@pragma('vm:entry-point')
Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  await Firebase.initializeApp();
  if (message.notification != null) {
    BadgeCounter.incrementBadgeCount();
    NotificationApi().showNotification(message);
  }
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
  runApp(ProviderScope(child: MyApp()));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Badge Notification',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: HomeView(),
    );
  }
}

class BadgeCounter {
  static ValueNotifier<int> badgeNotifier = ValueNotifier<int>(0);
  static const String keyBadgeCount = 'keyBadgeCount';

  static Future<void> loadBadgeCount() async {
    final prefs = await SharedPreferences.getInstance();
    badgeNotifier.value = prefs.getInt(keyBadgeCount) ?? 0;
  }

  static Future<void> incrementBadgeCount() async {
    final prefs = await SharedPreferences.getInstance();
    int currentCount = prefs.getInt(keyBadgeCount) ?? 0;
    currentCount++;
    await prefs.setInt(keyBadgeCount, currentCount);
    badgeNotifier.value = currentCount;
  }

  static Future<void> resetBadgeCount() async {
    final prefs = await SharedPreferences.getInstance();
    badgeNotifier.value = 0;
    await prefs.setInt(keyBadgeCount, badgeNotifier.value);
  }
}

class NotificationApi {
  Future<void> initNotifications() async {
    await initPushNotifications();
  }

  Future<void> initPushNotifications() async {
    FirebaseMessaging.instance.getInitialMessage().then(_handleMessage);
    FirebaseMessaging.onMessageOpenedApp.listen(_handleMessage);
    FirebaseMessaging.onMessage.listen((message) {
      BadgeCounter.incrementBadgeCount();
      showNotification(message);
    });
  }

  void _handleMessage(RemoteMessage? message) {
    if (message != null) {
      showNotification(message);
    }
  }

  void showNotification(RemoteMessage message) {
    debugPrint('Notification: ${message.notification?.title ?? 'No Title'}');
  }
}

class HomeView extends ConsumerStatefulWidget {
  @override
  _HomeViewState createState() => _HomeViewState();
}

class _HomeViewState extends ConsumerState<HomeView> with WidgetsBindingObserver {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    NotificationApi().initNotifications();
    BadgeCounter.loadBadgeCount();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    super.didChangeAppLifecycleState(state);
    if (state == AppLifecycleState.resumed) {
      BadgeCounter.loadBadgeCount();
    }
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home View'),
      ),
      body: Center(
        child: ValueListenableBuilder<int>(
          valueListenable: BadgeCounter.badgeNotifier,
          builder: (context, badgeCount, _) {
            return Text('Badge Count: $badgeCount');
          },
        ),
      ),
    );
  }
}

class NotificationView extends ConsumerStatefulWidget {
  @override
  _NotificationViewState createState() => _NotificationViewState();
}

class _NotificationViewState extends ConsumerState<NotificationView> {
  @override
  void initState() {
    super.initState();
    BadgeCounter.resetBadgeCount();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Notification View'),
      ),
      body: Center(
        child: Text('Notifications'),
      ),
    );
  }
}