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

void main() => runApp(const ProviderScope(child: MyApp()));

final GlobalKey<NavigatorState> _rootNavigatorKey =
    GlobalKey<NavigatorState>(debugLabel: 'root');
final GlobalKey<NavigatorState> _shellNavigatorKey =
    GlobalKey<NavigatorState>(debugLabel: 'shell');

final routesProvider = Provider<GoRouter>(
  (ref) {
    return GoRouter(
      debugLogDiagnostics: true,
      initialLocation: '/a',
      navigatorKey: _rootNavigatorKey,
      routes: [
        ShellRoute(
          navigatorKey: _shellNavigatorKey,
          builder: (context, state, child) => ShellWidget(child: child),
          routes: [
            GoRoute(
              path: '/a',
              builder: (context, state) => const DummyScreen(
                color: Colors.green,
                text: '/b',
              ),
            ),
            GoRoute(
              path: '/c',
              builder: (context, state) => const DummyScreen(
                color: Colors.green,
                text: '/d',
              ),
            ),
          ],
        ),
        GoRoute(
          path: '/d',
          parentNavigatorKey: _rootNavigatorKey,
          builder: (context, state) => const DummyScreen(
            color: Colors.red,
            text: '/d/e',
          ),
          routes: [
            GoRoute(
              // can't push this page at all
              path: 'e',
              builder: (context, state) => const DummyScreen(
                color: Colors.red,
                text: '/c',
              ),
            ),
          ],
        ),
        GoRoute(
          // can't push this page on the shell without key
          // even though it is outside of shell route
          path: '/b',
          builder: (context, state) => const DummyScreen(
            color: Colors.green,
            text: '',
          ),
        ),
      ],
    );
  },
);

class ShellWidget extends StatefulWidget {
  const ShellWidget({
    super.key,
    required this.child,
  });
  final Widget child;

  @override
  State<ShellWidget> createState() => _ShellWidgetState();
}

class _ShellWidgetState extends State<ShellWidget> {
  int index = 0;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Hello")),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: index,
        onTap: (value) {
          setState(() {
            index = value;
            switch (value) {
              case 0:
                context.go('/a');
                break;
              case 1:
                context.go('/c');
                break;
              default:
            }
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon: Icon(
              Icons.access_alarm,
            ),
            label: 'a',
          ),
          BottomNavigationBarItem(
            icon: Icon(
              Icons.access_alarm,
            ),
            label: 'c',
          ),
        ],
      ),
      body: widget.child,
    );
  }
}

class MyApp extends ConsumerWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final routes = ref.watch(routesProvider);
    return MaterialApp.router(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      routeInformationParser: routes.routeInformationParser,
      routeInformationProvider: routes.routeInformationProvider,
      routerDelegate: routes.routerDelegate,
    );
  }
}

class DummyScreen extends StatelessWidget {
  const DummyScreen({
    super.key,
    required this.color,
    required this.text,
  });
  final Color color;
  final String text;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(GoRouter.of(context).location)),
      backgroundColor: color,
      body: Center(
        child: ElevatedButton(
          onPressed: text.isNotEmpty ? () => context.push(text) : null,
          child: Text(text),
        ),
      ),
    );
  }
}