import 'dart:async';

import 'package:audio_service/audio_service.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:just_audio/just_audio.dart';
import 'package:pluriwave/modelos/emisora.dart';
import 'package:pluriwave/servicios/emisoras_destacadas.dart';
import 'package:pluriwave/servicios/servicio_audio.dart';
import 'package:shared_preferences/shared_preferences.dart';

import '../helpers/handlers_audio.dart';

/// Resuming the last station in Android Auto — the three defects that made a
/// car-only session unable to remember, restart or even NAME what it was
/// playing.
///
/// Every test here runs with NO widget tree and NO browse source registered:
/// that is the engine Android Auto actually starts
/// (`AudioServicePlugin.java:75-111` builds `new FlutterEngine(context)` with
/// no Activity), so `EstadoRadio` — the only thing that used to write
/// `ultima_emisora_v1` — is never constructed there.
///
///  A1. The last station was written EXCLUSIVELY by `EstadoRadio`, so a
///      session that happened only in the car never updated the key and the
///      head unit was offered the station from the last time the PHONE was
///      used. The same key feeds `resolverEmisorasDestacadas`, so the free
///      tier's featured folder was stale too.
///
///  A2. `play()` with no source called `_player.play()`, and
///      `just_audio.dart:937-967` publishes `_playingSubject.add(true)`
///      BEFORE the `_audioSource != null` gate — so the platform was never
///      touched, the returned Future never completed, and `playing: true`
///      was forwarded over `processingState: idle`.
///      `AudioService.java:559-560` then runs `enterPlayingState()` while
///      `getPlaybackState()` is `STATE_NONE`: a notification with a pause
///      button, no audio, no title and no artwork (or a
///      `ForegroundServiceStartNotAllowedException` on API 31+).
///
///  A3. `mediaItem` was null on a cold start — the only `mediaItem.add` sites
///      are the duration update, `_cambiarFuente` and `stop` — so
///      `audio_service.dart:1029-1033` returned before `setMediaItem` and the
///      native side got no metadata at all.
void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  final crearHandler = registrarHandlersLiberables();

  late _GuionReproductor guion;

  /// The free set's first station: resolvable from the binary alone, so it
  /// works on a bind where no browse source was ever registered — which is
  /// the whole point of these tests.
  const emisoraFip = Emisora(
    uuid: 'pw-destacada-fip',
    nombre: 'FIP',
    url: 'https://icecast.radiofrance.fr/fip-midfi.mp3',
    pais: 'France',
    codigoPais: 'FR',
    idioma: 'french',
  );

  setUp(() {
    guion = _GuionReproductor();
    PluriWaveAudioHandler.fabricaReproductorPrueba =
        (pipeline, carga) => _ReproductorFalso(guion, pipeline, carga);
    // Fresh install = free tier (`esPremiumPersistido` is `getBool(...) ??
    // false`) and no `ultima_emisora_v1`.
    SharedPreferences.setMockInitialValues({});
  });

  tearDown(() {
    PluriWaveAudioHandler.fabricaReproductorPrueba = null;
  });

  group('A1 — el coche escribe la ultima emisora', () {
    test(
      'playFromMediaId desde el coche persiste ESA emisora por el puerto '
      'inyectado, sin arbol de widgets',
      () async {
        final prefs = await SharedPreferences.getInstance();
        final handler = crearHandler();
        final guardadas = <Emisora>[];
        registrarHandler(
          handler,
          guardarUltimaEmisora: (emisora) async {
            guardadas.add(emisora);
            await guardarUltimaEmisoraPersistida(emisora, prefs: prefs);
          },
        );

        await handler.playFromMediaId('emisora:${emisoraFip.uuid}');
        await pumpEventQueue();

        expect(
          guardadas.map((e) => e.uuid),
          [emisoraFip.uuid],
          reason:
              'a car-only session must update `ultima_emisora_v1` itself — '
              '`EstadoRadio` is never built on a headless engine',
        );
        final persistida = await ultimaEmisoraPersistida(prefs: prefs);
        expect(persistida?.uuid, emisoraFip.uuid);
        expect(
          persistida?.url,
          emisoraFip.url,
          reason:
              'the record has to be PLAYABLE: it is what the recent root and '
              '`resolverEmisorasDestacadas` hand back to the head unit',
        );
      },
    );

    test('playMediaItem directo (voz, telefono) persiste igual', () async {
      final handler = crearHandler();
      final guardadas = <Emisora>[];
      registrarHandler(
        handler,
        guardarUltimaEmisora: (emisora) async => guardadas.add(emisora),
      );

      await handler.playMediaItem(
        const MediaItem(
          id: 'https://ejemplo/stream',
          title: 'Ejemplo',
          extras: {'uuid': 'uuid-ejemplo'},
        ),
      );
      await pumpEventQueue();

      expect(guardadas.map((e) => e.uuid), ['uuid-ejemplo']);
      expect(guardadas.single.url, 'https://ejemplo/stream');
    });

    test(
      'una pista local NO se persiste como ultima emisora',
      () async {
        final handler = crearHandler();
        final guardadas = <Emisora>[];
        registrarHandler(
          handler,
          guardarUltimaEmisora: (emisora) async => guardadas.add(emisora),
        );

        await handler.playMediaItem(
          const MediaItem(
            id: 'content://media/audio/7',
            title: 'Pista local',
            extras: {'documentId': 'doc-7'},
          ),
        );
        await pumpEventQueue();

        expect(
          guardadas,
          isEmpty,
          reason:
              '`ultima_emisora_v1` feeds the recent root and the featured '
              'folder as an `emisora:<uuid>` row — a `content://` track '
              'there is a row that does nothing when tapped',
        );
      },
    );

    test('un fallo del puerto se traza y NUNCA propaga', () async {
      final handler = crearHandler();
      registrarHandler(
        handler,
        guardarUltimaEmisora: (_) async => throw StateError('sin disco'),
      );

      await expectLater(
        handler.playMediaItem(
          const MediaItem(
            id: 'https://ejemplo/stream',
            title: 'Ejemplo',
            extras: {'uuid': 'uuid-ejemplo'},
          ),
        ),
        completes,
      );
      await pumpEventQueue();
    });

    test('sin puerto (tests de widget, fakes) no pasa nada', () async {
      final handler = crearHandler();
      registrarHandler(handler);

      await expectLater(
        handler.playMediaItem(
          const MediaItem(
            id: 'https://ejemplo/stream',
            title: 'Ejemplo',
            extras: {'uuid': 'uuid-ejemplo'},
          ),
        ),
        completes,
      );
    });
  });

  group('A2 — play() sin fuente no publica una sesion fantasma', () {
    test(
      'con una emisora persistida, play() resuelve y arranca ESA emisora: el '
      'reproductor recibe su url',
      () async {
        final handler = crearHandler();
        registrarHandler(
          handler,
          leerUltimaEmisora: () async => emisoraFip,
        );
        await pumpEventQueue();

        unawaited(handler.play().catchError((_) {}));
        await pumpEventQueue();

        expect(
          guion.urlsSolicitadas,
          contains(emisoraFip.url),
          reason:
              '`AudioService.java:920` routes the car KEYCODE_MEDIA_PLAY '
              'straight into play(); on a cold engine there is no source, so '
              'it has to resolve the persisted station instead',
        );
      },
    );

    test(
      'y NINGUN estado publicado lleva playing:true sobre processingState '
      'idle',
      () async {
        final handler = crearHandler();
        registrarHandler(
          handler,
          leerUltimaEmisora: () async => emisoraFip,
        );
        await pumpEventQueue();

        final fantasmas = <PlaybackState>[];
        final sub = handler.playbackState.listen((estado) {
          if (estado.playing &&
              estado.processingState == AudioProcessingState.idle) {
            fantasmas.add(estado);
          }
        });

        unawaited(handler.play().catchError((_) {}));
        await pumpEventQueue();
        await sub.cancel();

        expect(
          fantasmas,
          isEmpty,
          reason:
              'playing:true over idle is what makes `AudioService.java:559` '
              'call enterPlayingState() with STATE_NONE — a PluriWave '
              'notification with a pause button, no audio and no title',
        );
      },
    );

    test(
      'sin nada persistido: no se toca el reproductor, no hay estado '
      'fantasma y play() no se queda colgado',
      () async {
        final handler = crearHandler();
        registrarHandler(handler, leerUltimaEmisora: () async => null);
        await pumpEventQueue();

        final fantasmas = <PlaybackState>[];
        final sub = handler.playbackState.listen((estado) {
          if (estado.playing &&
              estado.processingState == AudioProcessingState.idle) {
            fantasmas.add(estado);
          }
        });

        await expectLater(
          handler.play().timeout(const Duration(seconds: 2)),
          completes,
        );
        await pumpEventQueue();
        await sub.cancel();

        expect(
          guion.llamadasPlay,
          0,
          reason:
              'with nothing to restore the player must not be touched at '
              'all: `just_audio` publishes playing:true before its source '
              'gate and never completes the future it returns',
        );
        expect(guion.llamadasSetUrl, 0);
        expect(fantasmas, isEmpty);
      },
    );

    test(
      'con una fuente ya abierta, play() sigue siendo la reanudacion de '
      'siempre (pausa -> play no reabre nada)',
      () async {
        final handler = crearHandler();
        registrarHandler(
          handler,
          leerUltimaEmisora: () async => emisoraFip,
        );
        await handler.playMediaItem(
          const MediaItem(
            id: 'https://ejemplo/stream',
            title: 'Ejemplo',
            extras: {'uuid': 'uuid-ejemplo'},
          ),
        );
        await pumpEventQueue();
        await handler.pause();
        final urlsAntes = List<String>.from(guion.urlsSolicitadas);

        await handler.play();
        await pumpEventQueue();

        expect(
          guion.urlsSolicitadas,
          urlsAntes,
          reason:
              'a resume must NOT re-open the source, and must never replace '
              'the live station with the persisted one',
        );
        expect(handler.intencionReproducir, isTrue);
      },
    );
  });

  group('A3 — arranque en frio: el coche recibe metadatos', () {
    test(
      'con una emisora persistida se publica su mediaItem SIN arrancar '
      'reproduccion',
      () async {
        final handler = crearHandler();

        registrarHandler(
          handler,
          leerUltimaEmisora: () async => emisoraFip,
        );
        await pumpEventQueue();

        expect(
          handler.mediaItem.value,
          isNotNull,
          reason:
              '`audio_service.dart:1029-1033` returns before setMediaItem '
              'when mediaItem is null, so a cold engine sent the head unit '
              'no metadata whatsoever',
        );
        expect(handler.mediaItem.value?.id, emisoraFip.url);
        expect(handler.playbackState.value.playing, isFalse);
        expect(
          guion.llamadasSetUrl,
          0,
          reason:
              'publishing metadata must not open a stream: a cold bind '
              'happens on every reconnect and must stay silent',
        );
      },
    );

    test('sin nada persistido el mediaItem sigue vacio', () async {
      final handler = crearHandler();

      registrarHandler(handler, leerUltimaEmisora: () async => null);
      await pumpEventQueue();

      expect(handler.mediaItem.value, isNull);
    });

    test(
      'una emisora que ya empezo a sonar NO es pisada por la siembra',
      () async {
        final handler = crearHandler();
        final lectura = Completer<Emisora?>();

        registrarHandler(handler, leerUltimaEmisora: () => lectura.future);
        await handler.playMediaItem(
          const MediaItem(
            id: 'https://enVivo/stream',
            title: 'En vivo',
            extras: {'uuid': 'uuid-en-vivo'},
          ),
        );
        lectura.complete(emisoraFip);
        await pumpEventQueue();

        expect(
          handler.mediaItem.value?.id,
          'https://enVivo/stream',
          reason:
              'the seed exists to fill a VOID; clobbering the live station '
              'would rename what the driver is listening to',
        );
      },
    );
  });

  group('getMediaItem resuelve tambien el set destacado', () {
    test(
      'sin fuente de navegacion registrada, una emisora destacada resuelve',
      () async {
        final handler = crearHandler();
        registrarHandler(handler);

        final item = await handler.getMediaItem('emisora:${emisoraFip.uuid}');

        expect(
          item,
          isNotNull,
          reason:
              '`porUuid` already falls back to the featured set, so the car '
              'could BROWSE a featured station and not resolve its media '
              'item — the asymmetry is the bug',
        );
        expect(item?.id, 'emisora:${emisoraFip.uuid}');
        expect(item?.title, emisoraFip.nombre);
      },
    );

    test('un id que no es de emisora sigue devolviendo null', () async {
      final handler = crearHandler();
      registrarHandler(handler);

      expect(await handler.getMediaItem('pista:doc-1'), isNull);
      expect(await handler.getMediaItem('emisora:'), isNull);
    });
  });
}

/// Shared script/observation record for every [_ReproductorFalso] the handler
/// builds (it rebuilds its player on every source change, so counters cannot
/// live on the instance).
class _GuionReproductor {
  int llamadasPlay = 0;
  int llamadasSetUrl = 0;
  final urlsSolicitadas = <String>[];
}

/// An [AudioPlayer] double that reproduces the ONE `just_audio` behaviour
/// defect A2 is about: `play()` (`just_audio.dart:937-967`) publishes
/// `playing: true` BEFORE the `_audioSource != null` gate, and with no source
/// it never touches the platform and never completes the future it returned.
class _ReproductorFalso extends AudioPlayer {
  _ReproductorFalso(
    this._guion,
    AudioPipeline pipeline,
    AudioLoadConfiguration carga,
  ) : super(audioPipeline: pipeline, audioLoadConfiguration: carga);

  final _GuionReproductor _guion;
  final _estados = StreamController<PlayerState>.broadcast();

  /// A fresh player has no source, exactly like the real one.
  bool _fuenteCargada = false;

  @override
  Stream<PlayerState> get playerStateStream => _estados.stream;

  @override
  Future<Duration?> setUrl(
    String url, {
    Map<String, String>? headers,
    Duration? initialPosition,
    bool preload = true,
    dynamic tag,
  }) async {
    _guion.llamadasSetUrl++;
    _guion.urlsSolicitadas.add(url);
    _fuenteCargada = true;
    return null;
  }

  @override
  Future<void> play() {
    _guion.llamadasPlay++;
    if (!_estados.isClosed) {
      _estados.add(
        PlayerState(
          true,
          _fuenteCargada ? ProcessingState.ready : ProcessingState.idle,
        ),
      );
    }
    // The dangling future: with no source, upstream `play()` awaits a
    // `_playingSubject` transition the platform will never produce.
    if (!_fuenteCargada) return Completer<void>().future;
    return Future<void>.value();
  }

  @override
  Future<void> pause() async {}

  @override
  Future<void> stop() async {}

  @override
  Future<void> setVolume(double volume) async {}

  @override
  Future<void> dispose() async {
    await _estados.close();
  }
}