void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final container = ProviderContainer();

  final routerDelegate = createDelegate(container.read);
  final routeInformationParser = BeamerParser();

  F.appFlavor = Flavor.DEV;
  await Firebase.initializeApp();
  runApp(
    UncontrolledProviderScope(
      container: container,
      child: BeamerProvider(
        routerDelegate: routerDelegate,
        child: App(
          routeInformationParser,
          routerDelegate,
        ),
      ),
    ),
  );
}

BeamerDelegate createDelegate(Reader read) {
  return BeamerDelegate(
    initialPath: '/home',
    locationBuilder: BeamerLocationBuilder(
      beamLocations: [
        AuthenticationLocation(),
        HomeLocation(),
      ],
    ),
    guards: [
      BeamGuard(
          pathPatterns: ['/login', '/register', '/forgot_password'],
          guardNonMatching: true,
          check: (_, __) => read(authenticationListenerProvider),
          beamToNamed: '/login'),
    ],
  );
}

class App extends ConsumerWidget {
  const App(this.routeInformationParser, this.routerDelegate, {Key? key}) : super(key: key);

  final RouteInformationParser<Object> routeInformationParser;
  final BeamerDelegate routerDelegate;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    //* Authentication listener
    ref.listen(authenticationListenerProvider, (bool isLoggedIn) {
      if (isLoggedIn) {
        context.beamTo(HomeLocation());
      } else {
        context.beamTo(AuthenticationLocation());
      }
    });
    return MaterialApp.router(
      routeInformationParser: routeInformationParser,
      routerDelegate: routerDelegate,
      title: F.title,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
    );
  }
}

class AuthenticationNotifier extends StateNotifier<bool> {
  AuthenticationNotifier(this._authenticationRepository) : super(false) {
    _authenticationRepository.getUser().listen((user) {
      if (user.uid == null) {
        state = false;
      } else {
        state = true;
      }
    });
  }

  final AuthenticationRepository _authenticationRepository;
  late final StreamSubscription<User?> _userSubscription;

  @override
  void dispose() {
    _userSubscription.cancel();
    super.dispose();
  }
}

final authenticationListenerProvider = StateNotifierProvider<AuthenticationNotifier, bool>(
  (ref) => AuthenticationNotifier(ref.watch(authenticationRepositoryProvider)),
);