changes

.gitignore

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

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

@@ -102,7 +102,7 @@
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
-      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;$(ProjectDir)core\sharedmemory;$(ProjectDir)core\events;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;$(ProjectDir)datastores\sharedmemory;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -117,7 +117,7 @@
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
-      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;$(ProjectDir)core\sharedmemory;$(ProjectDir)core\events;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>$(ProjectDir)models;$(ProjectDir)controllers;$(ProjectDir)factories;$(ProjectDir)views;$(ProjectDir)services;$(ProjectDir)utilities;$(ProjectDir)core\patterns;$(ProjectDir)datastores;$(ProjectDir)datastores\sharedmemory;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -126,11 +126,10 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="controllers\Controller.cpp" />
-    <ClCompile Include="core\events\EventManager.cpp" />
     <ClCompile Include="core\patterns\Observer.cpp" />
     <ClCompile Include="core\patterns\Subject.cpp" />
-    <ClCompile Include="core\sharedmemory\SharedMemory.cpp" />
     <ClCompile Include="datastores\DataStore.cpp" />
+    <ClCompile Include="datastores\sharedmemory\SharedMemory.cpp" />
     <ClCompile Include="models\ComboPackage.cpp" />
     <ClCompile Include="models\InventoryItem.cpp" />
     <ClCompile Include="models\Invoice.cpp" />
@@ -141,6 +140,7 @@
     <ClCompile Include="models\User.cpp" />
     <ClCompile Include="services\AuthenticationManagementService.cpp" />
     <ClCompile Include="services\InventoryManagementService.cpp" />
+    <ClCompile Include="services\NotificationManagementService.cpp" />
     <ClCompile Include="services\PaymentManagementService.cpp" />
     <ClCompile Include="services\ServiceManagementService.cpp" />
     <ClCompile Include="services\UserManagementService.cpp" />
@@ -149,23 +149,20 @@
     <ClCompile Include="utilities\Validator.cpp" />
     <ClCompile Include="views\AdminMenu.cpp" />
     <ClCompile Include="views\CustomerMenu.cpp" />
-    <ClCompile Include="views\Menu.cpp" />
     <ClCompile Include="views\TechnicianMenu.cpp" />
     <ClCompile Include="views\UserInterface.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="controllers\Controller.h" />
-    <ClInclude Include="core\events\EventManager.h" />
     <ClInclude Include="core\patterns\Observer.h" />
     <ClInclude Include="core\patterns\Subject.h" />
-    <ClInclude Include="core\sharedmemory\FileHeader.h" />
-    <ClInclude Include="core\sharedmemory\MappingInfo.h" />
-    <ClInclude Include="core\sharedmemory\RecordState.h" />
-    <ClInclude Include="core\sharedmemory\SerializedRecords.h" />
-    <ClInclude Include="core\sharedmemory\SharedMemory.h" />
-    <ClInclude Include="core\sharedmemory\TrackedRecord.h" />
     <ClInclude Include="datastores\DataStore.h" />
-    <ClInclude Include="datastores\DataStoreLockGuard.h" />
+    <ClInclude Include="datastores\sharedmemory\FileHeader.h" />
+    <ClInclude Include="datastores\sharedmemory\MappingInfo.h" />
+    <ClInclude Include="datastores\sharedmemory\RecordState.h" />
+    <ClInclude Include="datastores\sharedmemory\SerializedRecords.h" />
+    <ClInclude Include="datastores\sharedmemory\SharedMemory.h" />
+    <ClInclude Include="datastores\sharedmemory\TrackedRecord.h" />
     <ClInclude Include="factories\Factory.h" />
     <ClInclude Include="models\ComboPackage.h" />
     <ClInclude Include="models\InventoryItem.h" />
@@ -184,6 +181,7 @@
     <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" />
@@ -194,7 +192,6 @@
     <ClInclude Include="utilities\Vector.h" />
     <ClInclude Include="views\AdminMenu.h" />
     <ClInclude Include="views\CustomerMenu.h" />
-    <ClInclude Include="views\Menu.h" />
     <ClInclude Include="views\MenuHelper.h" />
     <ClInclude Include="views\TechnicianMenu.h" />
     <ClInclude Include="views\UserInterface.h" />

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

@@ -64,17 +64,11 @@
     <Filter Include="Source Files\Core\Patterns">
       <UniqueIdentifier>{8057b93d-51a9-42df-b06e-01ce395f6308}</UniqueIdentifier>
     </Filter>
-    <Filter Include="Header Files\Core\SharedMemory">
+    <Filter Include="Header Files\DataStores\SharedMemory">
-      <UniqueIdentifier>{d9da9793-fe6f-4914-bee3-99d5934da228}</UniqueIdentifier>
+      <UniqueIdentifier>{ec639004-44c6-4bd6-9963-077adde82b5f}</UniqueIdentifier>
     </Filter>
-    <Filter Include="Source Files\Core\SharedMemory">
+    <Filter Include="Source Files\DataStores\SharedMemory">
-      <UniqueIdentifier>{0769afb6-f57d-4ae3-a1cf-ceca6e606af0}</UniqueIdentifier>
+      <UniqueIdentifier>{7aa8722e-adfa-466e-8211-de63f3b7892b}</UniqueIdentifier>
-    </Filter>
-    <Filter Include="Header Files\Core\Events">
-      <UniqueIdentifier>{85029bdb-6941-41dc-a3a7-9e5841671d8c}</UniqueIdentifier>
-    </Filter>
-    <Filter Include="Source Files\Core\Events">
-      <UniqueIdentifier>{1050aca7-6f2c-4ccb-a446-db9c898c3599}</UniqueIdentifier>
     </Filter>
   </ItemGroup>
   <ItemGroup>
@@ -120,6 +114,9 @@
     <ClCompile Include="datastores\DataStore.cpp">
       <Filter>Source Files\DataStores</Filter>
     </ClCompile>
+    <ClCompile Include="services\NotificationManagementService.cpp">
+      <Filter>Source Files\Services</Filter>
+    </ClCompile>
     <ClCompile Include="core\patterns\Observer.cpp">
       <Filter>Source Files\Core\Patterns</Filter>
     </ClCompile>
@@ -150,14 +147,8 @@
     <ClCompile Include="models\ComboPackage.cpp">
       <Filter>Source Files\Models</Filter>
     </ClCompile>
-    <ClCompile Include="core\sharedmemory\SharedMemory.cpp">
+    <ClCompile Include="datastores\sharedmemory\SharedMemory.cpp">
-      <Filter>Source Files\Core\SharedMemory</Filter>
+      <Filter>Source Files\DataStores\SharedMemory</Filter>
-    </ClCompile>
-    <ClCompile Include="core\events\EventManager.cpp">
-      <Filter>Source Files\Core\Events</Filter>
-    </ClCompile>
-    <ClCompile Include="views\Menu.cpp">
-      <Filter>Source Files\Views</Filter>
     </ClCompile>
   </ItemGroup>
   <ItemGroup>
@@ -254,6 +245,9 @@
     <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>
@@ -266,32 +260,23 @@
     <ClInclude Include="views\MenuHelper.h">
       <Filter>Header Files\Views</Filter>
     </ClInclude>
-    <ClInclude Include="datastores\DataStoreLockGuard.h">
+    <ClInclude Include="datastores\sharedmemory\FileHeader.h">
-      <Filter>Header Files\DataStores</Filter>
+      <Filter>Header Files\DataStores\SharedMemory</Filter>
     </ClInclude>
-    <ClInclude Include="core\sharedmemory\FileHeader.h">
+    <ClInclude Include="datastores\sharedmemory\MappingInfo.h">
-      <Filter>Header Files\Core\SharedMemory</Filter>
+      <Filter>Header Files\DataStores\SharedMemory</Filter>
     </ClInclude>
-    <ClInclude Include="core\sharedmemory\MappingInfo.h">
+    <ClInclude Include="datastores\sharedmemory\RecordState.h">
-      <Filter>Header Files\Core\SharedMemory</Filter>
+      <Filter>Header Files\DataStores\SharedMemory</Filter>
     </ClInclude>
-    <ClInclude Include="core\sharedmemory\RecordState.h">
+    <ClInclude Include="datastores\sharedmemory\TrackedRecord.h">
-      <Filter>Header Files\Core\SharedMemory</Filter>
+      <Filter>Header Files\DataStores\SharedMemory</Filter>
     </ClInclude>
-    <ClInclude Include="core\sharedmemory\SerializedRecords.h">
+    <ClInclude Include="datastores\sharedmemory\SerializedRecords.h">
-      <Filter>Header Files\Core\SharedMemory</Filter>
+      <Filter>Header Files\DataStores\SharedMemory</Filter>
     </ClInclude>
-    <ClInclude Include="core\sharedmemory\SharedMemory.h">
+    <ClInclude Include="datastores\sharedmemory\SharedMemory.h">
-      <Filter>Header Files\Core\SharedMemory</Filter>
+      <Filter>Header Files\DataStores\SharedMemory</Filter>
-    </ClInclude>
-    <ClInclude Include="core\sharedmemory\TrackedRecord.h">
-      <Filter>Header Files\Core\SharedMemory</Filter>
-    </ClInclude>
-    <ClInclude Include="core\events\EventManager.h">
-      <Filter>Header Files\Core\Events</Filter>
-    </ClInclude>
-    <ClInclude Include="views\Menu.h">
-      <Filter>Header Files\Views</Filter>
     </ClInclude>
   </ItemGroup>
 </Project>

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

@@ -234,17 +234,6 @@ void Controller::removeInventoryItem(const std::string& inventoryItemID)
     m_inventoryManagementService.removeInventoryItem(inventoryItemID);
 }
 
-/*
-Function: removeServiceBooking
-Description: Removes a service booking from the service management system by its booking ID.
-Parameter: const std::string& bookingID - ID of the service booking
-Return type: void
-*/
-void Controller::removeServiceBooking(const std::string& bookingID)
-{
-    m_serviceManagementService.removeServiceBooking(bookingID);
-}
-
 /*
 Function: addInventoryItemStock
 Description: Adds stock to an existing inventory item in the inventory management service.
@@ -276,7 +265,6 @@ util::Map<std::string, const ServiceBooking*> Controller::getServiceBookings()
     return readOnlyServiceBookings;
 }
 
-
 /*
 Function: getServiceBookingsByUser
 Description: Retrieves all service bookings for a specific user.
@@ -600,50 +588,63 @@ void Controller::configureNotifications(bool paymentNotifications, bool serviceN
 }
 
 /*
-Function: initialize
+Function: loadSystemData
-Description: Initializes the system and run system checks to ensure critical configurations, such as verifying admin existence.
+Description: Loads all system data from persistent storage into memory.
-Parameters:
+             Invokes the respective management services to load users, inventory items, services,
-    - None
+             combo packages, service bookings, job cards, invoices, and observers.
-Returns:
-    - bool
-*/
-bool Controller::initialize()
-{
-    auto& dataStore = DataStore::getInstance();
-
-    if (!dataStore.initialize())
-    {
-        return false;
-    }
-    m_userManagementService.ensureAdminExists();
-    m_inventoryManagementService.sendLowStockAlerts();
-    m_paymentManagementService.sendPaymentReminders();
-    return true;
-}
-
-/*
-Function: shutdown
-Description: Shutdown the system, and do necessary cleanups
 Parameters:
     - None
 Returns:
     - void
 */
-void Controller::shutdown()
+void Controller::loadSystemData()
 {
-    auto& dataStore = DataStore::getInstance();
+    m_userManagementService.loadUsers();
-    dataStore.shutdown();
+    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: registerEvents
+Function: saveSystemData
-Description: Registers menu event handles with the authentication
+Description: Saves all system data from memory back to persistent storage.
-             service.
+             Invokes the respective management services to save users, inventory items, services,
-Parameter: HANDLE accountDisabledEvent - account disabled event handle
+             combo packages, service bookings, job cards, invoices, and observers.
-           HANDLE notificationAvailableEvent - notification event handle
+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.
+Parameter: None
 Return type: void
 */
-void Controller::registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent)
+void Controller::runSystemChecks()
 {
-    m_authenticationManagementService.registerEvents(accountDisabledEvent, notificationAvailableEvent);
+    m_userManagementService.ensureAdminExists();
+    m_inventoryManagementService.sendLowStockAlerts();
+    m_paymentManagementService.sendPaymentReminders();
 }
+

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

@@ -8,7 +8,6 @@ Date:19-May-2026
 */
 
 #pragma once
-#include <windows.h>
 #include <string>
 #include "AuthenticationManagementService.h"
 #include "Enums.h"
@@ -58,7 +57,6 @@ public:
     util::Map<std::string, const User*> getUsers(util::UserType userType);
     void createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID);
     void createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost);
-    void removeServiceBooking(const std::string& bookingID);
     void removeService(const std::string& serviceID);
     util::Map<std::string, const JobCard*> getJobCardsByUser();
     void updateJobStatus(const std::string& jobID);
@@ -72,7 +70,7 @@ public:
     util::Vector<const Notification*> getNotifications();
     void deleteNotification(const std::string& notificationID);
     void configureNotifications(bool paymentNotifications, bool serviceNotifications);
-    bool initialize();
+    void loadSystemData();
-    void shutdown();
+    void saveSystemData();
-    void registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent);
+    void runSystemChecks();
 };

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

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

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

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

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

@@ -7,8 +7,11 @@ Date: 19-May-2026
 
 #pragma once
 
+class Notification;
+
 class Observer
 {
 public:
     virtual ~Observer() = default;
+    virtual void addNotification(Notification* notification) = 0;
 };

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

@@ -12,46 +12,10 @@ Date: 19-May-2026
 #include "Config.h"
 #include "SerializedRecords.h"
 #include "FileHelper.h"
-#include "ServiceBooking.h"
-#include "JobCard.h"
-#include "Invoice.h"
 
-/*
-Function: DataStore
-Description: Constructs the DataStore singleton and initializes
-             internal handles to their default values.
-Parameters:
-    - None
-Returns:
-    - None
-*/
 DataStore::DataStore() :
     m_globalMutex(NULL) {}
 
-/*
-Function: ~DataStore
-Description: Destroys the DataStore singleton and releases all
-             cached application objects owned by the datastore.
-             This includes users, notifications, services,
-             combo packages, inventory items, service bookings,
-             job cards, and invoices.
-Parameters:
-    - None
-Returns:
-    - None
-*/
-DataStore::~DataStore()
-{
-    clearCache(m_userCache);
-    clearCache(m_notificationCache);
-    clearCache(m_serviceCache);
-    clearCache(m_comboPackageCache);
-    clearCache(m_inventoryItemCache);
-    clearCache(m_serviceBookingCache);
-    clearCache(m_jobCardCache);
-    clearCache(m_invoiceCache);
-}
-
 /*
 Function: initialize
 Description: Initializes the shared-memory datastore.
@@ -147,6 +111,11 @@ bool DataStore::initialize()
             success = false;
             break;
         }
+        if (!SharedMemory::createOrOpenMapping(m_payments))
+        {
+            success = false;
+            break;
+        }
         if (!SharedMemory::createOrOpenMapping(m_serviceManagementObservers))
         {
             success = false;
@@ -191,6 +160,7 @@ void DataStore::shutdown()
     SharedMemory::closeMapping(m_serviceBookings);
     SharedMemory::closeMapping(m_jobCards);
     SharedMemory::closeMapping(m_invoices);
+    SharedMemory::closeMapping(m_payments);
     SharedMemory::closeMapping(m_serviceManagementObservers);
     SharedMemory::closeMapping(m_paymentManagementObservers);
     SharedMemory::closeMapping(m_inventoryManagementObservers);
@@ -223,11 +193,9 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<User>>: Collection of user records
 */
-util::Map<std::string, TrackedRecord<User>>& DataStore::getUsers()
+util::Map<std::string, TrackedRecord<User>> DataStore::getUsers()
 {
-    auto users = loadRecords<User, SerializedUser>(m_users);
+    return util::Map<std::string, TrackedRecord<User>>();
-    refreshCache(m_userCache, users);
-    return m_userCache;
 }
 
 /*
@@ -238,11 +206,9 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<Notification>>: Collection of notification records
 */
-util::Map<std::string, TrackedRecord<Notification>>& DataStore::getNotifications()
+util::Map<std::string, TrackedRecord<Notification>> DataStore::getNotifications()
 {
-    auto notifications = loadRecords<Notification, SerializedNotification>(m_notifications);
+    return util::Map<std::string, TrackedRecord<Notification>>();
-    refreshCache(m_notificationCache, notifications);
-    return m_notificationCache;
 }
 
 /*
@@ -253,31 +219,9 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<Service>>: Collection of service records
 */
-util::Map<std::string, TrackedRecord<Service>>& DataStore::getServices()
+util::Map<std::string, TrackedRecord<Service>> DataStore::getServices()
 {
-    util::Map<std::string, TrackedRecord<Service>> services = loadRecords<Service, SerializedService>(m_services);
+    return util::Map<std::string, TrackedRecord<Service>>();
-    refreshCache(m_serviceCache, services);
-    util::Map<std::string, TrackedRecord<InventoryItem>>& inventoryItems = getInventoryItems();
-    size_t numberOfServices = m_serviceCache.getSize();
-    for (int iteratorOne =0; iteratorOne < numberOfServices; iteratorOne++)
-    {
-        Service* currentService = m_serviceCache.getValueAt(iteratorOne).data;
-        util::Map<std::string, InventoryItem*> inventoryItemMap;
-        util::Vector<std::string> currentServiceInventoryItem = currentService->getRequiredInventoryItemIDs();
-        for (int iteratorTwo = 0; iteratorTwo < currentServiceInventoryItem.getSize(); iteratorTwo++)
-        {
-            const std::string& currentInventoryItemId = currentServiceInventoryItem[iteratorTwo];
-            int currentInventoryItemIndex = inventoryItems.find(currentInventoryItemId);
-            if (currentInventoryItemIndex == -1)
-            {
-                throw std::runtime_error("Invalid inventory item ID");
-            }
-            InventoryItem* currentItem = inventoryItems.getValueAt(currentInventoryItemIndex).data;
-            inventoryItemMap[currentInventoryItemId] = currentItem;
-        }
-        currentService->setRequiredInventoryItems(inventoryItemMap);
-    }
-    return m_serviceCache;
 }
 
 /*
@@ -288,31 +232,9 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<ComboPackage>>: Collection of combo package records
 */
-util::Map<std::string, TrackedRecord<ComboPackage>>& DataStore::getComboPackages()
+util::Map<std::string, TrackedRecord<ComboPackage>> DataStore::getComboPackages()
 {
-    util::Map<std::string, TrackedRecord<ComboPackage>> comboPackages = loadRecords<ComboPackage, SerializedComboPackage>(m_comboPackages);
+    return util::Map<std::string, TrackedRecord<ComboPackage>>();
-    refreshCache(m_comboPackageCache, comboPackages);
-    util::Map<std::string, TrackedRecord<Service>>& services = getServices();
-    size_t numberOfComboPackages = m_comboPackageCache.getSize();
-    for (int iteratorOne = 0; iteratorOne < numberOfComboPackages; iteratorOne++)
-    {
-        ComboPackage* currentComboPackage =  m_comboPackageCache.getValueAt(iteratorOne).data;
-        util::Vector<std::string> currentServiceIds = currentComboPackage->getServiceIDs();
-        util::Map<std::string, Service*> currentComboPackageServices;
-        for (int iteratorTwo = 0; iteratorTwo < currentServiceIds.getSize(); iteratorTwo++)
-        {
-            const std::string& currentServiceId = currentServiceIds[iteratorTwo];
-            int serviceIndex = services.find(currentServiceId);
-            if (serviceIndex == -1)
-            {
-                throw std::runtime_error("Invalid service ID");
-            }
-            Service* currentService = services.getValueAt(serviceIndex).data;
-            currentComboPackageServices[currentServiceId] = currentService;
-        }
-        currentComboPackage->setServices(currentComboPackageServices);
-    }
-    return m_comboPackageCache;
 }
 
 /*
@@ -323,11 +245,9 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<InventoryItem>>: Collection of inventory item records
 */
-util::Map<std::string, TrackedRecord<InventoryItem>>& DataStore::getInventoryItems()
+util::Map<std::string, TrackedRecord<InventoryItem>> DataStore::getInventoryItems()
 {
-    auto inventoryItems = loadRecords<InventoryItem, SerializedInventoryItem>(m_inventoryItems);
+    return util::Map<std::string, TrackedRecord<InventoryItem>>();
-    refreshCache(m_inventoryItemCache, inventoryItems);
-    return m_inventoryItemCache;
 }
 
 /*
@@ -338,52 +258,9 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<ServiceBooking>>: Collection of service booking records
 */
-util::Map<std::string, TrackedRecord<ServiceBooking>>& DataStore::getServiceBookings()
+util::Map<std::string, TrackedRecord<ServiceBooking>> DataStore::getServiceBookings()
 {
-    util::Map<std::string, TrackedRecord<ServiceBooking>> serviceBookings = loadRecords<ServiceBooking, SerializedServiceBooking>(m_serviceBookings);
+    return util::Map<std::string, TrackedRecord<ServiceBooking>>();
-    refreshCache(m_serviceBookingCache, serviceBookings);
-    auto& users = getUsers();
-    auto& services = getServices();
-    size_t numberOfServiceBookings = m_serviceBookingCache.getSize();
-    for (int iteratorOne = 0; iteratorOne < numberOfServiceBookings; iteratorOne++)
-    {
-        ServiceBooking* serviceBooking = m_serviceBookingCache.getValueAt(iteratorOne).data;
-        auto& serviceIds = serviceBooking->getServiceIDs();
-        util::Map<std::string, Service*> servicesInBooking;
-        for (int iteratorTwo = 0; iteratorTwo < serviceIds.getSize(); iteratorTwo++)
-        {
-            const std::string& currentServiceId = serviceIds[iteratorTwo];
-            int serviceIndex = services.find(currentServiceId);
-            if (serviceIndex == -1)
-            {
-                throw std::runtime_error("Invalid service index.");
-            }
-            auto& currentService = services.getValueAt(serviceIndex);
-            servicesInBooking[currentServiceId] = currentService.data;
-        }
-        serviceBooking->setServices(servicesInBooking);
-        if (!serviceBooking->getCustomerId().empty())
-        {
-            int userIndex = users.find(serviceBooking->getCustomerId());
-            if (userIndex == -1)
-            {
-                throw std::runtime_error("Invalid user index.");
-            }
-            auto& customer = users.getValueAt(userIndex);
-            serviceBooking->setCustomer(customer.data);
-        }
-        if (!serviceBooking->getAssignedTechnicianId().empty())
-        {
-            int technicianIndex = users.find(serviceBooking->getAssignedTechnicianId());
-            if (technicianIndex == -1)
-            {
-                throw std::runtime_error("Invalid technician index.");
-            }
-            auto& technician = users.getValueAt(technicianIndex);
-            serviceBooking->setAssignedTechnician(technician.data);
-        }
-    }
-    return m_serviceBookingCache;
 }
 
 /*
@@ -394,53 +271,11 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<JobCard>>: Collection of job card records
 */
-util::Map<std::string, TrackedRecord<JobCard>>& DataStore::getJobCards()
+util::Map<std::string, TrackedRecord<JobCard>> DataStore::getJobCards()
 {
-    util::Map<std::string, TrackedRecord<JobCard>> jobCards = loadRecords<JobCard, SerializedJobCard>(m_jobCards);
+    return util::Map<std::string, TrackedRecord<JobCard>>();
-    refreshCache(m_jobCardCache, jobCards);
-    auto& serviceBookings = getServiceBookings();
-    auto& services = getServices();
-    auto& users = getUsers();
-    int numberOfJobCards = m_jobCardCache.getSize();
-    for (int iterator = 0; iterator < numberOfJobCards; iterator++)
-    {
-        JobCard* jobCard = m_jobCardCache.getValueAt(iterator).data;
-        if (!jobCard)
-        {
-            continue;
-        }
-        const std::string& bookingId = jobCard->getBookingId();
-        int bookingIndex = serviceBookings.find(bookingId);
-        if (bookingIndex == -1)
-        {
-            throw std::runtime_error("Invalid booking ID: " + bookingId);
-        }
-        auto& trackedBooking = serviceBookings.getValueAt(bookingIndex);
-        jobCard->setBooking(trackedBooking.data);
-        const std::string& serviceId = jobCard->getServiceId();
-        int serviceIndex = services.find(serviceId);
-        if (serviceIndex == -1)
-        {
-            throw std::runtime_error("Invalid service ID: " + serviceId);
-        }
-        auto& trackedService = services.getValueAt(serviceIndex);
-        jobCard->setService(trackedService.data);
-        const std::string& technicianId = jobCard->getTechnicianId();
-        if (!technicianId.empty())
-        {
-            int technicianIndex = users.find(technicianId);
-            if (technicianIndex == -1)
-            {
-                throw std::runtime_error("Invalid technician ID: " + technicianId);
-            }
-            auto& trackedTechnician = users.getValueAt(technicianIndex);
-            jobCard->setTechnician(trackedTechnician.data);
-        }
-    }
-    return m_jobCardCache;
 }
 
-
 /*
 Function: getInvoices
 Description: Retrieves all invoice records from the datastore.
@@ -449,79 +284,22 @@ Parameters:
 Returns:
     - util::Map<std::string, TrackedRecord<Invoice>>: Collection of invoice records
 */
-util::Map<std::string, TrackedRecord<Invoice>>& DataStore::getInvoices()
+util::Map<std::string, TrackedRecord<Invoice>> DataStore::getInvoices()
 {
-    auto& serviceBookings = getServiceBookings();
+    return util::Map<std::string, TrackedRecord<Invoice>>();
-    auto& inventoryItems = getInventoryItems();
-    util::Map<std::string, TrackedRecord<Invoice>> invoices = loadRecords<Invoice, SerializedInvoice>(m_invoices);
-    refreshCache(m_invoiceCache, invoices);
-    for (int iterator = 0; iterator < m_invoiceCache.getSize(); iterator++)
-    {
-        auto& trackedInvoice = m_invoiceCache.getValueAt(iterator);
-        Invoice* invoice = trackedInvoice.data;
-        if (!invoice)
-        {
-            continue;
-        }
-        const std::string& currentBookingId = invoice->getBookingId();
-        int currentBookingIndex = serviceBookings.find(currentBookingId);
-        if (currentBookingIndex == -1)
-        {
-            throw std::runtime_error("Invalid Service Booking Index.");
-        }
-        ServiceBooking* currentBooking = serviceBookings.getValueAt(currentBookingIndex).data;
-        auto& currentInventoryItemIds = invoice->getPartIDs();
-        util::Map<std::string, InventoryItem*> currentInventoryItems;
-        for (int iterator = 0; iterator < currentInventoryItemIds.getSize(); iterator++)
-        {
-            const std::string& currentItemId = currentInventoryItemIds[iterator];
-            int currentItemIndex = inventoryItems.find(currentItemId);
-            if (currentItemIndex == -1)
-            {
-                throw std::runtime_error("Invalid Inventory item id.");
-            }
-            InventoryItem* currentItem = inventoryItems.getValueAt(currentItemIndex).data;
-            if (!currentItem)
-            {
-                continue;
-            }
-            currentInventoryItems[currentItemId] = currentItem;
-        }
-        invoice->setBooking(currentBooking);
-        invoice->setParts(currentInventoryItems);
-    }
-    return m_invoiceCache;
 }
 
 /*
-Function: getObservers
+Function: getPayments
-Description: Retrieves observer records from the specified observer mapping
+Description: Retrieves all payment records from the datastore.
-             and resolves them to User objects.
 Parameters:
-    - mapping: Observer mapping to read from
+    - None
 Returns:
-    - util::Map<std::string, User*>: Collection of observer records
+    - util::Map<std::string, TrackedRecord<Payment>>: Collection of payment records
-Throws:
-    - std::runtime_error if an observer references an invalid user ID
 */
-util::Map<std::string, User*> DataStore::getObservers(MappingInfo& mapping)
+util::Map<std::string, TrackedRecord<Payment>> DataStore::getPayments()
 {
-    auto& users = getUsers();
+    return util::Map<std::string, TrackedRecord<Payment>>();
-    util::Map<std::string, User*> observers;
-    SharedMemory::ensureLatestMapping(mapping);
-    size_t recordCount = SharedMemory::getRecordCount(mapping);
-    for (size_t index = 0; index < recordCount; index++)
-    {
-        const SerializedObserver* observer = static_cast<SerializedObserver*>(SharedMemory::getRecordAddress(mapping, index));
-        int userIndex = users.find(observer->id);
-        if (userIndex == -1)
-        {
-            throw std::runtime_error("Invalid observer user ID");
-        }
-        User* user = users.getValueAt(userIndex).data;
-        observers.insert(user->getId(), user);
-    }
-    return observers;
 }
 
 /*
@@ -530,11 +308,11 @@ Description: Retrieves all service management observer records from the datastor
 Parameters:
     - None
 Returns:
-    - util::Map<std::string, User*>: Collection of observer records
+    - util::Map<std::string, TrackedRecord<std::string>>: Collection of observer records
 */
-util::Map<std::string, User*> DataStore::getServiceManagementObservers()
+util::Map<std::string, TrackedRecord<std::string>> DataStore::getServiceManagementObservers()
 {
-    return getObservers(m_serviceManagementObservers);
+    return util::Map<std::string, TrackedRecord<std::string>>();
 }
 
 /*
@@ -543,11 +321,11 @@ Description: Retrieves all payment management observer records from the datastor
 Parameters:
     - None
 Returns:
-    - util::Map<std::string, User*>: Collection of observer records
+    - util::Map<std::string, TrackedRecord<std::string>>: Collection of observer records
 */
-util::Map<std::string, User*> DataStore::getPaymentManagementObservers()
+util::Map<std::string, TrackedRecord<std::string>> DataStore::getPaymentManagementObservers()
 {
-    return getObservers(m_paymentManagementObservers);
+    return util::Map<std::string, TrackedRecord<std::string>>();
 }
 
 /*
@@ -556,186 +334,181 @@ Description: Retrieves all inventory management observer records from the datast
 Parameters:
     - None
 Returns:
-    - util::Map<std::string, User*>: Collection of observer records
+    - util::Map<std::string, TrackedRecord<std::string>>: Collection of observer records
 */
-util::Map<std::string, User*> DataStore::getInventoryManagementObservers()
+util::Map<std::string, TrackedRecord<std::string>> DataStore::getInventoryManagementObservers()
 {
-    return getObservers(m_inventoryManagementObservers);
+    return util::Map<std::string, TrackedRecord<std::string>>();
 }
 
 /*
 Function: saveUsers
 Description: Persists all user records to the datastore.
 Parameters:
-    - None
+    - users: util::Map<std::string, TrackedRecord<User>>&, collection of user records
 Returns:
     - None
 */
-void DataStore::saveUsers()
+void DataStore::saveUsers(util::Map<std::string, TrackedRecord<User>>& users)
 {
-    saveRecords<User, SerializedUser>(m_users, m_userCache);
 }
 
 /*
 Function: saveNotifications
 Description: Persists all notification records to the datastore.
 Parameters:
-    - None
+    - notifications: util::Map<std::string, TrackedRecord<Notification>>&, collection of notification records
 Returns:
     - None
 */
-void DataStore::saveNotifications()
+void DataStore::saveNotifications(util::Map<std::string, TrackedRecord<Notification>>& notifications)
 {
-    saveRecords<Notification, SerializedNotification>(m_notifications, m_notificationCache);
 }
 
 /*
 Function: saveServices
 Description: Persists all service records to the datastore.
 Parameters:
-    - None
+    - services: util::Map<std::string, TrackedRecord<Service>>&, collection of service records
 Returns:
     - None
 */
-void DataStore::saveServices()
+void DataStore::saveServices(util::Map<std::string, TrackedRecord<Service>>& services)
 {
-    saveRecords<Service, SerializedService>(m_services, m_serviceCache);
 }
 
 /*
 Function: saveComboPackages
 Description: Persists all combo package records to the datastore.
 Parameters:
-    - None
+    - comboPackages: util::Map<std::string, TrackedRecord<ComboPackage>>&, collection of combo package records
 Returns:
     - None
 */
-void DataStore::saveComboPackages()
+void DataStore::saveComboPackages(util::Map<std::string, TrackedRecord<ComboPackage>>& comboPackages)
 {
-    saveRecords<ComboPackage, SerializedComboPackage>(m_comboPackages, m_comboPackageCache);
 }
 
 /*
 Function: saveInventoryItems
 Description: Persists all inventory item records to the datastore.
 Parameters:
-    - None
+    - inventoryItems: util::Map<std::string, TrackedRecord<InventoryItem>>&, collection of inventory item records
 Returns:
     - None
 */
-void DataStore::saveInventoryItems()
+void DataStore::saveInventoryItems(util::Map<std::string, TrackedRecord<InventoryItem>>& inventoryItems)
 {
-    saveRecords<InventoryItem, SerializedInventoryItem>(m_inventoryItems, m_inventoryItemCache);
 }
 
 /*
 Function: saveServiceBookings
 Description: Persists all service booking records to the datastore.
 Parameters:
-    - None
+    - bookings: util::Map<std::string, TrackedRecord<ServiceBooking>>&, collection of service booking records
 Returns:
     - None
 */
-void DataStore::saveServiceBookings()
+void DataStore::saveServiceBookings(util::Map<std::string, TrackedRecord<ServiceBooking>>& bookings)
 {
-    saveRecords<ServiceBooking, SerializedServiceBooking>(m_serviceBookings, m_serviceBookingCache);
 }
 
 /*
 Function: saveJobCards
 Description: Persists all job card records to the datastore.
 Parameters:
-    - None
+    - jobCards: util::Map<std::string, TrackedRecord<JobCard>>&, collection of job card records
 Returns:
     - None
 */
-void DataStore::saveJobCards()
+void DataStore::saveJobCards(util::Map<std::string, TrackedRecord<JobCard>>& jobCards)
 {
-    saveRecords<JobCard, SerializedJobCard>(m_jobCards, m_jobCardCache);
 }
 
 /*
 Function: saveInvoices
 Description: Persists all invoice records to the datastore.
 Parameters:
-    - None
+    - invoices: util::Map<std::string, TrackedRecord<Invoice>>&, collection of invoice records
 Returns:
     - None
 */
-void DataStore::saveInvoices()
+void DataStore::saveInvoices(util::Map<std::string, TrackedRecord<Invoice>>& invoices)
 {
-    saveRecords<Invoice, SerializedInvoice>(m_invoices, m_invoiceCache);
 }
 
 /*
-Function: saveObservers
+Function: savePayments
-Description: Persists observer records to the specified observer mapping.
+Description: Persists all payment records to the datastore.
 Parameters:
-    - mapping: MappingInfo&, observer mapping to save to
+    - payments: util::Map<std::string, TrackedRecord<Payment>>&, collection of payment records
-    - observers: util::Map<std::string, User*>&, collection of observer records
 Returns:
     - None
 */
-void DataStore::saveObservers(MappingInfo& mapping, util::Map<std::string, User*>& observers)
+void DataStore::savePayments(util::Map<std::string, TrackedRecord<Payment>>& payments)
 {
-    size_t observerCount = static_cast<size_t>(observers.getSize());
-    size_t capacity = config::file::INITIAL_CAPACITY;
-    while (capacity < observerCount)
-    {
-        capacity *= config::file::GROWTH_FACTOR;
-    }
-    if (!SharedMemory::resizeMapping(mapping, capacity))
-    {
-        throw std::runtime_error("Failed to resize observer mapping");
-    }
-    SharedMemory::setRecordCount(mapping, observerCount);
-    for (size_t index = 0; index < observerCount; index++)
-    {
-        SerializedObserver serializedObserver{};
-        User* user = observers.getValueAt(static_cast<int>(index));
-        strcpy_s(serializedObserver.id, sizeof(serializedObserver.id), user->getId().c_str());
-        SerializedObserver* destination = static_cast<SerializedObserver*>(SharedMemory::getRecordAddress(mapping, index));
-        *destination = serializedObserver;
-    }
 }
 
 /*
 Function: saveServiceManagementObservers
 Description: Persists all service management observer records to the datastore.
 Parameters:
-    - observers: util::Map<std::string, User*>&, collection of observer records
+    - observers: util::Map<std::string, TrackedRecord<std::string>>&, collection of observer records
 Returns:
     - None
 */
-void DataStore::saveServiceManagementObservers(util::Map<std::string, User*>& observers)
+void DataStore::saveServiceManagementObservers(util::Map<std::string, TrackedRecord<std::string>>& observers)
 {
-    saveObservers(m_serviceManagementObservers, observers);
 }
 
 /*
 Function: savePaymentManagementObservers
 Description: Persists all payment management observer records to the datastore.
 Parameters:
-    - observers: util::Map<std::string, User*>&, collection of observer records
+    - observers: util::Map<std::string, TrackedRecord<std::string>>&, collection of observer records
 Returns:
     - None
 */
-void DataStore::savePaymentManagementObservers(util::Map<std::string, User*>& observers)
+void DataStore::savePaymentManagementObservers(util::Map<std::string, TrackedRecord<std::string>>& observers)
 {
-    saveObservers(m_paymentManagementObservers, observers);
 }
 
 /*
 Function: saveInventoryManagementObservers
 Description: Persists all inventory management observer records to the datastore.
 Parameters:
-    - observers: util::Map<std::string, User*>&, collection of observer records
+    - observers: util::Map<std::string, TrackedRecord<std::string>>&, collection of observer records
 Returns:
     - None
 */
-void DataStore::saveInventoryManagementObservers(util::Map<std::string, User*>& observers)
+void DataStore::saveInventoryManagementObservers(util::Map<std::string, TrackedRecord<std::string>>& observers)
 {
-    saveObservers(m_inventoryManagementObservers, observers);
+}
+
+/*
+Function: lockDataStore
+Description: Acquires exclusive access to the datastore.
+Parameters:
+    - None
+Returns:
+    - bool: True if the datastore was successfully locked, otherwise false
+*/
+bool DataStore::lockDataStore()
+{
+    return false;
+}
+
+/*
+Function: unlockDataStore
+Description: Releases exclusive access to the datastore.
+Parameters:
+    - None
+Returns:
+    - bool: True if the datastore was successfully unlocked, otherwise false
+*/
+bool DataStore::unlockDataStore()
+{
+    return false;
 }
 
 /*

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

@@ -11,22 +11,21 @@ Date: 19-May-2026
 #include "Map.h"
 #include "MappingInfo.h"
 #include "TrackedRecord.h"
-#include "SerializedRecords.h"
 #include "SharedMemory.h"
-#include "User.h"
+class User;
-#include "Notification.h"
+class Notification;
-#include "Service.h"
+class Service;
-#include "ComboPackage.h"
+class ComboPackage;
-#include "InventoryItem.h"
+class InventoryItem;
-#include "ServiceBooking.h"
+class ServiceBooking;
-#include "JobCard.h"
+class JobCard;
-#include "Invoice.h"
+class Invoice;
+class Payment;
 
 class DataStore
 {
 private:
     DataStore();
-    ~DataStore();
     DataStore(const DataStore&) = delete;
     DataStore& operator=(const DataStore&) = delete;
     DataStore(DataStore&&) = delete;
@@ -40,43 +39,38 @@ private:
     MappingInfo m_serviceBookings;
     MappingInfo m_jobCards;
     MappingInfo m_invoices;
+    MappingInfo m_payments;
     MappingInfo m_serviceManagementObservers;
     MappingInfo m_paymentManagementObservers;
     MappingInfo m_inventoryManagementObservers;
-    util::Map<std::string, TrackedRecord<User>> m_userCache;
-    util::Map<std::string, TrackedRecord<Notification>> m_notificationCache;
-    util::Map<std::string, TrackedRecord<Service>> m_serviceCache;
-    util::Map<std::string, TrackedRecord<ComboPackage>> m_comboPackageCache;
-    util::Map<std::string, TrackedRecord<InventoryItem>> m_inventoryItemCache;
-    util::Map<std::string, TrackedRecord<ServiceBooking>> m_serviceBookingCache;
-    util::Map<std::string, TrackedRecord<JobCard>> m_jobCardCache;
-    util::Map<std::string, TrackedRecord<Invoice>> m_invoiceCache;
 public:
     static DataStore& getInstance();
     bool initialize();
     void shutdown();
-    util::Map<std::string, TrackedRecord<User>>& getUsers();
+    util::Map<std::string, TrackedRecord<User>> getUsers();
-    util::Map<std::string, TrackedRecord<Notification>>& getNotifications();
+    util::Map<std::string, TrackedRecord<Notification>> getNotifications();
-    util::Map<std::string, TrackedRecord<Service>>& getServices();
+    util::Map<std::string, TrackedRecord<Service>> getServices();
-    util::Map<std::string, TrackedRecord<ComboPackage>>& getComboPackages();
+    util::Map<std::string, TrackedRecord<ComboPackage>> getComboPackages();
-    util::Map<std::string, TrackedRecord<InventoryItem>>& getInventoryItems();
+    util::Map<std::string, TrackedRecord<InventoryItem>> getInventoryItems();
-    util::Map<std::string, TrackedRecord<ServiceBooking>>& getServiceBookings();
+    util::Map<std::string, TrackedRecord<ServiceBooking>> getServiceBookings();
-    util::Map<std::string, TrackedRecord<JobCard>>& getJobCards();
+    util::Map<std::string, TrackedRecord<JobCard>> getJobCards();
-    util::Map<std::string, TrackedRecord<Invoice>>& getInvoices();
+    util::Map<std::string, TrackedRecord<Invoice>> getInvoices();
-    util::Map<std::string, User*> getServiceManagementObservers();
+    util::Map<std::string, TrackedRecord<Payment>> getPayments();
-    util::Map<std::string, User*> getPaymentManagementObservers();
+    util::Map<std::string, TrackedRecord<std::string>> getServiceManagementObservers();
-    util::Map<std::string, User*> getInventoryManagementObservers();
+    util::Map<std::string, TrackedRecord<std::string>> getPaymentManagementObservers();
-    void saveUsers();
+    util::Map<std::string, TrackedRecord<std::string>> getInventoryManagementObservers();
-    void saveNotifications();
+    void saveUsers(util::Map<std::string, TrackedRecord<User>>& users);
-    void saveServices();
+    void saveNotifications(util::Map<std::string, TrackedRecord<Notification>>& notifications);
-    void saveComboPackages();
+    void saveServices(util::Map<std::string, TrackedRecord<Service>>& services);
-    void saveInventoryItems();
+    void saveComboPackages(util::Map<std::string, TrackedRecord<ComboPackage>>& comboPackages);
-    void saveServiceBookings();
+    void saveInventoryItems(util::Map<std::string, TrackedRecord<InventoryItem>>& inventoryItems);
-    void saveJobCards();
+    void saveServiceBookings(util::Map<std::string, TrackedRecord<ServiceBooking>>& bookings);
-    void saveInvoices();
+    void saveJobCards(util::Map<std::string, TrackedRecord<JobCard>>& jobCards);
-    void saveServiceManagementObservers(util::Map<std::string, User*>& observers);
+    void saveInvoices(util::Map<std::string, TrackedRecord<Invoice>>& invoices);
-    void savePaymentManagementObservers(util::Map<std::string, User*>& observers);
+    void savePayments(util::Map<std::string, TrackedRecord<Payment>>& payments);
-    void saveInventoryManagementObservers(util::Map<std::string, User*>& observers);
+    void saveServiceManagementObservers(util::Map<std::string, TrackedRecord<std::string>>& observers);
+    void savePaymentManagementObservers(util::Map<std::string, TrackedRecord<std::string>>& observers);
+    void saveInventoryManagementObservers(util::Map<std::string, TrackedRecord<std::string>>& observers);
     bool lockDataStore();
     bool unlockDataStore();
 private:
@@ -84,10 +78,6 @@ private:
     util::Map<std::string, TrackedRecord<TObject>> loadRecords(MappingInfo& mapping);
     template<typename TObject, typename TSerialized>
     void saveRecords(MappingInfo& mapping, util::Map<std::string, TrackedRecord<TObject>>& records);
-    template<typename TObject> void clearCache(util::Map<std::string, TrackedRecord<TObject>>&cache);
-    template<typename TObject> void refreshCache(util::Map<std::string, TrackedRecord<TObject>>&cache, util::Map<std::string, TrackedRecord<TObject>>&refreshedCache);
-    util::Map<std::string, User*> getObservers(MappingInfo& mapping);
-    void saveObservers(MappingInfo& mapping, util::Map<std::string, User*>& observers);
 };
 
 /*
@@ -133,7 +123,9 @@ Description: Persists all modified and newly added records
              shared-memory mapping. Modified records overwrite
              their existing slots, while new records are
              appended to the end of the mapping. Records marked
-             as CLEAN are ignored.
+             as CLEAN are ignored. After persistence, all
+             temporary objects owned by the tracked records are
+             destroyed to release memory.
 Parameter:
     - mapping: Reference to the mapping where records are
                stored.
@@ -166,88 +158,14 @@ template<typename TObject, typename TSerialized> void DataStore::saveRecords(Map
                 continue;
             }
             size_t recordCount = SharedMemory::getRecordCount(mapping);
-            TSerialized* destination = static_cast<TSerialized*>(SharedMemory::getRecordAddress(mapping,recordCount));
+            TSerialized* destination = static_cast<TSerialized*>(SharedMemory::getRecordAddress(mapping, recordCount));
             *destination = serialized;
             SharedMemory::setRecordCount(mapping, recordCount + 1);
-            record.slotIndex = recordCount;
-        }
-        record.state = RecordState::CLEAN;
-    }
-}
-
-/*
-Function: clearCache
-Description: Releases all objects owned by the cache and
-             clears the cache contents.
-Parameters:
-    - cache: Cache to be cleared.
-Returns:
-    - None
-*/
-template<typename TObject>
-void DataStore::clearCache(util::Map<std::string, TrackedRecord<TObject>>&cache)
-{
-    for (int index = 0; index < cache.getSize(); ++index)
-    {
-        delete cache.getValueAt(index).data;
-        cache.getValueAt(index).data = nullptr;
-    }
-    cache.clear();
-}
-
-/*
-Function: refreshCache
-Description: Refreshes the cache while preserving object addresses
-             for records that already exist. Existing objects are
-             updated in-place so that pointers held elsewhere remain
-             valid after the refresh.
-Parameters:
-    - cache: Existing cache to refresh.
-    - refreshedCache: Newly loaded cache contents.
-Returns:
-    - None
-*/
-template<typename TObject>
-void DataStore::refreshCache(util::Map<std::string, TrackedRecord<TObject>>& cache, util::Map<std::string, TrackedRecord<TObject>>& refreshedCache)
-{
-    util::Map<std::string, TrackedRecord<TObject>> oldCache = cache;
-    cache.clear();
-    for (int index = 0; index < refreshedCache.getSize(); ++index)
-    {
-        const std::string& id = refreshedCache.getKeyAt(index);
-        TrackedRecord<TObject>& refreshedRecord = refreshedCache.getValueAt(index);
-        int oldIndex = oldCache.find(id);
-        if (oldIndex != -1)
-        {
-            TrackedRecord<TObject>& oldRecord = oldCache.getValueAt(oldIndex);
-            if (oldRecord.state == RecordState::MODIFIED)
-            {
-                delete refreshedRecord.data;
-                cache.insert(id, oldRecord);
-                continue;
-            }
-            *oldRecord.data = *refreshedRecord.data;
-            oldRecord.slotIndex = refreshedRecord.slotIndex;
-            oldRecord.state = refreshedRecord.state;
-            delete refreshedRecord.data;
-            refreshedRecord.data = oldRecord.data;
-        }
-        cache.insert(id, refreshedRecord);
-    }
-    for (int index = 0; index < oldCache.getSize(); ++index)
-    {
-        const std::string& id = oldCache.getKeyAt(index);
-        const TrackedRecord<TObject>& localTrackedRecord = oldCache.getValueAt(index);
-        if (cache.find(id) == -1)
-        {
-            if (localTrackedRecord.state == RecordState::NEW_RECORD)
-            {
-                cache.insert(id, localTrackedRecord);
-            }
-            else
-            {
-                delete localTrackedRecord.data;
-            }
         }
     }
+    for (int index = 0; index < records.getSize(); ++index)
+    {
+        delete records.getValueAt(index).data;
+        records.getValueAt(index).data = nullptr;
+    }
 }

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

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

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/sharedmemory/SharedMemory.cpp

@@ -10,7 +10,6 @@ Created: 11-June-2026
 */
 
 #include "SharedMemory.h"
-#include "Windows.h"
 #include "Config.h"
 
 /*
@@ -320,7 +319,7 @@ bool SharedMemory::ensureCapacityForInsert(MappingInfo& mapping)
     {
         return true;
     }
-    return resizeMapping(mapping, capacity * config::file::GROWTH_FACTOR);
+    return resizeMapping(mapping, capacity * 2);
 }
 
 /*

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

@@ -29,8 +29,7 @@ Returns:
 ComboPackage::ComboPackage()
     : m_id("CMP" + std::to_string(++m_uid)),
     m_status(util::State::ACTIVE),
-    m_discountPercentage(0.0) {
+    m_discountPercentage(0.0) {}
-}
 
 /*
 Function: ComboPackage

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

@@ -12,7 +12,7 @@ Date: 19-May-2026
 #include "Enums.h"
 
 class Service;
-struct SerializedComboPackage;
+class SerializedComboPackage;
 
 class ComboPackage
 {

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

@@ -28,8 +28,7 @@ InventoryItem::InventoryItem()
     : m_id("IIM" + std::to_string(++m_uid)),
     m_quantity(0),
     m_status(util::State::ACTIVE),
-    m_price(0.0) {
+    m_price(0.0) {}
-}
 
 /*
 Function: InventoryItem
@@ -47,8 +46,7 @@ InventoryItem::InventoryItem(const std::string& partName, int quantity, double p
     m_partName(partName),
     m_quantity(quantity),
     m_status(util::State::ACTIVE),
-    m_price(price) {
+    m_price(price) {}
-}
 
 /*
 Function: InventoryItem (parameterized constructor with ID)

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

@@ -35,8 +35,7 @@ Invoice::Invoice()
     m_discountPercentage(0.0),
     m_totalAmount(0.0),
     m_paymentMethod(util::PaymentMode()),
-    m_status(util::PaymentStatus()) {
+    m_status(util::PaymentStatus()) {}
-}
 
 /*
 Function: Invoice
@@ -68,7 +67,7 @@ Invoice::Invoice(
     const util::Timestamp& paymentDate, 
     util::PaymentMode paymentMethod, 
     util::PaymentStatus status
-)
+    )
     : m_id("INV" + std::to_string(++m_uid)),
     m_bookingId(bookingId),
     m_booking(booking),

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

@@ -6,6 +6,7 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -41,7 +42,7 @@ public:
         ServiceBooking* booking,
         const util::Timestamp& invoiceDate, 
         double laborCost, 
-        const util::Map<std::string, InventoryItem*>& parts,
+        const util::Map<std::string,InventoryItem*>& parts,
         double partsCost,
         double discountPercentage, 
         double totalAmount, 

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

@@ -29,8 +29,7 @@ JobCard::JobCard()
     m_booking(nullptr),
     m_service(nullptr),
     m_technician(nullptr),
-    m_status(util::ServiceJobStatus()) {
+    m_status(util::ServiceJobStatus()) {}
-}
 
 /*
 Function: JobCard
@@ -67,8 +66,7 @@ JobCard::JobCard(const std::string& bookingId,
     m_technician(technician),
     m_assignedDate(assignedDate),
     m_status(status),
-    m_completionDate(completionDate) {
+    m_completionDate(completionDate) {}
-}
 
 /*
 Function: JobCard (parameterized constructor with ID)

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

@@ -1,7 +1,7 @@
 /*
 File: Notification.cpp
 Description: Implements the Notification class which represents system notifications in the Vehicle Service Management System.
-             Provides constructors, accessors, and mutators for notification details such as ID, recipientID, title, message, and timestamp.
+             Provides constructors, accessors, and mutators for notification details such as ID, recipient, title, message, and timestamp.
 Author: Trenser
 Date: 19-May-2026
 */
@@ -24,7 +24,7 @@ Returns:
 */
 Notification::Notification()
     : m_id("NOT" + std::to_string(++m_uid)),
-    m_state(util::State::ACTIVE) {}
+    m_recipient(nullptr), m_state(util::State::ACTIVE) {}
 
 /*
 Function: Notification
@@ -38,14 +38,14 @@ Parameters:
 Returns:
     - A new Notification object.
 */
-Notification::Notification(const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt)
+Notification::Notification(const std::string& recipientUserId, User* recipient, const std::string& title, const std::string& message, const util::Timestamp& createdAt)
     : m_id("NOT" + std::to_string(++m_uid)),
     m_recipientUserId(recipientUserId),
+    m_recipient(recipient),
     m_title(title),
     m_message(message),
     m_state(util::State::ACTIVE),
-    m_createdAt(createdAt) {
+    m_createdAt(createdAt){}
-}
 
 /*
 Function: Notification (parameterized constructor with ID)
@@ -63,6 +63,7 @@ Returns:
 Notification::Notification(const std::string& id, const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt, const util::State& state)
     : m_id(id),
     m_recipientUserId(recipientUserId),
+    m_recipient(nullptr),
     m_title(title),
     m_message(message),
     m_createdAt(createdAt),
@@ -97,6 +98,17 @@ const std::string& Notification::getRecipientUserId() const
     return m_recipientUserId;
 }
 
+/*
+Function: getRecipient
+Description: Retrieves the pointer to the recipient user.
+Returns:
+    - User* representing the recipient.
+*/
+User* Notification::getRecipient() const
+{
+    return m_recipient;
+}
+
 /*
 Function: getTitle
 Description: Retrieves the title of the notification.
@@ -130,17 +142,6 @@ const util::Timestamp& Notification::getCreatedAt() const
     return m_createdAt;
 }
 
-/*
-Function: getState
-Description: Retrieves the Notification state
-Returns:
-    - const util::Timestamp& representing the creation timestamp.
-*/
-util::State Notification::getState() const
-{
-    return m_state;
-}
-
 /*
 Function: setId
 Description: Sets the unique ID of the notification.
@@ -167,6 +168,19 @@ void Notification::setRecipientUserId(const std::string& recipientUserId)
     m_recipientUserId = recipientUserId;
 }
 
+/*
+Function: setRecipient
+Description: Sets the recipient user pointer for the notification.
+Parameters:
+    - recipient: Pointer to the User object.
+Returns:
+    - void
+*/
+void Notification::setRecipient(User* recipient)
+{
+    m_recipient = recipient;
+}
+
 /*
 Function: setTitle
 Description: Sets the title of the notification.
@@ -206,19 +220,6 @@ void Notification::setCreatedAt(const util::Timestamp& createdAt)
     m_createdAt = createdAt;
 }
 
-/*
-Function: setState
-Description: Sets the Notification state.
-Parameters:
-    - state: Notification state value.
-Returns:
-    - void
-*/
-void Notification::setState(util::State state)
-{
-    m_state = state;
-}
-
 /*
 Function: serialize
 Description: Serializes the Notification object into a SerializedNotification record.

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

@@ -20,25 +20,28 @@ private:
     static int m_uid;
     std::string m_id;
     std::string m_recipientUserId;
+    User* m_recipient;
     std::string m_title;
     std::string m_message;
     util::Timestamp m_createdAt;
     util::State m_state;
 public:
     Notification();
-    Notification(const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt);
+    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 util::State& state);
     const std::string& getId() const;
     const std::string& getRecipientUserId() const;
+    User* getRecipient() const;
     const std::string& getTitle() const;
     const std::string& getMessage() const;
     const util::Timestamp& getCreatedAt() const;
     void setId(const std::string& id);
     void setRecipientUserId(const std::string& recipientUserId);
+    void setRecipient(User* recipient);
     void setTitle(const std::string& title);
     void setMessage(const std::string& message);
     void setCreatedAt(const util::Timestamp& createdAt);
-    util::State getState() const;
+    util::State getState();
     void setState(util::State state);
     SerializedNotification serialize() const;
     static Notification* deserialize(const SerializedNotification&);

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

@@ -28,8 +28,7 @@ Returns:
 Service::Service()
     : m_id("SRV" + std::to_string(++m_uid)),
     m_status(util::State::ACTIVE),
-    m_laborCost(0.0) {
+    m_laborCost(0.0) {}
-}
 
 /*
 Function: Service

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

@@ -30,8 +30,7 @@ ServiceBooking::ServiceBooking()
     m_customer(nullptr),
     m_assignedTechnician(nullptr),
     m_status(util::ServiceJobStatus::PENDING),
-    m_discountPercentage(0.0) {
+    m_discountPercentage(0.0) {}
-}
 
 /*
 Function: ServiceBooking

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

@@ -29,8 +29,7 @@ Returns:
 User::User()
     : m_id("USR" + std::to_string(++m_uid)),
     m_type(util::UserType::CUSTOMER),
-    m_status(util::State::ACTIVE) {
+    m_status(util::State::ACTIVE) {}
-}
 
 /*
 Function: User
@@ -53,8 +52,7 @@ User::User(const std::string& userName, const std::string& password, const std::
     m_phone(phone),
     m_email(email),
     m_type(role),
-    m_status(util::State::ACTIVE) {
+    m_status(util::State::ACTIVE) {}
-}
 
 /*
 Function: User (parameterized constructor with ID)
@@ -89,6 +87,23 @@ User::User(const std::string& userId, const std::string& userName, const std::st
     }
 }
 
+/*
+Function: ~User
+Description: Destructor that cleans up dynamically allocated notifications associated with the user.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+User::~User()
+{
+    auto values = m_notifications.getValues();
+    for (int index = 0; index < values.getSize(); index++)
+    {
+        delete values[index];
+    }
+}
+
 /*
 Function: getId
 Description: Retrieves the unique ID of the user.
@@ -155,6 +170,17 @@ const std::string& User::getEmail() const
     return m_email;
 }
 
+/*
+Function: getNotifications
+Description: Retrieves the map of notifications associated with the user.
+Returns:
+    - util::Map<std::string, Notification*>& representing the notifications.
+*/
+util::Map<std::string, Notification*>& User::getNotifications()
+{
+    return m_notifications;
+}
+
 /*
 Function: getUserType
 Description: Retrieves the role of the user.
@@ -255,6 +281,22 @@ void User::setEmail(const std::string& email)
     m_email = email;
 }
 
+/*
+Function: addNotification
+Description: Adds a new notification to the user’s notification map.
+Parameters:
+    - notification: Pointer to the Notification object.
+Returns:
+    - void
+*/
+void User::addNotification(Notification* notification)
+{
+    if (notification)
+    {
+        m_notifications.insert(notification->getId(), notification);
+    }
+}
+
 /*
 Function: setRole
 Description: Sets the role of the user.

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

@@ -26,19 +26,21 @@ private:
     std::string m_name;
     std::string m_phone;
     std::string m_email;
+    util::Map<std::string, Notification*> m_notifications;
     util::UserType m_type;
     util::State m_status;
 public:
     User();
     User(const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role);
     User(const std::string& userId, const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role, util::State status);
-    ~User() = default;
+    ~User();
     const std::string& getId() const;
     const std::string& getUserName() const;
     const std::string& getPassword() const;
     const std::string& getName() const;
     const std::string& getPhone() const;
     const std::string& getEmail() const;
+    util::Map<std::string, Notification*>& getNotifications();
     util::UserType getUserType() const;
     util::State getState() const;
     void setId(const std::string& id);
@@ -47,6 +49,7 @@ public:
     void setName(const std::string& name);
     void setPhone(const std::string& phone);
     void setEmail(const std::string& email);
+    void addNotification(Notification* notification) override;
     void setRole(util::UserType role);
     void setState(util::State status);
     SerializedUser serialize() const;

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

@@ -10,32 +10,8 @@ Date:19-May-2026
 #include <stdexcept>
 #include "AuthenticationManagementService.h"
 #include "User.h"
-#include "Utility.h"
-#include "DataStoreLockGuard.h"
 
 User* AuthenticationManagementService::m_authenticatedUser = nullptr;
-bool AuthenticationManagementService::m_isAuthorized = false;
-EventManager AuthenticationManagementService::m_eventManager;
-HANDLE AuthenticationManagementService::m_accountDisabledEvent = NULL;
-HANDLE AuthenticationManagementService::m_notificationsAvailableEvent = NULL;
-
-
-/*
-Function: ensureAuthorization
-Description: Verifies that a user is currently authenticated before allowing
-			 access to a protected operation. Throws an exception if no
-			 authorized user session exists.
-Parameter: None
-Return type: void
-Throws: std::runtime_error - if the user is not authorized
-*/
-void AuthenticationManagementService::ensureAuthorization()
-{
-	if (!m_authenticatedUser || !m_isAuthorized)
-	{
-		throw std::runtime_error("You are not authorized to do this operation!");
-	}
-}
 
 /*
 Function: login
@@ -48,35 +24,16 @@ Return type: bool - true if login successful, false otherwise
 */
 bool AuthenticationManagementService::login(const std::string& username, const std::string& password)
 {
-	DataStoreLockGuard lock(m_dataStore);
+	util::Map<std::string, User*> users = m_dataStore.getUsers();
-	auto& trackedUserMap = m_dataStore.getUsers();
+	int usersMapSize = users.getSize();
-	int trackedUserMapSize = trackedUserMap.getSize();
+	for (int index = 0; index < usersMapSize; index++)
-	for (int index = 0; index < trackedUserMapSize; index++)
 	{
-		User* user = trackedUserMap.getValueAt(index).data;
+		User* user = users.getValueAt(index);
 		if (username == user->getUserName())
 		{
 			if (password == user->getPassword())
 			{
 				m_authenticatedUser = user;
-				m_isAuthorized = true;
-				m_eventManager.initialize(
-					user->getId(),
-					[]()
-					{
-						if (m_accountDisabledEvent)
-						{
-							AuthenticationManagementService::m_isAuthorized = false;
-							SetEvent(m_accountDisabledEvent);
-						}
-					},
-					[]()
-					{
-						if (m_notificationsAvailableEvent)
-						{
-							SetEvent(m_notificationsAvailableEvent);
-						}
-					});
 				return true;
 			}
 			return false;
@@ -105,11 +62,7 @@ Return type: void
 */
 void AuthenticationManagementService::logout()
 {
-	m_eventManager.shutdown();
 	m_authenticatedUser = nullptr;
-	m_isAuthorized = false;
-	m_accountDisabledEvent = NULL;
-	m_notificationsAvailableEvent = NULL;
 }
 
 /*
@@ -121,33 +74,9 @@ Return type: void
 */
 void AuthenticationManagementService::changePassword(const std::string& newPassword)
 {
-    AuthenticationManagementService::ensureAuthorization();
-	DataStoreLockGuard lock(m_dataStore);
-	auto& trackedUsersMap = m_dataStore.getUsers();
 	if (m_authenticatedUser == nullptr)
 	{
 		throw std::runtime_error("There is no user currently logged in!");
 	}
-	int index = trackedUsersMap.find(m_authenticatedUser->getId());
-	if (index == -1)
-	{
-		throw std::runtime_error("User does not exist!\n");
-	}
 	m_authenticatedUser->setPassword(newPassword);
-	trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
-	m_dataStore.saveUsers();
-}
-
-/*
-Function: registerEvents
-Description: Registers menu event handles used to notify the active
-			 menu of account disable and notification events.
-Parameter: HANDLE accountDisabledEvent - account disabled event handle
-		   HANDLE notificationAvailableEvent - notification event handle
-Return type: void
-*/
-void AuthenticationManagementService::registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent)
-{
-	m_accountDisabledEvent = accountDisabledEvent;
-	m_notificationsAvailableEvent = notificationAvailableEvent;
 }

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

@@ -9,8 +9,6 @@ Date:19-May-2026
 
 #pragma once
 #include <string>
-#include <windows.h>
-#include "EventManager.h"
 #include "DataStore.h"
 
 class User;
@@ -19,17 +17,11 @@ class AuthenticationManagementService
 {
 private:
     static User* m_authenticatedUser;
-    static bool m_isAuthorized;
-    static EventManager m_eventManager;
-    static HANDLE m_accountDisabledEvent;
-    static HANDLE m_notificationsAvailableEvent;
     DataStore& m_dataStore;
 public:
     AuthenticationManagementService() : m_dataStore(DataStore::getInstance()) {}
-    static void ensureAuthorization();
     bool login(const std::string& username, const std::string& password);
     void logout();
     void changePassword(const std::string& newPassword);
     User* getAuthenticatedUser();
-    void registerEvents(HANDLE accountDisabledEvent, HANDLE notificationAvailableEvent);
 };

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

@@ -12,15 +12,14 @@ Date: 22-May-2026
 #include "Config.h"
 #include "Enums.h"
 #include "Factory.h"
+#include "FileManager.h"
 #include "InventoryItem.h"
 #include "InventoryManagementService.h"
-#include "AuthenticationManagementService.h"
 #include "Timestamp.h"
 #include "User.h"
 #include "Utility.h"
 #include "Vector.h"
-#include "DataStoreLockGuard.h"
+
-#include "EventManager.h"
 
 util::Map<std::string, User*> InventoryManagementService::m_observers{};
 
@@ -59,19 +58,18 @@ Returns:
 */
 void InventoryManagementService::sendLowStockAlerts()
 {
-	DataStoreLockGuard lock(m_dataStore);
+	auto& inventoryItems = m_dataStore.getInventoryItems();
-	auto& trackedInventoryItemsMap = m_dataStore.getInventoryItems();
+	if (inventoryItems.isEmpty())
-	auto& trackedUserMap = m_dataStore.getUsers();
-	if (trackedInventoryItemsMap.isEmpty())
 	{
 		return;
 	}
-	int inventoryItemsSize = trackedInventoryItemsMap.getSize();
+	int inventoryItemsSize = inventoryItems.getSize();
-	int usersMapSize = trackedUserMap.getSize();
+	auto& usersMap = m_dataStore.getUsers();
+	int usersMapSize = usersMap.getSize();
 	util::Vector<User*> adminUsers;
 	for (int index = 0; index < usersMapSize; index++)
 	{
-		User* user = trackedUserMap.getValueAt(index).data;
+		User* user = usersMap.getValueAt(index);
 		if (user->getUserType() == util::UserType::ADMIN)
 		{
 			adminUsers.push_back(user);
@@ -84,7 +82,7 @@ void InventoryManagementService::sendLowStockAlerts()
 	}
 	for (int index = 0; index < inventoryItemsSize; index++)
 	{
-		InventoryItem* inventoryItem = trackedInventoryItemsMap.getValueAt(index).data;
+		InventoryItem* inventoryItem = inventoryItems.getValueAt(index);
 		if (inventoryItem && inventoryItem->getQuantity() < config::threshold::INVENTORY_LOW_STOCK_THRESHOLD)
 		{
 			sendLowStockAlertsToAdmins(*this, inventoryItem, adminUsers);
@@ -92,6 +90,95 @@ 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
@@ -103,12 +190,8 @@ Return type: void
 */
 void InventoryManagementService::addInventoryItem(const std::string& partName, int quantity, double price)
 {
-    AuthenticationManagementService::ensureAuthorization();
-	DataStoreLockGuard lock(m_dataStore);
-	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
     InventoryItem* newItem = Factory::getObject<InventoryItem>(partName, quantity, price);
-	trackedInventoryItemMap.insert(newItem->getId(), util::createNewRecord(newItem));
+    m_dataStore.getInventoryItems().insert(newItem->getId(), newItem);
-	m_dataStore.saveInventoryItems();
 }
 
 /*
@@ -120,23 +203,16 @@ Return type: void
 */
 void InventoryManagementService::addInventoryItemStock(const std::string& selectedItemId, int quantity)
 {
-    AuthenticationManagementService::ensureAuthorization();
+    int index = m_dataStore.getInventoryItems().find(selectedItemId);
-	DataStoreLockGuard lock(m_dataStore);
+    if (index != -1)
-	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
-	int index = trackedInventoryItemMap.find(selectedItemId);
-	if (index == -1)
     {
-		throw std::runtime_error("Inventory update failed: Item ID '" + selectedItemId + "' not found.");
+        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
-	}
+        if (item != nullptr)
-	InventoryItem* item = trackedInventoryItemMap.getValueAt(index).data;
-	if (item == nullptr)
         {
-		throw std::runtime_error("Inventory update failed. Item does not exist.\n");
-	}
             int totalQuantity = item->getQuantity() + quantity;
             item->setQuantity(totalQuantity);
-	trackedInventoryItemMap.getValueAt(index).state = RecordState::MODIFIED;
+        }
-	m_dataStore.saveInventoryItems();
+    }
 }
 
 /*
@@ -147,11 +223,7 @@ Return type: util::Map<std::string, InventoryItem*>
 */
 util::Map<std::string, InventoryItem*> InventoryManagementService::getInventoryItems()
 {
-    AuthenticationManagementService::ensureAuthorization();
+	return m_dataStore.getInventoryItems();
-	DataStoreLockGuard lock(m_dataStore);
-	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
-	auto inventoryMap = util::getObjects(trackedInventoryItemMap);
-	return inventoryMap;
 }
 
 /*
@@ -162,22 +234,15 @@ Return type: void
 */
 void InventoryManagementService::removeInventoryItem(const std::string& inventoryItemID)
 {
-    AuthenticationManagementService::ensureAuthorization();
+    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
-	DataStoreLockGuard lock(m_dataStore);
+    if (index != -1)
-	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
-	int index = trackedInventoryItemMap.find(inventoryItemID);
-	if (index == -1)
     {
-		throw std::runtime_error("Inventory removal failed: Item ID '" + inventoryItemID + "' not found.");
+        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
-	}
+        if (item != nullptr)
-	InventoryItem* item = trackedInventoryItemMap.getValueAt(index).data;
-	if (item == nullptr)
         {
-		throw std::runtime_error("Inventory removal failed: Item ID does not exist.");
-	}
             item->setState(util::State::INACTIVE);
-	trackedInventoryItemMap.getValueAt(index).state = RecordState::MODIFIED;
+        }
-	m_dataStore.saveInventoryItems();
+    }
 }
 
 /*
@@ -188,20 +253,12 @@ Return type: InventoryItem*
 */
 InventoryItem* InventoryManagementService::getInventoryItem(const std::string& inventoryItemID)
 {
-    AuthenticationManagementService::ensureAuthorization();
+    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
-	DataStoreLockGuard lock(m_dataStore);
+    if (index != -1)
-	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
-    int index = trackedInventoryItemMap.find(inventoryItemID);
-    if (index == -1)
     {
+        return m_dataStore.getInventoryItems().getValueAt(index);
+    }
     return nullptr;
-    }
-	InventoryItem* inventoryItem = trackedInventoryItemMap.getValueAt(index).data;
-	if (inventoryItem == nullptr)
-	{
-		throw std::runtime_error("Item ID does not exist.");
-	}
-	return inventoryItem;
 }
 
 /*
@@ -214,9 +271,6 @@ Returns:
 */
 void InventoryManagementService::attach(User* user)
 {
-	DataStoreLockGuard lock(m_dataStore);
-	m_observers.clear();
-	m_observers = m_dataStore.getInventoryManagementObservers();
 	if (user)
 	{
 		const std::string& userID = user->getId();
@@ -225,7 +279,6 @@ void InventoryManagementService::attach(User* user)
 			m_observers[userID] = user;
 		}
 	}
-	m_dataStore.saveInventoryManagementObservers(m_observers);
 }
 
 /*
@@ -238,9 +291,6 @@ Returns:
 */
 void InventoryManagementService::detach(User* user)
 {
-	DataStoreLockGuard lock(m_dataStore);
-	m_observers.clear();
-	m_observers = m_dataStore.getInventoryManagementObservers();
 	if (user)
 	{
 		const std::string& userID = user->getId();
@@ -249,7 +299,6 @@ void InventoryManagementService::detach(User* user)
 			m_observers.remove(userID);
 		}
 	}
-	m_dataStore.saveInventoryManagementObservers(m_observers);
 }
 
 /*
@@ -266,28 +315,27 @@ Throws:
 */
 void InventoryManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
 {
-	if (!user)
+	if (user)
 	{
-		return;
+		if (m_observers.find(user->getId()) != -1)
-	}
-	DataStoreLockGuard lock(m_dataStore);
-	m_observers = m_dataStore.getInventoryManagementObservers();
-	if (m_observers.find(user->getId()) == -1)
 		{
-		return;
+			Notification* notification =
-	}
+				Factory::getObject<Notification>(
-	auto& trackedNotificationsMap = m_dataStore.getNotifications();
-	Notification* notification = Factory::getObject<Notification>(
 					user->getId(),
+					user,
 					title,
 					message,
-		util::Timestamp());
+					util::Timestamp()
-	if (!notification)
+				);
+			if (notification)
+			{
+				user->addNotification(notification);
+			}
+			else
 			{
 				throw std::runtime_error("Failed to create notification");
 			}
-	trackedNotificationsMap.insert(notification->getId(), util::createNewRecord(notification));
+		}
-	m_dataStore.saveNotifications();
+	}
-	EventManager::sendNotificationAvailableEvent(user->getId());
 }
 

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

@@ -21,6 +21,7 @@ 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();
@@ -32,4 +33,8 @@ 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 loadInventoryItems();
+    void saveInventoryItems();
+    void loadObservers();
+    void saveObservers();
 };

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

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

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

@@ -11,19 +11,16 @@ Date: 20-May-2026
 #include "Config.h"
 #include "Enums.h"
 #include "Factory.h"
+#include "FileManager.h"
 #include "InventoryItem.h"
 #include "Invoice.h"
 #include "JobCard.h"
 #include "PaymentManagementService.h"
-#include "AuthenticationManagementService.h"
-#include "DataStoreLockGuard.h"
 #include "Service.h"
 #include "ServiceBooking.h"
 #include "Timestamp.h"
 #include "User.h"
 #include "Utility.h"
-#include "DataStoreLockGuard.h"
-#include "EventManager.h"
 
 util::Map<std::string, User*> PaymentManagementService::m_observers{};
 
@@ -37,9 +34,6 @@ Returns:
 */
 void PaymentManagementService::attach(User* user)
 {
-	DataStoreLockGuard lock(m_dataStore);
-	m_observers.clear();
-	m_observers = m_dataStore.getPaymentManagementObservers();
 	if (user)
 	{
 		const std::string& userID = user->getId();
@@ -48,7 +42,6 @@ void PaymentManagementService::attach(User* user)
 			m_observers[userID] = user;
 		}
 	}
-	m_dataStore.savePaymentManagementObservers(m_observers);
 }
 
 /*
@@ -61,9 +54,6 @@ Returns:
 */
 void PaymentManagementService::detach(User* user)
 {
-	DataStoreLockGuard lock(m_dataStore);
-	m_observers.clear();
-	m_observers = m_dataStore.getPaymentManagementObservers();
 	if (user)
 	{
 		const std::string& userID = user->getId();
@@ -72,7 +62,6 @@ void PaymentManagementService::detach(User* user)
 			m_observers.remove(userID);
 		}
 	}
-	m_dataStore.savePaymentManagementObservers(m_observers);
 }
 
 /*
@@ -89,29 +78,28 @@ Throws:
 */
 void PaymentManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
 {
-	if (!user)
+	if (user)
 	{
-		return;
+		if (m_observers.find(user->getId()) != -1)
-	}
-	DataStoreLockGuard lock(m_dataStore);
-	m_observers = m_dataStore.getPaymentManagementObservers();
-	if (m_observers.find(user->getId()) == -1)
 		{
-		return;
+			Notification* notification =
-	}
+				Factory::getObject<Notification>(
-	auto& trackedNotificationsMap = m_dataStore.getNotifications();
-	Notification* notification = Factory::getObject<Notification>(
 					user->getId(),
+					user,
 					title,
 					message,
-		util::Timestamp());
+					util::Timestamp()
-	if (!notification)
+				);
+			if (notification)
+			{
+				user->addNotification(notification);
+			}
+			else
 			{
 				throw std::runtime_error("Failed to create notification");
 			}
-	trackedNotificationsMap.insert(notification->getId(), util::createNewRecord(notification));
+		}
-	m_dataStore.saveNotifications();
+	}
-	EventManager::sendNotificationAvailableEvent(user->getId());
 }
 
 /*
@@ -125,12 +113,11 @@ Returns:
 */
 void PaymentManagementService::sendPaymentReminders()
 {
-	DataStoreLockGuard lock(m_dataStore);
+	auto& invoicesMap = m_dataStore.getInvoices();
-	auto& trackedInvoicesMap = m_dataStore.getInvoices();
+	int invoicesMapSize = invoicesMap.getSize();
-	int invoicesMapSize = trackedInvoicesMap.getSize();
 	for (int index = 0; index < invoicesMapSize; index++)
 	{
-		const Invoice* invoice = trackedInvoicesMap.getValueAt(index).data;
+		const Invoice* invoice = invoicesMap.getValueAt(index);
 		if (invoice && invoice->getStatus() == util::PaymentStatus::PENDING)
 		{
 			util::Timestamp invoiceCreationTimestamp = invoice->getInvoiceDate();
@@ -153,6 +140,123 @@ void PaymentManagementService::sendPaymentReminders()
 	}
 }
 
+/*
+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);
+}
+
 /*
 Function: createInventoryItemsMap (static helper)
 Description: Builds a map of inventory items required for a given service and adds them to the booking’s inventory map.
@@ -186,7 +290,6 @@ Throws:
 */
 void PaymentManagementService::generateInvoice(ServiceBooking* booking)
 {
-	DataStoreLockGuard lock(m_dataStore);
 	if (!booking)
 	{
 		throw std::runtime_error("Invoice generation failed: booking is null.");
@@ -196,10 +299,10 @@ void PaymentManagementService::generateInvoice(ServiceBooking* booking)
 	std::string bookingID = booking->getId();
 	util::Map<std::string, Service*> servicesInTheBookedService = booking->getServices();
 	util::Map<std::string, InventoryItem*> completeInventoryItemMapOfBooking;
-	auto& currentTrackedJobCards = m_dataStore.getJobCards();
+	util::Map<std::string, JobCard*> currentJobCards = m_dataStore.getJobCards();
-	for (int iterator = 0; iterator < currentTrackedJobCards.getSize(); iterator++)
+	for (int iterator = 0; iterator < currentJobCards.getSize(); iterator++)
 	{
-		JobCard* currentJobCard = currentTrackedJobCards.getValueAt(iterator).data;
+		JobCard* currentJobCard = currentJobCards.getValueAt(iterator);
 		util::ServiceJobStatus currentJobCardStatus = currentJobCard->getStatus();
 		if (currentJobCard->getBookingId() == bookingID && currentJobCardStatus != util::ServiceJobStatus::CANCELLED && currentJobCardStatus != util::ServiceJobStatus::COMPLETED)
 		{
@@ -219,9 +322,8 @@ void PaymentManagementService::generateInvoice(ServiceBooking* booking)
 	totalServiceCost = totalLaborCost + totalPartsCost;
 	totalServiceCost -= (totalServiceCost * (discountPercentage / 100));
 	Invoice* invoice = Factory::getObject<Invoice>(bookingID, booking, util::Timestamp(), totalLaborCost, completeInventoryItemMapOfBooking, totalPartsCost, discountPercentage, totalServiceCost, util::Timestamp(), util::PaymentMode::NOTSET, util::PaymentStatus::PENDING);
-	auto& currentTrackedInvoices = m_dataStore.getInvoices();
+	util::Map<std::string, Invoice*>& currentInvoices = m_dataStore.getInvoices();
-	currentTrackedInvoices.insert(invoice->getId(), util::createNewRecord(invoice));
+	currentInvoices.insert(invoice->getId(), invoice);
-	m_dataStore.saveInvoices();
 }
 
 /*
@@ -234,13 +336,11 @@ Returns:
 */
 util::Map<std::string, Invoice*> PaymentManagementService::getInvoices(const std::string& customerID)
 {
-    AuthenticationManagementService::ensureAuthorization();
+	util::Map<std::string, Invoice*>& currentInvoices = m_dataStore.getInvoices();
-	DataStoreLockGuard lock(m_dataStore);
-	auto& currentTrackedInvoices = m_dataStore.getInvoices();
 	util::Map<std::string, Invoice*> currentUserInvoices;
-	for (int iterator = 0; iterator < currentTrackedInvoices.getSize(); iterator++)
+	for (int iterator = 0; iterator < currentInvoices.getSize(); iterator++)
 	{
-		Invoice* currentInvoice = currentTrackedInvoices.getValueAt(iterator).data;
+		Invoice* currentInvoice = currentInvoices.getValueAt(iterator);
 		if (currentInvoice->getBooking()->getCustomerId() == customerID)
 		{
 			currentUserInvoices.insert(currentInvoice->getId(), currentInvoice);
@@ -263,14 +363,11 @@ Throws:
 */
 void PaymentManagementService::completePayment(const std::string& invoiceID, util::PaymentMode paymentMode)
 {
-    AuthenticationManagementService::ensureAuthorization();
+	auto& currentInvoices = m_dataStore.getInvoices();
-	DataStoreLockGuard lock(m_dataStore);
+	int invoiceIndex = currentInvoices.find(invoiceID);
-	auto& currentTrackedInvoices = m_dataStore.getInvoices();
-	int invoiceIndex = currentTrackedInvoices.find(invoiceID);
 	if (invoiceIndex != -1)
 	{
-		auto& trackedInvoice = currentTrackedInvoices.getValueAt(invoiceIndex);
+		Invoice* invoice = currentInvoices.getValueAt(invoiceIndex);
-		Invoice* invoice = trackedInvoice.data;
 		if (invoice && invoice->getStatus() != util::PaymentStatus::PAID)
 		{
 			User* currentUser = invoice->getBooking()->getCustomer();
@@ -281,31 +378,25 @@ void PaymentManagementService::completePayment(const std::string& invoiceID, uti
 			title = "Payment successful";
 			message = "Payment successful for Invoice ID " + invoiceID;
 			sendNotification(currentUser, title, message);
-			trackedInvoice.state = RecordState::MODIFIED;
 		}
 	}
 	else
 	{
 		throw std::runtime_error("Payment failed: invalid invoice ID.");
 	}
-	m_dataStore.saveInvoices();
 }
 
 /*
-Function: getAllInvoices
+Function: getAllInvoice
 Description: Provides access to all invoices stored in the data store.
 Parameters:
 	- none
 Returns:
-	- util::Map<std::string, Invoice*>: Map of invoice IDs to invoice objects
+	- util::Map<std::string, Invoice*>&: Map of invoice IDs to invoice objects
 */
-util::Map<std::string, Invoice*> PaymentManagementService::getAllInvoices()
+util::Map<std::string, Invoice*>& PaymentManagementService::getAllInvoices()
 {
-    AuthenticationManagementService::ensureAuthorization();
+	return m_dataStore.getInvoices();
-	DataStoreLockGuard lock(m_dataStore);
-	util::Map<std::string, Invoice*> invoices;
-	invoices = util::getObjects(m_dataStore.getInvoices());
-	return invoices;
 }
 
 /*
@@ -321,25 +412,20 @@ Throws:
 */
 void PaymentManagementService::confirmPayment(const std::string& invoiceID)
 {
-    AuthenticationManagementService::ensureAuthorization();
+	auto& currentInvoices = m_dataStore.getInvoices();
-	DataStoreLockGuard lock(m_dataStore);
+	int invoiceIndex = currentInvoices.find(invoiceID);
-	auto& currentTrackedInvoices = m_dataStore.getInvoices();
-	int invoiceIndex = currentTrackedInvoices.find(invoiceID);
 	if (invoiceIndex == -1)
 	{
 		throw std::runtime_error("Payment confirmation failed: invalid invoice ID.");
 	}
-	auto& trackedInvoice = currentTrackedInvoices.getValueAt(invoiceIndex);
+	Invoice* invoice = currentInvoices.getValueAt(invoiceIndex);
-	Invoice* invoice = trackedInvoice.data;
 	if (!invoice || invoice->getStatus() != util::PaymentStatus::PAID)
 	{
 		throw std::runtime_error("Payment confirmation failed: invoice is not awaiting confirmation.");
 	}
 	User* currentUser = invoice->getBooking()->getCustomer();
 	invoice->setStatus(util::PaymentStatus::COMPLETED);
-	trackedInvoice.state = RecordState::MODIFIED;
 	std::string title = "Payment Confirmed";
 	std::string message = "Payment Confirmed for Invoice ID " + invoiceID;
 	sendNotification(currentUser, title, message);
-	m_dataStore.saveInvoices();
 }

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

@@ -22,15 +22,20 @@ 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);
     util::Map<std::string, Invoice*> getInvoices(const std::string& customerID);
     void completePayment(const std::string& invoiceID, util::PaymentMode paymentMode);
-    util::Map<std::string, Invoice*> getAllInvoices();
+    util::Map<std::string, Invoice*>& getAllInvoices();
     void confirmPayment(const std::string& invoiceID);
     void sendPaymentReminders();
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;
     void detach(User* user) override;
+    void loadInvoices();
+    void saveInvoices();
+    void loadObservers();
+    void saveObservers();
 };

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

@@ -23,6 +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();
@@ -35,7 +36,6 @@ public:
     void createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID);
     void createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost);
     void removeService(const std::string& serviceID);
-    void removeServiceBooking(const std::string& bookingID);
     util::Map<std::string, JobCard*> getJobCards(const std::string& technicianID);
     void updateJobStatus(const std::string& jobID);
     void cancelCustomerServiceBookings(const std::string& customerID);
@@ -45,4 +45,14 @@ 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 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

@@ -11,19 +11,15 @@ Date:19-May-2026
 #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 "AuthenticationManagementService.h"
 #include "User.h"
 #include "UserManagementService.h"
 #include "Vector.h"
 #include "Validator.h"
-#include "Utility.h"
-#include "TrackedRecord.h"
-#include "DataStoreLockGuard.h"
-#include "EventManager.h"
 
 /*
 Function: ensureAdminExists
@@ -35,13 +31,12 @@ Return type: void
 */
 void UserManagementService::ensureAdminExists()
 {
-	DataStoreLockGuard lock(m_dataStore);
 	auto& usersMap = m_dataStore.getUsers();
 	int usersMapSize = usersMap.getSize();
 	bool isAdminFound = false;
 	for (int index = 0; index < usersMapSize; index++)
 	{
-		User* user = usersMap.getValueAt(index).data;
+		User* user = usersMap.getValueAt(index);
 		if (user && user->getUserType() == util::UserType::ADMIN)
 		{
 			isAdminFound = true;
@@ -78,9 +73,7 @@ void UserManagementService::createUser(const std::string& username, const std::s
 	InventoryManagementService inventoryManagementService;
 	PaymentManagementService paymentManagementService;
 	ServiceManagementService serviceManagementService;
-	DataStoreLockGuard lock(m_dataStore);
+	auto& usersMap = m_dataStore.getUsers();
-	auto& trackedUsersMap = m_dataStore.getUsers();
-	auto usersMap = util::getObjects(trackedUsersMap);
 	if (util::isUsernameDuplicate(username, usersMap))
 	{
 		throw std::runtime_error("Username already exists");
@@ -94,14 +87,13 @@ void UserManagementService::createUser(const std::string& username, const std::s
 		throw std::runtime_error("Phone already exists");
 	}
 	User* newUser = Factory::getObject<User>(username, password, name, phone, email, type);
-	trackedUsersMap.insert(newUser->getId(), util::createNewRecord(newUser));
+	usersMap.insert(newUser->getId(), newUser);
 	paymentManagementService.attach(newUser);
 	serviceManagementService.attach(newUser);
 	if (newUser->getUserType() == util::UserType::ADMIN)
 	{
 		inventoryManagementService.attach(newUser);
 	}
-	m_dataStore.saveUsers();
 }
 
 /*
@@ -115,25 +107,19 @@ Return type: void
 */
 void UserManagementService::updateUserDetails(const std::string& userID, const std::string& email, const std::string& phone)
 {
-    AuthenticationManagementService::ensureAuthorization();
+	auto& usersMap = m_dataStore.getUsers();
-	DataStoreLockGuard lock(m_dataStore);
+	int index = usersMap.find(userID);
-	auto& trackedUsersMap = m_dataStore.getUsers();
-	auto usersMap = util::getObjects(trackedUsersMap);
-	int index = trackedUsersMap.find(userID);
 	if (index == -1)
 	{
 		throw std::runtime_error("User does not exist!\n");
 	}
-	User* user = trackedUsersMap.getValueAt(index).data;
+	User* user = usersMap.getValueAt(index);
-	bool isModified = false;
 	if (email != user->getEmail())
 	{
 		if (util::isEmailDuplicate(email, usersMap))
 		{
 			throw std::runtime_error("Email already exists!\n");
 		}
-		user->setEmail(email);
-		isModified = true;
 	}
 	if (phone != user->getPhone())
 	{
@@ -141,14 +127,9 @@ void UserManagementService::updateUserDetails(const std::string& userID, const s
 		{
 			throw std::runtime_error("Phone number already exists!\n");
 		}
+	}
+	user->setEmail(email);
 	user->setPhone(phone);
-		isModified = true;
-	}
-	if (isModified)
-	{
-		trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
-		m_dataStore.saveUsers();
-	}
 }
 
 /*
@@ -163,26 +144,20 @@ Throws:
 */
 util::Vector<Notification*> UserManagementService::getUserNotifications(const std::string& userID)
 {
-    AuthenticationManagementService::ensureAuthorization();
+	auto& usersMap = m_dataStore.getUsers();
-	DataStoreLockGuard lock(m_dataStore);
+	if (usersMap.find(userID) == -1)
-	auto& trackedUsersMap = m_dataStore.getUsers(); 
-	if (trackedUsersMap.find(userID) == -1)
 	{
 		throw std::runtime_error("No user found with given UserID");
 	}
-	User* user = trackedUsersMap[userID].data;
+	User* user = usersMap[userID];
 	if (user)
 	{
-		auto& trackedNotificationMap = m_dataStore.getNotifications();
+		auto& notifications = user->getNotifications();
-		int numberOfNotifications = trackedNotificationMap.getSize();
+		int numberOfNotifications = notifications.getSize();
 		util::Vector<Notification*> notificationsVector;
 		for (int index = 0; index < numberOfNotifications; index++)
 		{
-			Notification* notification = trackedNotificationMap.getValueAt(index).data;
+		    notificationsVector.push_back(notifications.getValueAt(index));
-			if (notification->getRecipientUserId() == userID && notification->getState() == util::State::ACTIVE)
-			{
-				notificationsVector.push_back(notification);
-			}
 		}
 		return notificationsVector;
 	}
@@ -194,40 +169,97 @@ util::Vector<Notification*> UserManagementService::getUserNotifications(const st
 
 /*
 Function: deleteNotification
-Description: Marks a specific notification associated with a given user
+Description: Deletes a specific notification associated with a given user ID.
-			 as inactive.
 Parameters:
 	- notificationID: The unique ID of the notification to be deleted.
 	- userID: The unique ID of the user whose notification is to be deleted.
 Returns:
 	- void
 Throws:
-	- std::runtime_error if no user is found with the given UserID or
+	- std::runtime_error if no user is found with the given UserID or if no notification is found with the given NotificationID.
-	  if no notification is found with the given NotificationID.
 */
 void UserManagementService::deleteNotification(const std::string& notificationID, const std::string& userID)
 {
-    AuthenticationManagementService::ensureAuthorization();
+	auto& usersMap = m_dataStore.getUsers();
-	DataStoreLockGuard lock(m_dataStore);
+	if (usersMap.find(userID) == -1)
-	auto& trackedUsersMap = m_dataStore.getUsers();
-	auto& trackedNotificationsMap = m_dataStore.getNotifications();
-	int userIndex = trackedUsersMap.find(userID);
-	if (userIndex == -1)
 	{
 		throw std::runtime_error("No user found with given UserID");
 	}
-	int notificationIndex = trackedNotificationsMap.find(notificationID);
+	User* user = usersMap[userID];
-	if (notificationIndex == -1)
+	auto& notifications = user->getNotifications();
+	if (notifications.find(notificationID) == -1)
 	{
 		throw std::runtime_error("No notification found with given NotificationID");
 	}
-	Notification* notification = trackedNotificationsMap.getValueAt(notificationIndex).data;
+	notifications.remove(notificationID);
-	if (notification->getRecipientUserId() == userID)
+}
+
+/*
+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++)
     {
-		notification->setState(util::State::INACTIVE);
+        users[usersMap.getKeyAt(index)] = usersMap.getValueAt(index);
-		trackedNotificationsMap.getValueAt(notificationIndex).state = RecordState::MODIFIED;
-		m_dataStore.saveNotifications();
     }
+    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);
 }
 
 /*
@@ -238,9 +270,7 @@ Return type: util::Map<std::string, User*>
 */
 util::Map<std::string, User*> UserManagementService::getUsers()
 {
-	DataStoreLockGuard lock(m_dataStore);
+	return m_dataStore.getUsers();
-	auto users = util::getObjects(m_dataStore.getUsers());
-	return users;
 }
 
 /*
@@ -251,12 +281,10 @@ Return type: User*
 */
 User* UserManagementService::getUser(const std::string& userID)
 {
-	DataStoreLockGuard lock(m_dataStore);
+	int index = m_dataStore.getUsers().find(userID);
-	auto& trackedUsersMap = m_dataStore.getUsers();
-	int index = trackedUsersMap.find(userID);
 	if (index != -1)
 	{
-		return trackedUsersMap.getValueAt(index).data;
+		return m_dataStore.getUsers().getValueAt(index);
 	}
 	return nullptr;
 }
@@ -269,18 +297,13 @@ Return type: void
 */
 void UserManagementService::removeUser(const std::string& userID)
 {
-    AuthenticationManagementService::ensureAuthorization();
 	InventoryManagementService inventoryManagementService;
 	PaymentManagementService paymentManagementService;
 	ServiceManagementService serviceManagementService;
-	std::string removedUserID;
+	int index = m_dataStore.getUsers().find(userID);
-	{
-		DataStoreLockGuard lock(m_dataStore);
-		auto& trackedUsersMap = m_dataStore.getUsers();
-		int index = trackedUsersMap.find(userID);
 	if (index != -1)
 	{
-			User* user = trackedUsersMap.getValueAt(index).data;
+		User* user = m_dataStore.getUsers().getValueAt(index);
 		if (user != nullptr)
 		{
 			if (user->getUserType() == util::UserType::CUSTOMER)
@@ -291,43 +314,21 @@ void UserManagementService::removeUser(const std::string& userID)
 			{
 				serviceManagementService.cancelTechnicianJobs(userID);
 			}
+			user->setState(util::State::INACTIVE);
 			inventoryManagementService.detach(user);
 			paymentManagementService.detach(user);
 			serviceManagementService.detach(user);
-				user->setState(util::State::INACTIVE);
-				trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
-				removedUserID = user->getId();
-				m_dataStore.saveUsers();
 		}
 	}
-	}
-	if (!removedUserID.empty())
-	{
-		EventManager::sendUserDisabledEvent(removedUserID);
-	}
 }
 
-/*
-Function: getUsers
-Description: Retrieves all active users of the specified type from
-			 the DataStore.
-Parameters:
-	- type: The user type to filter by
-			(ADMIN, CUSTOMER, or TECHNICIAN).
-Returns:
-	- util::Map<std::string, User*>:
-	  Collection of active users matching the specified type,
-	  keyed by user ID.
-*/
 util::Map<std::string, User*> UserManagementService::getUsers(util::UserType type)
 {
-	DataStoreLockGuard lock(m_dataStore);
+	util::Map<std::string, User*>& currentUsers = m_dataStore.getUsers();
-	auto& trackedUsersMap = m_dataStore.getUsers();
-	util::Map<std::string, User*> currentUsers = util::getObjects(trackedUsersMap);
 	util::Map<std::string, User*> filteredUsersMap;
-	for (int index = 0; index < currentUsers.getSize(); index++)
+	for (int iterator = 0; iterator < currentUsers.getSize(); iterator++)
 	{
-		User* currentUser = currentUsers.getValueAt(index);
+		User* currentUser = currentUsers.getValueAt(iterator);
 		if (currentUser && currentUser->getState() == util::State::ACTIVE && currentUser->getUserType() == type)
 		{
 			filteredUsersMap.insert(currentUser->getId(), currentUser);

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

@@ -31,4 +31,6 @@ 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

@@ -29,7 +29,6 @@ namespace config
 	namespace file
 	{
 		const size_t INITIAL_CAPACITY = 100;
-		const size_t GROWTH_FACTOR = 2;
 		constexpr const char* DIRECTORY = "files/";
 		constexpr const char* INVENTORYITEM_FILE = "files/InventoryItem.dat";
 		constexpr const char* USER_FILE = "files/User.dat";

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

@@ -43,4 +43,67 @@ namespace util
             position++;
         }
     }
+
+    /*
+    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())
+        {
+            ensureDirectoryExists(filePath);
+            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 +1,119 @@
+/*
+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"
+#include "FileHelper.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())
+		{
+			ensureDirectoryExists(m_filePath);
+			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

@@ -28,7 +28,7 @@ namespace util
         if (!(std::cin >> value))
         {
             std::cin.clear();
-            std::cin.ignore((std::numeric_limits<std::streamsize>::max)(), '\n');
+            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
             throw std::runtime_error("Invalid console input");
         }
     }

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

@@ -54,79 +54,49 @@ namespace util
         return cost;
     }
 
-    template<typename TObject>
+    /*
-    Map<std::string, TObject*> getObjects(const Map<std::string, TrackedRecord<TObject>>& trackedRecords);
+    Function: loadObservers
-
+    Description: Loads observer IDs from a file and attaches the corresponding users
-    template<typename TObject>
+                 to the notification management service. Validates that each observer ID
-    Map<std::string, const TObject*> getConstObjects(const Map<std::string, TrackedRecord<TObject>>& trackedRecords);
+                 exists in the datastore before attaching.
-
+    Parameters:
-    template<typename TObject>
+        - filePath: const std::string&, path to the file containing observer IDs
-    TrackedRecord<TObject> createNewRecord(TObject* object);
+        - service: NotificationManagementService*, pointer to the notification service
-}
+        - dataStore: DataStore&, reference to the datastore containing users
-
+    Returns:
-/*
+        - void
-Function: getObjects
+    Throws:
-Description: Extracts the object pointers from a tracked-record
+        - std::runtime_error if an observer ID is invalid (not found in datastore)
-             collection and returns them as a map keyed by the
+    */
-             same identifiers.
+    inline void loadObservers(const std::string& filePath, NotificationManagementService* service, DataStore& dataStore)
-Parameters:
-    - trackedRecords: Collection of tracked records.
-Returns:
-    - Map<std::string, TObject*>: Collection of object pointers.
-*/
-template<typename TObject>
-util::Map<std::string, TObject*> util::getObjects(const util::Map<std::string, TrackedRecord<TObject>>& trackedRecords)
-{
-    util::Map<std::string, TObject*> objects;
-    for (int index = 0; index < trackedRecords.getSize(); ++index)
     {
-        const std::string& key = trackedRecords.getKeyAt(index);
+        auto observerIDs = util::loadRecords(filePath);
-        TObject* object = trackedRecords.getValueAt(index).data;
+        auto& users = dataStore.getUsers();
-        objects.insert(key, object);
+        for (int index = 0; index < observerIDs.getSize(); index++)
-    }
-    return objects;
-}
-
-/*
-Function: getConstObjects
-Description: Extracts the object pointers from a tracked-record
-             collection and returns them as a read-only map
-             keyed by the same identifiers.
-Parameters:
-    - trackedRecords: Collection of tracked records.
-Returns:
-    - Map<std::string, const TObject*>:
-      Collection of read-only object pointers.
-*/
-template<typename TObject>
-util::Map<std::string, const TObject*> util::getConstObjects(
-    const util::Map<std::string, TrackedRecord<TObject>>& trackedRecords)
-{
-    util::Map<std::string, const TObject*> objects;
-    for (int index = 0; index < trackedRecords.getSize(); ++index)
         {
-        const std::string& key = trackedRecords.getKeyAt(index);
+            const std::string& observerID = observerIDs[index];
-        const TObject* object = trackedRecords.getValueAt(index).data;
+            int userIndex = users.find(observerID);
-        objects.insert(key, object);
+            if (userIndex == -1)
+            {
+                throw std::runtime_error("Invalid Observer ID");
+            }
+            service->attach(users.getValueAt(userIndex));
+        }
     }
-    return objects;
-}
 
-/*
+    /*
-Function: createNewRecord
+    Function: saveObservers
-Description: Creates a tracked record for a newly created
+    Description: Saves the current observer IDs from the notification management service
-             object. The record is initialized with
+                 to a file for persistence.
-             NEW_RECORD state.
+    Parameters:
-Parameters:
+        - filePath: const std::string&, path to the file where observer IDs will be saved
-    - object: Pointer to the newly created object.
+        - service: NotificationManagementService*, pointer to the notification service
-Returns:
+    Returns:
-    - TrackedRecord<TObject>: Initialized tracked record.
+        - void
-*/
+    */
-template<typename TObject>
+    inline void saveObservers(const std::string& filePath, NotificationManagementService* service)
-TrackedRecord<TObject> util::createNewRecord(TObject* object)
+    {
-{
+        auto observerIDs = service->getObserverIDs();
-    TrackedRecord<TObject> record;
+        util::saveRecords(filePath, observerIDs);
-    record.data = object;
+    }
-    record.state = RecordState::NEW_RECORD;
-    return record;
 }

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

@@ -30,16 +30,10 @@ Return type: void
 */
 void AdminMenu::showMenu()
 {
-	startEventListener();
     while (true)
     {
         try
         {
-			if (!m_isMenuActive)
-			{
-				logout();
-				break;
-			}
             int choice;
             util::clear();
             std::cout << "Admin Menu"
@@ -74,7 +68,6 @@ void AdminMenu::showMenu()
             util::pressEnter();
         }
     }
-	stopEventListener();
 }
 
 /*
@@ -85,11 +78,6 @@ Return type: bool - true if menu continues, false if logout
 */
 bool AdminMenu::handleOperation(int choice)
 {
-	if (!m_isMenuActive)
-	{
-		logout();
-		return false;
-	}
     switch (choice)
     {
     case 1:
@@ -153,25 +141,6 @@ bool AdminMenu::handleOperation(int choice)
     return true;
 }
 
-/*
-Function: handleNotificationEvent
-Description: Retrieves and displays the latest notification for the
-			 currently logged in admin.
-Parameter: None
-Return type: void
-*/
-void AdminMenu::handleNotificationEvent()
-{
-	auto notifications = m_controller.getNotifications();
-	const User* authenticatedUser = m_controller.getAuthenticatedUser();
-	std::string name;
-	if (authenticatedUser)
-	{
-		name = authenticatedUser->getName();
-	}
-	displayNewNotification(notifications, name);
-}
-
 /*
 Function: logout
 Description: Logs out the currently authenticated admin user.
@@ -338,23 +307,6 @@ void AdminMenu::removeInventoryItem()
             std::string selectedItemId = selectedItem->getId();
             m_controller.removeInventoryItem(selectedItemId);
             std::cout << "Item " << selectedItem->getPartName() << " removed successfully." << std::endl;
-			const util::Map<std::string, const Service*>& listOfService = m_controller.getServices();
-			for (int serviceIndex = 0; serviceIndex < listOfService.getSize(); serviceIndex++)
-			{
-				const Service* service = listOfService.getValueAt(serviceIndex);
-				if (!service)
-				{
-					continue;
-				}
-				const util::Map<std::string, InventoryItem*>& requiredItems = service->getRequiredInventoryItems();
-				if (requiredItems.find(selectedItemId) != -1) 
-				{
-					m_controller.removeService(service->getId()); 
-					std::cout << "Service " << service->getName()
-						<< " removed as the item "
-						<< selectedItem->getPartName() << " required for the service has been removed." << std::endl;
-				}
-			}
         }
     }
     util::pressEnter();

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

@@ -9,13 +9,12 @@ Date:19-May-2026
 
 #pragma once
 #include "Controller.h"
-#include "Menu.h"
 
-class AdminMenu : public Menu
+class AdminMenu
 {
 private:
+    Controller m_controller;
     bool handleOperation(int choice);
-    void handleNotificationEvent() override;
 public:
     void showMenu();
     void logout();

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

@@ -32,17 +32,10 @@ Return type: void
 */
 void CustomerMenu::showMenu()
 {
-
-    startEventListener();
     while (true)
     {
         try
         {
-            if (!m_isMenuActive)
-            {
-                logout();
-                break;
-            }
             int choice;
             util::clear();
             std::cout << "Customer Menu"
@@ -51,12 +44,11 @@ void CustomerMenu::showMenu()
                 << "\n3. Update Profile"
                 << "\n4. Change Password"
                 << "\n5. View Service History"
-                << "\n6. Cancel Service Booking"
+                << "\n6. Complete Payments"
-                << "\n7. Complete Payments"
+                << "\n7. View Invoices"
-                << "\n8. View Invoices"
+                << "\n8. View Notifications"
-                << "\n9. View Notifications"
+                << "\n9. Configure Notifications"
-                << "\n10. Configure Notifications"
+                << "\n10. Logout"
-                << "\n11. Logout"
                 << "\nEnter a choice: ";
             util::read(choice);
             if (!handleOperation(choice))
@@ -70,7 +62,6 @@ void CustomerMenu::showMenu()
             util::pressEnter();
         }
     }
-    stopEventListener();
 }
 
 /*
@@ -81,11 +72,6 @@ Return type: bool - true if menu continues, false if logout
 */
 bool CustomerMenu::handleOperation(int choice)
 {
-    if (!m_isMenuActive)
-    {
-        logout();
-        return false;
-    }
     switch (choice)
     {
     case 1:
@@ -104,21 +90,18 @@ bool CustomerMenu::handleOperation(int choice)
         viewServiceHistory();
         break;
     case 6:
-        cancelServiceBooking();
-        break;
-    case 7:
         completePayments();
         break;
-    case 8:
+    case 7:
         viewInvoices();
         break;
-    case 9:
+    case 8:
         viewNotifications();
         break;
-    case 10:
+    case 9:
         configureNotifications();
         break;
-    case 11:
+    case 10:
         logout();
         return false;
     default:
@@ -128,25 +111,6 @@ bool CustomerMenu::handleOperation(int choice)
     return true;
 }
 
-/*
-Function: handleNotificationEvent
-Description: Retrieves and displays the latest notification for the
-             currently logged in admin.
-Parameter: None
-Return type: void
-*/
-void CustomerMenu::handleNotificationEvent()
-{
-    auto notifications = m_controller.getNotifications();
-    const User* authenticatedUser = m_controller.getAuthenticatedUser();
-    std::string name;
-    if (authenticatedUser)
-    {
-        name = authenticatedUser->getName();
-    }
-    displayNewNotification(notifications, name);
-}
-
 /*
 Function: logout
 Description: Logs out the currently authenticated customer user.
@@ -337,46 +301,6 @@ void CustomerMenu::viewServiceHistory()
     util::pressEnter();
 }
 
-/*
-Function: cancelServiceBooking
-Description: Allows the customer to cancel a pending service booking.
-             Displays the list of active bookings, lets the user select one,
-             and removes it from the system. If no bookings are available,
-             an appropriate message is shown.
-Parameter: None
-Return type: void
-*/
-void CustomerMenu::cancelServiceBooking()
-{
-    util::clear();
-    std::cout << "Cancel Service Booking\n";
-    const User* currentUser = m_controller.getAuthenticatedUser();
-    std::string currentUserID = currentUser->getId();
-    util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
-    util::Map<int, const ServiceBooking*> serviceBookingsMap;
-    auto currentPendingServiceBookings = filterActiveServiceBookings(serviceBookingsByCurrentUser);
-    int bookingsSize = currentPendingServiceBookings.getSize();
-    if (listServiceBookings(currentPendingServiceBookings, bookingsSize, serviceBookingsMap))
-    {
-        const ServiceBooking* selectedService = selectPendingServiceBookings(serviceBookingsMap);
-        if (selectedService)
-        {
-            m_controller.removeServiceBooking(selectedService->getId());
-            std::cout << "Cancelled Service booking of id " + selectedService->getId() << std::endl << std::endl;
-        }
-        else
-        {
-            std::cout << "Invalid service booking index.\n\n";
-            return;
-        }
-    }
-    else
-    {
-        std::cout << "No pending service bookings available.\n\n";
-    }
-    util::pressEnter();
-}
-
 /*
 Function: completePayments
 Description: Allows the customer to complete pending payments for invoices.

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

@@ -9,14 +9,13 @@ Date:19-May-2026
 */
 
 #pragma once
-#include "Menu.h"
 #include "Controller.h"
 
-class CustomerMenu : public Menu
+class CustomerMenu
 {
 private:
+    Controller m_controller;
     bool handleOperation(int choice);
-    void handleNotificationEvent();
 public:
     void showMenu();
     void logout();
@@ -28,6 +27,5 @@ public:
     void completePayments();
     void viewInvoices();
     void viewNotifications();
-    void cancelServiceBooking();
     void configureNotifications();
 };

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

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

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

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

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

@@ -28,7 +28,6 @@ Date: 21-May-2026
 #include "Utility.h"
 #include "Validator.h"
 #include "Vector.h"
-#include "StringHelper.h"
 
 /*
 Function: displayAllServices
@@ -588,7 +587,7 @@ inline void displayInvoices(util::Map<std::string, const Invoice*> currentUserIn
                     << util::getPaymentStatusString(selectedInvoice->getStatus()) << std::endl;
                 std::cout << std::left << std::setw(20) << "Payment Mode:"
                     << util::getPaymentModeString(selectedInvoice->getPaymentMethod()) << std::endl;
-                auto& inventoryItemsInInvoice = selectedInvoice->getParts();
+                auto inventoryItemsInInvoice = selectedInvoice->getParts();
                 if (inventoryItemsInInvoice.isEmpty())
                 {
                     std::cout << "No inventory items used.\n\n";
@@ -597,6 +596,7 @@ inline void displayInvoices(util::Map<std::string, const Invoice*> currentUserIn
                 std::cout << "\nItems Used:\n";
                 std::cout << std::left
                     << std::setw(20) << "ItemName"
+                    << std::setw(10) << "Quantity"
                     << std::setw(10) << "Price"
                     << std::endl;
                 std::cout << std::string(40, '-') << std::endl;
@@ -605,6 +605,7 @@ inline void displayInvoices(util::Map<std::string, const Invoice*> currentUserIn
                     InventoryItem* currentItem = inventoryItemsInInvoice.getValueAt(iterator);
                     std::cout << std::left
                         << std::setw(20) << currentItem->getPartName()
+                        << std::setw(10) << currentItem->getQuantity()
                         << std::setw(10) << currentItem->getPrice()
                         << std::endl;
                 }
@@ -1055,21 +1056,6 @@ inline const Service* selectServiceFromServices(const util::Map<std::string, con
         {
             continue;
         }
-        bool hasDepletedItem = false;
-        const util::Map<std::string, InventoryItem*>& requiredItems = currentService->getRequiredInventoryItems();
-        for (int itemIndex = 0; itemIndex < requiredItems.getSize(); itemIndex++)
-        {
-            const InventoryItem* item = requiredItems.getValueAt(itemIndex);
-            if (!item || item->getQuantity() < 1)
-            {
-                hasDepletedItem = true;
-                break;
-            }
-        }
-        if (hasDepletedItem)
-        {
-            continue; 
-        }
         activeServicesMap.insert(currentIndex, currentService);
         double partsCost = util::calculatePartsCost(currentService);
         std::cout << std::left
@@ -1144,9 +1130,7 @@ inline void displayAllComboPackages(util::Map<std::string, const ComboPackage*>
     for (int index = 0; index < comboPackages.getSize(); index++)
     {
         const ComboPackage* currentComboPackage = comboPackages.getValueAt(index);
-        if (currentComboPackage) 
+        if (currentComboPackage && currentComboPackage->getState() != util::State::ACTIVE)
-        {
-            if (currentComboPackage->getState() != util::State::ACTIVE)
         {
             continue;
         }
@@ -1156,7 +1140,6 @@ inline void displayAllComboPackages(util::Map<std::string, const ComboPackage*>
             << std::setw(15) << util::calculateComboServiceEstimatedCost(currentComboPackage)
             << std::endl;
     }
-    }
 }
 
 
@@ -1181,9 +1164,7 @@ inline const ComboPackage* selectComboPackageFromPackages(const util::Map<std::s
     for (int index = 0; index < comboPackages.getSize(); index++)
     {
         const ComboPackage* currentComboPackage = comboPackages.getValueAt(index);
-        if (currentComboPackage)
+        if (currentComboPackage && currentComboPackage->getState() != util::State::ACTIVE)
-        {
-            if (currentComboPackage->getState() != util::State::ACTIVE)
         {
             continue;
         }
@@ -1196,7 +1177,6 @@ inline const ComboPackage* selectComboPackageFromPackages(const util::Map<std::s
             << std::endl;
         currentIndex++;
     }
-    }
     if (activeComboPackages.getSize() == 0)
     {
         std::cout << "No active combo packages available." << std::endl;
@@ -1428,46 +1408,3 @@ inline std::string selectComboPackage(util::Map<std::string, const ComboPackage*
         return "";
     }
 }
-
-/*
-Function: displayNewNotification
-Description: Displays the most recent notification from the supplied
-             notification collection.
-Parameter: util::Vector<const Notification*> notifications -
-           collection of notifications
-           const std::string& - The name of the user currently authenticated with the system
-Return type: void
-*/
-inline void displayNewNotification(util::Vector<const Notification*> notifications, const std::string& name)
-{
-    const Notification* notification = nullptr;
-	size_t numberOfNotifications = notifications.getSize();
-	for (int index = 0; index < numberOfNotifications; index++)
-	{
-		if (!notification)
-		{
-			notification = notifications[index];
-		}
-		else
-		{
-            if (util::extractNumber(notification->getId()) < util::extractNumber(notifications[index]->getId()))
-			{
-				notification = notifications[index];
-			}
-		}
-	}
-    if (notification)
-    {
-        std::string messageTitle = notification->getTitle();
-        if (!name.empty())
-        {
-            messageTitle += " - " + name;
-        }
-        MessageBoxA(
-            GetConsoleWindow(),
-            notification->getMessage().c_str(),
-            messageTitle.c_str(),
-            MB_OK |
-            MB_ICONINFORMATION);
-    }
-}

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

@@ -27,16 +27,10 @@ Returns:
 */
 void TechnicianMenu::showMenu()
 {
-    startEventListener();
     while (true)
     {
         try
         {
-            if (!m_isMenuActive)
-            {
-                logout();
-                break;
-            }
             int choice;
             util::clear();
             std::cout << "Technician Menu"
@@ -58,7 +52,6 @@ void TechnicianMenu::showMenu()
             util::pressEnter();
         }
     }
-    stopEventListener();
 }
 
 /*
@@ -69,11 +62,6 @@ Return type: bool - true if menu continues, false if logout
 */
 bool TechnicianMenu::handleOperation(int choice)
 {
-    if (!m_isMenuActive)
-    {
-        logout();
-        return false;
-    }
     switch (choice)
     {
     case 1:
@@ -98,25 +86,6 @@ bool TechnicianMenu::handleOperation(int choice)
     return true;
 }
 
-/*
-Function: handleNotificationEvent
-Description: Retrieves and displays the latest notification for the
-             currently logged in admin.
-Parameter: None
-Return type: void
-*/
-void TechnicianMenu::handleNotificationEvent()
-{
-    auto notifications = m_controller.getNotifications();
-    const User* authenticatedUser = m_controller.getAuthenticatedUser();
-    std::string name;
-    if (authenticatedUser)
-    {
-        name = authenticatedUser->getName();
-    }
-    displayNewNotification(notifications, name);
-}
-
 /*
 Function: displayJobs
 Description: Displays all Jobs assigned to a Technician

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

@@ -9,13 +9,12 @@ Date:19-May-2026
 
 #pragma once
 #include "Controller.h"
-#include "Menu.h"
 
-class TechnicianMenu : public Menu
+class TechnicianMenu
 {
 private:
+    Controller m_controller;
     bool handleOperation(int choice);
-    void handleNotificationEvent();
 public:
     void showMenu();
     void displayJobs();

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

@@ -27,11 +27,8 @@ void UserInterface::run()
 {
 	try
 	{
-		if (!m_controller.initialize())
+		m_controller.loadSystemData();
-		{
+		m_controller.runSystemChecks();
-			std::cout << "Error: Failed to initialize the system!";
-			return;
-		}
 		bool isMenuActive = true;
 		while (isMenuActive)
 		{
@@ -52,7 +49,7 @@ void UserInterface::run()
 				util::pressEnter();
 			}
 		}
-		m_controller.shutdown();
+		m_controller.saveSystemData();
 	}
 	catch (const std::invalid_argument& exception)
 	{