Implement Confirm Payment Functionality

<User Story> Complete Payments - 1797</User Story>

<Changes>
1. Added Controller::getAllInvoices
   - Retrieves all invoices from PaymentManagementService and returns them as a read-only map.
2. Implemented Controller::confirmPayment
   - Delegates payment confirmation for a given invoice ID to PaymentManagementService.
3. Introduced PaymentManagementService::getAllInvoice
   - Provides access to all invoices stored in the datastore.
4. Added PaymentManagementService::confirmPayment
   - Confirms payment for a specific invoice, updates payment date and status, and sends notification.
5. Extended util::PaymentStatus enum
   - Added PAID status and updated string conversion.
6. Integrated AdminMenu::confirmPayment
   - Validates invoice list, filters by status, allows selection, and confirms payment.
7. Updated CustomerMenu::completePayments
   - Uses parameterized status filtering for invoice selection.
8. Enhanced MenuHelper::selectInvoiceFromUserForPayment
   - Accepts requiredStatus parameter for flexible filtering.
9. Adjusted AdminMenu options
   - Added "Confirm Payment" before Logout.
</Changes>

<Test>
Acceptance Criteria:
1. Admin selects "Confirm Payment" from menu.
   - Verify system prompts and displays invoices filtered by status.
2. Admin selects invoice with status = PAID.
   - Verify payment confirmation updates date, sets status, and sends notification.
3. Admin attempts confirmation with empty invoice list.
   - Verify error message: "No pending invoices available for confirmation."
4. Customer completes payment.
   - Verify selection uses util::PaymentStatus::PENDING and payment flow works correctly.
5. Invalid invoice ID entered.
   - Verify system throws runtime_error with "Payment failed: invalid invoice ID."

Precondition:
1. Admin logged into system.
2. At least one invoice exists in datastore.
3. Notification system available.

Steps:
1. Navigate to Admin menu → Confirm Payment.
2. Select invoice with PAID status.
3. Confirm payment and check notification.
4. Attempt with empty invoice list.
5. Attempt with invalid invoice ID.
</Test>

<Review>
Sreeja Reghukumar
</Review>

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

@@ -462,6 +462,38 @@ util::Map<std::string, const Invoice*> Controller::getInvoicesByUser()
     return userInvoicesReadOnly;
 }
 
+/*
+Function: getAllInvoices
+Description: Retrieves all invoices from the PaymentManagementService and returns them as a read-only map.
+Parameters:
+    - none
+Returns:
+    - util::Map<std::string, const Invoice*>: Map of invoice IDs to invoice objects
+*/
+util::Map<std::string, const Invoice*> Controller::getAllInvoices()
+{
+    auto invoices = m_paymentManagementService.getAllInvoice();
+    util::Map<std::string, const Invoice*> readOnlyInvoice;
+    for (int iterator = 0; iterator < invoices.getSize(); iterator++)
+    {
+        readOnlyInvoice.insert(invoices.getKeyAt(iterator), invoices.getValueAt(iterator));
+    }
+    return readOnlyInvoice;
+}
+
+/*
+Function: confirmPayment
+Description: Delegates payment confirmation for a given invoice ID to the PaymentManagementService.
+Parameters:
+    - invoiceID: std::string, ID of the invoice to confirm
+Returns:
+    - void
+*/
+void Controller::confirmPayment(std::string invoiceID)
+{
+    m_paymentManagementService.confirmPayment(invoiceID);
+}
+
 /*
 Function: completePayment
 Description: Completes payment for a specific invoice using the given payment mode.

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

@@ -64,6 +64,8 @@ public:
     void createComboPackage(const std::string& name, const util::Vector<std::string>& serviceIDs, double discountPercentage);
     void removeComboPackage(const std::string& comboPackageID);
     util::Map<std::string, const Invoice*> getInvoicesByUser();
+    util::Map<std::string, const Invoice*> getAllInvoices();
+    void confirmPayment(std::string invoiceID);
     void completePayment(const std::string& invoiceID, util::PaymentMode paymentMode);
     util::Vector<const Notification*> getNotifications();
     void deleteNotification(const std::string& notificationID);

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

@@ -368,12 +368,12 @@ void PaymentManagementService::completePayment(const std::string& invoiceID, uti
 	if (invoiceIndex != -1)
 	{
 		Invoice* invoice = currentInvoices.getValueAt(invoiceIndex);
-		if (invoice && invoice->getStatus() != util::PaymentStatus::COMPLETED)
+		if (invoice && invoice->getStatus() != util::PaymentStatus::PAID)
 		{
 			User* currentUser = invoice->getBooking()->getCustomer();
 			invoice->setPaymentMethod(paymentMode);
 			invoice->setPaymentDate(util::Timestamp());
-			invoice->setStatus(util::PaymentStatus::COMPLETED);
+			invoice->setStatus(util::PaymentStatus::PAID);
 			std::string title, message;
 			title = "Payment successful";
 			message = "Payment successful for Invoice ID " + invoiceID;
@@ -385,3 +385,51 @@ void PaymentManagementService::completePayment(const std::string& invoiceID, uti
 		throw std::runtime_error("Payment failed: invalid invoice ID.");
 	}
 }
+
+/*
+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*>& PaymentManagementService::getAllInvoice()
+{
+	return m_dataStore.getInvoices();
+}
+
+/*
+Function: confirmPayment
+Description: Confirms payment for a specific invoice. Updates payment date and status,
+			 then sends a notification to the customer.
+Parameters:
+	- invoiceID: std::string, ID of the invoice to confirm
+Returns:
+	- void
+Throws:
+	- std::runtime_error if the invoice ID is invalid
+*/
+void PaymentManagementService::confirmPayment(std::string invoiceID)
+{
+	std::string title, message;
+	auto& currentInvoices = m_dataStore.getInvoices();
+	int invoiceIndex = currentInvoices.find(invoiceID);
+	if (invoiceIndex != -1)
+	{
+		Invoice* invoice = currentInvoices.getValueAt(invoiceIndex);
+		if (invoice && invoice->getStatus() != util::PaymentStatus::COMPLETED)
+		{
+			User* currentUser = invoice->getBooking()->getCustomer();
+			invoice->setPaymentDate(util::Timestamp());
+			invoice->setStatus(util::PaymentStatus::COMPLETED);
+			title = "Payment Confirmed";
+			message = "Payment Confirmed for Invoice ID " + invoiceID;
+			sendNotification(currentUser, title, message);
+		}
+	}
+	else
+	{
+		throw std::runtime_error("Payment failed: invalid invoice ID.");
+	}
+}

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

@@ -28,6 +28,8 @@ public:
     void generateInvoice(ServiceBooking* booking);
     util::Map<std::string, Invoice*> getInvoices(const std::string& customerID);
     void completePayment(const std::string& invoiceID, util::PaymentMode paymentMode);
+    util::Map<std::string, Invoice*>& getAllInvoice();
+    void confirmPayment(std::string invoiceID);
     void sendPaymentReminders();
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;

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

@@ -29,7 +29,8 @@ namespace util
 	enum class PaymentStatus
 	{
 		PENDING,
-		COMPLETED
+		COMPLETED,
+        PAID
 	};
 
 	enum class ServiceJobStatus
@@ -161,6 +162,8 @@ namespace util
             return "PENDING";
         case PaymentStatus::COMPLETED:
             return "COMPLETED";
+        case PaymentStatus::PAID:
+            return "PAID";
         }
         throw std::invalid_argument("Invalid PaymentStatus");
     }

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

@@ -53,7 +53,8 @@ void AdminMenu::showMenu()
                 << "\n14. Remove Combo Package"
                 << "\n15. View Notifications"
                 << "\n16. Change Password"
-                << "\n17. Logout"
+				<< "\n17. Confirm Payment"
+                << "\n18. Logout"
                 << "\nEnter a choice: ";
             util::read(choice);
             if (!handleOperation(choice))
@@ -128,6 +129,9 @@ bool AdminMenu::handleOperation(int choice)
         changePassword();
         break;
 	case 17:
+		confirmPayment();
+		break;
+    case 18:
         logout();
         return false;
     default:
@@ -496,6 +500,54 @@ void AdminMenu::displayUsers()
 	util::pressEnter();
 }
 
+/*
+Function: confirmPayment
+Description: Confirms payment for a selected invoice. Validates invoice status, updates payment date,
+			 sets status to PAID, and sends a notification to the customer.
+Parameters:
+	- invoiceID: std::string, ID of the invoice to confirm
+Returns:
+	- void
+*/
+void AdminMenu::confirmPayment()
+{
+	util::clear();
+	std::cout << "Confirm Payment\n";
+	auto invoiceList = m_controller.getAllInvoices();
+	if (invoiceList.isEmpty())
+	{
+		std::cout << "No pending invoices available for confirmation.";
+		util::pressEnter();
+		return;
+	}
+	bool hasPaidInvoice = false;
+	for (int index = 0; index < invoiceList.getSize(); ++index)
+	{
+		const Invoice* invoice = invoiceList.getValueAt(index);
+		if (invoice && invoice->getStatus() == util::PaymentStatus::PAID)
+		{
+			hasPaidInvoice = true;
+			break;
+		}
+	}
+	if (!hasPaidInvoice)
+	{
+		std::cout << "No pending invoices available for payment.\n";
+		util::pressEnter();
+		return;
+	}
+	std::string selectedID = selectInvoiceFromUserForPayment(invoiceList, util::PaymentStatus::PAID);
+	if (selectedID == "")
+	{
+		std::cout << "Payment failed.\n";
+		util::pressEnter();
+		return;
+	}
+	m_controller.confirmPayment(selectedID);
+	std::cout << "Payment Confirmed successfully.\n";
+	util::pressEnter();
+}
+
 /*
 Function: addTechnician
 Description: Adds a new technician after validating username, password, email, and phone number.

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

@@ -28,6 +28,7 @@ public:
     void createService();
     void removeService();
     void displayUsers();
+    void confirmPayment();
     void addTechnician();
     void removeUser();
     void displayComboPackages();

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

@@ -338,7 +338,7 @@ void CustomerMenu::completePayments()
         util::pressEnter();
         return;
     }
-	std::string selectedID = selectInvoiceFromUserForPayment(currentInvoices);
+	std::string selectedID = selectInvoiceFromUserForPayment(currentInvoices, util::PaymentStatus::PENDING);
     if (selectedID == "")
     {
         std::cout << "Payment failed.\n";

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

@@ -365,13 +365,17 @@ inline const User* selectTechnician(util::Map<int, const User*>& currentAvailabl
 
 /*
 Function: selectInvoiceFromUserForPayment
-Description: Lists all pending invoices for the customer and allows selection by index.
+Description: Displays a list of invoices filtered by the required payment status.
+             Allows the user to select an invoice by index and returns the corresponding invoice ID.
 Parameters:
-	- currentInvoices: util::Map<std::string, const Invoice*>&, map of customer invoices
+    - currentInvoices: const util::Map<std::string, const Invoice*>&,
+                       map of all invoices keyed by invoice ID
+    - requiredStatus: util::PaymentStatus,
+                      the status to filter invoices (e.g., PENDING, PAID, COMPLETED)
 Returns:
-	- std::string: ID of the selected invoice, or empty string if none selected
+    - std::string: ID of the selected invoice, or empty string if none selected or invalid index
 */
-inline std::string selectInvoiceFromUserForPayment(const util::Map<std::string, const Invoice*>& currentInvoices)
+inline std::string selectInvoiceFromUserForPayment(const util::Map<std::string, const Invoice*>& currentInvoices, util::PaymentStatus requiredStatus)
 {
 	int currentIndex = 1, choice;
 	util::Map<int, const Invoice*> pendingInvoicesForPayment;
@@ -389,7 +393,7 @@ inline std::string selectInvoiceFromUserForPayment(const util::Map<std::string,
 	for (int iterator = 0; iterator < currentInvoices.getSize(); iterator++)
 	{
 		const Invoice* currentInvoice = currentInvoices.getValueAt(iterator);
-		if (currentInvoice && currentInvoice->getStatus() == util::PaymentStatus::PENDING)
+		if (currentInvoice && currentInvoice->getStatus() == requiredStatus)
 {
 			const User* currentTechnician = currentInvoice->getBooking()->getAssignedTechnician();
             std::cout << std::left