// lib/services/audio_player_handler.dart
import 'dart:io';
import 'dart:typed_data';
import 'package:flutter/foundation.dart';
import 'package:path_provider/path_provider.dart';
import 'package:audio_service/audio_service.dart' as audio_service;
import '../audio/player_controller.dart';
import '../audio/playback_state_manager.dart';
import '../services/audio_service.dart';
import '../utils/file_provider_utils.dart';
import 'dart:convert';
import 'package:crypto/crypto.dart';

class AudioPlayerHandler extends audio_service.BaseAudioHandler {
  final PlayerController _player = PlayerController();
  final PlaybackStateManager _state = PlaybackStateManager();

  String? _currentId;
  String? _currentTitle;
  String? _currentArtist;

  Duration _currentPosition = Duration.zero;
  DateTime _lastPublishTime = DateTime.now();
  static const Duration _publishInterval = Duration(milliseconds: 500);

  // ⭐ 缓存 artwork 文件路径，避免重复写入
  String? _currentArtworkPath;

  AudioPlayerHandler() {
    _player.playingStream.listen((playing) {
      _state.updatePlaying(playing);
      _publishState();
    });

    _player.positionStream.listen((position) {
      _currentPosition = position;
      _state.updatePosition(position);

      final now = DateTime.now();
      if (now.difference(_lastPublishTime) >= _publishInterval) {
        _lastPublishTime = now;
        // ⭐ 只保留 _publishStateOnly()
        _publishStateOnly();
      }
    });

    _player.durationStream.listen((duration) {
      debugPrint('🎯 [durationStream] duration=$duration');
      _state.updateDuration(duration);
      if (_currentId != null && _currentTitle != null) {
        _updateMediaItem(
          id: _currentId!,
          title: _currentTitle!,
          artist: _currentArtist!,
          duration: duration,
        );
      }
      _publishState();
    });
  }

  // ---- 发布状态 ----
  void _publishState() {
    final state = _state.playbackState;
    playbackState.add(audio_service.PlaybackState(
      controls: state.controls,
      processingState: state.processingState,
      playing: state.playing,
      androidCompactActionIndices: state.androidCompactActionIndices,
      updatePosition: _currentPosition,
      updateTime: DateTime.now(),
      systemActions: const {
        audio_service.MediaAction.seek,
      },
    ));
  }

  void _publishStateOnly() {
    final current = playbackState.value;

    playbackState.add(audio_service.PlaybackState(
      controls: current.controls.isNotEmpty
          ? current.controls
          : _state.playbackState.controls,
      processingState: _state.playbackState.processingState,
      playing: current.playing,
      androidCompactActionIndices: current.androidCompactActionIndices,
      updatePosition: _currentPosition,
      updateTime: DateTime.now(),
      systemActions: const {
        audio_service.MediaAction.seek,
      },
    ));
  }

  // ---- 更新媒体信息 ----
  void _updateMediaItem({
    required String id,
    required String title,
    required String artist,
    Duration? duration,
    Uint8List? artwork,
  }) {
    debugPrint(
        '📢 [handler] _updateMediaItem: artwork is ${artwork != null ? 'not null (${artwork.length} bytes)' : 'null'}');
    _currentId = id;
    _currentTitle = title;
    _currentArtist = artist;
    final position = _player.position;

    debugPrint('📢 [handler] updateMediaItem: $title - $artist');

    // ⭐ 异步处理 artwork（不阻塞主流程）
    _handleArtwork(id, artwork).then((artUri) {
      // 如果 artUri 变化，重新推送 MediaItem
      final current = mediaItem.value;
      if (current != null && current.artUri != artUri) {
        debugPrint('📢 [handler] updating artUri: $artUri');
        mediaItem.add(audio_service.MediaItem(
          id: current.id,
          title: current.title,
          artist: current.artist,
          duration: current.duration,
          artUri: artUri,
          extras: current.extras,
        ));
      }
    });

    // 先推送不带封面图的 MediaItem（让 UI 尽快显示）
    mediaItem.add(audio_service.MediaItem(
      id: id,
      title: title,
      artist: artist,
      duration: duration ?? _player.duration,
      extras: {'position': position.inMilliseconds},
    ));
  }

  /// 处理封面图：保存到本地并生成 content URI
  Future<Uri?> _handleArtwork(String id, Uint8List? artwork) async {
    if (artwork == null || artwork.isEmpty) {
      _currentArtworkPath = null;
      return null;
    }

    try {
      final dir = await getApplicationDocumentsDirectory();
      final artworkDir = Directory('${dir.path}/artworks');
      if (!await artworkDir.exists()) {
        await artworkDir.create(recursive: true);
      }

      // 使用 md5 生成安全的文件名
      final bytes = utf8.encode(id);
      final digest = md5.convert(bytes);
      final fileName = '$digest.jpg';
      final path = '${artworkDir.path}/$fileName';
      final file = File(path);

      // 检查文件是否已存在
      if (await file.exists()) {
        final existingBytes = await file.readAsBytes();
        if (existingBytes.length == artwork.length &&
            existingBytes.hashCode == artwork.hashCode) {
          _currentArtworkPath = path;
          return await FileProviderUtils.getContentUri(file);
        }
      }

      // 写入新文件
      await file.writeAsBytes(artwork);
      _currentArtworkPath = path;
      debugPrint('📢 [handler] artwork saved: $path');

      return await FileProviderUtils.getContentUri(file);
    } catch (e) {
      debugPrint('⚠️ [handler] artwork handling failed: $e');
      return null;
    }
  }

  // ---- 外部接口 ----
  void updateNotification({
    required String id,
    required String title,
    required String artist,
    Uint8List? artwork,
  }) {
    _updateMediaItem(
      id: id,
      title: title,
      artist: artist,
      artwork: artwork,
    );
    _publishState();
  }

  // ---- 控制命令 ----
  @override
  Future<void> play() async {
    debugPrint('▶️ [handler] play() called');
    _player.play();
    _publishState();
  }

  @override
  Future<void> pause() async {
    debugPrint('⏸️ [handler] pause() called');
    _player.pause();
    _publishState();
  }

  @override
  Future<void> stop() async {
    debugPrint('⏹️ [handler] stop() called');
    _player.stop();
    _publishState();
  }

  @override
  Future<void> seek(Duration position) async {
    debugPrint('⏩ [handler] seek() called: $position');
    await _player.seek(position);
    _currentPosition = position;
    _publishStateOnly();
  }

  @override
  Future<void> skipToNext() async {
    debugPrint('⏭️ [handler] skipToNext() called');
    AudioService().next();
  }

  @override
  Future<void> skipToPrevious() async {
    debugPrint('⏮️ [handler] skipToPrevious() called');
    AudioService().previous();
  }

  @override
  Future<void> click(
      [audio_service.MediaButton button =
          audio_service.MediaButton.media]) async {
    debugPrint('🎯 [handler] click() called with button: ${button.name}');
    switch (button) {
      case audio_service.MediaButton.next:
        await skipToNext();
        break;
      case audio_service.MediaButton.previous:
        await skipToPrevious();
        break;
      case audio_service.MediaButton.media:
        if (_player.isPlaying) {
          await pause();
        } else {
          await play();
        }
        break;
      default:
        if (_player.isPlaying) {
          await pause();
        } else {
          await play();
        }
    }
  }
}