import 'dart:async';

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

void main() {
  runApp(
    ProviderScope(
      observers: [DisposeObserver()],
      child: const App(),
    ),
  );
}

final delayedStreamProvider = StreamProvider.autoDispose<int>((ref) async* {
  debugPrint('delayedStreamProvider: started');
  ref.onDispose(() {
    debugPrint('delayedStreamProvider: disposed');
  });

  await Future<void>.delayed(const Duration(seconds: 3));
  debugPrint('delayedStreamProvider: emitting first value');
  yield 1;
}, name: 'delayedStreamProvider');

final dependentProvider = FutureProvider.autoDispose<String>((ref) async {
  debugPrint('dependentProvider: awaiting delayedStreamProvider.future');
  final value = await ref.watch(delayedStreamProvider.future);
  return 'Resolved with $value';
}, name: 'dependentProvider');

final class DisposeObserver extends ProviderObserver {
  @override
  void providerDidFail(
    ProviderObserverContext context,
    Object error,
    StackTrace stackTrace,
  ) {
    debugPrint(
      'providerDidFail: ${context.provider.name} ${context.provider.argument}',
    );
    debugPrint('error: $error');
    debugPrint('stackTrace: $stackTrace');
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: const ReproScreen(),
    );
  }
}

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

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final state = ref.watch(dependentProvider);

    return Scaffold(
      appBar: AppBar(title: const Text('Riverpod Dispose Repro')),
      body: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          spacing: 16,
          children: [
            Text('Current state: $state'),
            FilledButton(
              onPressed: () {
                Navigator.of(context).pushReplacement(
                  MaterialPageRoute<void>(
                    builder: (_) => const FinishedScreen(),
                  ),
                );
              },
              child: const Text('Replace screen before first value'),
            ),
          ],
        ),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('After dispose')),
      body: const Center(
        child: Text('Check the console output from ProviderObserver.'),
      ),
    );
  }
}