void main() {
  runApp(
    ProviderScope(
      child: MaterialApp.router(
        routerConfig: router,
      ),
    ),
  );
}

class GroupsPage extends ConsumerWidget {
  const GroupsPage({super.key, required this.groupId});

  final String groupId;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Group $groupId'),
        actions: [
          IconButton(
            onPressed: () => context.go('/groups/$groupId/settings'),
            icon: const Icon(Icons.settings),
          ),
        ],
      ),
      body: ListView.builder(
        itemCount: 10,
        itemBuilder: (context, index) => ListTile(
          onTap: () => context.go('/groups/$groupId/posts/$index'),
          tileColor: [Colors.red.shade300, Colors.blue.shade300][index % 2],
          title: Text('Post of group $groupId n°$index'),
        ),
      ),
    );
  }
}

class PostPage extends ConsumerWidget {
  const PostPage({super.key, required this.postId});

  final String postId;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
          onPressed: () => context.pop(),
          icon: const Icon(Icons.arrow_back),
        ),
        title: Text('Post $postId'),
      ),
      body: Text('This is the content of post $postId'),
    );
  }
}

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

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
          onPressed: () => context.pop(),
          icon: const Icon(Icons.arrow_back),
        ),
      ),
      body: const Center(
        child: Column(
          children: [
            Text('Settings'),
          ],
        ),
      ),
    );
  }
}

part 'router.g.dart';

final router = GoRouter(
  debugLogDiagnostics: true,
  initialLocation: '/groups/1',
  routes: [
    StatefulShellRoute.indexedStack(
      builder: (context, state, child) => Scaffold(
        appBar: AppBar(
          title: const Text('Test App'),
        ),
        body: child,
      ),
      branches: [
        StatefulShellBranch(
          routes: [
            ShellRoute(
              builder: (context, state, child) => Scaffold(
                appBar: AppBar(
                  title: const Text('Group List'),
                ),
                body: child,
              ),
              routes: [
                GoRoute(
                  path: '/groups/empty',
                  builder: (context, state) => const GroupsPage(
                    groupId: 'all',
                  ),
                  redirect: (context, state) => '/groups/1',
                ),
                GoRoute(
                  path: '/groups/:id',
                  builder: (context, state) => GroupsPage(
                    groupId: state.pathParameters['id']!,
                  ),
                  routes: [
                    PostDetailPage.route,
                    GoRoute(
                      path: 'settings',
                      builder: (context, state) => const SettingsPage(),
                    ),
                  ],
                ),
              ],
            ),
          ],
        )
      ],
    )
  ],
);

@TypedGoRoute<PostDetailPage>(path: 'posts/:id')
class PostDetailPage extends GoRouteData with _$PostDetailPage {
  const PostDetailPage({required this.id});

  static final route = $postDetailPage;

  final String id;

  @override
  Widget build(BuildContext context, GoRouterState state) {
    return PostPage(
      postId: id,
    );
  }
}