Fix Admin Inventory Management UI Issues and Workflow Enhancements

- Added heading output to Remove Inventory Item submenu for clearer user context.
- Prevented service creation with empty inventory selection by adding validation and early return.
- Improved combo package creation by simplifying null checks with modern idioms.
- Enhanced inventory selection flow:
  - Clear screen and context header for better UX.
  - Prevent duplicate item selection by checking already chosen items.
  - Changed exit option from -1 to 0 for consistency.
  - Added pressEnter prompt after successful item addition.
- Simplified pointer checks using concise conditions (e.g., if (item)).

Fixes #1778

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

@@ -263,6 +263,7 @@ Return type: void
 void AdminMenu::removeInventoryItem()
 {
     util::clear();
+	std::cout << "Remove Inventory Item\n";
     auto inventoryItems = m_controller.getInventoryItems();
     auto activeItems = filterActiveItems(inventoryItems);
     int activeItemsSize = activeItems.getSize();
@@ -402,6 +403,11 @@ void AdminMenu::createService()
 	util::Map<std::string, const InventoryItem*> activeInventoryItems = filterActiveItems(currentInventoryItems);
 	util::Vector<std::string> selectedInventoryItems;
 	selectInventoryItems(activeInventoryItems,selectedInventoryItems);
+	if (selectedInventoryItems.isEmpty())
+	{
+		util::pressEnter();
+		return;
+	}
 	std::cout << "\nEnter the labour cost: ";
 	util::read(labourCost);
     m_controller.createService(serviceName, selectedInventoryItems, labourCost);
@@ -541,7 +547,7 @@ void AdminMenu::createComboPackages()
         while (true)
         {
             chosenService = selectServiceFromServices(activeServices);
-            if (chosenService == nullptr)
+            if (!chosenService)
             {
                 std::cout << "Failed to create combo package!\n\n";
                 util::pressEnter();

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

@@ -94,13 +94,15 @@ inline void selectInventoryItems(util::Map<std::string, const InventoryItem*>& c
     bool doRun = true;
     util::Map<int, const InventoryItem*> currentInventoryMap;
     int choice;
-    if (currentInventoryItems.getSize() == 0)
+    if (currentInventoryItems.isEmpty())
     {
         std::cout << "No Items Present, Inventory empty.\n";
         return;
     }
     while (doRun)
     {
+        util::clear();
+        std::cout << "Create Service\n";
         std::cout << "\nSelect Required Items\n";
         bool hasInventoryItems = false;
         int currentIndex = 1;
@@ -119,6 +121,19 @@ inline void selectInventoryItems(util::Map<std::string, const InventoryItem*>& c
             {
                 continue;
             }
+            bool alreadySelected = false;
+            for (int iteratorOne = 0; iteratorOne < selectedInventoryItems.getSize(); iteratorOne++)
+            {
+                if (selectedInventoryItems[iteratorOne] == currentInventoryItem->getId())
+                {
+                    alreadySelected = true;
+                    break;
+                }
+            }
+            if (alreadySelected)
+            {
+                continue;
+            }
             std::cout << std::left
                 << std::setw(6) << currentIndex
                 << std::setw(12) << currentInventoryItem->getId()
@@ -133,10 +148,9 @@ inline void selectInventoryItems(util::Map<std::string, const InventoryItem*>& c
         {
             break;
         }
-        std::cout << "Select the item (Index) or enter -1 to exit: ";
+        std::cout << "Select the item (Index) or enter 0 to exit: ";
         util::read(choice);
-
-        if (choice == -1)
+        if (choice == 0)
         {
             doRun = false;
         }
@@ -144,6 +158,7 @@ inline void selectInventoryItems(util::Map<std::string, const InventoryItem*>& c
         {
             selectedInventoryItems.push_back(currentInventoryMap.getValueAt(currentInventoryMap.find(choice))->getId());
             std::cout << "Item added successfully.\n" << std::endl;
+            util::pressEnter();
         }
         else
         {
@@ -1066,7 +1081,7 @@ inline util::Map<std::string, const InventoryItem*> filterActiveItems(const util
     for (int index = 0; index < inventorySize; index++)
     {
         const InventoryItem* item = inventoryItems.getValueAt(index);
-        if (item != nullptr && item->getState() != util::State::INACTIVE)
+        if (item && item->getState() != util::State::INACTIVE)
         {
             activeItems.insert(item->getId(), item);
         }