Merge branch 'feature' into feature-1552-1560

Changes:

- Added missing include for MenuHelper.h in project and AdminMenu
- Fixed typo in variable name inventoryIems to inventoryItems in Controller.cpp
- Removed stray semicolon from include in Controller.h
- Cleaned up duplicate comments in Controller.cpp description header
- Minor formatting adjustments with blank lines after headers in multiple files
- Updated ServiceManagementService notification message to remove informal wording
- Refactored AdminMenu::changePassword to use changePasswordHelper
- Added util::clear() call at start of viewStockLevels
- Removed redundant helper functions from AdminMenu.cpp and moved to shared helpers
- Fixed bug in removeInventoryItem to use activeItems instead of inventoryItems
- Enhanced createComboPackages to enforce selection of two distinct services
- General comment cleanup and formatting consistency across headers and implementation files

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

@@ -173,9 +173,12 @@
     <ClInclude Include="services\UserManagementService.h" />
     <ClInclude Include="utilities\Config.h" />
     <ClInclude Include="utilities\Enums.h" />
+    <ClInclude Include="utilities\FileHelper.h" />
+    <ClInclude Include="utilities\FileManager.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" />

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

@@ -233,6 +233,21 @@
     <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\FileManager.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>

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

@@ -10,6 +10,8 @@ Date:19-May-2026
 #include "Controller.h"
 #include "Enums.h"
 #include "User.h"
+#include "ComboPackage.h"
+#include "User.h"
 
 /*
 Function: login
@@ -55,6 +57,7 @@ Parameter: const std::string& username - customer
            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);
@@ -71,8 +74,19 @@ const User* Controller::getAuthenticatedUser()
     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);
 }
 
 /*
@@ -97,9 +111,26 @@ util::Map<std::string, const Service*> Controller::getServices()
     return util::Map<std::string, const Service*>();
 }
 
+/*
+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;
 }
 
 /*
@@ -130,22 +161,70 @@ void Controller::purchaseComboPackage(const std::string& comboPackageID, const s
     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: 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);
 }
 
 util::Map<std::string, const ServiceBooking*> Controller::getServiceBookings()
@@ -158,9 +237,22 @@ util::Map<std::string, const ServiceBooking*> Controller::getServiceBookingsByUs
     return util::Map<std::string, const ServiceBooking*>();
 }
 
+/*
+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;
 }
 
 util::Map<std::string, const User*> Controller::getUsers(util::UserType userType)
@@ -189,16 +281,49 @@ void Controller::completeJob(const std::string& 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_serviceManagementService.cancelCustomerServiceBookings(userID);
+    m_serviceManagementService.cancelTechnicianJobs(userID);
+    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);
 }
 
 util::Map<std::string, const Invoice*> Controller::getInvoicesByUser()
@@ -288,6 +413,54 @@ void Controller::configureNotifications(bool paymentNotifications, bool serviceN
     }
 }
 
+/*
+Function: loadSystemData
+Description: Loads all system data from persistent storage into memory.
+             Invokes the respective management services to load users, inventory items, services,
+             combo packages, service bookings, job cards, invoices, and observers.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void Controller::loadSystemData()
+{
+    m_userManagementService.loadUsers();
+    m_inventoryManagementService.loadInventoryItems();
+    m_serviceManagementService.loadServices();
+    m_serviceManagementService.loadComboPackages();
+    m_serviceManagementService.loadServiceBookings();
+    m_serviceManagementService.loadJobCards();
+    m_paymentManagementService.loadInvoices();
+    m_serviceManagementService.loadObservers();
+    m_paymentManagementService.loadObservers();
+    m_inventoryManagementService.loadObservers();
+}
+
+/*
+Function: saveSystemData
+Description: Saves all system data from memory back to persistent storage.
+             Invokes the respective management services to save users, inventory items, services,
+             combo packages, service bookings, job cards, invoices, and observers.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void Controller::saveSystemData()
+{
+    m_userManagementService.saveUsers();
+    m_inventoryManagementService.saveInventoryItems();
+    m_serviceManagementService.saveServices();
+    m_serviceManagementService.saveComboPackages();
+    m_serviceManagementService.saveServiceBookings();
+    m_serviceManagementService.saveJobCards();
+    m_paymentManagementService.saveInvoices();
+    m_serviceManagementService.saveObservers();
+    m_paymentManagementService.saveObservers();
+    m_inventoryManagementService.saveObservers();
+}
+
 /*
 Function: runSystemChecks
 Description: Runs system checks to ensure critical configurations, such as verifying admin existence.

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

@@ -1,20 +1,26 @@
 /*
 File: Controller.h
-Description: Header file declaring the Controller class, which coordinates
+Description: Header file declaring the Controller class, which manages
-             authentication, user management, service management, inventory,
+             user authentication, inventory, services, bookings, job cards,
-             and notifications across the Vehicle Service System.
+             invoices, and notifications in the system.
 Author: Trenser
 Date:19-May-2026
 */
+
 #pragma once
-#include <string>
 #include "AuthenticationManagementService.h"
 #include "Enums.h"
 #include "InventoryManagementService.h"
 #include "Map.h"
 #include "PaymentManagementService.h"
+#include "PaymentManagementService.h"
+#include "ServiceManagementService.h"
+#include "ServiceManagementService.h"
 #include "ServiceManagementService.h"
 #include "UserManagementService.h"
+#include "UserManagementService.h"
+#include "UserManagementService.h"
+#include <string>
 
 class Service;
 class ComboPackage;
@@ -28,7 +34,7 @@ class Notification;
 class Controller
 {
 private:
-    AuthenticationManagementService m_authenticationManagementService;
+    AuthenticationManagementService  m_authenticationManagementService;
     UserManagementService m_userManagementService;
     ServiceManagementService m_serviceManagementService;    
     InventoryManagementService m_inventoryManagementService;
@@ -39,7 +45,7 @@ public:
     void changePassword(const std::string& newPassword);
     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();
@@ -48,6 +54,7 @@ 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);
@@ -66,5 +73,7 @@ public:
     util::Vector<const Notification*> getNotifications();
     void deleteNotification(const std::string& notificationID);
     void configureNotifications(bool paymentNotifications, bool serviceNotifications);
+    void loadSystemData();
+    void saveSystemData();
     void runSystemChecks();
 };

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

@@ -8,6 +8,7 @@ Date: 19-May-2026
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 
 class User;
 class Notification;

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/files/README.md

@@ -0,0 +1 @@
+Place files here.

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

@@ -7,7 +7,12 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <sstream>
+#include <stdexcept>
 #include "ComboPackage.h"
+#include "Service.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ComboPackage::m_uid = 0;
 
@@ -41,7 +46,42 @@ ComboPackage::ComboPackage(const std::string& packageName, double discountPercen
     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
@@ -95,6 +135,11 @@ 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.
@@ -158,6 +203,13 @@ Returns:
 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());
+    }
 }
 
 /*
@@ -172,3 +224,118 @@ 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 combo package into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized combo package record
+*/
+std::string ComboPackage::serialize() const
+{
+    std::ostringstream serializedComboPackage;
+    serializedComboPackage << m_id << ','
+        << m_packageName << ','
+        << m_discountPercentage << ','
+        << getServiceIDsAsString(m_serviceIDs) << ','
+        << util::getStateString(m_status);
+    return serializedComboPackage.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a ComboPackage object.
+Parameters:
+    - record: const std::string&, serialized combo package record
+Returns:
+    - ComboPackage*: Pointer to the deserialized ComboPackage object
+Throws:
+    - std::runtime_error if data is invalid
+*/
+ComboPackage* ComboPackage::deserialize(const std::string& record)
+{
+    std::string id, packageName;
+    std::string discountPercentageString, serviceIDsString, statusString;
+    double discountPercentage;
+    std::istringstream serializedComboPackage(record);
+    getline(serializedComboPackage, id, ',');
+    getline(serializedComboPackage, packageName, ',');
+    getline(serializedComboPackage, discountPercentageString, ',');
+    getline(serializedComboPackage, serviceIDsString, ',');
+    getline(serializedComboPackage, statusString, ',');
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid combo package data");
+    }
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    util::State status = util::getState(statusString);
+    return Factory::getObject<ComboPackage>(
+        id,
+        packageName,
+        discountPercentage,
+        serviceIDs,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for combo package serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,PackageName,DiscountPercentage,ServiceIDs,Status")
+*/
+std::string ComboPackage::getHeaders()
+{
+    return "ID,PackageName,DiscountPercentage,ServiceIDs,Status";
+}

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

@@ -8,6 +8,7 @@ Date: 19-May-2026
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class Service;
@@ -19,14 +20,17 @@ 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);
@@ -34,4 +38,7 @@ public:
     void setDiscountPercentage(double discountPercentage);
     void setServices(const util::Map<std::string, Service*>& services);
     void setState(util::State status);
+    std::string serialize() const;
+    static ComboPackage* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -6,6 +6,10 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <sstream>
+#include <stdexcept>
+#include "Factory.h"
+#include "StringHelper.h"
 #include "InventoryItem.h"
 
 int InventoryItem::m_uid = 0;
@@ -43,6 +47,33 @@ InventoryItem::InventoryItem(const std::string& partName, int quantity, double p
     m_status(util::State::ACTIVE),
     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.
@@ -172,3 +203,76 @@ void InventoryItem::setState(util::State status)
 {
     m_status = status;
 }
+
+/*
+Function: serialize
+Description: Serializes the inventory item into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized inventory item record
+*/
+std::string InventoryItem::serialize() const
+{
+    std::ostringstream serializedInventoryItem;
+    serializedInventoryItem << m_id << ','
+        << m_partName << ','
+        << m_quantity << ','
+        << m_price << ','
+        << util::getStateString(m_status);
+    return serializedInventoryItem.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into an InventoryItem object.
+Parameters:
+    - record: const std::string&, serialized inventory item record
+Returns:
+    - InventoryItem*: Pointer to the deserialized InventoryItem object
+Throws:
+    - std::runtime_error if data is invalid
+*/
+InventoryItem* InventoryItem::deserialize(const std::string& record)
+{
+    std::string id, partName;
+    std::string quantityString, priceString, statusString;
+    int quantity;
+    double price;
+    std::istringstream serializedInventoryItem(record);
+    getline(serializedInventoryItem, id, ',');
+    getline(serializedInventoryItem, partName, ',');
+    getline(serializedInventoryItem, quantityString, ',');
+    getline(serializedInventoryItem, priceString, ',');
+    getline(serializedInventoryItem, statusString, ',');
+    try
+    {
+        quantity = std::stoi(quantityString);
+        price = std::stod(priceString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid inventory item data");
+    }
+    util::State status = util::getState(statusString);
+    return Factory::getObject<InventoryItem>(
+        id,
+        partName,
+        quantity,
+        price,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for inventory item serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,PartName,Quantity,Price,Status")
+*/
+std::string InventoryItem::getHeaders()
+{
+    return "ID,PartName,Quantity,Price,Status";
+}

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

@@ -23,6 +23,7 @@ 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;
@@ -33,4 +34,7 @@ public:
     void setQuantity(int quantity);
     void setPrice(double price);
     void setState(util::State status);
+    std::string serialize() const;
+    static InventoryItem* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -7,7 +7,12 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <sstream>
+#include <stdexcept>
 #include "Invoice.h"
+#include "Factory.h"
+#include "InventoryItem.h"
+#include "StringHelper.h"
 
 int Invoice::m_uid = 0;
 
@@ -53,7 +58,7 @@ Invoice::Invoice(
     const std::string& bookingId,
     ServiceBooking* booking,
     const util::Timestamp& invoiceDate, 
-    double laborCost, const util::Map<int,
+    double laborCost, const util::Map<std::string,
     InventoryItem*>& parts,
     double partsCost,
     double discountPercentage, 
@@ -73,7 +78,48 @@ 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
@@ -130,13 +176,26 @@ 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<int, InventoryItem*>& Invoice::getParts() const
+const util::Map<std::string, InventoryItem*>& Invoice::getParts() const
 {
     return m_parts;
 }
@@ -280,9 +339,16 @@ Parameters:
 Returns:
     - void
 */
-void Invoice::setParts(const util::Map<int, InventoryItem*>& parts)
+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());
+    }
 }
 
 /*
@@ -362,3 +428,146 @@ 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 into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized invoice record
+*/
+std::string Invoice::serialize() const
+{
+    std::ostringstream serializedInvoice;
+    serializedInvoice << m_id << ','
+        << m_bookingId << ','
+        << m_invoiceDate.toString() << ','
+        << m_laborCost << ','
+        << getPartIDsAsString(m_partIDs) << ','
+        << m_partsCost << ','
+        << m_discountPercentage << ','
+        << m_totalAmount << ','
+        << m_paymentDate.toString() << ','
+        << util::getPaymentModeString(m_paymentMethod) << ','
+        << util::getPaymentStatusString(m_status);
+    return serializedInvoice.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into an Invoice object.
+Parameters:
+    - record: const std::string&, serialized invoice record
+Returns:
+    - Invoice*: Pointer to the deserialized Invoice object
+Throws:
+    - std::runtime_error if data is invalid
+*/
+Invoice* Invoice::deserialize(const std::string& record)
+{
+    std::string id, bookingId;
+    std::string invoiceDateString, laborCostString, partIDsString;
+    std::string partsCostString, discountPercentageString, totalAmountString;
+    std::string paymentDateString, paymentMethodString, statusString;
+    double laborCost, partsCost, discountPercentage, totalAmount;
+    std::istringstream serializedInvoice(record);
+    getline(serializedInvoice, id, ',');
+    getline(serializedInvoice, bookingId, ',');
+    getline(serializedInvoice, invoiceDateString, ',');
+    getline(serializedInvoice, laborCostString, ',');
+    getline(serializedInvoice, partIDsString, ',');
+    getline(serializedInvoice, partsCostString, ',');
+    getline(serializedInvoice, discountPercentageString, ',');
+    getline(serializedInvoice, totalAmountString, ',');
+    getline(serializedInvoice, paymentDateString, ',');
+    getline(serializedInvoice, paymentMethodString, ',');
+    getline(serializedInvoice, statusString, ',');
+    util::Timestamp invoiceDate;
+    util::Timestamp paymentDate;
+    try
+    {
+        invoiceDate = util::Timestamp::fromString(invoiceDateString);
+        paymentDate = util::Timestamp::fromString(paymentDateString);
+        laborCost = std::stod(laborCostString);
+        partsCost = std::stod(partsCostString);
+        discountPercentage = std::stod(discountPercentageString);
+        totalAmount = std::stod(totalAmountString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid invoice data");
+    }
+    util::Vector<std::string> partIDs = getPartIDsAsVector(partIDsString);
+    util::PaymentMode paymentMethod = util::getPaymentMode(paymentMethodString);
+    util::PaymentStatus status = util::getPaymentStatus(statusString);
+    return Factory::getObject<Invoice>(
+        id,
+        bookingId,
+        invoiceDate,
+        partIDs,
+        laborCost,
+        partsCost,
+        discountPercentage,
+        totalAmount,
+        paymentDate,
+        paymentMethod,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for invoice serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,BookingID,InvoiceDate,LaborCost,PartIDs,PartsCost,DiscountPercentage,TotalAmount,PaymentDate,PaymentMethod,Status")
+*/
+std::string Invoice::getHeaders()
+{
+    return "ID,BookingID,InvoiceDate,LaborCost,PartIDs,PartsCost,DiscountPercentage,TotalAmount,PaymentDate,PaymentMethod,Status";
+}

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

@@ -10,6 +10,7 @@ Date: 19-May-2026
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Timestamp.h"
 #include "Enums.h"
 
@@ -25,21 +26,21 @@ private:
     ServiceBooking* m_booking;
     util::Timestamp m_invoiceDate;
     double m_laborCost;
-    util::Map<int, InventoryItem*> m_parts;
+    util::Vector<std::string> m_partIDs;
+    util::Map<std::string, InventoryItem*> m_parts;
     double m_partsCost;
     double m_discountPercentage;
     double m_totalAmount;
     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<int,
+        double laborCost, const util::Map<std::string,
         InventoryItem*>& parts,
         double partsCost,
         double discountPercentage, 
@@ -48,12 +49,26 @@ public:
         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;
     const std::string& getBookingId() const;
     ServiceBooking* getBooking() const;
     const util::Timestamp& getInvoiceDate() const;
     double getLaborCost() const;
-    const util::Map<int, InventoryItem*>& getParts() const;
+    const util::Vector<std::string>& getPartIDs() const;
+    const util::Map<std::string, InventoryItem*>& getParts() const;
     double getPartsCost() const;
     double getDiscountPercentage() const;
     double getTotalAmount() const;
@@ -65,11 +80,14 @@ public:
     void setBooking(ServiceBooking* booking);
     void setInvoiceDate(const util::Timestamp& invoiceDate);
     void setLaborCost(double laborCost);
-    void setParts(const util::Map<int, InventoryItem*>& parts);
+    void setParts(const util::Map<std::string, InventoryItem*>& parts);
     void setPartsCost(double partsCost);
     void setDiscountPercentage(double discountPercentage);
     void setTotalAmount(double totalAmount);
     void setPaymentDate(const util::Timestamp& paymentDate);
     void setPaymentMethod(util::PaymentMode paymentMethod);
     void setStatus(util::PaymentStatus status);
+    std::string serialize() const;
+    static Invoice* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -1,31 +1,34 @@
 /*
 File: JobCard.cpp
-Description: Implements the JobCard class which represents a technician’s job assignment in the Vehicle Service Management System.
+Description: Implementation file containing the method definitions of the
-             Provides constructors, accessors, and mutators for job details such as ID, booking, service, technician,
+             JobCard class, including constructors, getters, and setters
-             assigned date, completion date, and job status.
+             for job card attributes.
 Author: Trenser
-Date: 19-May-2026
+Date:19-May-2026
 */
 
+#include <sstream>
+#include <stdexcept>
 #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,
+Description: Default constructor that initializes a new job card with
-             null booking, null service, null technician, and default job status.
+             a unique ID and default values.
-Parameters:
+Parameter: None
-    - None
+Return type: Constructor
-Returns:
-    - A new JobCard object.
 */
 JobCard::JobCard()
     : m_id("JC" + std::to_string(++m_uid)),
     m_booking(nullptr),
     m_service(nullptr),
     m_technician(nullptr),
-    m_status(ServiceJobStatus()) {}
+    m_status(util::ServiceJobStatus()) {}
 
 /*
 Function: JobCard
@@ -50,7 +53,7 @@ JobCard::JobCard(const std::string& bookingId,
     const std::string& technicianId,
     User* technician,
     const util::Timestamp& assignedDate,
-    ServiceJobStatus status,
+    util::ServiceJobStatus status,
     const util::Timestamp& completionDate
 )
     : m_id("JC" + std::to_string(++m_uid)),
@@ -64,6 +67,48 @@ JobCard::JobCard(const std::string& bookingId,
     m_status(status),
     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.
@@ -158,7 +203,7 @@ Description: Retrieves the current status of the job.
 Returns:
     - ServiceJobStatus representing the job status.
 */
-ServiceJobStatus JobCard::getStatus() const
+util::ServiceJobStatus JobCard::getStatus() const
 {
     return m_status;
 }
@@ -286,7 +331,7 @@ Parameters:
 Returns:
     - void
 */
-void JobCard::setStatus(ServiceJobStatus status)
+void JobCard::setStatus(util::ServiceJobStatus status)
 {
     m_status = status;
 }
@@ -303,3 +348,82 @@ void JobCard::setCompletionDate(const util::Timestamp& completionDate)
 {
     m_completionDate = completionDate;
 }
+
+/*
+Function: serialize
+Description: Serializes the job card into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized job card record
+*/
+std::string JobCard::serialize() const
+{
+    std::ostringstream serializedJobCard;
+    serializedJobCard << m_id << ','
+        << m_bookingId << ','
+        << m_serviceId << ','
+        << m_technicianId << ','
+        << m_assignedDate.toString() << ','
+        << util::getServiceJobStatusString(m_status) << ','
+        << m_completionDate.toString();
+    return serializedJobCard.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a JobCard object.
+Parameters:
+    - record: const std::string&, serialized job card record
+Returns:
+    - JobCard*: Pointer to the deserialized JobCard object
+Throws:
+    - std::runtime_error if timestamp parsing fails
+*/
+JobCard* JobCard::deserialize(const std::string& record)
+{
+    std::string id, bookingId, serviceId, technicianId;
+    std::string assignedDateString, statusString, completionDateString;
+    std::istringstream serializedJobCard(record);
+    getline(serializedJobCard, id, ',');
+    getline(serializedJobCard, bookingId, ',');
+    getline(serializedJobCard, serviceId, ',');
+    getline(serializedJobCard, technicianId, ',');
+    getline(serializedJobCard, assignedDateString, ',');
+    getline(serializedJobCard, statusString, ',');
+    getline(serializedJobCard, completionDateString, ',');
+    util::Timestamp assignedDate;
+    util::Timestamp completionDate;
+    try
+    {
+        assignedDate = util::Timestamp::fromString(assignedDateString);
+        completionDate = util::Timestamp::fromString(completionDateString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid timestamp");
+    }
+    util::ServiceJobStatus status = util::getServiceJobStatus(statusString);
+    return Factory::getObject<JobCard>(
+        id,
+        bookingId,
+        serviceId,
+        technicianId,
+        assignedDate,
+        status,
+        completionDate
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for job card serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,BookingID,ServiceID,TechnicianID,AssignedDate,Status,CompletionDate")
+*/
+std::string JobCard::getHeaders()
+{
+    return "ID,BookingID,ServiceID,TechnicianID,AssignedDate,Status,CompletionDate";
+}

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

@@ -1,21 +1,21 @@
 /*
 File: JobCard.h
-Description: Declares the JobCard class which represents a technician’s job assignment in the Vehicle Service Management System.
+Description: Header file declaring the JobCard class, which represents
-             Each job card includes booking details, associated service, technician information, assigned and completion dates, and job status.
+             a service job card containing booking, service, technician,
+             and status details.
 Author: Trenser
-Date: 19-May-2026
+Date:19-May-2026
 */
 
 #pragma once
 #include <string>
 #include "Timestamp.h"
+#include "Enums.h"
 
 class ServiceBooking;
 class Service;
 class User;
 
-enum class ServiceJobStatus : int;
-
 class JobCard
 {
 private:
@@ -28,9 +28,8 @@ private:
     std::string m_technicianId;
     User* m_technician;
     util::Timestamp m_assignedDate;
-    ServiceJobStatus m_status;
+    util::ServiceJobStatus m_status;
     util::Timestamp m_completionDate;
-
 public:
     JobCard();
     JobCard(const std::string& bookingId,
@@ -40,7 +39,15 @@ public:
         const std::string& technicianId, 
         User* technician, 
         const util::Timestamp& assignedDate, 
-        ServiceJobStatus status,
+        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
     );
     const std::string& getId() const;
@@ -51,7 +58,7 @@ public:
     const std::string& getTechnicianId() const;
     User* getTechnician() const;
     const util::Timestamp& getAssignedDate() const;
-    ServiceJobStatus getStatus() const;
+    util::ServiceJobStatus getStatus() const;
     const util::Timestamp& getCompletionDate() const;
     void setId(const std::string& id);
     void setBookingId(const std::string& bookingId);
@@ -61,6 +68,9 @@ public:
     void setTechnicianId(const std::string& technicianId);
     void setTechnician(User* technician);
     void setAssignedDate(const util::Timestamp& assignedDate);
-    void setStatus(ServiceJobStatus status);
+    void setStatus(util::ServiceJobStatus status);
     void setCompletionDate(const util::Timestamp& completionDate);
+    std::string serialize() const;
+    static JobCard* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -6,7 +6,10 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <sstream>
 #include "Notification.h"
+#include "StringHelper.h"
+#include "Factory.h"
 
 int Notification::m_uid = 0;
 
@@ -42,6 +45,34 @@ Notification::Notification(const std::string& recipientUserId, User* recipient,
     m_message(message),
     m_createdAt(createdAt) {}
 
+/*
+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)
+    : m_id(id),
+    m_recipientUserId(recipientUserId),
+    m_recipient(nullptr),
+    m_title(title),
+    m_message(message),
+    m_createdAt(createdAt) 
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
 /*
 Function: getId
 Description: Retrieves the unique ID of the notification.
@@ -185,3 +216,72 @@ void Notification::setCreatedAt(const util::Timestamp& createdAt)
 {
     m_createdAt = createdAt;
 }
+
+/*
+Function: serialize
+Description: Serializes the notification into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized notification record
+*/
+std::string Notification::serialize() const
+{
+    std::ostringstream serializedNotification;
+    serializedNotification << m_id << ','
+        << m_recipientUserId << ','
+        << m_title << ','
+        << m_message << ','
+        << m_createdAt.toString();
+    return serializedNotification.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a Notification object.
+Parameters:
+    - record: const std::string&, serialized notification record
+Returns:
+    - Notification*: Pointer to the deserialized Notification object
+Throws:
+    - std::runtime_error if timestamp parsing fails
+*/
+Notification* Notification::deserialize(const std::string& record)
+{
+    std::string id, recipientUserId, title, message, createdAtTimestampString;
+    std::istringstream serializedNotification(record);
+    getline(serializedNotification, id, ',');
+    getline(serializedNotification, recipientUserId, ',');
+    getline(serializedNotification, title, ',');
+    getline(serializedNotification, message, ',');
+    getline(serializedNotification, createdAtTimestampString, ',');
+    util::Timestamp createdAtTimestamp;
+    try
+    {
+        createdAtTimestamp = util::Timestamp::fromString(createdAtTimestampString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid createdAt timestamp");
+    }
+    return Factory::getObject<Notification>(
+        id,
+        recipientUserId,
+        title,
+        message,
+        createdAtTimestamp
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for notification serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,RecipientID,Title,Message,Timestamp")
+*/
+std::string Notification::getHeaders()
+{
+    return "ID,RecipientID,Title,Message,Timestamp";
+}

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

@@ -25,6 +25,7 @@ private:
 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& id, const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt);
     const std::string& getId() const;
     const std::string& getRecipientUserId() const;
     User* getRecipient() const;
@@ -37,4 +38,7 @@ public:
     void setTitle(const std::string& title);
     void setMessage(const std::string& message);
     void setCreatedAt(const util::Timestamp& createdAt);
+    std::string serialize() const;
+    static Notification* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -7,7 +7,11 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <sstream>
 #include "Service.h"
+#include "InventoryItem.h"
+#include "StringHelper.h"
+#include "Factory.h"
 
 int Service::m_uid = 0;
 
@@ -40,7 +44,42 @@ Service::Service(const std::string& name, const util::Map<std::string, Inventory
     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
@@ -64,6 +103,19 @@ 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.
@@ -134,6 +186,13 @@ Returns:
 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());
+    }
 }
 
 /*
@@ -161,3 +220,118 @@ 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 into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized service record
+*/
+std::string Service::serialize() const
+{
+    std::ostringstream serializedService;
+    serializedService << m_id << ','
+        << m_name << ','
+        << getInventoryItemIDsAsString(m_requiredInventoryItemIDs) << ','
+        << m_laborCost << ','
+        << util::getStateString(m_status);
+    return serializedService.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a Service object.
+Parameters:
+    - record: const std::string&, serialized service record
+Returns:
+    - Service*: Pointer to the deserialized Service object
+Throws:
+    - std::runtime_error if labor cost parsing fails
+*/
+Service* Service::deserialize(const std::string& record)
+{
+    std::string id, name;
+    std::string inventoryItemIDsString, laborCostString, statusString;
+    double laborCost;
+    std::istringstream serializedService(record);
+    getline(serializedService, id, ',');
+    getline(serializedService, name, ',');
+    getline(serializedService, inventoryItemIDsString, ',');
+    getline(serializedService, laborCostString, ',');
+    getline(serializedService, statusString, ',');
+    util::Vector<std::string> inventoryItemIDs = getInventoryItemIDsAsVector(inventoryItemIDsString);
+    try
+    {
+        laborCost = std::stod(laborCostString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid labor cost");
+    }
+    util::State status = util::getState(statusString);
+    return Factory::getObject<Service>(
+        id,
+        name,
+        inventoryItemIDs,
+        laborCost,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for service serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Name,InventoryIDs,LaborCost,Status")
+*/
+std::string Service::getHeaders()
+{
+    return "ID,Name,InventoryIDs,LaborCost,Status";
+}

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

@@ -10,6 +10,7 @@ Date: 19-May-2026
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class InventoryItem;
@@ -20,14 +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;
@@ -36,4 +40,7 @@ public:
     void setRequiredInventoryItems(const util::Map<std::string, InventoryItem*>& requiredInventoryItems);
     void setLaborCost(double laborCost);
     void setState(util::State status);
+    std::string serialize() const;
+    static Service* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -6,7 +6,13 @@ Description: Implementation file containing the method definitions of the
 Author: Trenser
 Date:19-May-2026
 */
+#include <stdexcept>
+#include <sstream>
 #include "ServiceBooking.h"
+#include "Service.h"
+#include "Enums.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ServiceBooking::m_uid = 0;
 
@@ -35,8 +41,6 @@ Parameters:
     - vehicleNumber: Vehicle registration number.
     - vehicleBrand: Brand of the vehicle.
     - vehicleModel: Model of the vehicle.
-    - assignedTechnicianId: ID of the assigned technician.
-    - assignedTechnician: Name of the assigned technician.
     - discountPercentage: Discount applied to the booking.
 Returns:
     - A new ServiceBooking object.
@@ -64,6 +68,60 @@ ServiceBooking::ServiceBooking(
     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;
+    }
 }
 
 /*
@@ -88,6 +146,25 @@ 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.
@@ -217,6 +294,13 @@ 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());
+    }
 }
 
 /*
@@ -306,3 +390,130 @@ 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 service booking into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized booking record
+*/
+std::string ServiceBooking::serialize() const
+{
+    std::ostringstream serializedBooking;
+    serializedBooking << m_id << ','
+        << util::getServiceJobStatusString(m_status) << ','
+        << getServiceIDsAsString(m_serviceIDs) << ','
+        << m_customerId << ','
+        << m_vehicleNumber << ','
+        << m_vehicleBrand << ','
+        << m_vehicleModel << ','
+        << m_assignedTechnicianId << ','
+        << m_discountPercentage << ',';
+    return serializedBooking.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a ServiceBooking object.
+Parameters:
+    - record: const std::string&, serialized booking record
+Returns:
+    - ServiceBooking*: Pointer to the deserialized ServiceBooking object
+Throws:
+    - std::runtime_error if discount percentage parsing fails
+*/
+ServiceBooking* ServiceBooking::deserialize(const std::string& record)
+{
+    std::string id, customerId, vehicleNumber, vehicleBrand, vehicleModel, assignedTechnicianId;
+    std::string serviceJobStatusString, serviceIDsString, discountPercentageString;
+    double discountPercentage;
+    std::istringstream serializedBooking(record);
+    getline(serializedBooking, id, ',');
+    getline(serializedBooking, serviceJobStatusString, ',');
+    getline(serializedBooking, serviceIDsString, ',');
+    getline(serializedBooking, customerId, ',');
+    getline(serializedBooking, vehicleNumber, ',');
+    getline(serializedBooking, vehicleBrand, ',');
+    getline(serializedBooking, vehicleModel, ',');
+    getline(serializedBooking, assignedTechnicianId, ',');
+    getline(serializedBooking, discountPercentageString, ',');
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid discount percentage");
+    }
+    util::ServiceJobStatus status = util::getServiceJobStatus(serviceJobStatusString);
+    return Factory::getObject<ServiceBooking>(
+        id,
+        status,
+        serviceIDs,
+        customerId,
+        vehicleNumber,
+        vehicleBrand,
+        vehicleModel,
+        assignedTechnicianId,
+        discountPercentage
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for service booking serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Status,ServiceIDs,CustomerID,VehicleNumber,VehicleBrand,VehicleModel,AssignedTechnicianID,DiscountPercentage")
+*/
+std::string ServiceBooking::getHeaders()
+{
+    return "ID,Status,ServiceIDs,CustomerID,VehicleNumber,VehicleBrand,VehicleModel,AssignedTechnicianID,DiscountPercentage";
+}

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

@@ -9,6 +9,7 @@ Date:19-May-2026
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class Service;
@@ -20,6 +21,7 @@ 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;
@@ -42,8 +44,20 @@ public:
         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,
+        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;
@@ -64,4 +78,7 @@ public:
     void setAssignedTechnicianId(const std::string& assignedTechnicianId);
     void setAssignedTechnician(User* assignedTechnician);
     void setDiscountPercentage(double discountPercentage);
+    std::string serialize() const;
+    static ServiceBooking* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -7,9 +7,12 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <sstream>
 #include "User.h"
 #include "Notification.h"
 #include "Enums.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int User::m_uid = 0;
 
@@ -50,6 +53,39 @@ User::User(const std::string& userName, const std::string& password, const std::
     m_type(role),
     m_status(util::State::ACTIVE) {}
 
+/*
+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)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
 /*
 Function: ~User
 Description: Destructor that cleans up dynamically allocated notifications associated with the user.
@@ -60,9 +96,10 @@ Returns:
 */
 User::~User()
 {
-    for (int index = 0; index < m_notifications.getSize(); index++)
+    auto values = m_notifications.getValues();
+    for (int index = 0; index < values.getSize(); index++)
     {
-        delete m_notifications.getValues()[index];
+        delete values[index];
     }
 }
 
@@ -284,3 +321,71 @@ void User::setState(util::State status)
 {
     m_status = status;
 }
+
+/*
+Function: serialize
+Description: Serializes the user into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized user record
+*/
+std::string User::serialize() const
+{
+    std::ostringstream serializedUser;
+    serializedUser << m_id << ','
+        << m_userName << ','
+        << m_password << ','
+        << m_name << ','
+        << m_phone << ','
+        << m_email << ','
+        << util::getUserTypeString(m_type) << ','
+        << util::getStateString(m_status);
+    return serializedUser.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a User object.
+Parameters:
+    - record: const std::string&, serialized user record
+Returns:
+    - User*: Pointer to the deserialized User object
+*/
+User* User::deserialize(const std::string& record)
+{
+    std::string id, name, username, phone, password, email;
+    std::string userTypeString, stateString;
+    std::istringstream serializedUser(record);
+    getline(serializedUser, id, ',');
+    getline(serializedUser, username, ',');
+    getline(serializedUser, password, ',');
+    getline(serializedUser, name, ',');
+    getline(serializedUser, phone, ',');
+    getline(serializedUser, email, ',');
+    getline(serializedUser, userTypeString, ',');
+    getline(serializedUser, stateString);
+    util::UserType userType = util::getUserType(userTypeString);
+    util::State status = util::getState(stateString);
+    return Factory::getObject<User>(id,
+        username,
+        password,
+        name,
+        phone,
+        email,
+        userType,
+        status);
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for user serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Username,Password,Name,Phone,Email,UserType,UserStatus")
+*/
+std::string User::getHeaders()
+{
+    return "ID,Username,Password,Name,Phone,Email,UserType,UserStatus";
+}

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

@@ -31,6 +31,7 @@ private:
 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(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();
     const std::string& getId() const;
     const std::string& getUserName() const;
@@ -50,4 +51,7 @@ public:
     void addNotification(Notification* notification) override;
     void setRole(util::UserType role);
     void setState(util::State status);
+    std::string serialize() const;
+    static User* deserialize(const std::string&);
+    static std::string getHeaders();
 };

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

@@ -1,11 +1,12 @@
 /*
 File: AuthenticationManagementService.cpp
 Description: Implementation file containing the method definitions of the
-			 AuthenticationManagementService class, including login, logout,
+			 AuthenticationManagementService class, including logout and
-			 password change, and retrieval of the authenticated user.
+			 password change logic.
 Author: Trenser
 Date:19-May-2026
 */
+
 #include <stdexcept>
 #include "AuthenticationManagementService.h"
 #include "User.h"

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

@@ -6,6 +6,7 @@ Description: Header file declaring the AuthenticationManagementService class, wh
 Author: Trenser
 Date:19-May-2026
 */
+
 #pragma once
 #include <string>
 #include "DataStore.h"

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

@@ -1,79 +1,61 @@
+/*
+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 "InventoryManagementService.h"
-#include "Vector.h"
-#include "Enums.h"
-#include "InventoryItem.h"
 #include "Config.h"
-#include "User.h"
+#include "Enums.h"
 #include "Factory.h"
+#include "FileManager.h"
+#include "InventoryItem.h"
+#include "InventoryManagementService.h"
 #include "Timestamp.h"
+#include "User.h"
+#include "Utility.h"
+#include "Vector.h"
+
 
 util::Map<std::string, User*> InventoryManagementService::m_observers{};
 
-void InventoryManagementService::attach(User* user)
+/*
-{
+Function: sendLowStockAlertsToAdmins (static helper)
-	if (user)
+Description: Sends low stock alert notifications to all admin users for a given inventory item.
-	{
+Parameters:
-		const std::string& userID = user->getId();
+	- inventoryManagementService: InventoryManagementService&, service used to send notifications
-		if (m_observers.find(userID) == -1)
+	- inventoryItem: const InventoryItem*, pointer to the low-stock inventory item
-		{
+	- adminUsers: const util::Vector<User*>&, list of admin users to notify
-			m_observers[userID] = user;
+Returns:
-		}
+	- None
-	}
+*/
-}
-
-void InventoryManagementService::detach(User* user)
-{
-	if (user)
-	{
-		const std::string& userID = user->getId();
-		if (m_observers.find(userID) != -1)
-		{
-			m_observers.remove(userID);
-		}
-	}
-}
-
-void InventoryManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
-{
-	if (user)
-	{
-		if (m_observers.find(user->getId()) != -1)
-		{
-			Notification* notification =
-				Factory::getObject<Notification>(
-					user->getId(),
-					user,
-					"InventoryManagementService: " + title,
-					message,
-					util::Timestamp()
-				);
-			if (notification)
-			{
-				user->addNotification(notification);
-			}
-			else
-			{
-				throw std::runtime_error("Failed to create notification");
-			}
-		}
-	}
-}
-
 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],
-			"Low Stock Alert",
+			title,
-			"The inventory item with ID " + inventoryItem->getId() +
+			message
-			" has very low quantity in the inventory"
+		);
-			);
 	}
 }
 
+/*
+Function: sendLowStockAlerts
+Description: Sends alerts to user for inventory items with low stock
+Parameters:
+	- None
+Returns:
+	- None
+*/
 void InventoryManagementService::sendLowStockAlerts()
 {
 	auto& inventoryItems = m_dataStore.getInventoryItems();
@@ -103,3 +85,253 @@ void InventoryManagementService::sendLowStockAlerts()
 		}
 	}
 }
+
+/*
+Function: getObserverIDs
+Description: Retrieves the IDs of all observers currently attached to the
+			 InventoryManagementService.
+Parameters:
+	- None
+Returns:
+	- util::Vector<std::string>: Vector of observer user IDs
+*/
+util::Vector<std::string> InventoryManagementService::getObserverIDs()
+{
+	util::Vector<std::string> observerIDs;
+	int numberOfObservers = m_observers.getSize();
+	for (int index = 0; index < numberOfObservers; index++)
+	{
+		User* observer = m_observers.getValueAt(index);
+		if (observer)
+		{
+			observerIDs.push_back(observer->getId());
+		}
+	}
+	return observerIDs;
+}
+
+/*
+Function: loadInventoryItems
+Description: Loads inventory items from persistent storage into the datastore.
+			 Uses FileManager to deserialize inventory items from the configured file.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::loadInventoryItems()
+{
+	util::FileManager<InventoryItem> inventoryItemFileManager(config::file::INVENTORYITEM_FILE);
+	auto& inventoryItems = m_dataStore.getInventoryItems();
+	auto inventoryItemsMap = inventoryItemFileManager.load();
+	int numberOfInventoryItems = inventoryItemsMap.getSize();
+	for (int index = 0; index < numberOfInventoryItems; index++)
+	{
+		inventoryItems[inventoryItemsMap.getKeyAt(index)] = inventoryItemsMap.getValueAt(index);
+	}
+}
+
+/*
+Function: saveInventoryItems
+Description: Saves inventory items from the datastore to persistent storage.
+			 Uses FileManager to serialize inventory items into the configured file.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::saveInventoryItems()
+{
+	util::FileManager<InventoryItem> inventoryItemFileManager(config::file::INVENTORYITEM_FILE);
+	auto& inventoryItems = m_dataStore.getInventoryItems();
+	inventoryItemFileManager.save(inventoryItems);
+}
+
+/*
+Function: loadObservers
+Description: Loads observer IDs from persistent storage and attaches corresponding
+			 users as observers to the InventoryManagementService.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::loadObservers()
+{
+	util::loadObservers(config::file::INVENTORYMANAGEMENTOBSERVERS, this, m_dataStore);
+}
+
+/*
+Function: saveObservers
+Description: Saves the current observer IDs of the InventoryManagementService
+			 to persistent storage for future retrieval.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::saveObservers()
+{
+	util::saveObservers(config::file::INVENTORYMANAGEMENTOBSERVERS, this);
+}
+
+/*
+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)
+{
+    InventoryItem* newItem = Factory::getObject<InventoryItem>(partName, quantity, price);
+    m_dataStore.getInventoryItems().insert(newItem->getId(), newItem);
+}
+
+/*
+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)
+{
+    int index = m_dataStore.getInventoryItems().find(selectedItemId);
+    if (index != -1)
+    {
+        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
+        if (item != nullptr)
+        {
+            int totalQuantity = item->getQuantity() + quantity;
+            item->setQuantity(totalQuantity);
+        }
+    }
+}
+
+/*
+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()
+{
+	return m_dataStore.getInventoryItems();
+}
+
+/*
+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)
+{
+    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
+    if (index != -1)
+    {
+        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
+        if (item != nullptr)
+        {
+            item->setState(util::State::INACTIVE);
+        }
+    }
+}
+
+/*
+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)
+{
+    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
+    if (index != -1)
+    {
+        return m_dataStore.getInventoryItems().getValueAt(index);
+    }
+    return nullptr;
+}
+
+/*
+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)
+{
+	if (user)
+	{
+		const std::string& userID = user->getId();
+		if (m_observers.find(userID) == -1)
+		{
+			m_observers[userID] = user;
+		}
+	}
+}
+
+/*
+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)
+{
+	if (user)
+	{
+		const std::string& userID = user->getId();
+		if (m_observers.find(userID) != -1)
+		{
+			m_observers.remove(userID);
+		}
+	}
+}
+
+/*
+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)
+	{
+		if (m_observers.find(user->getId()) != -1)
+		{
+			Notification* notification =
+				Factory::getObject<Notification>(
+					user->getId(),
+					user,
+					"InventoryManagementService: " + title,
+					message,
+					util::Timestamp()
+				);
+			if (notification)
+			{
+				user->addNotification(notification);
+			}
+			else
+			{
+				throw std::runtime_error("Failed to create notification");
+			}
+		}
+	}
+}
+

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

@@ -1,14 +1,16 @@
 /*
 File: InventoryManagementService.h
-Description: Declares the InventoryManagementService class which manages inventory operations in the Vehicle Service Management System.
+Description: Header file declaring the InventoryManagementService class,
-             Provides functionality to retrieve, add, and remove inventory items, send low stock alerts, and handle notifications using the Observer pattern.
+             which manages inventory items, stock updates, and notifications
+             related to low stock alerts. Inherits from NotificationManagementService.
 Author: Trenser
-Date: 19-May-2026
+Date:19-May-2026
 */
 
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "NotificationManagementService.h"
 #include "DataStore.h"
 
@@ -19,14 +21,20 @@ class InventoryManagementService : public NotificationManagementService
 private:
     DataStore& m_dataStore;
     static util::Map<std::string, User*> m_observers;
+    util::Vector<std::string> getObserverIDs() override;
 public:
     InventoryManagementService() : m_dataStore(DataStore::getInstance()) {}
     util::Map<std::string, InventoryItem*> getInventoryItems();
     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;
     void detach(User* user) override;
+    void loadInventoryItems();
+    void saveInventoryItems();
+    void loadObservers();
+    void saveObservers();
 };

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

@@ -19,4 +19,5 @@ public:
 	virtual void sendNotification(User* recipient, const std::string& title, const std::string& message) = 0;
 	virtual void attach(User* user) = 0;
 	virtual void detach(User* user) = 0;
+	virtual util::Vector<std::string> getObserverIDs() = 0;
 };

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

@@ -8,14 +8,16 @@ Date: 20-May-2026
 */
 
 #include <stdexcept>
-#include "PaymentManagementService.h"
-#include "Invoice.h"
-#include "ServiceBooking.h"
-#include "Enums.h"
-#include "Timestamp.h"
 #include "Config.h"
-#include "User.h"
+#include "Enums.h"
 #include "Factory.h"
+#include "FileManager.h"
+#include "Invoice.h"
+#include "PaymentManagementService.h"
+#include "ServiceBooking.h"
+#include "Timestamp.h"
+#include "User.h"
+#include "Utility.h"
 
 util::Map<std::string, User*> PaymentManagementService::m_observers{};
 
@@ -125,12 +127,129 @@ void PaymentManagementService::sendPaymentReminders()
 					User* customer = serviceBooking->getCustomer();
 					if (customer)
 					{
-						sendNotification(customer,
+						std::string title = "Payment Reminder";
-							"Payment Reminder",
+						std::string message = "Your payment for Invoice ID " + invoice->getId() + " is still pending. Please complete the payment.";
-							"Your payment for Invoice ID " + invoice->getId() + " is still pending.Please complete the payment." + invoice->getId());
+						sendNotification(customer, title, message);
 					}
 				}
 			}
 		}
 	}
 }
+
+/*
+Function: getObserverIDs
+Description: Retrieves the IDs of all observers currently attached to the
+             PaymentManagementService.
+Parameters:
+    - None
+Returns:
+    - util::Vector<std::string>: Vector of observer user IDs
+*/
+util::Vector<std::string> PaymentManagementService::getObserverIDs()
+{
+	util::Vector<std::string> observerIDs;
+	int numberOfObservers = m_observers.getSize();
+	for (int index = 0; index < numberOfObservers; index++)
+	{
+		User* observer = m_observers.getValueAt(index);
+		if (observer)
+		{
+			observerIDs.push_back(observer->getId());
+		}
+	}
+	return observerIDs;
+}
+
+/*
+Function: loadInvoices
+Description: Loads invoices from persistent storage into the datastore.
+             Validates associated service bookings and inventory parts before
+             attaching them to each invoice. Throws exceptions if invalid IDs
+             are encountered.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a booking ID or part ID is invalid
+*/
+void PaymentManagementService::loadInvoices()
+{
+    util::FileManager<Invoice> invoiceFileManager(config::file::INVOICE_FILE);
+    auto& invoices = m_dataStore.getInvoices();
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    auto& inventoryItems = m_dataStore.getInventoryItems();
+    auto invoicesMap = invoiceFileManager.load();
+    for (int invoiceIndex = 0; invoiceIndex < invoicesMap.getSize(); invoiceIndex++)
+    {
+        Invoice* invoice = invoicesMap.getValueAt(invoiceIndex);
+        int bookingIndex = serviceBookings.find(invoice->getBookingId());
+        if (bookingIndex == -1)
+        {
+            throw std::runtime_error("Invalid Booking ID");
+        }
+        ServiceBooking* booking = serviceBookings.getValueAt(bookingIndex);
+        invoice->setBooking(booking);
+        util::Map<std::string, InventoryItem*> invoiceParts;
+        auto& partIDs = invoice->getPartIDs();
+        for (int partIndex = 0; partIndex < partIDs.getSize(); partIndex++)
+        {
+            const std::string& partID = partIDs[partIndex];
+            int inventoryIndex = inventoryItems.find(partID);
+            if (inventoryIndex == -1)
+            {
+                throw std::runtime_error("Invalid Part ID");
+            }
+            invoiceParts[partID] = inventoryItems.getValueAt(inventoryIndex);
+        }
+        invoice->setParts(invoiceParts);
+        invoices[invoice->getId()] = invoice;
+    }
+}
+
+/*
+Function: saveInvoices
+Description: Saves invoices from the datastore to persistent storage.
+             Uses FileManager to serialize invoices into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void PaymentManagementService::saveInvoices()
+{
+    util::FileManager<Invoice> invoiceFileManager(config::file::INVOICE_FILE);
+    auto& invoices = m_dataStore.getInvoices();
+    invoiceFileManager.save(invoices);
+}
+
+/*
+Function: loadObservers
+Description: Loads observer IDs from persistent storage and attaches corresponding
+             users as observers to the PaymentManagementService.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if an observer ID is invalid (not found in datastore)
+*/
+void PaymentManagementService::loadObservers()
+{
+    util::loadObservers(config::file::PAYMENTMANAGEMENTOBSERVERS, this, m_dataStore);
+}
+
+/*
+Function: saveObservers
+Description: Saves the current observer IDs of the PaymentManagementService
+             to persistent storage for future retrieval.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void PaymentManagementService::saveObservers()
+{
+    util::saveObservers(config::file::PAYMENTMANAGEMENTOBSERVERS, this);
+}

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

@@ -22,6 +22,7 @@ class PaymentManagementService : public NotificationManagementService
 private:
     DataStore& m_dataStore;
     static util::Map<std::string, User*> m_observers;
+    util::Vector<std::string> getObserverIDs() override;
 public:
     PaymentManagementService() : m_dataStore(DataStore::getInstance()) {}
     void generateInvoice(ServiceBooking* booking);
@@ -31,4 +32,8 @@ public:
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;
     void detach(User* user) override;
+    void loadInvoices();
+    void saveInvoices();
+    void loadObservers();
+    void saveObservers();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp

@@ -6,15 +6,24 @@ Description: Implementation file containing the method definitions of the
 Author: Trenser
 Date:19-May-2026
 */
+
 #include <stdexcept>
 #include "AuthenticationManagementService.h"
 #include "ComboPackage.h"
+#include "Config.h"
+#include "DataStore.h"
 #include "Factory.h"
+#include "FileManager.h"
+#include "InventoryItem.h"
+#include "JobCard.h"
 #include "Service.h"
 #include "ServiceBooking.h"
+#include "ServiceBooking.h"
+
 #include "ServiceManagementService.h"
 #include "Timestamp.h"
 #include "User.h"
+#include "Utility.h"
 
 /*
 Function: purchaseService
@@ -55,9 +64,9 @@ void ServiceManagementService::purchaseService(const util::Vector<std::string>&
 		throw std::runtime_error("Failed to create service booking");
 	}
 	serviceBookingMap[serviceBooking->getId()] = serviceBooking;
-	sendNotification(authenticatedUser,
+    std::string title = "Service Booking succeeded";
-		"Service Booking succeeded",
+    std::string message = "Your service booking has been successfully placed with ID " + serviceBooking->getId();
-		"Your service booking has been successfully placed with ID " + serviceBooking->getId());
+    sendNotification(authenticatedUser, title, message);
 }
 
 /*
@@ -94,9 +103,9 @@ void ServiceManagementService::purchaseComboPackage(const std::string& comboPack
 		throw std::runtime_error("Failed to create combo package service booking");
 	}
 	serviceBookingMap[serviceBooking->getId()] = serviceBooking;
-	sendNotification(authenticatedUser,
+    std::string title = "Combo Package Service Booking succeeded";
-		"Combo Package Service Booking succeeded",
+    std::string message = "Your service booking for the combo package has been successfully placed with ID " + serviceBooking->getId();
-		"Your service booking for the combo package has been successfully placed with ID " + serviceBooking->getId());
+    sendNotification(authenticatedUser, title, message);
 }
 
 util::Map<std::string, User*> ServiceManagementService::m_observers{};
@@ -178,3 +187,541 @@ void ServiceManagementService::sendNotification(User* user, const std::string& t
 		}
 	}
 }
+
+/*
+Function: getObserverIDs
+Description: Retrieves the IDs of all observers currently attached to the
+             ServiceManagementService.
+Parameters:
+    - None
+Returns:
+    - util::Vector<std::string>: Vector of observer user IDs
+*/
+util::Vector<std::string> ServiceManagementService::getObserverIDs()
+{
+	util::Vector<std::string> observerIDs;
+	int numberOfObservers = m_observers.getSize();
+	for (int index = 0; index < numberOfObservers; index++)
+	{
+		User* observer = m_observers.getValueAt(index);
+		if (observer)
+		{
+			observerIDs.push_back(observer->getId());
+		}
+	}
+	return observerIDs;
+}
+
+/*
+Function: loadServices
+Description: Loads services from persistent storage into the datastore.
+             Validates required inventory items and attaches them to each service.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if an inventory item ID is invalid
+*/
+void ServiceManagementService::loadServices()
+{
+    util::FileManager<Service> serviceFileManager(config::file::SERVICE_FILE);
+    auto& services = m_dataStore.getServices();
+    auto& inventoryItems = m_dataStore.getInventoryItems();
+    auto servicesMap = serviceFileManager.load();
+    for (int serviceIndex = 0; serviceIndex < servicesMap.getSize(); serviceIndex++)
+    {
+        Service* service = servicesMap.getValueAt(serviceIndex);
+        services[service->getId()] = service;
+        util::Map<std::string, InventoryItem*> inventoryItemsMap;
+        auto& inventoryItemIDs = service->getRequiredInventoryItemIDs();
+        for (int inventoryItemIndex = 0; inventoryItemIndex < inventoryItemIDs.getSize(); inventoryItemIndex++)
+        {
+            const std::string& inventoryItemID = inventoryItemIDs[inventoryItemIndex];
+            int index = inventoryItems.find(inventoryItemID);
+            if (index == -1)
+            {
+                throw std::runtime_error("Invalid Inventory Item ID");
+            }
+            inventoryItemsMap[inventoryItemID] = inventoryItems.getValueAt(index);
+        }
+        service->setRequiredInventoryItems(inventoryItemsMap);
+    }
+}
+
+/*
+Function: saveServices
+Description: Saves services from the datastore to persistent storage.
+             Uses FileManager to serialize services into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveServices()
+{
+	util::FileManager<Service> serviceFileManager(config::file::SERVICE_FILE);
+	auto& services = m_dataStore.getServices();
+	serviceFileManager.save(services);
+}
+
+/*
+Function: loadComboPackages
+Description: Loads combo packages from persistent storage into the datastore.
+             Validates associated services and attaches them to each package.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a service ID is invalid
+*/
+void ServiceManagementService::loadComboPackages()
+{
+    util::FileManager<ComboPackage> comboPackageFileManager(config::file::COMBOPACKAGE_FILE);
+    auto& comboPackages = m_dataStore.getComboPackages();
+    auto& services = m_dataStore.getServices();
+    auto comboPackagesMap = comboPackageFileManager.load();
+    for (int packageIndex = 0; packageIndex < comboPackagesMap.getSize(); packageIndex++)
+    {
+        ComboPackage* comboPackage = comboPackagesMap.getValueAt(packageIndex);
+        util::Map<std::string, Service*> packageServices;
+        auto& serviceIDs = comboPackage->getServiceIDs();
+        for (int serviceIndex = 0; serviceIndex < serviceIDs.getSize(); serviceIndex++)
+        {
+            const std::string& serviceID = serviceIDs[serviceIndex];
+            int serviceMapIndex = services.find(serviceID);
+            if (serviceMapIndex == -1)
+            {
+                throw std::runtime_error("Invalid Service ID");
+            }
+            packageServices[serviceID] = services.getValueAt(serviceMapIndex);
+        }
+        comboPackage->setServices(packageServices);
+        comboPackages[comboPackage->getId()] = comboPackage;
+    }
+}
+
+/*
+Function: saveComboPackages
+Description: Saves combo packages from the datastore to persistent storage.
+             Uses FileManager to serialize combo packages into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveComboPackages()
+{
+    util::FileManager<ComboPackage> comboPackageFileManager(config::file::COMBOPACKAGE_FILE);
+    auto& comboPackages = m_dataStore.getComboPackages();
+    comboPackageFileManager.save(comboPackages);
+}
+
+/*
+Function: loadServiceBookings
+Description: Loads service bookings from persistent storage into the datastore.
+             Validates associated services, customers, and technicians before
+             attaching them to each booking.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a service ID, customer ID, or technician ID is invalid
+    - std::runtime_error if a user is not of the expected type (customer/technician)
+*/
+void ServiceManagementService::loadServiceBookings()
+{
+    util::FileManager<ServiceBooking> bookingFileManager(config::file::SERVICEBOOKING_FILE);
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    auto& services = m_dataStore.getServices();
+    auto& users = m_dataStore.getUsers();
+    auto bookingsMap = bookingFileManager.load();
+    for (int bookingIndex = 0; bookingIndex < bookingsMap.getSize(); bookingIndex++)
+    {
+        ServiceBooking* booking = bookingsMap.getValueAt(bookingIndex);
+        util::Map<std::string, Service*> bookingServices;
+        auto& serviceIDs = booking->getServiceIDs();
+        for (int serviceIndex = 0; serviceIndex < serviceIDs.getSize(); serviceIndex++)
+        {
+            const std::string& serviceID = serviceIDs[serviceIndex];
+            int serviceMapIndex = services.find(serviceID);
+            if (serviceMapIndex == -1)
+            {
+                throw std::runtime_error("Invalid Service ID");
+            }
+
+            bookingServices[serviceID] = services.getValueAt(serviceMapIndex);
+        }
+        booking->setServices(bookingServices);
+        int customerIndex = users.find(booking->getCustomerId());
+        if (customerIndex == -1)
+        {
+            throw std::runtime_error("Invalid Customer ID");
+        }
+        User* customer = users.getValueAt(customerIndex);
+        if (customer->getUserType() != util::UserType::CUSTOMER)
+        {
+            throw std::runtime_error("User is not a customer");
+        }
+        booking->setCustomer(customer);
+        const std::string& technicianId = booking->getAssignedTechnicianId();
+        if (!technicianId.empty())
+        {
+            int technicianIndex = users.find(technicianId);
+            if (technicianIndex == -1)
+            {
+                throw std::runtime_error("Invalid Technician ID");
+            }
+            User* technician = users.getValueAt(technicianIndex);
+            if (technician->getUserType() != util::UserType::TECHNICIAN)
+            {
+                throw std::runtime_error("User is not a technician");
+            }
+            booking->setAssignedTechnician(technician);
+        }
+        serviceBookings[booking->getId()] = booking;
+    }
+}
+
+/*
+Function: saveServiceBookings
+Description: Saves service bookings from the datastore to persistent storage.
+             Uses FileManager to serialize bookings into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveServiceBookings()
+{
+    util::FileManager<ServiceBooking> bookingFileManager(config::file::SERVICEBOOKING_FILE);
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    bookingFileManager.save(serviceBookings);
+}
+
+/*
+Function: loadJobCards
+Description: Loads job cards from persistent storage into the datastore.
+             Validates associated bookings, services, and technicians before
+             attaching them to each job card.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a booking ID, service ID, or technician ID is invalid
+    - std::runtime_error if a service does not belong to the booking
+    - std::runtime_error if a user is not a technician
+*/
+void ServiceManagementService::loadJobCards()
+{
+    util::FileManager<JobCard> jobCardFileManager(config::file::JOBCARD_FILE);
+    auto& jobCards = m_dataStore.getJobCards();
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    auto& services = m_dataStore.getServices();
+    auto& users = m_dataStore.getUsers();
+    auto jobCardsMap = jobCardFileManager.load();
+    for (int jobCardIndex = 0; jobCardIndex < jobCardsMap.getSize(); jobCardIndex++)
+    {
+        JobCard* jobCard = jobCardsMap.getValueAt(jobCardIndex);
+        int bookingIndex = serviceBookings.find(jobCard->getBookingId());
+        if (bookingIndex == -1)
+        {
+            throw std::runtime_error("Invalid Booking ID");
+        }
+        ServiceBooking* booking = serviceBookings.getValueAt(bookingIndex);
+        jobCard->setBooking(booking);
+        int serviceIndex = services.find(jobCard->getServiceId());
+        if (serviceIndex == -1)
+        {
+            throw std::runtime_error("Invalid Service ID");
+        }
+        Service* service = services.getValueAt(serviceIndex);
+        if (booking->getServices().find(jobCard->getServiceId()) == -1)
+        {
+            throw std::runtime_error("Service does not belong to booking");
+        }
+        jobCard->setService(service);
+        int technicianIndex = users.find(jobCard->getTechnicianId());
+        if (technicianIndex == -1)
+        {
+            throw std::runtime_error("Invalid Technician ID");
+        }
+        User* technician = users.getValueAt(technicianIndex);
+        if (technician->getUserType() != util::UserType::TECHNICIAN)
+        {
+            throw std::runtime_error("User is not a technician");
+        }
+        jobCard->setTechnician(technician);
+        jobCards[jobCard->getId()] = jobCard;
+    }
+}
+
+/*
+Function: saveJobCards
+Description: Saves job cards from the datastore to persistent storage.
+             Uses FileManager to serialize job cards into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveJobCards()
+{
+    util::FileManager<JobCard> jobCardFileManager(config::file::JOBCARD_FILE);
+    auto& jobCards = m_dataStore.getJobCards();
+    jobCardFileManager.save(jobCards);
+}
+
+/*
+Function: loadObservers
+Description: Loads observer IDs from persistent storage and attaches corresponding
+             users as observers to the ServiceManagementService.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if an observer ID is invalid (not found in datastore)
+*/
+void ServiceManagementService::loadObservers()
+{
+    util::loadObservers(config::file::SERVICEMANAGEMENTOBSERVERS, this, m_dataStore);
+}
+
+/*
+Function: saveObservers
+Description: Saves the current observer IDs of the ServiceManagementService
+             to persistent storage for future retrieval.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveObservers()
+{
+    util::saveObservers(config::file::SERVICEMANAGEMENTOBSERVERS, this);
+}
+
+/*
+Function: cancelCustomerServiceBookings
+Description: Cancels all service bookings associated with a given customer or technician.
+             Updates booking status, resets customer/technician assignments, sends notifications,
+             and restocks inventory items.
+Parameter: const std::string& userID - ID of the customer or technician
+Return type: void
+*/
+void ServiceManagementService::cancelCustomerServiceBookings(const std::string& userID)
+{
+    const int INCREMENT_VALUE = 1;
+    auto& users = m_dataStore.getUsers();
+    int userIndex = users.find(userID);
+    if (userIndex == -1)
+    {
+        throw std::runtime_error("User not found: " + userID);
+    }
+    User* user = users.getValueAt(userIndex);
+    if (user == nullptr)
+    {
+        throw std::runtime_error("User not found: " + userID);
+    }
+    util::UserType type = user->getUserType();
+    auto& bookings = DataStore::getInstance().getServiceBookings();
+    for (int bookingIterator = 0; bookingIterator < bookings.getSize(); bookingIterator++)
+    {
+        ServiceBooking* booking = bookings.getValueAt(bookingIterator);
+        if (booking != nullptr &&
+            (booking->getCustomerId() == userID || booking->getAssignedTechnicianId() == userID))
+        {
+            if (booking->getStatus() == util::ServiceJobStatus::PENDING ||
+                booking->getStatus() == util::ServiceJobStatus::STARTED)
+            {
+                if (type == util::UserType::CUSTOMER)
+                {
+                    booking->setStatus(util::ServiceJobStatus::CANCELLED);
+                    booking->setCustomer(nullptr);
+                    booking->setCustomerId("");
+                    User* assignedTechnician = booking->getAssignedTechnician();
+                    std::string title = "Customer Service Cancelled";
+                    std::string message = "The customer has cancelled their service booking. Your assigned job card has been cancelled and the inventory has been restocked.";
+                    sendNotification(assignedTechnician, title, message);
+                }
+                else if (type == util::UserType::TECHNICIAN)
+                {
+                    booking->setStatus(util::ServiceJobStatus::PENDING);
+                    std::string title = "Technician Unavailable";
+                    std::string message = "Your assigned technician is no longer available. Your booking has been reset to pending, and we will reassign a new technician shortly.";
+                    sendNotification(booking->getCustomer(), title, message); 
+                }
+                booking->setAssignedTechnician(nullptr);
+                booking->setAssignedTechnicianId("");
+                const auto& ListOfServices = booking->getServices();
+                for (int serviceIterator = 0; serviceIterator < ListOfServices.getSize(); serviceIterator++)
+                {
+                    Service* service = ListOfServices.getValueAt(serviceIterator);
+                    if (service != nullptr)
+                    {
+                        const auto& items = service->getRequiredInventoryItems();
+                        for (int itemIterator = 0; itemIterator < items.getSize(); itemIterator++)
+                        {
+                            InventoryItem* item = items.getValueAt(itemIterator);
+                            if (item != nullptr)
+                            {
+                                item->setQuantity(item->getQuantity() + INCREMENT_VALUE);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/*
+Function: cancelTechnicianJobs
+Description: Cancels all jobs assigned to a technician. Updates job status, sends notifications,
+             and restocks inventory items used in the service.
+Parameter: const std::string& technicianID - ID of the technician
+Return type: void
+*/
+void ServiceManagementService::cancelTechnicianJobs(const std::string& technicianID)
+{
+    const int INCREMENT_VALUE = 1;
+    auto& jobs = m_dataStore.getJobCards();
+    for (int jobIterator = 0; jobIterator < jobs.getSize(); jobIterator++)
+    {
+        JobCard* job = jobs.getValueAt(jobIterator);
+        if (job != nullptr && job->getTechnicianId() == technicianID)
+        {
+            if (job->getStatus() == util::ServiceJobStatus::PENDING || job->getStatus() == util::ServiceJobStatus::STARTED)
+            {
+                job->setStatus(util::ServiceJobStatus::CANCELLED);
+                std::string title = "Job Cancelled";
+                std::string message = "The Job has cancelled. Your job card has been cancelled and the inventory has been restocked.";
+                sendNotification(job->getTechnician(), title, message);
+                Service* service = job->getService();
+                if (service != nullptr)
+                {
+                    const auto& items = service->getRequiredInventoryItems();
+                    for (int itemIterator = 0; itemIterator < items.getSize(); itemIterator++)
+                    {
+                        InventoryItem* item = items.getValueAt(itemIterator);
+                        if (item != nullptr)
+                        {
+                            item->setQuantity(item->getQuantity() + INCREMENT_VALUE);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/*
+Function: createComboPackage
+Description: Creates a new combo package with two services and a discount percentage.
+             Validates service IDs, ensures uniqueness, and inserts the new package into the DataStore.
+Parameter: const std::string& packageName - name of the combo package
+           const util::Vector<std::string>& serviceIDsInNewCombo - list of service IDs
+           double discountPercentage - discount percentage for the package
+Return type: void
+*/
+void ServiceManagementService::createComboPackage(const std::string& packageName, const util::Vector<std::string>& serviceIDsInNewCombo, double discountPercentage)
+{
+    if (packageName.empty())
+    {
+        throw std::invalid_argument("The Combo Package Name cannot be empty.\n");
+    }
+    if (serviceIDsInNewCombo.getSize() < 2 || serviceIDsInNewCombo.getSize() > 2)
+    {
+        throw std::invalid_argument("Combo package must contain only two services.");
+    }
+    if (discountPercentage < 0.0 || discountPercentage > 100.0)
+    {
+        throw std::invalid_argument("Discount percentage must be between 0 and 100.");
+    }
+    auto& servicesMap = m_dataStore.getServices();
+    for (int index = 0; index < serviceIDsInNewCombo.getSize(); index++)
+    {
+        const std::string serviceid = serviceIDsInNewCombo[index];
+        if (servicesMap.find(serviceid) == -1)
+        {
+            throw std::runtime_error("Service ID not found: " + serviceid);
+        }
+    }
+    auto& comboPackageMap = m_dataStore.getComboPackages();
+    for (int iterator = 0; iterator < comboPackageMap.getSize(); iterator++)
+    {
+        ComboPackage* existingCombos = comboPackageMap.getValueAt(iterator);
+        const util::Map<std::string, Service*>& servicesInsideExistingCombos = existingCombos->getServices();
+        if (servicesInsideExistingCombos.getSize() == serviceIDsInNewCombo.getSize())
+        {
+            bool isIdentical = true;
+            for (int serviceIterator = 0; serviceIterator < serviceIDsInNewCombo.getSize(); serviceIterator++)
+            {
+                const std::string& id = serviceIDsInNewCombo[serviceIterator];
+                if (servicesInsideExistingCombos.find(id) == -1)
+                {
+                    isIdentical = false;
+                    break;
+                }
+            }
+            if (isIdentical)
+            {
+                throw std::runtime_error("A combo package with the same services already exists.");
+            }
+        }
+    }
+    util::Map<std::string, Service*> selectedServices;
+    for (int iteratorOne = 0; iteratorOne < serviceIDsInNewCombo.getSize(); iteratorOne++)
+    {
+        const std::string& serviceId = serviceIDsInNewCombo[iteratorOne];
+        int serviceIndex = servicesMap.find(serviceId);
+        if (serviceIndex == -1)
+        {
+            throw std::runtime_error("Service ID not found: " + serviceId);
+        }
+        selectedServices.insert(serviceId, servicesMap.getValueAt(serviceIndex));
+    }
+    ComboPackage* newComboPackage = Factory::getObject<ComboPackage>(packageName, discountPercentage, selectedServices);
+    comboPackageMap.insert(newComboPackage->getId(), newComboPackage);
+}
+
+/*
+Function: getComboPackages
+Description: Retrieves all combo packages stored in the DataStore.
+Parameter: None
+Return type: util::Map<std::string, ComboPackage*>
+*/
+util::Map<std::string, ComboPackage*> ServiceManagementService::getComboPackages()
+{
+    return m_dataStore.getComboPackages();
+}
+
+/*
+Function: removeComboPackage
+Description: Removes a combo package by marking it inactive. Throws an exception if the package ID is not found.
+Parameter: const std::string& comboPackageID - ID of the combo package
+Return type: void
+*/
+void ServiceManagementService::removeComboPackage(const std::string& comboPackageID)
+{
+    bool removed = false;
+    util::Map<std::string, ComboPackage*>& currentComboPackages = m_dataStore.getComboPackages();
+    for (int iterator = 0; iterator < currentComboPackages.getSize(); iterator++)
+    {
+        ComboPackage* currentComboPackage = currentComboPackages.getValueAt(iterator);
+        if (currentComboPackage && currentComboPackage->getId() == comboPackageID)
+        {
+            currentComboPackage->setState(util::State::INACTIVE);
+            removed = true;
+            break;
+        }
+    }
+    if (!removed)
+    {
+        throw std::runtime_error("Combo package with ID '" + comboPackageID + "' not found.");
+    }
+}

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

@@ -6,6 +6,7 @@ Description: Header file declaring the ServiceManagementService class, which man
 Author: Trenser
 Date:19-May-2026
 */
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -22,6 +23,7 @@ class ServiceManagementService : public NotificationManagementService
 private:
     DataStore& m_dataStore;
     static util::Map<std::string, User*> m_observers;
+    util::Vector<std::string> getObserverIDs() override;
 public:
     ServiceManagementService() : m_dataStore(DataStore::getInstance()) {}
     util::Map<std::string, Service*> getServices();
@@ -37,9 +39,19 @@ public:
     void completeJob(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;
     void detach(User* user) override;
+    void loadServices();
+    void saveServices();
+    void loadComboPackages();
+    void saveComboPackages();
+    void loadServiceBookings();
+    void saveServiceBookings();
+    void loadJobCards();
+    void saveJobCards();
+    void loadObservers();
+    void saveObservers();
 };

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

@@ -6,16 +6,18 @@ Description: Implementation file containing the method definitions of the
 Author: Trenser
 Date:19-May-2026
 */
-#include <stdexcept>
 #include "Config.h"
 #include "Enums.h"
 #include "Factory.h"
+#include "FileManager.h"
 #include "InventoryManagementService.h"
+#include "Notification.h"
 #include "PaymentManagementService.h"
 #include "ServiceManagementService.h"
 #include "User.h"
 #include "UserManagementService.h"
 #include "Vector.h"
+#include <stdexcept>
 
 
 /*
@@ -174,3 +176,117 @@ void UserManagementService::deleteNotification(const std::string& notificationID
 	}
 	notifications.remove(notificationID);
 }
+
+/*
+Function: loadUsers
+Description: Loads users and notifications from persistent storage into the datastore.
+             Validates that each notification’s recipient exists and attaches the
+             notification to the corresponding user.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a notification recipient user ID is invalid
+*/
+void UserManagementService::loadUsers()
+{
+    util::FileManager<User> userFileManager(config::file::USER_FILE);
+    util::FileManager<Notification> notificationFileManager(config::file::NOTIFICATION_FILE);
+    auto& users = m_dataStore.getUsers();
+    auto usersMap = userFileManager.load();
+    auto notificationsMap = notificationFileManager.load();
+    int numberOfUsers = usersMap.getSize();
+    int numberOfNotifications = notificationsMap.getSize();
+    for (int index = 0; index < numberOfUsers; index++)
+    {
+        users[usersMap.getKeyAt(index)] = usersMap.getValueAt(index);
+    }
+    for (int index = 0; index < numberOfNotifications; index++)
+    {
+        Notification* notification = notificationsMap.getValueAt(index);
+        const std::string& recipientUserId = notification->getRecipientUserId();
+        int userIndex = users.find(recipientUserId);
+        if (userIndex == -1)
+        {
+            throw std::runtime_error("Invalid recipient user ID");
+        }
+        User* user = users.getValueAt(userIndex);
+        user->addNotification(notification);
+    }
+}
+
+/*
+Function: saveUsers
+Description: Saves users and their notifications from the datastore to persistent storage.
+             Collects notifications from all users into a single map before saving.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void UserManagementService::saveUsers()
+{
+    util::FileManager<User> userFileManager(config::file::USER_FILE);
+    util::FileManager<Notification> notificationFileManager(config::file::NOTIFICATION_FILE);
+    auto& users = m_dataStore.getUsers();
+    util::Map<std::string, Notification*> notifications;
+    for (int userIndex = 0; userIndex < users.getSize(); userIndex++)
+    {
+        User* user = users.getValueAt(userIndex);
+        auto& userNotifications = user->getNotifications();
+        for (int notificationIndex = 0; notificationIndex < userNotifications.getSize(); notificationIndex++)
+        {
+            notifications[userNotifications.getKeyAt(notificationIndex)] =
+                userNotifications.getValueAt(notificationIndex);
+        }
+    }
+    userFileManager.save(users);
+    notificationFileManager.save(notifications);
+}
+
+/*
+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()
+{
+	return m_dataStore.getUsers();
+}
+
+/*
+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)
+{
+	int index = m_dataStore.getUsers().find(userID);
+	if (index != -1)
+	{
+		return m_dataStore.getUsers().getValueAt(index);
+	}
+	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)
+{
+	int index = m_dataStore.getUsers().find(userID);
+	if (index != -1)
+	{
+		User* user = m_dataStore.getUsers().getValueAt(index);
+		if (user != nullptr)
+		{
+			user->setState(util::State::INACTIVE);
+		}
+	}
+}

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

@@ -30,4 +30,6 @@ public:
     util::Vector<Notification*> getUserNotifications(const std::string& userID);
     void deleteNotification(const std::string& notificationID, const std::string& userID);
     void ensureAdminExists();
+    void loadUsers();
+    void saveUsers();
 };

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

@@ -25,4 +25,19 @@ namespace config
 		constexpr int INVENTORY_LOW_STOCK_THRESHOLD = 5;
 		constexpr int PAYMENT_REMINDER_THRESHOLD_HOURS = 168;
 	}
+
+	namespace file
+	{
+		constexpr const char* INVENTORYITEM_FILE = "files/InventoryItem.csv";
+		constexpr const char* USER_FILE = "files/User.csv";
+		constexpr const char* NOTIFICATION_FILE = "files/Notification.csv";
+		constexpr const char* SERVICE_FILE = "files/Service.csv";
+		constexpr const char* COMBOPACKAGE_FILE = "files/ComboPackage.csv";
+		constexpr const char* SERVICEBOOKING_FILE = "files/ServiceBooking.csv";
+		constexpr const char* JOBCARD_FILE = "files/JobCard.csv";
+		constexpr const char* INVOICE_FILE = "files/Invoice.csv";
+		constexpr const char* SERVICEMANAGEMENTOBSERVERS = "files/ServiceManagementObservers.csv";
+		constexpr const char* PAYMENTMANAGEMENTOBSERVERS = "files/PaymentManagementObservers.csv";
+		constexpr const char* INVENTORYMANAGEMENTOBSERVERS = "files/InventoryManagementObservers.csv";
+	}
 }

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

@@ -33,8 +33,10 @@ namespace util
 
 	enum class ServiceJobStatus
 	{
+        PENDING,
 		STARTED,
-		COMPLETED
+		COMPLETED,
+        CANCELLED
 	};
 
     enum class State
@@ -192,10 +194,14 @@ namespace util
     {
         switch (status)
         {
+        case ServiceJobStatus::PENDING:
+            return "PENDING";
         case ServiceJobStatus::STARTED:
             return "STARTED";
         case ServiceJobStatus::COMPLETED:
             return "COMPLETED";
+        case ServiceJobStatus::CANCELLED:
+            return "CANCELLED";
         }
         throw std::invalid_argument("Invalid ServiceJobStatus");
     }
@@ -220,6 +226,14 @@ namespace util
         {
             return ServiceJobStatus::COMPLETED;
         }
+        if (value == "PENDING")
+        {
+            return ServiceJobStatus::PENDING;
+        }
+        if (value == "CANCELLED")
+        {
+            return ServiceJobStatus::CANCELLED;
+        }
         throw std::invalid_argument("Invalid ServiceJobStatus string");
     }
 
@@ -236,9 +250,9 @@ namespace util
         switch (status)
         {
         case State::ACTIVE:
-            return "STARTED";
+            return "ACTIVE";
         case State::INACTIVE:
-            return "COMPLETED";
+            return "INACTIVE";
         }
         throw std::invalid_argument("Invalid State");
     }
@@ -259,7 +273,7 @@ namespace util
         {
             return State::ACTIVE;
         }
-        if (value == "COMPLETED")
+        if (value == "INACTIVE")
         {
             return State::INACTIVE;
         }

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

@@ -0,0 +1,79 @@
+/*
+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 "Vector.h"
+
+namespace util
+{
+    /*
+    Function: loadRecords
+    Description: Loads records from a given file path into a vector of strings.
+                 Skips the header line if present. Creates the file if it does not exist.
+    Parameters:
+        - filePath: const std::string&, path to the file
+    Returns:
+        - util::Vector<std::string>: Vector containing all records (excluding header)
+    Throws:
+        - None (creates file if missing)
+    */
+    inline util::Vector<std::string> loadRecords(const std::string& filePath)
+    {
+        util::Vector<std::string> records;
+        std::ifstream file(filePath);
+        if (!file.is_open())
+        {
+            std::ofstream newFile(filePath);
+            newFile.close();
+            file.open(filePath);
+        }
+        std::string line;
+        bool isHeader = true;
+        while (std::getline(file, line))
+        {
+            if (isHeader)
+            {
+                isHeader = false;
+                continue;
+            }
+            records.push_back(line);
+        }
+        return records;
+    }
+
+    /*
+    Function: saveRecords
+    Description: Saves records to a given file path. Overwrites existing content
+                 and writes a header line followed by all records.
+    Parameters:
+        - filePath: const std::string&, path to the file
+        - records: const util::Vector<std::string>&, vector of records to save
+    Returns:
+        - void
+    Throws:
+        - std::runtime_error if the file cannot be opened for writing
+    */
+    inline void saveRecords(const std::string& filePath, const util::Vector<std::string>& records)
+    {
+        std::ofstream file(filePath, std::ios::trunc);
+        if (!file.is_open())
+        {
+            throw std::runtime_error("Failed to open file " + filePath);
+        }
+        file << "Values" << '\n';
+        int numberOfRecords = records.getSize();
+        for (int index = 0; index < numberOfRecords; index++)
+        {
+            file << records[index] << '\n';
+        }
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/FileManager.h

@@ -0,0 +1,117 @@
+/*
+File: FileManager.h
+Description: Declares and implements a generic FileManager template class for
+			 loading and saving objects to and from files. Uses serialization
+			 and deserialization methods defined in the object type T.
+			 Provides persistence support for system entities such as Users,
+			 Services, InventoryItems, etc.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#pragma once
+#include <stdexcept>
+#include <string>
+#include <fstream>
+#include "Vector.h"
+#include "Map.h"
+
+namespace util
+{
+	template <typename T> using objects = util::Map<std::string, T*>;
+
+	template <typename T>
+	class FileManager
+	{
+	private:
+		std::string m_filePath;
+	public:
+		FileManager() : m_filePath("") {}
+		FileManager(const std::string& filePath) : m_filePath(filePath) {}
+		objects<T> load();
+		void save(const objects<T>&);
+	};
+
+	/*
+	Function: load
+	Description: Loads records from the file into a map of objects.
+				 Skips the header line, deserializes each record into an object of type T,
+				 and stores them in a map keyed by object ID.
+	Parameters:
+		- None
+	Returns:
+		- util::Map<std::string, T*> containing deserialized objects
+	Throws:
+		- std::runtime_error if deserialization fails for any record
+	*/
+	template <typename T>
+	objects<T> FileManager<T>::load()
+	{
+		objects<T> records;
+		std::ifstream file(m_filePath);
+		if (!file.is_open())
+		{
+			std::ofstream newFile(m_filePath);
+			newFile.close();
+			file.open(m_filePath);
+		}
+		util::Vector<std::string> lines;
+		std::string line;
+		while (std::getline(file, line))
+		{
+			lines.push_back(line);
+		}
+		int numberOfLines = lines.getSize();
+		bool isHeader = true;
+		for (int lineIndex = 0; lineIndex < numberOfLines; lineIndex++)
+		{
+			const auto& record = lines[lineIndex];
+			if (isHeader)
+			{
+				isHeader = false;
+				continue;
+			}
+			auto object = T::deserialize(record);
+			if (!object)
+			{
+				throw std::runtime_error("Failed to deserialize record");
+			}
+			records[object->getId()] = object;
+		}
+		return records;
+	}
+
+	/*
+	Function: save
+	Description: Saves records to the file. Serializes each object of type T into a string,
+				 writes a header line, and then writes all serialized records to the file.
+	Parameters:
+		- records: const util::Map<std::string, T*>&, map of objects to save
+	Returns:
+		- void
+	Throws:
+		- std::runtime_error if the file cannot be opened for writing
+	*/
+	template <typename T>
+	void FileManager<T>::save(const objects<T>& records)
+	{
+		util::Vector<std::string> lines;
+		lines.push_back(T::getHeaders());
+		int numberOfRecords = records.getSize();
+		for (int recordIndex = 0; recordIndex < numberOfRecords; recordIndex++)
+		{
+			const auto& record = records.getValueAt(recordIndex);
+			lines.push_back(record->serialize());
+		}
+		std::ofstream file(m_filePath, std::ios::trunc);
+		if (!file.is_open())
+		{
+			throw std::runtime_error("Failed to open file " + m_filePath);
+		}
+		int numberOfLines = lines.getSize();
+		for (int lineIndex = 0; lineIndex < numberOfLines; lineIndex++)
+		{
+			file << lines[lineIndex] << '\n';
+		}
+	}
+}

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

@@ -34,7 +34,7 @@ namespace util
 
     /*
      * 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 +43,15 @@ 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;
     }
 
     /*

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

@@ -1,49 +1,103 @@
 /*
 File: Utility.h
-Description: Header file declaring utility functions used across the system,
+Description: Header file declaring utility functions used across the system
-             including cost calculation for services and combo packages.
 Author: Trenser
 Date:19-May-2026
 */
+
 #pragma once
-#include "Service.h"
+#include "ComboPackage.h"
+#include "DataStore.h"
+#include "FileHelper.h"
 #include "InventoryItem.h"
+#include "InventoryItem.h"
+#include "NotificationManagementService.h"
+#include "Service.h"
 
-/*
+namespace util
-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)
 {
-    double cost = 0;
+    /*
-    auto& requiredInventoryItems = service->getRequiredInventoryItems();
+    Function: calculatePartsCost
-    int requiredInventoryItemsSize = requiredInventoryItems.getSize();
+    Description: Calculates the total cost of parts required for a given service
-    for (int index = 0; index < requiredInventoryItemsSize; index++)
+                 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
+    Function: calculateComboServiceEstimatedCost
-Description: Calculates the estimated total cost of a combo package by summing
+    Description: Calculates the estimated total cost of a combo package by summing
-             the labor and parts costs of all services included in the package.
+                  the labor and parts costs of all services included in the package.
-Parameter: const ComboPackage* comboPackage - pointer to the combo package object
+    Parameter: const ComboPackage* comboPackage - pointer to the combo package object
-Return type: double - estimated total cost of the combo package
+    Return type: double - estimated total cost of the combo package
-*/
+    */
-inline double calculateComboServiceEstimatedCost(const ComboPackage* comboPackage)
+    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);
+        double cost = 0;
-        cost += calculatePartsCost(service) + service->getLaborCost();
+        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;
+    }
+
+    /*
+    Function: loadObservers
+    Description: Loads observer IDs from a file and attaches the corresponding users
+                 to the notification management service. Validates that each observer ID
+                 exists in the datastore before attaching.
+    Parameters:
+        - filePath: const std::string&, path to the file containing observer IDs
+        - service: NotificationManagementService*, pointer to the notification service
+        - dataStore: DataStore&, reference to the datastore containing users
+    Returns:
+        - void
+    Throws:
+        - std::runtime_error if an observer ID is invalid (not found in datastore)
+    */
+    inline void loadObservers(const std::string& filePath, NotificationManagementService* service, DataStore& dataStore)
+    {
+        auto observerIDs = util::loadRecords(filePath);
+        auto& users = dataStore.getUsers();
+        for (int index = 0; index < observerIDs.getSize(); index++)
+        {
+            const std::string& observerID = observerIDs[index];
+            int userIndex = users.find(observerID);
+            if (userIndex == -1)
+            {
+                throw std::runtime_error("Invalid Observer ID");
+            }
+            service->attach(users.getValueAt(userIndex));
+        }
+    }
+
+    /*
+    Function: saveObservers
+    Description: Saves the current observer IDs from the notification management service
+                 to a file for persistence.
+    Parameters:
+        - filePath: const std::string&, path to the file where observer IDs will be saved
+        - service: NotificationManagementService*, pointer to the notification service
+    Returns:
+        - void
+    */
+    inline void saveObservers(const std::string& filePath, NotificationManagementService* service)
+    {
+        auto observerIDs = service->getObserverIDs();
+        util::saveRecords(filePath, observerIDs);
     }
-    return cost;
 }

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

@@ -8,72 +8,286 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+#include <iomanip>
+#include <iostream>
 #include "AdminMenu.h"
+#include "ComboPackage.h"
+#include "Enums.h"
 #include "InputHelper.h"
-#include "OutputHelper.h"
+#include "InventoryItem.h"
 #include "MenuHelper.h"
+#include "OutputHelper.h"
+#include "Service.h"
+#include "User.h"
+#include "Utility.h"
+#include "Validator.h"
 
 /*
 Function: showMenu
-Description: Displays the admin menu in a loop until the user chooses to logout.
+Description: Displays the admin menu and handles user input until logout is selected.
-			 Handles exceptions and ensures smooth user interaction.
+Parameter: None
-Parameters:
+Return type: void
-	- None
-Returns:
-	- void
 */
 void AdminMenu::showMenu()
 {
-	bool isMenuActive = true;
+    while (true)
-	while (isMenuActive)
+    {
+        try
+        {
+            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. Add Technician"
+                << "\n7. Remove Customer/Technician"
+                << "\n8. Create Service"
+                << "\n9. Remove Service"
+                << "\n10. Create Combo Package"
+                << "\n11. Remove Combo Package"
+                << "\n12. View Notifications"
+                << "\n13. Change Password"
+                << "\n14. 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();
+        }
+    }
+}
+
+/*
+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)
+{
+    switch (choice)
+    {
+    case 1:
+        viewStockLevels();
+        break;
+    case 2:
+        addInventoryItem();
+        break;
+    case 3:
+        removeInventoryItem();
+        break;
+    case 4:
+        checkStockAvailability();
+        break;
+    case 5:
+        assignJob();
+        break;
+    case 6:
+        addTechnician();
+        break;
+    case 7:
+        removeUser();
+        break;
+    case 8:
+        createService();
+        break;
+    case 9:
+        removeService();
+        break;
+    case 10:
+        createComboPackages();
+        break;
+    case 11:
+        removeComboPackage();
+        break;
+    case 12:
+        viewNotifications();
+        break;
+    case 13:
+        changePassword();
+        break;
+    case 14:
+        logout();
+        return false;
+    default:
+        std::cout << "Enter a valid choice!" << std::endl;
+        util::pressEnter();
+    }
+    return true;
+}
+
+/*
+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();
+	std::cout << std::left << std::setw(15) << "Item ID"
+		<< std::setw(25) << "Part Name"
+		<< std::setw(10) << "Quantity"
+		<< std::setw(10) << "Price"
+		<< std::endl;
+	for (int iterator = 0; iterator < inventoryItems.getSize(); ++iterator)
 	{
-		try
+		const InventoryItem* item = inventoryItems.getValueAt(iterator);
+		if (item != nullptr)
 		{
-			int choice;
+			if (item->getState() != util::State::INACTIVE)
-			util::clear();
-			std::cout << "" << std::endl;
-			util::read(choice);
-			if (!handleOperation(choice))
 			{
-				isMenuActive = false;
+				std::cout << std::left << std::setw(15) << item->getId()
+					<< std::setw(25) << item->getPartName()
+					<< std::setw(10) << item->getQuantity()
+					<< std::setw(10) << item->getPrice()
+					<< std::endl;
 			}
 		}
-		catch (const std::exception& e)
-		{
-			std::cout << "Exception: " << e.what() << std::endl;
-			util::pressEnter();
-		}
 	}
 }
 
-bool AdminMenu::handleOperation(int choice)
+/*
-{
+Function: addInventoryItem
-	return false;
+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::logout()
+*/
-{
-}
-
-void AdminMenu::changePassword()
-{
-}
-
-void AdminMenu::viewStockLevels()
-{
-}
-
 void AdminMenu::addInventoryItem()
 {
+	util::clear();
+	int choice, quantity;
+	double price;
+	std::string partName;
+	std::cout << "1. Add new item \n2. Add Quantity\nEnter your choice : ";
+	util::read(choice);
+	switch (choice)
+	{
+	case 1: 
+	{
+		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 << "New Item " << partName << " added to the Inventory.\n";
+		break;
+	}
+	case 2:
+	{
+		auto inventoryItems = m_controller.getInventoryItems();
+		addQuantityToItem(inventoryItems, m_controller);
+		break;
+	}
+	}
+	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();
+    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;
+        }
+    }
+    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 << "Enter the Item Id : ";
+	util::read(itemId);
+	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";
+		}
+	}
+	util::pressEnter();
 }
 
 void AdminMenu::assignJob()
@@ -88,20 +302,168 @@ void AdminMenu::removeService()
 {
 }
 
+/*
+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 << std::left << std::setw(25) << "Enter Technician Username: ";
+	util::read(username);
+	std::cout << std::left << std::setw(25) << "Enter Technician Name: ";
+	util::read(name);
+	std::cout << std::setw(25) << "Enter Technician Password: ";
+	util::read(password);
+	if(!util::isPasswordValid(password))
+	{
+		std::cout << "Error: Password is invalid!";
+		util::pressEnter();
+		return;
+	}
+	std::cout << std::setw(25) << "Enter Technician Email: ";
+	util::read(email);
+	if(!util::isEmailValid(email))
+	{
+		std::cout << "Error: Email is invalid!";
+		util::pressEnter();
+		return;
+	}
+	std::cout << std::setw(25) << "Enter Technician Phone: ";
+	util::read(phoneNumber);
+	if(!util::isPhoneNumberValid(phoneNumber))
+	{
+		std::cout << "Error: Phone Number is invalid!";
+		util::pressEnter();
+		return;
+	}
+	m_controller.createTechnician(username, name, password, email, phoneNumber);
+	std::cout << "\nTechnician Added Successfully.\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();
+	if (activeUserCount < 1)
+	{
+		std::cout << "No Active users." << std::endl;
+		util::pressEnter();
+		return;
+	}
+	displayAllActiveUsers(listOfActiveUsers, activeUserCount);
+	std::cout << "Enter the index of the user to delete : ";
+	util::read(indexChoice);
+	if (indexChoice < 1 || indexChoice > activeUserCount)
+	{
+		std::cout << "Error Invaild 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: 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();
+	auto serviceList = m_controller.getServices();
+    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(serviceList);
+            if (chosenService == nullptr)
+            {
+                std::cout << "Failed to create combo package!";
+                util::pressEnter();
+                return;
+            }
+            bool alreadyChosen = false;
+            for (int iteratorOne = 0; iteratorOne < selectedServiceID.getSize(); iteratorOne++)
+            {
+                if (selectedServiceID[iteratorOne] == chosenService->getId())
+                {
+                    alreadyChosen = true;
+                    break;
+                }
+            }
+            if (alreadyChosen)
+            {
+                std::cout << "Service already selected. Please choose a different one." << std::endl;
+                continue; 
+            }
+            selectedServiceID.push_back(chosenService->getId());
+            util::clear();
+            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();
+	util::Map<std::string, const ComboPackage*> currentComboPackages = m_controller.getComboPackages();
+	std::string selectedComboPackageID = selectComboPackage(currentComboPackages);
+	if (selectedComboPackageID != "")
+	{
+		m_controller.removeComboPackage(selectedComboPackageID);
+		std::cout << "Combo Package removed successfully.\n";
+	}
+	else
+	{
+		std::cout << "Combo package removal failed.\n";
+	}
+	util::pressEnter();
 }
 
 /*

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

@@ -1,10 +1,10 @@
 /*
 File: AdminMenu.h
-Description: Declares the AdminMenu class which provides the administrative console menu in the Vehicle Service Management System.
+Description: Header file declaring the AdminMenu class, which provides
-             Supports operations such as inventory management, job assignment, service creation/removal, technician management,
+             administrative operations such as inventory management,
-             combo package handling, notification viewing, and account management functions like logout and password change.
+             user management, service configuration, and notifications.
 Author: Trenser
-Date: 19-May-2026
+Date:19-May-2026
 */
 
 #pragma once

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

@@ -15,7 +15,6 @@ Date:19-May-2026
 #include "MenuHelper.h"
 #include "OutputHelper.h"
 #include "Service.h"
-#include "Utility.h"
 #include "Validator.h"
 #include "Vector.h"
 
@@ -25,6 +24,7 @@ Description: Displays the customer menu and handles user input until logout is s
 Parameter: None
 Return type: void
 */
+
 void CustomerMenu::showMenu()
 {
     while (true)
@@ -125,19 +125,7 @@ Return type: void
 */
 void CustomerMenu::changePassword()
 {
-	std::string newPassword;
+    changePasswordHelper(m_controller);
-	util::clear();
-	std::cout << "Enter new password: ";
-	util::read(newPassword);
-	m_controller.changePassword(newPassword);
-	if (!util::isPasswordValid(newPassword))
-	{
-		std::cout << "Error: Password is not strong enough!";
-		util::pressEnter();
-		return;
-	}
-	std::cout << "Password changed successfully";
-	util::pressEnter();
 }
 
 /*
@@ -171,55 +159,6 @@ void CustomerMenu::updateDetails()
 	util::pressEnter();
 }
 
-/*
-Function: selectServiceFromServices
-Description: Displays active services and allows the customer to select one by index.
-Parameter: const util::Map<std::string, const Service*>& services - list of services
-Return type: const Service* - selected service
-*/
-static const Service* selectServiceFromServices(const util::Map<std::string, const Service*>& services)
-{
-    util::Map<int, const Service*> activeServicesMap;
-    int currentIndex = 1;
-    int userInputIndex;
-    std::cout << std::left
-        << std::setw(10) << "Index"
-        << std::setw(15) << "Service ID"
-        << std::setw(25) << "Service Name"
-        << std::setw(15) << "Estimated Cost"
-        << std::endl;
-    for (int index = 0; index < services.getSize(); index++)
-    {
-        const Service* currentService = services.getValueAt(index);
-        if (currentService->getState() != util::State::ACTIVE)
-        {
-            continue;
-        }
-        activeServicesMap.insert(currentIndex, currentService);
-        double partsCost = calculatePartsCost(currentService);
-        std::cout << std::left
-            << std::setw(10) << currentIndex
-            << std::setw(15) << currentService->getId()
-            << std::setw(25) << currentService->getName()
-            << std::setw(15) << (currentService->getLaborCost() + partsCost)
-            << std::endl;
-        currentIndex++;
-    }
-    if (activeServicesMap.getSize() == 0)
-    {
-        std::cout << "No active services available." << std::endl;
-        return nullptr;
-    }
-    std::cout << "Enter service index: ";
-    util::read(userInputIndex);
-    if (activeServicesMap.find(userInputIndex) == -1)
-    {
-        std::cout << "Invalid service index." << std::endl;
-        return nullptr;
-    }
-    return activeServicesMap[userInputIndex];
-}
-
 /*
 Function: selectService
 Description: Allows the customer to select a service, provide vehicle details,
@@ -253,54 +192,6 @@ void CustomerMenu::selectService()
     util::pressEnter();
 }
 
-/*
-Function: selectComboPackageFromPackages
-Description: Displays active combo packages and allows the customer to select one by index.
-Parameter: const util::Map<std::string, const ComboPackage*>& comboPackages - list of combo packages
-Return type: const ComboPackage* - selected combo package
-*/
-static const ComboPackage* selectComboPackageFromPackages(const util::Map<std::string, const ComboPackage*>& comboPackages)
-{
-    util::Map<int, const ComboPackage*> activeComboPackages;
-    int currentIndex = 1;
-    int userInputIndex;
-    std::cout << std::left
-        << std::setw(10) << "Index"
-        << std::setw(15) << "Combo Package ID"
-        << std::setw(15) << "Combo Package Name"
-        << std::setw(15) << "Estimate Cost"
-        << std::endl;
-    for (int index = 0; index < comboPackages.getSize(); index++)
-    {
-        const ComboPackage* currentComboPackage = comboPackages.getValueAt(index);
-        if (currentComboPackage->getState() != util::State::ACTIVE)
-        {
-            continue;
-        }
-        activeComboPackages.insert(currentIndex, currentComboPackage);
-        std::cout << std::left
-            << std::setw(10) << currentIndex
-            << std::setw(15) << currentComboPackage->getId()
-            << std::setw(25) << currentComboPackage->getPackageName()
-            << std::setw(15) << calculateComboServiceEstimatedCost(currentComboPackage)
-            << std::endl;
-        currentIndex++;
-    }
-    if (activeComboPackages.getSize() == 0)
-    {
-        std::cout << "No active combo packages available." << std::endl;
-        return nullptr;
-    }
-    std::cout << "Enter combo package index: ";
-    util::read(userInputIndex);
-    if (activeComboPackages.find(userInputIndex) == -1)
-    {
-        std::cout << "Invalid combo package index." << std::endl;
-        return nullptr;
-    }
-    return activeComboPackages[userInputIndex];
-}
-
 /*
 Function: selectComboPackage
 Description: Allows the customer to select a combo package, provide vehicle details,
@@ -357,38 +248,6 @@ void CustomerMenu::viewNotifications()
 	viewAndDeleteNotification(m_controller);
 }
 
-/*
-Function: getNotificationPreference (static helper)
-Description: Helper function to configure notification preferences for a specific service.
-Parameters:
-    - serviceName: Name of the service for which notifications are being configured.
-Returns:
-    - bool: True if notifications are enabled, False if disabled.
-*/
-static bool getNotificationPreference(const std::string& serviceName)
-{
-    int choice;
-    while (true)
-    {
-        util::clear();
-        std::cout << "    Configure Notification Preferences\n";
-        std::cout << "\n" << serviceName << " Notifications\n";
-        std::cout << "1. Enable Notifications\n";
-        std::cout << "2. Disable Notifications\n";
-        std::cout << "Enter your choice: ";
-        util::read(choice);
-        if (choice == 1)
-        {
-            return true;
-        }
-        if (choice == 2)
-        {
-            return false;
-        }
-        std::cout << "\nInvalid choice. Please enter 1 or 2.\n";
-        util::pressEnter();
-    }
-}
 
 /*
 Function: configureNotifications

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

@@ -7,6 +7,7 @@ Description: Header file declaring the CustomerMenu class, which provides
 Author: Trenser
 Date:19-May-2026
 */
+
 #pragma once
 #include "Controller.h"
 

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/MenuHelper.h

@@ -8,14 +8,20 @@ Date: 21-May-2026
 */
 
 #pragma once
+#include <iostream>
 #include <iomanip>
 #include <string>
+#include "Utility.h"
 #include "Controller.h"
 #include "InputHelper.h"
 #include "Map.h"
 #include "Notification.h"
 #include "OutputHelper.h"
 #include "Vector.h"
+#include "Validator.h"
+#include "Service.h"
+#include "ComboPackage.h"
+#include "Utility.h"
 
 /*
 Function: selectNotification
@@ -112,3 +118,412 @@ inline void viewAndDeleteNotification(Controller& controller)
     controller.deleteNotification(selectedNotification->getId());
     util::pressEnter();
 }
+
+/*
+Function: changePassword
+Description: Helper function to change password
+Parameter: controller: Reference to the Controller object used to manage notifications.
+Return type: void
+*/
+inline void changePasswordHelper(Controller& controller)
+{
+    util::clear();
+    std::string newPassword;
+    while (true)
+    {
+        util::clear();
+        std::cout << "Enter new password: ";
+        util::read(newPassword);
+        if (!util::isPasswordValid(newPassword))
+        {
+            std::cout << "Error: Password is not strong enough!\n";
+            util::pressEnter();
+            continue;
+        }
+        controller.changePassword(newPassword);
+        std::cout << "Password changed successfully\n";
+        util::pressEnter();
+        break;
+    }
+}
+
+/*
+Function: filterActiveUsers
+Description: Filters out inactive users and returns a map of active users.
+Parameter: const util::Map<std::string, const User*>& listOfUsers - all users
+Return type: util::Map<std::string, const User*>
+*/
+inline util::Map<std::string, const User*> filterActiveUsers(const util::Map<std::string, const User*>& listOfUsers)
+{
+    util::Map<std::string, const User*> activeUsers;
+    int inventorySize = listOfUsers.getSize();
+    for (int index = 0; index < inventorySize; index++)
+    {
+        const User* user = listOfUsers.getValueAt(index);
+        if (user != nullptr && user->getState() != util::State::INACTIVE)
+        {
+            activeUsers.insert(user->getId(), user);
+        }
+    }
+    return activeUsers;
+}
+
+/*
+Function: displayAllActiveUsers
+Description: Displays all active users in a tabular format with index, ID, username, and type.
+Parameter: util::Map<std::string, const User*>& activeUsers - active users list
+           int activeUserCount - number of active users
+Return type: void
+*/
+inline void displayAllActiveUsers(util::Map<std::string, const User*>& activeUsers, int activeUserCount)
+{
+    std::cout << std::left << std::setw(10) << "Index"
+        << std::setw(15) << "User ID"
+        << std::setw(25) << "Username"
+        << std::setw(25) << "User Type"
+        << std::endl;
+    for (int iterator = 0; iterator < activeUserCount; iterator++)
+    {
+        const User* user = activeUsers.getValueAt(iterator);
+        if (user != nullptr)
+        {
+            std::cout << std::left << std::setw(10) << (iterator + 1)
+                << std::setw(15) << user->getId()
+                << std::setw(25) << user->getUserName()
+                << std::setw(25) << util::getUserTypeString(user->getUserType())
+                << std::endl;
+        }
+        else
+        {
+            std::cout << "No users found.\n";
+            util::pressEnter();
+            return;
+        }
+    }
+}
+
+/*
+Function: selectServiceFromServices
+Description: Displays active services and allows the customer to select one by index.
+Parameter: const util::Map<std::string, const Service*>& services - list of services
+Return type: const Service* - selected service
+*/
+inline const Service* selectServiceFromServices(const util::Map<std::string, const Service*>& services)
+{
+    util::Map<int, const Service*> activeServicesMap;
+    int currentIndex = 1;
+    int userInputIndex;
+    std::cout << std::left
+        << std::setw(10) << "Index"
+        << std::setw(15) << "Service ID"
+        << std::setw(25) << "Service Name"
+        << std::setw(15) << "Estimated Cost"
+        << std::endl;
+    for (int index = 0; index < services.getSize(); index++)
+    {
+        const Service* currentService = services.getValueAt(index);
+        if (currentService == nullptr)
+        {
+            throw std::runtime_error("Warning: Encountered a null service\n");
+            continue;
+        }
+        if (currentService->getState() != util::State::ACTIVE)
+        {
+            continue;
+        }
+        activeServicesMap.insert(currentIndex, currentService);
+        double partsCost = util::calculatePartsCost(currentService);
+        std::cout << std::left
+            << std::setw(10) << currentIndex
+            << std::setw(15) << currentService->getId()
+            << std::setw(25) << currentService->getName()
+            << std::setw(15) << (currentService->getLaborCost() + partsCost)
+            << std::endl;
+        currentIndex++;
+    }
+    if (activeServicesMap.getSize() == 0)
+    {
+        std::cout << "No active services available." << std::endl;
+        return nullptr;
+    }
+    std::cout << "Enter service index: ";
+    util::read(userInputIndex);
+    if (activeServicesMap.find(userInputIndex) == -1)
+    {
+        std::cout << "Invalid service index." << std::endl;
+        return nullptr;
+    }
+    return activeServicesMap[userInputIndex];
+}
+
+/*
+Function: selectComboPackageFromPackages
+Description: Displays active combo packages and allows the customer to select one by index.
+Parameter: const util::Map<std::string, const ComboPackage*>& comboPackages - list of combo packages
+Return type: const ComboPackage* - selected combo package
+*/
+inline const ComboPackage* selectComboPackageFromPackages(const util::Map<std::string, const ComboPackage*>& comboPackages)
+{
+    util::Map<int, const ComboPackage*> activeComboPackages;
+    int currentIndex = 1;
+    int userInputIndex;
+    std::cout << std::left
+        << std::setw(10) << "Index"
+        << std::setw(15) << "Combo Package ID"
+        << std::setw(15) << "Combo Package Name"
+        << std::setw(15) << "Estimate Cost"
+        << std::endl;
+    for (int index = 0; index < comboPackages.getSize(); index++)
+    {
+        const ComboPackage* currentComboPackage = comboPackages.getValueAt(index);
+        if (currentComboPackage->getState() != util::State::ACTIVE)
+        {
+            continue;
+        }
+        activeComboPackages.insert(currentIndex, currentComboPackage);
+        std::cout << std::left
+            << std::setw(10) << currentIndex
+            << std::setw(15) << currentComboPackage->getId()
+            << std::setw(25) << currentComboPackage->getPackageName()
+            << std::setw(15) << util::calculateComboServiceEstimatedCost(currentComboPackage)
+            << std::endl;
+        currentIndex++;
+    }
+    if (activeComboPackages.getSize() == 0)
+    {
+        std::cout << "No active combo packages available." << std::endl;
+        return nullptr;
+    }
+    std::cout << "Enter combo package index: ";
+    util::read(userInputIndex);
+    if (activeComboPackages.find(userInputIndex) == -1)
+    {
+        std::cout << "Invalid combo package index." << std::endl;
+        return nullptr;
+    }
+    return activeComboPackages[userInputIndex];
+}
+
+/*
+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
+*/
+
+/*
+Function: getNotificationPreference (static helper)
+Description: Helper function to configure notification preferences for a specific service.
+Parameters:
+    - serviceName: Name of the service for which notifications are being configured.
+Returns:
+    - bool: True if notifications are enabled, False if disabled.
+*/
+inline bool getNotificationPreference(const std::string& serviceName)
+{
+    int choice;
+    while (true)
+    {
+        util::clear();
+        std::cout << "    Configure Notification Preferences\n";
+        std::cout << "\n" << serviceName << " Notifications\n";
+        std::cout << "1. Enable Notifications\n";
+        std::cout << "2. Disable Notifications\n";
+        std::cout << "Enter your choice: ";
+        util::read(choice);
+        if (choice == 1)
+        {
+            return true;
+        }
+        if (choice == 2)
+        {
+            return false;
+        }
+        std::cout << "\nInvalid choice. Please enter 1 or 2.\n";
+        util::pressEnter();
+    }
+}
+
+/*
+Function: filterActiveItems
+Description: Filters out inactive inventory items and returns a map
+             containing only active items.
+Parameter: const util::Map<std::string, const InventoryItem*>& inventoryItems -
+           map of all inventory items
+Return type: util::Map<std::string, const InventoryItem*>
+*/
+inline util::Map<std::string, const InventoryItem*> filterActiveItems(const util::Map<std::string, const InventoryItem*>& inventoryItems)
+{
+    util::Map<std::string, const InventoryItem*> activeItems;
+    int inventorySize = inventoryItems.getSize();
+    for (int index = 0; index < inventorySize; index++)
+    {
+        const InventoryItem* item = inventoryItems.getValueAt(index);
+        if (item != nullptr && item->getState() != util::State::INACTIVE)
+        {
+            activeItems.insert(item->getId(), item);
+        }
+    }
+    return activeItems;
+}
+
+/*
+Function: displayInventoryWithItems
+Description: Displays inventory items in a tabular format with index, ID,
+             part name, quantity, and price.
+Parameter: util::Map<std::string, const InventoryItem*>& inventoryItems -
+           map of inventory items to display
+Return type: void
+*/
+inline void displayInventoryWithItems(util::Map<std::string, const InventoryItem*>& inventoryItems)
+{
+    int inventorySize = inventoryItems.getSize();
+    std::cout << std::left << std::setw(10) << "Index"
+        << std::setw(15) << "Item ID"
+        << std::setw(25) << "Part Name"
+        << std::setw(10) << "Quantity"
+        << std::setw(10) << "Price"
+        << std::endl;
+    for (int iterator = 0; iterator < inventorySize; iterator++)
+    {
+        const InventoryItem* item = inventoryItems.getValueAt(iterator);
+        if (item != nullptr)
+        {
+            std::cout << std::left << std::setw(10) << (iterator + 1)
+                << std::setw(15) << item->getId()
+                << std::setw(25) << item->getPartName()
+                << std::setw(10) << item->getQuantity()
+                << std::setw(10) << item->getPrice()
+                << std::endl;
+        }
+    }
+}
+
+/*
+Function: addQuantityToItem
+Description: Allows the admin to select an active inventory item and
+             increase its stock quantity.
+Parameter: util::Map<std::string, const InventoryItem*>& inventoryItems -
+           map of inventory items
+           Controller& m_controller - controller instance to update stock
+Return type: void
+*/
+inline void addQuantityToItem(util::Map<std::string, const InventoryItem*>& inventoryItems, Controller& m_controller)
+{
+    int itemIndex;
+    int quantity;
+    auto activeItems = filterActiveItems(inventoryItems);
+    int activeSize = activeItems.getSize();
+    if (activeSize == 0)
+    {
+        std::cout << "No active items available in Inventory" << std::endl;
+        return;
+    }
+    displayInventoryWithItems(activeItems);
+    std::cout << "Enter the index of the item to update: ";
+    util::read(itemIndex);
+    if (itemIndex < 1 || itemIndex > activeSize)
+    {
+        std::cout << "Invalid index selected." << std::endl;
+        return;
+    }
+    std::cout << "Enter quantity to add: ";
+    util::read(quantity);
+    if (quantity < 0)
+    {
+        std::cout << "The quantity should be Greater than 0." << std::endl;
+        return;
+    }
+    const InventoryItem* selectedItem = activeItems.getValueAt(itemIndex - 1);
+    if (selectedItem != nullptr)
+    {
+        std::string selectedItemId = selectedItem->getId();
+        m_controller.addInventoryItemStock(selectedItemId, quantity);
+        std::cout << "Updated " << selectedItem->getPartName()
+            << " stock. New quantity: " << selectedItem->getQuantity()
+            << std::endl;
+    }
+    else
+    {
+        std::cout << "Error: Selected item could not be found." << std::endl;
+    }
+}
+
+/*
+Function: displayComboPackagesWithIndex
+Description: Displays combo packages with index, ID, name, and discount percentage.
+Parameter: util::Map<int, const ComboPackage*>& currentComboPackageIndexMap - combo packages map
+Return type: void
+*/
+inline void displayComboPackagesWithIndex(util::Map<int, const ComboPackage*>& currentComboPackageIndexMap)
+{
+    for (int iterator = 0; iterator < currentComboPackageIndexMap.getSize(); iterator++)
+    {
+        const ComboPackage* currentComboPackage = currentComboPackageIndexMap.getValueAt(iterator);
+        if (currentComboPackage == nullptr)
+        {
+            throw std::runtime_error("Error accessing the combopackage.\n");
+        }
+        if (iterator == 0)
+        {
+            std::cout << std::left
+                << std::setw(8) << "Index"
+                << std::setw(10) << "ID"
+                << std::setw(20) << "Package Name"
+                << std::setw(15) << "Discount (%)"
+                << "\n";
+        }
+        std::cout << std::left
+            << std::setw(8) << currentComboPackageIndexMap.getKeyAt(iterator)
+            << std::setw(10) << currentComboPackage->getId()
+            << std::setw(20) << currentComboPackage->getPackageName()
+            << std::setw(15) << currentComboPackage->getDiscountPercentage()
+            << "\n";
+    }
+}
+
+/*
+Function: selectComboPackage
+Description: Allows the admin to select an active combo package by index.
+Parameter: util::Map<std::string, const ComboPackage*>& currentComboPackages - combo packages list
+Return type: std::string - ID of the selected combo package
+*/
+inline std::string selectComboPackage(util::Map<std::string, const ComboPackage*>& currentComboPackages)
+{
+    util::Map<int, const ComboPackage*> currentComboPackageIndexMap;
+    if (currentComboPackages.getSize() == 0)
+    {
+        throw std::runtime_error("No combo packages are available.\n");
+    }
+    int currentIndex = 1, choice, selectedIndex;
+    for (int iterator = 0; iterator < currentComboPackages.getSize(); iterator++)
+    {
+        if (currentComboPackages.getValueAt(iterator)->getState() == util::State::INACTIVE)
+        {
+            continue;
+        }
+        currentComboPackageIndexMap.insert(currentIndex++, currentComboPackages.getValueAt(iterator));
+    }
+    if (currentComboPackageIndexMap.getSize() == 0)
+    {
+        throw std::runtime_error("No combo packages currently active.");
+    }
+    displayComboPackagesWithIndex(currentComboPackageIndexMap);
+    std::cout << "Enter your choice(Index): ";
+    util::read(choice);
+    selectedIndex = currentComboPackageIndexMap.find(choice);
+    if (selectedIndex != -1)
+    {
+        std::string selectedComboPackageID = currentComboPackageIndexMap.getValueAt(selectedIndex)->getId();
+        return selectedComboPackageID;
+    }
+    else
+    {
+        std::cout << "Enter a valid choice.\n";
+        return "";
+    }
+}

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

@@ -1,15 +1,16 @@
 /*
 File: TechnicianMenu.cpp
-Description: Implements the TechnicianMenu class which provides the technician’s console interface
+Description: Implementation file containing the method definitions of the
-			 in the Vehicle Service Management System. Handles menu display, user input, and
+             TechnicianMenu class, including menu handling, job completion,
-			 technician-specific operations such as completing jobs and viewing notifications.
+             notification viewing, password management, and logout logic.
 Author: Trenser
-Date: 19-May-2026
+Date:19-May-2026
 */
-
 #include "TechnicianMenu.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
+#include "Validator.h"
+#include "MenuHelper.h"
 #include "MenuHelper.h"
 
 /*
@@ -23,33 +24,62 @@ Returns:
 */
 void TechnicianMenu::showMenu()
 {
-	bool isMenuActive = true;
+    while (true)
-	while (isMenuActive)
+    {
-	{
+        try
-		try
+        {
-		{
+            int choice;
-			int choice;
+            util::clear();
-			util::clear();
+            std::cout << "Technician Menu"
-			std::cout << "" << std::endl;
+                << "\n1. Mark Job as Completed"
-			util::read(choice);
+                << "\n2. View Notifications"
-			if (!handleOperation(choice))
+                << "\n3. Change Password"
-			{
+                << "\n4. Logout"
-				isMenuActive = false;
+                << "\nEnter a choice: ";
-			}
+            util::read(choice);
-		}
+            if (!handleOperation(choice))
-		catch (const std::exception& e)
+            {
-		{
+                break;
-			std::cout << "Exception: " << e.what() << std::endl;
+            }
-			util::pressEnter();
+        }
-		}
+        catch (const std::exception& e)
-	}
+        {
+            std::cout << "Exception: " << e.what() << std::endl;
+            util::pressEnter();
+        }
+    }
 }
 
+/*
+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;
+    switch (choice)
+    {
+    case 1:
+        completeJob();
+        break;
+    case 2:
+        viewNotifications();
+        break;
+    case 3:
+        changePassword();
+        break;
+    case 4:
+        logout();
+        return false;
+    default:
+        std::cout << "Enter a valid choice!" << std::endl;
+        util::pressEnter();
+    }
+    return true;
 }
 
+
 void TechnicianMenu::completeJob()
 {
 }
@@ -66,3 +96,26 @@ 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

@@ -1,9 +1,10 @@
 /*
 File: TechnicianMenu.h
-Description: Declares the TechnicianMenu class which provides the technician-facing console menu in the Vehicle Service Management System.
+Description: Header file declaring the TechnicianMenu class, which provides
-             Supports operations such as viewing assigned jobs, completing jobs, and managing notifications.
+             technician operations such as job completion, notification viewing,
+             password management, and logout functionality.
 Author: Trenser
-Date: 19-May-2026
+Date:19-May-2026
 */
 
 #pragma once
@@ -18,4 +19,6 @@ public:
     void showMenu();
     void completeJob();
     void viewNotifications();
+    void logout();
+    void changePassword();
 };

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

@@ -6,11 +6,12 @@ Description: Implementation file containing the method definitions of the
 Author: Trenser
 Date:19-May-2026
 */
-#include "UserInterface.h"
+
+#include "Enums.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
-#include "Enums.h"
 #include "User.h"
+#include "UserInterface.h"
 #include "Validator.h"
 
 /*
@@ -22,6 +23,7 @@ Return type: void
 */
 void UserInterface::run()
 {
+	m_controller.loadSystemData();
 	m_controller.runSystemChecks();
 	bool isMenuActive = true;
 	while (isMenuActive)
@@ -43,6 +45,7 @@ void UserInterface::run()
 			util::pressEnter();
 		}
 	}
+	m_controller.saveSystemData();
 }
 
 /*

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

@@ -7,6 +7,7 @@ Description: Header file declaring the UserInterface class, which provides
 Author: Trenser
 Date:19-May-2026
 */
+
 #pragma once
 #include "Controller.h"
 #include "AdminMenu.h"