prototype complete

lib/screens/gateway/gateway_controller.dart

@@ -0,0 +1,112 @@
+import 'package:flutter/material.dart';
+import 'dart:async'; // Add Timer import
+import 'package:qpay/http/http.dart';
+import 'package:qpay/screens/transaction_controller.dart';
+import 'package:provider/provider.dart';
+
+class GatewayModel {
+  bool isLoading = false;
+  String status = '';
+  String? errorMessage;
+  bool isCancelled = false;
+}
+
+class GatewayController extends ChangeNotifier {
+  final GatewayModel model = GatewayModel();
+  final Http http = Http();
+  Timer? _pollTimer; // Add timer field
+  BuildContext context;
+
+  late TransactionController transactionController;
+
+  GatewayController(this.context) {
+    transactionController = Provider.of<TransactionController>(
+      context,
+      listen: false,
+    );
+  }
+
+  void _showErrorSnackBar(String? message) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text(message.toString()),
+          behavior: SnackBarBehavior.floating,
+          backgroundColor: Colors.deepOrange,
+        ),
+      );
+    });
+  }
+
+  void startLoading() {
+    model.isLoading = true;
+    notifyListeners();
+  }
+
+  void finishLoading() {
+    model.isLoading = false;
+    notifyListeners();
+  }
+
+  Future<void> pollTransaction(String uid) async {
+    while (!model.isCancelled) {
+      // Check cancellation flag instead of true
+      // Wait 5 seconds before the next poll
+      await Future.delayed(const Duration(seconds: 5));
+
+      // Check again after delay in case it was cancelled during the delay
+      if (model.isCancelled) break;
+
+      try {
+        dynamic response = await http.get('/transaction/poll/$uid');
+        logger.i(response.toString());
+
+        if (response['status'] == 'SUCCESS') {
+          model.status = response['status'];
+          transactionController.updateReceiptData(response);
+          notifyListeners();
+          break;
+        }
+      } catch (e) {
+        logger.e(e);
+        _showErrorSnackBar(
+          "Network error. Please try again or contact support",
+        );
+      }
+    }
+  }
+
+  // Alternative method using Timer instead of while loop
+  void pollTransactionWithTimer(String uid) {
+    _pollTimer = Timer.periodic(const Duration(seconds: 5), (timer) async {
+      if (model.isCancelled) {
+        timer.cancel();
+        return;
+      }
+
+      try {
+        dynamic response = await http.get('/transaction/poll/$uid');
+        logger.i(response.toString());
+
+        if (response['status'] == 'SUCCESS') {
+          model.status = response['status'];
+          transactionController.updateReceiptData(response);
+          notifyListeners();
+          timer.cancel(); // Stop polling on success
+        }
+      } catch (e) {
+        logger.e(e);
+        _showErrorSnackBar(
+          "Network error. Please try again or contact support",
+        );
+      }
+    });
+  }
+
+  @override
+  void dispose() {
+    model.isCancelled = true;
+    _pollTimer?.cancel(); // Cancel timer if it exists
+    super.dispose();
+  }
+}