import 'dart:async';
import 'package:audio_service/audio_service.dart';
import 'package:just_audio/just_audio.dart';
import '../models/song.dart';
import 'player_service.dart';

/// Hintergrund-Audio-Handler für Sperrbildschirm & Benachrichtigung
class MeloAudioHandler extends BaseAudioHandler {
  final PlayerService _player = PlayerService();

  MeloAudioHandler() {
    // Zustand vom Player an audio_service weiterleiten
    _player.stateStream.listen(_updateState);
    _player.positionStream.listen((pos) {
      if (_playing) {
        playbackState.add(playbackState.value.copyWith(
          updatePosition: pos,
        ));
      }
    });
    _player.onSongWechsel.listen((song) {
      if (song != null) {
        mediaItem.add(_toMediaItem(song));
      }
    });
  }

  bool _playing = false;

  void _updateState(PlayerState state) {
    _playing = state.playing;
    playbackState.add(PlaybackState(
      controls: _playing
          ? [MediaControl.pause, MediaControl.skipToPrevious, MediaControl.skipToNext, MediaControl.stop]
          : [MediaControl.play, MediaControl.skipToPrevious, MediaControl.skipToNext, MediaControl.stop],
      systemActions: const {MediaAction.seek},
      androidCompactActionIndices: const [0, 1, 2],
      processingState: _playing ? AudioProcessingState.ready : AudioProcessingState.idle,
      playing: _playing,
      speed: 1.0,
    ));
  }

  MediaItem _toMediaItem(Song song) => MediaItem(
    id: song.id?.toString() ?? '0',
    album: song.album.isEmpty ? 'Melo' : song.album,
    title: song.titel,
    artist: song.kuenstler,
    duration: Duration(seconds: song.dauerSekunden),
    artUri: song.coverPfad != null ? Uri.file(song.coverPfad!) : null,
  );

  @override
  Future<void> play() async {
    if (_player.aktuellerSong != null) {
      _playing = true;
      await _player.playPause();
    }
  }

  @override
  Future<void> pause() async {
    _playing = false;
    await _player.playPause();
  }

  @override
  Future<void> stop() async {
    _playing = false;
    await _player.playPause();
    playbackState.add(playbackState.value.copyWith(
      controls: [MediaControl.play],
      playing: false,
      processingState: AudioProcessingState.idle,
    ));
  }

  @override
  Future<void> seek(Duration position) async {
    _player.spiele(_player.aktuellerSong!, position: position.inSeconds);
  }

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

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

  // Exposed for the ViewModel
  PlayerService get player => _player;
}