QingTing-Player/lib/pages/playlist_detail_page.dart

import 'dart:async';
// lib/pages/playlist_detail_page.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../database/song_database.dart';
import '../repositories/playlist_repository.dart';
import '../services/audio_service.dart';
import '../services/metadata_events.dart';
import '../widgets/song_artwork.dart';

/// 歌单详情：展示歌单内歌曲，支持播放全部 / 单曲播放 / 移除
class PlaylistDetailPage extends StatefulWidget {
  final String playlistId;
  final String playlistName;

  const PlaylistDetailPage({
    super.key,
    required this.playlistId,
    required this.playlistName,
  });

  @override
  State<PlaylistDetailPage> createState() => _PlaylistDetailPageState();
}

class _SongRow {
  final String path;
  final String title;
  final String artist;
  final String? artworkPath;

  const _SongRow({
    required this.path,
    required this.title,
    required this.artist,
    this.artworkPath,
  });
}

class _PlaylistDetailPageState extends State<PlaylistDetailPage> {
  final PlaylistRepository _repo = PlaylistRepository();
  final SongDatabase _db = SongDatabase();

  List<_SongRow> _songs = [];
  StreamSubscription<MetadataUpdate>? _metaSub;
  bool _loading = true;

  @override
  void initState() {
    super.initState();
    _metaSub = MetadataEvents().stream.listen(_onMetadataUpdate);
    _load();
  }

  @override
  void dispose() {
    _metaSub?.cancel();
    super.dispose();
  }

  /// 歌单里的歌补全元数据后，就地更新对应行
  void _onMetadataUpdate(MetadataUpdate update) {
    final index = _songs.indexWhere((item) => item.path == update.path);
    if (index < 0 || !mounted) return;
    final row = update.row;
    final title = (row['title'] as String?)?.trim() ?? '';
    final artist = (row['artist'] as String?)?.trim() ?? '';
    final artwork = (row['artwork_path'] as String?)?.trim() ?? '';
    final old = _songs[index];
    setState(() {
      _songs[index] = _SongRow(
        path: old.path,
        title: title.isNotEmpty ? title : old.title,
        artist: artist.isNotEmpty ? artist : old.artist,
        artworkPath: artwork.isNotEmpty ? artwork : old.artworkPath,
      );
    });
  }
  Future<void> _load() async {
    setState(() => _loading = true);
    try {
      final ids = await _repo.getPlaylistSongIds(widget.playlistId);
      final meta = await _db.getSongsByPaths(ids);
      final rows = <_SongRow>[];
      for (final id in ids) {
        final row = meta[id];
        final title = (row?['title'] as String?)?.trim() ?? '';
        final artist = (row?['artist'] as String?)?.trim() ?? '';
        String fallbackName = id.split('/').last;
        try {
          fallbackName = Uri.decodeComponent(fallbackName);
        } catch (_) {}
        rows.add(_SongRow(
          path: id,
          title: title.isNotEmpty
              ? title
              : fallbackName.replaceAll(RegExp(r'\.[^.]*$'), ''),
          artist: artist.isNotEmpty ? artist : '未知艺术家',
          artworkPath: (row?['artwork_path'] as String?)?.trim().isNotEmpty ==
                  true
              ? (row!['artwork_path'] as String).trim()
              : null,
        ));
      }
      if (!mounted) return;
      setState(() {
        _songs = rows;
        _loading = false;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() => _loading = false);
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text('读取歌单失败: $e')));
    }
  }

  Future<void> _play(int index) async {
    await context
        .read<AudioService>()
        .playPlaylist(widget.playlistId, startIndex: index);
  }

  Future<void> _remove(_SongRow song) async {
    await _repo.removeSong(widget.playlistId, song.path);
    await _load();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFF0E1211),
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        title: Text(widget.playlistName),
        actions: [
          IconButton(
            icon: const Icon(Icons.play_arrow_rounded, color: Color(0xFFB8D4D0)),
            tooltip: '播放全部',
            onPressed: _songs.isEmpty ? null : () => _play(0),
          ),
        ],
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : _songs.isEmpty
              ? _buildEmpty()
              : ListView.builder(
                  padding:
                      const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                  itemCount: _songs.length,
                  itemBuilder: (context, index) {
                    final song = _songs[index];
                    return ListTile(
                      contentPadding:
                          const EdgeInsets.symmetric(horizontal: 4),
                      visualDensity: VisualDensity.compact,
                      leading: SongArtwork(
                        filePath: song.artworkPath,
                        size: 44,
                        fallbackIcon: Icons.music_note,
                      ),
                      title: Text(
                        song.title,
                        style:
                            const TextStyle(color: Colors.white, fontSize: 16),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                      ),
                      subtitle: Text(
                        song.artist,
                        style: const TextStyle(color: Colors.grey, fontSize: 13),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                      ),
                      trailing: IconButton(
                        icon: const Icon(Icons.close,
                            color: Colors.white24, size: 18),
                        tooltip: '从歌单移除',
                        onPressed: () => _remove(song),
                      ),
                      onTap: () => _play(index),
                    );
                  },
                ),
    );
  }

  Widget _buildEmpty() {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(Icons.music_off_outlined, size: 44, color: Colors.grey[700]),
          const SizedBox(height: 14),
          Text(
            '歌单还是空的',
            style: TextStyle(color: Colors.grey[500], fontSize: 15),
          ),
          const SizedBox(height: 6),
          Text(
            '在文件列表长按歌曲即可加入',
            style: TextStyle(color: Colors.grey[700], fontSize: 12),
          ),
        ],
      ),
    );
  }
}