completed velocity integration

lib/screens/gateway/gateway_controller.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
-import 'dart:async'; // Add Timer import
+import 'dart:async';
 import 'package:qpay/http/http.dart';
+import 'package:qpay/models/api_response.dart';
 import 'package:qpay/screens/transaction_controller.dart';
 import 'package:provider/provider.dart';
 
@@ -50,10 +51,11 @@ class GatewayController extends ChangeNotifier {
     notifyListeners();
   }
 
-  Future<void> poll(String uid) async {
+  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());
 
@@ -63,41 +65,65 @@ class GatewayController extends ChangeNotifier {
       transactionController.model.paymentStatus = response['paymentStatus'];
 
       finishLoading();
-      if(model.status == 'SUCCESS') {
+      if (model.status == 'SUCCESS') {
         transactionController.updateReceiptData(response);
       }
       notifyListeners();
+      return ApiResponse.success(Map<String, dynamic>.from(response));
     } catch (e) {
       finishLoading();
+      model.status = 'FAILED';
+      model.errorMessage = "Network error. Please try again or contact support";
       logger.e(e);
-      _showErrorSnackBar(
+      notifyListeners();
+      return ApiResponse.failure(
         "Network error. Please try again or contact support",
       );
     }
   }
 
-  Future<void> pollTransaction(String uid) async {
-    // only poll for 5 minutes
-    int max = 30;
-    while (!model.isCancelled) {
-      max++;
-      // Check cancellation flag instead of true
-      // Wait 5 seconds before the next poll
+  Future<ApiResponse<Map<String, dynamic>>> pollTransaction(String uid) async {
+    // poll up to 30 times (~5 minutes at 10-second intervals)
+    int maxAttempts = 30;
+    int attempt = 0;
+
+    while (!model.isCancelled && attempt < maxAttempts) {
+      attempt++;
+
+      // Wait 10 seconds before each poll request
       await Future.delayed(const Duration(seconds: 10));
 
       // Check again after delay in case it was cancelled during the delay
       if (model.isCancelled) break;
 
-      await poll(uid);
+      ApiResponse<Map<String, dynamic>> result = await poll(uid);
 
-      if(max > 30) {
-        model.isCancelled = true;
+      // Only stop on success or failure
+      if (result.isSuccess) {
+        String status = model.status;
+        // If status is SUCCESS, we're done
+        if (status == 'SUCCESS') {
+          return result;
+        }
+        // Otherwise (e.g. PENDING), continue polling
+      } else {
+        // Network error — show failure UI and stop
+        return result;
       }
     }
+
+    // Timed out after max attempts
+    model.isCancelled = true;
+    model.status = 'FAILED';
+    model.errorMessage = 'We failed to check your transaction status';
+    finishLoading();
+    notifyListeners();
+    return ApiResponse.failure("Polling timed out");
   }
 
   // Alternative method using Timer instead of while loop
-  void pollTransactionWithTimer(String uid) {
+  Future<ApiResponse<Map<String, dynamic>>> pollTransactionWithTimer(
+      String uid) async {
     _pollTimer = Timer.periodic(const Duration(seconds: 5), (timer) async {
       if (model.isCancelled) {
         timer.cancel();
@@ -121,6 +147,10 @@ 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");
   }
 
   @override
@@ -129,4 +159,4 @@ class GatewayController extends ChangeNotifier {
     _pollTimer?.cancel(); // Cancel timer if it exists
     super.dispose();
   }
-}
+}