I am working on a Flutter app that receives call notifications via Firebase Cloud Messaging (FCM). The app is expected to ring and navigate to a call screen call_corridor.dart when a call notification (MessageType: "CONSULTATION") is received, even if the app is in the background or terminated state.

I have tried implementing a foreground service in Android using MethodChannel, and my FirebaseMessagingService in Kotlin receives the notification, but I am facing these issues:

App in background: The notification is received, but it does not trigger the ringing sound.

App in terminated state: The notification comes in but when the notification is clicked, the app seems frozen and it does not open through.

MethodChannel error: MissingPluginException(No implementation found for method startForegroundService on channel ..packagename../foreground).

This is is my main.dart:

    Future<SharedPreferences> _initializeApp() async {
  try {
    WidgetsFlutterBinding.ensureInitialized();
    if (Firebase.apps.isEmpty) {
      await Firebase.initializeApp(
          options: DefaultFirebaseOptions.currentPlatform
      );
    }
    try {
      PlatformChannels().setupChannels();
      //FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
      // Set up error handling
      FlutterError.onError =
          FirebaseCrashlytics.instance.recordFlutterFatalError;

      // Platform specific initialization
      if (Platform.isAndroid) {
        await FirebaseMessaging.instance.setAutoInitEnabled(true);
      } else if (Platform.isIOS) {
        await FirebaseMessaging.instance.getAPNSToken();
      }
    } catch(e){
      debugPrint('Firebase services initialization error (may be expected in tests): $e');
    }
    // Hive initialization
    await Hive.initFlutter();
    registerHiveAdapters();
    await Hive.openBox<NotificationHive>('notifications');

    await clearOldNotifications();

    // System orientation
    await SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);
    // Shared preferences
    final sharedPref = await SharedPreferences.getInstance();

    return sharedPref;
  } catch (e, stackTrace) {
    debugPrint('Initialization error: $e\n$stackTrace');
    rethrow;
  }
}

void main() async {
  try {
    final sharedPref = await _initializeApp();
    print("