import 'package:audio_service/audio_service.dart';
import 'package:just_audio/just_audio.dart';
import '../modelos/emisora.dart';

/// Estado de reproducción expuesto al UI.
enum EstadoReproduccion { detenido, cargando, reproduciendo, pausado, error }

// ─────────────────────────────────────────────────────────────
// Handler global — inicializado en main.dart con AudioService.init
// ─────────────────────────────────────────────────────────────
PluriWaveAudioHandler? _handlerGlobal;

/// Registra el handler. Llamar desde main.dart tras AudioService.init.
void registrarHandler(PluriWaveAudioHandler handler) {
  _handlerGlobal = handler;
}

/// Wrapper de alto nivel para el UI.
///
/// Delega TODA la reproducción al [PluriWaveAudioHandler] para garantizar
/// que el audio siga vivo en background con notificación foreground.
class ServicioAudio {
  PluriWaveAudioHandler get _handler {
    assert(_handlerGlobal != null,
        'ServicioAudio: handler no registrado. '
        'Llama registrarHandler() en main.dart tras AudioService.init.');
    return _handlerGlobal!;
  }

  Emisora? get emisoraActual => _handler.emisoraActual;

  Stream<EstadoReproduccion> get estadoStream =>
      _handler.playbackState.map((s) {
        if (s.processingState == AudioProcessingState.loading ||
            s.processingState == AudioProcessingState.buffering) {
          return EstadoReproduccion.cargando;
        }
        if (s.playing) return EstadoReproduccion.reproduciendo;
        if (s.processingState == AudioProcessingState.idle) {
          return EstadoReproduccion.detenido;
        }
        return EstadoReproduccion.pausado;
      });

  Future<void> reproducir(Emisora emisora) async {
    final item = MediaItem(
      id: emisora.url,
      title: emisora.nombre,
      artist: emisora.pais ?? '',
      album: 'PluriWave',
      artUri: emisora.favicon != null && emisora.favicon!.isNotEmpty
          ? Uri.tryParse(emisora.favicon!)
          : null,
      extras: {'uuid': emisora.uuid},
    );
    await _handler.playMediaItem(item);
  }

  Future<void> pausar() => _handler.pause();
  Future<void> reanudar() => _handler.play();

  Future<void> togglePlay() async {
    if (_handler.playbackState.value.playing) {
      await pausar();
    } else {
      await reanudar();
    }
  }

  Future<void> detener() => _handler.stop();

  Future<void> setVolumen(double vol) => _handler.setVolume(vol.clamp(0.0, 1.0));

  double get volumen => _handler.volumen;
  bool get estaSonando => _handler.playbackState.value.playing;

  /// No-op: el handler se limpia en main.dart al cerrar la app.
  Future<void> dispose() async {}
}

// ─────────────────────────────────────────────────────────────
// AudioHandler — núcleo del audio en background
// ─────────────────────────────────────────────────────────────

/// Handler de audio_service.
///
/// Gestiona la reproducción con `just_audio` y mantiene la notificación
/// foreground activa mientras hay audio reproduciéndose.
///
/// ### Inicialización en main.dart
/// ```dart
/// final handler = await AudioService.init(
///   builder: () => PluriWaveAudioHandler(),
///   config: const AudioServiceConfig(
///     androidNotificationChannelId: 'es.freetimelab.pluriwave.audio',
///     androidNotificationChannelName: 'PluriWave Radio',
///     androidNotificationOngoing: true,
///     androidStopForegroundOnPause: true,
///     androidNotificationIcon: 'drawable/ic_stat_radio',
///   ),
/// );
/// registrarHandler(handler);
/// ```
class PluriWaveAudioHandler extends BaseAudioHandler with SeekHandler {
  final AudioPlayer _player = AudioPlayer();
  Emisora? emisoraActual;
  double _volumen = 1.0;
  double get volumen => _volumen;

  PluriWaveAudioHandler() {
    _setupStreams();
  }

  void _setupStreams() {
    // Propagar estado del player → playbackState (lo que ve la notificación)
    _player.playerStateStream.listen((state) {
      final playing = state.playing;
      final proc = state.processingState;

      playbackState.add(playbackState.value.copyWith(
        controls: [
          if (playing) MediaControl.pause else MediaControl.play,
          MediaControl.stop,
        ],
        systemActions: const {MediaAction.seek, MediaAction.stop},
        androidCompactActionIndices: const [0],
        processingState: _mapProcState(proc),
        playing: playing,
        bufferedPosition: _player.bufferedPosition,
        speed: _player.speed,
      ));
    });

    // Actualizar bufferedPosition
    _player.bufferedPositionStream.listen((pos) {
      playbackState.add(playbackState.value.copyWith(bufferedPosition: pos));
    });
  }

  AudioProcessingState _mapProcState(ProcessingState state) {
    return switch (state) {
      ProcessingState.idle => AudioProcessingState.idle,
      ProcessingState.loading => AudioProcessingState.loading,
      ProcessingState.buffering => AudioProcessingState.buffering,
      ProcessingState.ready => AudioProcessingState.ready,
      ProcessingState.completed => AudioProcessingState.completed,
    };
  }

  @override
  Future<void> playMediaItem(MediaItem item) async {
    mediaItem.add(item);
    try {
      await _player.stop();
      await _player.setUrl(item.id);
      await _player.play();
    } on PlayerException catch (e) {
      playbackState.add(playbackState.value.copyWith(
        processingState: AudioProcessingState.error,
        errorMessage: e.message ?? 'Error de reproducción',
        errorCode: e.code,
      ));
      rethrow;
    }
  }

  @override
  Future<void> play() => _player.play();

  @override
  Future<void> pause() => _player.pause();

  @override
  Future<void> stop() async {
    await _player.stop();
    emisoraActual = null;
    mediaItem.add(null);
    await super.stop();
  }

  @override
  Future<void> seek(Duration position) => _player.seek(position);

  Future<void> setVolume(double vol) async {
    _volumen = vol.clamp(0.0, 1.0);
    await _player.setVolume(_volumen);
  }

  @override
  Future<void> onTaskRemoved() async {
    await stop();
    await _player.dispose();
  }
}