fix: reset room assignments after updated selection if required

src/Controller/Booking/Create/Step2Controller.php

@@ -74,6 +74,9 @@ class Step2Controller extends AbstractController
             fn ($user, $participant) => $this->prepopulationService->prepopulateApplicantFromUser($user, $participant)
         );
 
+        // Validate room assignments against current selection (handles back-navigation from step 2 to step 1)
+        $this->roomAssignmentService->validateAndResetInvalidAssignments($bookingCreateDto);
+
         // Auto-assign rooms if needed
         $this->roomAssignmentService->assignRoomsIfNeeded($bookingCreateDto);
 

src/Service/RoomAssignmentService.php

@@ -110,4 +110,48 @@ class RoomAssignmentService
 
         return false;
     }
+
+    /**
+     * Validates and resets room assignments that reference rooms no longer selected.
+     *
+     * This method ensures room assignments remain valid after room selection changes in Step 1.
+     * When a user goes back to Step 1 and changes room selections, existing assignments may
+     * reference room IDs that are no longer in the selected rooms list. This method detects
+     * such invalid assignments and resets them to null.
+     *
+     * @param BookingDto $dto The booking DTO to validate
+     *
+     * @return bool True if any assignments were reset, false if all were valid
+     */
+    public function validateAndResetInvalidAssignments(BookingDto $dto): bool
+    {
+        $selectedRoomIds = $this->getSelectedRoomIds($dto);
+        $resetOccurred = false;
+
+        foreach ($dto->participants as $participant) {
+            if (null !== $participant->assignedRoomId && false === in_array($participant->assignedRoomId, $selectedRoomIds, true)) {
+                $participant->assignedRoomId = null;
+                $resetOccurred = true;
+            }
+        }
+
+        return $resetOccurred;
+    }
+
+    /**
+     * Gets the list of room IDs from currently selected rooms.
+     *
+     * @param BookingDto $dto The booking DTO containing room selections
+     *
+     * @return array<int> Array of selected room IDs
+     */
+    private function getSelectedRoomIds(BookingDto $dto): array
+    {
+        $ids = [];
+        foreach ($dto->getSelectedRooms() as $roomSelection) {
+            $ids[] = $roomSelection->id;
+        }
+
+        return $ids;
+    }
 }

tests/Service/RoomAssignmentServiceTest.php

@@ -190,6 +190,109 @@ class RoomAssignmentServiceTest extends TestCase
         self::assertSame(100, $bookingDto->participants[1]->assignedRoomId);
     }
 
+    /**
+     * @test
+     */
+    public function validateAndResetInvalidAssignmentsResetsOrphanedAssignments(): void
+    {
+        // Create DTO with only room 100 selected
+        $bookingDto = $this->createBookingDtoWithRoomSelections([
+            ['roomId' => 100, 'quantity' => 2, 'capacity' => 2],
+        ]);
+
+        // Create participants with assignments to room 100 and room 200 (no longer selected)
+        $bookingDto->participants = [
+            new ParticipantDto(),
+            new ParticipantDto(),
+            new ParticipantDto(),
+            new ParticipantDto(),
+        ];
+        $bookingDto->participants[0]->assignedRoomId = 100;
+        $bookingDto->participants[1]->assignedRoomId = 100;
+        $bookingDto->participants[2]->assignedRoomId = 200; // Invalid - room not selected
+        $bookingDto->participants[3]->assignedRoomId = 200; // Invalid - room not selected
+
+        $result = $this->service->validateAndResetInvalidAssignments($bookingDto);
+
+        self::assertTrue($result, 'Should return true when assignments were reset');
+        self::assertSame(100, $bookingDto->participants[0]->assignedRoomId);
+        self::assertSame(100, $bookingDto->participants[1]->assignedRoomId);
+        self::assertNull($bookingDto->participants[2]->assignedRoomId, 'Invalid assignment should be reset to null');
+        self::assertNull($bookingDto->participants[3]->assignedRoomId, 'Invalid assignment should be reset to null');
+    }
+
+    /**
+     * @test
+     */
+    public function validateAndResetInvalidAssignmentsReturnsFalseWhenAllValid(): void
+    {
+        $bookingDto = $this->createBookingDtoWithRoomSelections([
+            ['roomId' => 100, 'quantity' => 2, 'capacity' => 2],
+        ]);
+
+        // All participants assigned to the valid room
+        $bookingDto->participants = [
+            new ParticipantDto(),
+            new ParticipantDto(),
+        ];
+        $bookingDto->participants[0]->assignedRoomId = 100;
+        $bookingDto->participants[1]->assignedRoomId = 100;
+
+        $result = $this->service->validateAndResetInvalidAssignments($bookingDto);
+
+        self::assertFalse($result, 'Should return false when no assignments needed reset');
+        self::assertSame(100, $bookingDto->participants[0]->assignedRoomId);
+        self::assertSame(100, $bookingDto->participants[1]->assignedRoomId);
+    }
+
+    /**
+     * @test
+     */
+    public function validateAndResetInvalidAssignmentsHandlesNullAssignments(): void
+    {
+        $bookingDto = $this->createBookingDtoWithRoomSelections([
+            ['roomId' => 100, 'quantity' => 1, 'capacity' => 2],
+        ]);
+
+        // Participants with null assignments should not trigger a reset
+        $bookingDto->participants = [
+            new ParticipantDto(),
+            new ParticipantDto(),
+        ];
+        $bookingDto->participants[0]->assignedRoomId = null;
+        $bookingDto->participants[1]->assignedRoomId = null;
+
+        $result = $this->service->validateAndResetInvalidAssignments($bookingDto);
+
+        self::assertFalse($result, 'Should return false when only null assignments exist');
+    }
+
+    /**
+     * @test
+     */
+    public function validateAndResetInvalidAssignmentsHandlesEmptySelectedRooms(): void
+    {
+        // All rooms have quantity 0 (none selected)
+        $bookingDto = $this->createBookingDtoWithRoomSelections([
+            ['roomId' => 100, 'quantity' => 0, 'capacity' => 2],
+            ['roomId' => 200, 'quantity' => 0, 'capacity' => 2],
+        ]);
+
+        // Participants still have old assignments
+        $bookingDto->participants = [
+            new ParticipantDto(),
+            new ParticipantDto(),
+        ];
+        $bookingDto->participants[0]->assignedRoomId = 100;
+        $bookingDto->participants[1]->assignedRoomId = 200;
+
+        $result = $this->service->validateAndResetInvalidAssignments($bookingDto);
+
+        self::assertTrue($result, 'Should return true when all assignments become invalid');
+        self::assertNull($bookingDto->participants[0]->assignedRoomId);
+        self::assertNull($bookingDto->participants[1]->assignedRoomId);
+    }
+
     private function createBookingDtoWithRoomSelections(array $selections): BookingDto
     {
         $travel = new Travel();