Background service to check if node goes offline

app/ios/Podfile.lock

@@ -257,4 +257,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 050ff199c8e97450c391a88d64db90da96da9995
 
-COCOAPODS: 1.16.2
+COCOAPODS: 1.16.2

app/ios/Runner/AppDelegate.swift

@@ -1,13 +1,27 @@
 import UIKit
 import Flutter
+import flutter_local_notifications
 
 @UIApplicationMain
 @objc class AppDelegate: FlutterAppDelegate {
-  override func application(	
+  override func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
+                  completionHandler([.alert, .badge, .sound])
+  }
+
+  override func application(
     _ application: UIApplication,
     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
   ) -> Bool {
+    FlutterLocalNotificationsPlugin.setPluginRegistrantCallback { (registry) in
+        GeneratedPluginRegistrant.register(with: registry)
+    }
+
+    if #available(iOS 10.0, *) {
+      UNUserNotificationCenter.current().delegate = self as UNUserNotificationCenterDelegate
+    }
+
     GeneratedPluginRegistrant.register(with: self)
     return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+
   }
-}
+}

app/ios/Runner/Info.plist

@@ -86,5 +86,19 @@
 	<false/>
 	<key>io.flutter.embedded_views_preview</key>
 	<true/>
+	<key>UIBackgroundModes</key>
+	<array>
+  		<string>fetch</string>
+  		<string>remote-notification</string>
+	</array>
+
+	<key>NSUserNotificationAlertStyle</key>
+	<string>alert</string>
+
+	<key>NSLocalNetworkUsageDescription</key>
+	<string>This app uses the network to monitor your node status.</string>
+
+	<key>NSUserNotificationUsageDescription</key>
+	<string>This app needs permission to send you notifications when your node is offline.</string>
 </dict>
 </plist>

app/lib/main.dart

@@ -1,8 +1,12 @@
+import 'package:background_fetch/background_fetch.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:threebotlogin/helpers/globals.dart';
+import 'package:threebotlogin/helpers/logger.dart';
 import 'package:threebotlogin/screens/splash_screen.dart';
+import 'package:threebotlogin/services/background_service.dart';
+import 'package:threebotlogin/services/notification_service.dart';
 import 'package:threebotlogin/services/shared_preference_service.dart';
 import 'package:google_fonts/google_fonts.dart';
 import 'package:threebotlogin/providers/theme_provider.dart';
@@ -33,6 +37,10 @@ Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
   SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);
 
+  await NotificationService().initNotification();
+
+  BackgroundFetch.registerHeadlessTask(backgroundFetchHeadlessTask);
+
   bool initDone = await getInitDone();
   String? doubleName = await getDoubleName();
 
@@ -44,6 +52,27 @@ Future<void> main() async {
       child: MyApp(initDone: initDone, registered: registered),
     ),
   );
+
+  BackgroundFetch.configure(
+    BackgroundFetchConfig(
+      minimumFetchInterval: 15,
+      stopOnTerminate: false,
+      enableHeadless: true,
+      requiresBatteryNotLow: false,
+      requiresCharging: false,
+      requiresStorageNotLow: false,
+      requiredNetworkType: NetworkType.ANY,
+    ),
+    (String taskId) async {
+      logger.i('[BackgroundFetch] Task: $taskId');
+      await checkNodeStatus();
+      BackgroundFetch.finish(taskId);
+    },
+    (String taskId) async {
+      logger.i('[BackgroundFetch] Timeout: $taskId');
+      BackgroundFetch.finish(taskId);
+    },
+  );
 }
 
 Future<void> setGlobalValues() async {
@@ -52,7 +81,6 @@ Future<void> setGlobalValues() async {
 
   Globals().emailVerified.value = (email['sei'] != null);
   Globals().phoneVerified.value = (phone['spi'] != null);
-
 }
 
 class MyApp extends ConsumerWidget {

app/lib/services/background_service.dart

@@ -0,0 +1,29 @@
+import 'package:background_fetch/background_fetch.dart';
+import 'package:threebotlogin/services/nodes_check_service.dart';
+import 'notification_service.dart';
+
+void backgroundFetchHeadlessTask(HeadlessTask task) async {
+  final String taskId = task.taskId;
+  final bool timeout = task.timeout;
+
+  if (timeout) {
+    BackgroundFetch.finish(taskId);
+    return;
+  }
+  await checkNodeStatus();
+
+  BackgroundFetch.finish(taskId);
+}
+
+Future<void> checkNodeStatus() async {
+  final offlineNodes = await NodeCheckService.pingNodesInBackground();
+
+  if (offlineNodes.isNotEmpty) {
+    final nodeIds = offlineNodes.map((n) => n.nodeId).join(', ');
+    await NotificationService().showNotification(
+      title: 'Node Alert 🚨',
+      body: 'Offline node(s): $nodeIds',
+    );
+  }
+}
+

app/lib/services/nodes_check_service.dart

@@ -0,0 +1,55 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:threebotlogin/helpers/logger.dart';
+import 'package:threebotlogin/models/farm.dart';
+import 'package:threebotlogin/models/wallet.dart';
+import 'package:threebotlogin/providers/wallets_provider.dart';
+import 'package:threebotlogin/services/gridproxy_service.dart';
+import 'package:threebotlogin/services/tfchain_service.dart';
+
+class NodeCheckService {
+  static Future<List<Node>> pingNodesInBackground() async {
+    final container = ProviderContainer();
+    try {
+      final walletsNotifierInstance = container.read(walletsNotifier.notifier);
+
+      await walletsNotifierInstance.waitUntilListed();
+
+      final List<Wallet> wallets = container.read(walletsNotifier);
+
+      final Map<int, Wallet> twinIdWallets = {};
+      for (final wallet in wallets) {
+        final twinId = await getTwinId(wallet.tfchainSecret);
+        if (twinId != 0) {
+          twinIdWallets[twinId] = wallet;
+        }
+      }
+      final farmsList = await getFarmsByTwinIds(twinIdWallets.keys.toList());
+      final allNodes = <Node>[];
+      for (final farm in farmsList) {
+        final nodesData = await getNodesByFarmId(farm.farmID);
+
+        final nodes = nodesData
+            .map((node) => Node(
+                  nodeId: node.nodeId,
+                  status: NodeStatus.values.firstWhere(
+                    (e) =>
+                        e.toString().toLowerCase() ==
+                        'nodestatus.${node.status.toLowerCase()}',
+                  ),
+                ))
+            .toList();
+        allNodes.addAll(nodes);
+      }
+            final offlineNodes =
+          allNodes.where((n) => n.status != NodeStatus.Up).toList();
+
+      return offlineNodes;
+
+    } catch (e) {
+      logger.e('[NodeCheckService] Error: $e');
+      return [];
+    } finally {
+      container.dispose();
+    }
+  }
+}

app/lib/services/notification_service.dart

@@ -0,0 +1,56 @@
+import 'package:flutter_local_notifications/flutter_local_notifications.dart';
+
+class NotificationService {
+  static final NotificationService _instance = NotificationService._internal();
+  factory NotificationService() => _instance;
+  NotificationService._internal();
+
+  final notificationsPlugin = FlutterLocalNotificationsPlugin();
+  bool _isInitialized = false;
+
+  Future<void> initNotification() async {
+    if (_isInitialized) return;
+
+    const initSettingsAndroid = AndroidInitializationSettings('@mipmap/ic_launcher');
+    const initSettingsIOS = DarwinInitializationSettings(
+      requestAlertPermission: true,
+      requestBadgePermission: true,
+      requestSoundPermission: true,
+    );
+
+    const initSettings = InitializationSettings(
+      android: initSettingsAndroid,
+      iOS: initSettingsIOS,
+    );
+
+    await notificationsPlugin.initialize(initSettings);
+
+    _isInitialized = true;
+  }
+
+  NotificationDetails _notificationDetails() {
+    return const NotificationDetails(
+      android: AndroidNotificationDetails(
+        'node_status_channel',
+        'Node Status',
+        channelDescription: 'Notify user when node goes offline',
+        importance: Importance.max,
+        priority: Priority.high,
+      ),
+      iOS: DarwinNotificationDetails(
+        presentAlert: true,
+        presentSound: true,
+        presentBadge: true,
+      ),
+    );
+  }
+
+  Future<void> showNotification({
+    int id = 0,
+    required String title,
+    required String body,
+  }) async {
+    await notificationsPlugin.show(id, title, body, _notificationDetails());
+  }
+}
+

app/pubspec.lock

@@ -70,6 +70,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.1.21"
+  background_fetch:
+    dependency: "direct main"
+    description:
+      name: background_fetch
+      sha256: "442e82f508708be89fd0cc7e1dc3b27bc7c6c8c39a47967ccb7ed1c57b9108b5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.8"
   base_x:
     dependency: transitive
     description:
@@ -595,6 +603,38 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "5.0.0"
+  flutter_local_notifications:
+    dependency: "direct main"
+    description:
+      name: flutter_local_notifications
+      sha256: d59eeafd6df92174b1d5f68fc9d66634c97ce2e7cfe2293476236547bb19bbbd
+      url: "https://pub.dev"
+    source: hosted
+    version: "19.0.0"
+  flutter_local_notifications_linux:
+    dependency: transitive
+    description:
+      name: flutter_local_notifications_linux
+      sha256: e3c277b2daab8e36ac5a6820536668d07e83851aeeb79c446e525a70710770a5
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.0.0"
+  flutter_local_notifications_platform_interface:
+    dependency: transitive
+    description:
+      name: flutter_local_notifications_platform_interface
+      sha256: "2569b973fc9d1f63a37410a9f7c1c552081226c597190cb359ef5d5762d1631c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "9.0.0"
+  flutter_local_notifications_windows:
+    dependency: transitive
+    description:
+      name: flutter_local_notifications_windows
+      sha256: f8fc0652a601f83419d623c85723a3e82ad81f92b33eaa9bcc21ea1b94773e6e
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.0"
   flutter_pkid:
     dependency: "direct main"
     description:
@@ -1816,6 +1856,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.7.0"
+  timezone:
+    dependency: transitive
+    description:
+      name: timezone
+      sha256: ffc9d5f4d1193534ef051f9254063fa53d588609418c84299956c3db9383587d
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.10.0"
   timing:
     dependency: transitive
     description:

app/pubspec.yaml

@@ -84,6 +84,8 @@ dependencies:
   infinite_scroll_pagination: ^4.1.0
   intl_mobile_field: ^1.1.1
   mobile_scanner: 5.2.3
+  flutter_local_notifications: ^19.0.0
+  background_fetch: ^1.3.8
 dev_dependencies:
   flutter_test:
     sdk: flutter