feat: correct determination of inquiry status and conditional voucher field display

src/Controller/Booking/Create/Step3Controller.php

@@ -88,6 +88,24 @@ class Step3Controller extends AbstractController
                 }
 
                 if (false === $inquiryResponse->isInquiryValid()) {
+                    // Check if API suggests inquiry booking instead of showing error
+                    if ($this->shouldFallbackToInquiryMode($inquiryResponse)) {
+                        // Auto-switch to inquiry mode
+                        $bookingCreateDto->bookingStatus = 'A';
+                        $bookingCreateDto->currentStep = 4;
+                        $this->bookingService->saveBookingCreateDto($request, $bookingCreateDto);
+
+                        $message = 'Buchung konnte nicht validiert werden.';
+                        if (null !== $inquiryResponse->message && '' !== trim($inquiryResponse->message)) {
+                            $message = $inquiryResponse->message;
+                        }
+
+                        $this->addFlash('info', $message);
+
+                        return $this->hxRedirect($request, $this->generateUrl('app_booking_create_step_4'));
+                    }
+
+                    // Not a fallback scenario - show validation error
                     $errorMessage = 'Buchung konnte nicht validiert werden.';
                     if (null !== $inquiryResponse->message && '' !== trim($inquiryResponse->message)) {
                         $errorMessage .= ' '.$inquiryResponse->message;
@@ -199,4 +217,31 @@ class Step3Controller extends AbstractController
             'groupedSelectedRooms' => $groupedSelectedRooms,
         ]);
     }
+
+    /**
+     * Determines if validation failure should trigger inquiry mode fallback.
+     *
+     * Checks if the API response indicates that the booking should proceed as
+     * an inquiry rather than showing an error. This handles scenarios where
+     * availability changes between booking initialization and validation.
+     *
+     * @param \App\BusProNet\Model\BookingResponse $response The API response
+     *
+     * @return bool True if should fallback to inquiry mode, false if should show error
+     */
+    private function shouldFallbackToInquiryMode(\App\BusProNet\Model\BookingResponse $response): bool
+    {
+        // Check for "nicht möglich" status + inquiry suggestion in message
+        if ('nicht möglich' !== $response->status) {
+            return false;
+        }
+
+        $message = $response->message ?? '';
+        if ('' === $message) {
+            return false;
+        }
+
+        // Check if message suggests inquiry booking (case-insensitive)
+        return 1 === preg_match('/anfrage/i', $message);
+    }
 }