import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

void main() => runApp(AuthStateProvider(child: const App()));

final router = GoRouter(
  initialLocation: '/',
  initialExtra: Info('Pressing the button will break the app'),
  routes: <RouteBase>[
    GoRoute(
      path: '/',
      builder: (context, state) => InfoScreen(
        info: state.extra as Info,
      ),
    ),
  ],
  redirect: (context, state) async {
    // accessing [AuthStateProvider] here leads to "type 'Null' is not a subtype of type 'Info' in type cast"
    AuthStateProvider.of(context);

    // no need to redirect for this example
    return null;
  },
);

class App extends StatelessWidget {
  const App({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(routerConfig: router);
  }
}

class InfoScreen extends StatelessWidget {
  final Info info;

  const InfoScreen({required this.info, super.key});

  @override
  Widget build(BuildContext context) {
    final authStateProvider = AuthStateProvider.of(context);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Async Redirection with complex extra parameter'),
      ),
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text('Current info: ${info.note}'),
            Text('isAuthenticated: ${authStateProvider.isAuthenticated}'),
            if (authStateProvider.isAuthenticated)
              ElevatedButton(
                onPressed: authStateProvider.logout,
                child: const Text('Logout'),
              )
            else
              ElevatedButton(
                onPressed: authStateProvider.login,
                child: const Text('Login'),
              ),
          ],
        ),
      ),
    );
  }
}

class Info {
  final String note;

  Info(this.note);
}

class AuthStateProvider extends InheritedNotifier<AuthState> {
  AuthStateProvider({super.key, required super.child}) : super(notifier: AuthState());

  static AuthState of(BuildContext context) {
    final result = context.dependOnInheritedWidgetOfExactType<AuthStateProvider>();
    assert(result != null, 'No AuthState found in context');
    return result!.notifier!;
  }
}

class AuthState extends ChangeNotifier {
  bool isAuthenticated = true;

  void login() {
    isAuthenticated = true;
    notifyListeners();
  }

  void logout() {
    isAuthenticated = false;
    notifyListeners();
  }
}