adding CityWallet functionality

lib/screens/gateway/gateway_controller.dart

@@ -49,8 +49,9 @@ class GatewayController extends ChangeNotifier {
   Future<ApiResponse<Map<String, dynamic>>> poll(String uid) async {
     startLoading();
     try {
-      dynamic workflowResponse =
-          await http.get('/public/transaction/poll/$uid');
+      dynamic workflowResponse = await http.get(
+        '/public/transaction/poll/$uid',
+      );
 
       logger.i(workflowResponse.toString());
 
@@ -62,6 +63,10 @@ class GatewayController extends ChangeNotifier {
       finishLoading();
       if (model.status == 'SUCCESS') {
         transactionController.updateReceiptData(response);
+      } else {
+        model.status = 'FAILED';
+        model.errorMessage = response['errorMessage'];
+        return ApiResponse.failure(response['errorMessage']);
       }
       notifyListeners();
       return ApiResponse.success(Map<String, dynamic>.from(response));
@@ -79,7 +84,7 @@ class GatewayController extends ChangeNotifier {
 
   Future<ApiResponse<Map<String, dynamic>>> pollTransaction(String uid) async {
     // poll up to 30 times (~5 minutes at 10-second intervals)
-    int maxAttempts = 30;
+    int maxAttempts = 15;
     int attempt = 0;
 
     while (!model.isCancelled && attempt < maxAttempts) {
@@ -103,6 +108,9 @@ class GatewayController extends ChangeNotifier {
         // Otherwise (e.g. PENDING), continue polling
       } else {
         // Network error — show failure UI and stop
+        model.isCancelled = true;
+        model.status = 'FAILED';
+        model.errorMessage = result.error;
         return result;
       }
     }
@@ -118,7 +126,8 @@ class GatewayController extends ChangeNotifier {
 
   // Alternative method using Timer instead of while loop
   Future<ApiResponse<Map<String, dynamic>>> pollTransactionWithTimer(
-      String uid) async {
+    String uid,
+  ) async {
     _pollTimer = Timer.periodic(const Duration(seconds: 5), (timer) async {
       if (model.isCancelled) {
         timer.cancel();
@@ -145,7 +154,8 @@ class GatewayController extends ChangeNotifier {
     // This returns immediately; the caller should use the timer callback approach.
     // Consider refactoring this to use poll(String uid) directly for a consistent API.
     return ApiResponse.failure(
-        "Polling via timer started; use a different flow for the result");
+      "Polling via timer started; use a different flow for the result",
+    );
   }
 
   @override
@@ -154,4 +164,4 @@ class GatewayController extends ChangeNotifier {
     _pollTimer?.cancel(); // Cancel timer if it exists
     super.dispose();
   }
-}
+}