feat: optional return url

src/Service/BookingService.php

@@ -18,6 +18,8 @@ class BookingService
     public const BOOKING_CREATE_KEY = 'booking_create';
     public const BOOKING_CREATE_BASELINE_KEY = 'booking_create_baseline_snapshot';
     public const BOOKING_EDIT_KEY = 'booking_edit';
+    public const RETURN_URL_KEY = 'booking_return_url';
+    public const DEFAULT_RETURN_URL = 'https://www.ep-reisen.de';
 
     public function __construct(
         private readonly TravelDataService $travelDataService,
@@ -146,6 +148,8 @@ class BookingService
      *
      * This method removes all booking session data including the main DTO
      * and any cached snapshots to ensure a completely fresh start.
+     * Note: RETURN_URL_KEY is intentionally preserved so it remains available
+     * for redirects after cancel or error flows.
      */
     public function clearBookingSession(Request $request): void
     {
@@ -154,6 +158,36 @@ class BookingService
         $session->remove(self::BOOKING_CREATE_BASELINE_KEY);
     }
 
+    /**
+     * Stores the return URL in the session.
+     *
+     * Validates that the URL is a valid absolute URL with http/https scheme.
+     * Falls back to the default return URL if null or invalid.
+     */
+    public function storeReturnUrl(Request $request, ?string $returnUrl): void
+    {
+        $url = self::DEFAULT_RETURN_URL;
+
+        if (null !== $returnUrl && '' !== trim($returnUrl)) {
+            if (false !== filter_var($returnUrl, \FILTER_VALIDATE_URL)
+                && 1 === preg_match('#^https?://#i', $returnUrl)) {
+                $url = $returnUrl;
+            }
+        }
+
+        $request->getSession()->set(self::RETURN_URL_KEY, $url);
+    }
+
+    /**
+     * Retrieves the return URL from the session.
+     *
+     * Returns the default URL if not set in session.
+     */
+    public function getReturnUrl(Request $request): string
+    {
+        return $request->getSession()->get(self::RETURN_URL_KEY, self::DEFAULT_RETURN_URL);
+    }
+
     /**
      * Creates a fresh booking session with the provided travel parameters.
      *