import 'package:audioplayers/audioplayers.dart';
import 'package:flutter/foundation.dart';
import '../models/spotify_track.dart';

class AudioService extends ChangeNotifier {
  static final AudioService _instance = AudioService._internal();
  factory AudioService() => _instance;
  AudioService._internal() {
    _initializePlayer();
  }

  final AudioPlayer _audioPlayer = AudioPlayer();
  
  // Current track state
  SpotifyTrack? _currentTrack;
  bool _isPlaying = false;
  bool _isLoading = false;
  Duration _currentPosition = Duration.zero;
  Duration _totalDuration = Duration.zero;
  
  // Getters
  SpotifyTrack? get currentTrack => _currentTrack;
  bool get isPlaying => _isPlaying;
  bool get isLoading => _isLoading;
  Duration get currentPosition => _currentPosition;
  Duration get totalDuration => _totalDuration;
  double get progress => _totalDuration.inMilliseconds > 0 
      ? _currentPosition.inMilliseconds / _totalDuration.inMilliseconds 
      : 0.0;

  // Free audio sources for demo purposes
  // Using royalty-free music from reliable sources
  final Map<String, String> _demoAudioUrls = {
    // Peaceful, lido-appropriate tracks
    'pop1': 'https://www.bensound.com/bensound-music/bensound-relaxing.mp3',
    'pop2': 'https://www.bensound.com/bensound-music/bensound-sunny.mp3',
    'pop3': 'https://www.bensound.com/bensound-music/bensound-jazzcomedy.mp3',
    'pop4': 'https://www.bensound.com/bensound-music/bensound-acousticbreeze.mp3',
    '1': 'https://www.bensound.com/bensound-music/bensound-creativeminds.mp3',
    '2': 'https://www.bensound.com/bensound-music/bensound-happyrock.mp3',
    '3': 'https://www.bensound.com/bensound-music/bensound-ukulele.mp3',
    '4': 'https://www.bensound.com/bensound-music/bensound-summer.mp3',
    '5': 'https://www.bensound.com/bensound-music/bensound-happiness.mp3',
  };

  void _initializePlayer() {
    // Listen to player state changes
    _audioPlayer.onPlayerStateChanged.listen((PlayerState state) {
      _isPlaying = state == PlayerState.playing;
      _isLoading = state == PlayerState.stopped && _currentTrack != null;
      notifyListeners();
    });

    // Listen to position changes
    _audioPlayer.onPositionChanged.listen((Duration position) {
      _currentPosition = position;
      notifyListeners();
    });

    // Listen to duration changes
    _audioPlayer.onDurationChanged.listen((Duration duration) {
      _totalDuration = duration;
      notifyListeners();
    });

    // Listen for track completion
    _audioPlayer.onPlayerComplete.listen((_) {
      _onTrackComplete();
    });
  }

  Future<void> playTrack(SpotifyTrack track) async {
    try {
      _isLoading = true;
      _currentTrack = track;
      notifyListeners();

      // Check if we have a demo URL for this track
      String? audioUrl = _demoAudioUrls[track.id];
      
      if (audioUrl != null) {
        // Play the demo audio
        await _audioPlayer.play(UrlSource(audioUrl));
        print('Playing audio for: ${track.name} by ${track.artistNames}');
      } else {
        // For tracks without demo URLs, simulate playback
        print('Simulating playback for: ${track.name} by ${track.artistNames}');
        _simulateTrackPlayback(track);
      }
      
      _isLoading = false;
      notifyListeners();
    } catch (e) {
      print('Error playing track: $e');
      _isLoading = false;
      // Fallback to simulation
      _simulateTrackPlayback(track);
      notifyListeners();
    }
  }

  void _simulateTrackPlayback(SpotifyTrack track) {
    // Set simulated duration
    _totalDuration = Duration(milliseconds: track.durationMs);
    _currentPosition = Duration.zero;
    _isPlaying = true;
    
    // Simulate playback progress
    _startSimulatedProgress();
  }

  void _startSimulatedProgress() {
    if (_isPlaying && _currentTrack != null) {
      Future.delayed(const Duration(seconds: 1), () {
        if (_isPlaying && _currentTrack != null) {
          _currentPosition = _currentPosition + const Duration(seconds: 1);
          
          if (_currentPosition >= _totalDuration) {
            _onTrackComplete();
          } else {
            notifyListeners();
            _startSimulatedProgress();
          }
        }
      });
    }
  }

  Future<void> togglePlayPause() async {
    try {
      if (_isPlaying) {
        await _audioPlayer.pause();
      } else {
        if (_currentTrack != null) {
          // Check if we have a real audio URL
          String? audioUrl = _demoAudioUrls[_currentTrack!.id];
          if (audioUrl != null) {
            await _audioPlayer.resume();
          } else {
            // Resume simulation
            _isPlaying = true;
            _startSimulatedProgress();
          }
        }
      }
      notifyListeners();
    } catch (e) {
      print('Error toggling play/pause: $e');
      // Fallback to simulation toggle
      _isPlaying = !_isPlaying;
      if (_isPlaying) {
        _startSimulatedProgress();
      }
      notifyListeners();
    }
  }

  Future<void> stop() async {
    try {
      await _audioPlayer.stop();
    } catch (e) {
      print('Error stopping audio: $e');
    }
    
    _isPlaying = false;
    _currentPosition = Duration.zero;
    _currentTrack = null;
    notifyListeners();
  }

  Future<void> seekTo(Duration position) async {
    try {
      // Check if we have a real audio URL
      if (_currentTrack != null && _demoAudioUrls.containsKey(_currentTrack!.id)) {
        await _audioPlayer.seek(position);
      } else {
        // Simulate seeking
        _currentPosition = position;
        notifyListeners();
      }
    } catch (e) {
      print('Error seeking: $e');
      // Fallback to simulation
      _currentPosition = position;
      notifyListeners();
    }
  }

  void _onTrackComplete() {
    _isPlaying = false;
    _currentPosition = Duration.zero;
    notifyListeners();
    
    // Notify that track is complete (for queue management)
    onTrackComplete?.call();
  }

  // Callback for when a track completes
  Function()? onTrackComplete;

  @override
  void dispose() {
    _audioPlayer.dispose();
    super.dispose();
  }

  // Get formatted time strings
  String get currentPositionString => _formatDuration(_currentPosition);
  String get totalDurationString => _formatDuration(_totalDuration);

  String _formatDuration(Duration duration) {
    String twoDigits(int n) => n.toString().padLeft(2, '0');
    String twoDigitMinutes = twoDigits(duration.inMinutes.remainder(60));
    String twoDigitSeconds = twoDigits(duration.inSeconds.remainder(60));
    return '$twoDigitMinutes:$twoDigitSeconds';
  }

  // Add better demo audio URLs (using royalty-free sources)
  void addDemoAudioUrl(String trackId, String audioUrl) {
    _demoAudioUrls[trackId] = audioUrl;
  }

  // Add local asset support
  Future<void> playAsset(SpotifyTrack track, String assetPath) async {
    try {
      _isLoading = true;
      _currentTrack = track;
      notifyListeners();

      await _audioPlayer.play(AssetSource(assetPath));
      print('Playing asset: $assetPath for ${track.name}');
      
      _isLoading = false;
      notifyListeners();
    } catch (e) {
      print('Error playing asset: $e');
      _isLoading = false;
      _simulateTrackPlayback(track);
      notifyListeners();
    }
  }
}