+		m_controller.shutdown();
+	}
+	catch (const std::invalid_argument& exception)
+	{
+		std::cout << "Exception: Invalid Argument: " << exception.what() << std::endl;
+	}
+	catch (const std::exception& exception)
+	{
+		std::cout << "Exception: " << exception.what() << std::endl;
+	}
+	catch (...)
+	{
+		std::cout << "Unknown error occurred." << std::endl;
 	}
 }
 
+/*
+Function: handleOperation
+Description: Executes the corresponding system operation based on the selected menu choice.
+Parameter: int choice - selected menu option
+Return type: bool - true if menu continues, false if exit
+*/
 bool UserInterface::handleOperation(int choice)
 {
 	switch (choice)
@@ -46,12 +94,98 @@ bool UserInterface::handleOperation(int choice)
 	return true;
 }
 
+/*
+Function: login
+Description: Handles user login by validating credentials. Based on the authenticated
+			 user type, navigates to the appropriate menu (Admin, Technician, Customer).
+Parameter: None
+Return type: void
+*/
 void UserInterface::login()
 {
-
+	std::string username, password;
+	util::clear();
+	std::cout << "Login\n";
+	std::cout << "Enter username: ";
+	util::read(username);
+	std::cout << "Enter password: ";
+	util::readPassword(password);
+	if (m_controller.login(username, password))
+	{
+		const User* authenticatedUser = m_controller.getAuthenticatedUser();
+		if (authenticatedUser && authenticatedUser->getState() != util::State::INACTIVE)
+		{
+			switch (authenticatedUser->getUserType())
+			{
+			case util::UserType::ADMIN:
+				m_adminMenu.showMenu();
+				break;
+			case util::UserType::TECHNICIAN:
+				m_technicianMenu.showMenu();
+				break;
+			case util::UserType::CUSTOMER:
+				m_customerMenu.showMenu();
+				break;
+			default:
+				std::cout << "\nError: Unknown user type";
+				break;
+			}
+		}
+		else if (authenticatedUser && authenticatedUser->getState() == util::State::INACTIVE)
+		{
+			std::cout << "\nError: Your account has been disabled. Please contact your Administrator.";
+			util::pressEnter();
+		}
+	}
+	else
+	{
+		std::cout << "\nError: Invalid Username or Password";
+		util::pressEnter();
+	}
 }
 
+/*
+Function: registerCustomer
+Description: Registers a new customer by collecting and validating details such as
+			 username, name, email, password, and phone number. Delegates creation
+			 to the controller.
+Parameter: None
+Return type: void
+*/
 void UserInterface::registerCustomer()
 {
-
-}
+	std::string username, name, email, phone, password;
+	util::clear();
+	std::cout << "Register Customer\n";
+	std::cout << "Enter username: ";
+	util::read(username);
+	std::cout << "Enter name: ";
+	util::read(name);
+	std::cout << "Enter email: ";
+	util::read(email);
+	if (!util::isEmailValid(email))
+	{
+		std::cout << "Error: Email is invalid!";
+		util::pressEnter();
+		return;
+	}
+	std::cout << "Enter password: ";
+	util::readPassword(password);
+	if (!util::isPasswordValid(password))
+	{
+		std::cout << "Error: Password is invalid!";
+		util::pressEnter();
+		return;
+	}
+	std::cout << "Enter phone: ";
+	util::read(phone);
+	if (!util::isPhoneNumberValid(phone))
+	{
+		std::cout << "Error: Phone number is invalid!";
+		util::pressEnter();
+		return;
+	}
+	m_controller.createCustomer(username, name, password, email, phone);
+	std::cout << "Registration is successful";
+	util::pressEnter();
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/UserInterface.h

@@ -1,3 +1,13 @@
+/*
+File: UserInterface.h
+Description: Header file declaring the UserInterface class, which provides
+             the main entry point for the Vehicle Service System. Handles
+             login, customer registration, and menu navigation for different
+             user roles (Admin, Technician, Customer).
+Author: Trenser
+Date:19-May-2026
+*/
+
 #pragma once
 #include "Controller.h"
 #include "AdminMenu.h"
@@ -17,4 +27,4 @@ public:
     void run();
     void login();
     void registerCustomer();
-};
+};