flutter_taglib 1.0.3

A high-performance Flutter plugin wrapping TagLib using Dart FFI and Native Assets to read/write audio metadata and properties.

example/lib/main.dart

import 'dart:async';
import 'dart:io';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter_taglib/flutter_taglib.dart';
import 'package:file_picker/file_picker.dart';
import 'package:logging/logging.dart';

void main() {
  Logger.root.level = Level.ALL;
  Logger.root.onRecord.listen((record) {
    debugPrint(
      '[${record.level.name}] ${record.loggerName}: ${record.message}',
    );
    if (record.error != null) {
      debugPrint('error=${record.error}');
    }
    if (record.stackTrace != null) {
      debugPrint('${record.stackTrace}');
    }
  });
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'TagLib Metadata Editor',
      theme: ThemeData.dark().copyWith(
        primaryColor: const Color(0xFF6366F1),
        scaffoldBackgroundColor: const Color(
          0xFF0F172A,
        ), // Slate 900 equivalent
        cardColor: const Color(0xFF1E293B), // Slate 800 equivalent
        colorScheme: const ColorScheme.dark(
          primary: Color(0xFF6366F1), // Indigo 500
          secondary: Color(0xFF10B981), // Emerald 500
          surface: Color(0xFF1E293B),
        ),
        inputDecorationTheme: InputDecorationTheme(
          filled: true,
          fillColor: const Color(0xFF334155), // Slate 700 equivalent
          labelStyle: TextStyle(color: Colors.grey.shade300),
          border: OutlineInputBorder(
            borderRadius: BorderRadius.circular(8),
            borderSide: BorderSide.none,
          ),
          focusedBorder: OutlineInputBorder(
            borderRadius: BorderRadius.circular(8),
            borderSide: const BorderSide(color: Color(0xFF6366F1), width: 2),
          ),
        ),
      ),
      home: const MetadataEditorScreen(),
      debugShowCheckedModeBanner: false,
    );
  }
}

class MetadataEditorScreen extends StatefulWidget {
  const MetadataEditorScreen({super.key});

  @override
  State<MetadataEditorScreen> createState() => _MetadataEditorScreenState();
}

class _MetadataEditorScreenState extends State<MetadataEditorScreen> {
  String? _filePath;
  String? _fileName;
  String? _fileDirectoryPath;
  PickedAudioFile? _pickedAudioFile;
  TagLibFile? _tagLibFile;
  String? _errorMessage;
  bool _isSaving = false;
  bool _isCheckingDirectoryAccess = false;
  bool _isAuthorizingDirectory = false;
  bool _hasDirectoryWriteAccess = true;
  AuthorizedDirectory? _authorizedDirectory;

  // Controllers for tag fields
  final titleController = TextEditingController();
  final artistController = TextEditingController();
  final albumController = TextEditingController();
  final genreController = TextEditingController();
  final yearController = TextEditingController();
  final trackController = TextEditingController();

  // Cover Art state
  Uint8List? _customCoverBytes;
  String? _customCoverMimeType;
  bool _coverChanged = false;

  @override
  void initState() {
    super.initState();
    // Auto-load test asset if available locally
    _loadDemoAsset();
  }

  @override
  void dispose() {
    unawaited(_releaseDirectoryAccess());
    _tagLibFile?.close();
    titleController.dispose();
    artistController.dispose();
    albumController.dispose();
    genreController.dispose();
    yearController.dispose();
    trackController.dispose();
    super.dispose();
  }

  /// Attempts to find and copy the project's test MP3 file as a default demo
  void _loadDemoAsset() {
    // Relative path to test file when running from the example directory
    final localPath = '../test/assets/01 TempleOS Hymn Risen (Remix).mp3';
    final localFile = File(localPath);
    if (localFile.existsSync()) {
      // Create a temporary copy to avoid editing the shared test assets directly
      try {
        final tempDir = Directory.systemTemp.createTempSync(
          'taglib_demo_flutter',
        );
        final tempMp3File = File('${tempDir.path}/demo_song.mp3');
        localFile.copySync(tempMp3File.path);
        _loadFile(tempMp3File.path);
      } catch (e) {
        debugPrint('Failed to copy default demo asset: $e');
      }
    }
  }

  /// Opens the file using TagLibFile and updates the state controllers
  Future<void> _loadFile(
    String path, {
    String? name,
    PickedAudioFile? pickedAudioFile,
  }) async {
    _tagLibFile?.close();
    debugPrint('TagLib _loadFile start path=$path name=$name');

    TagLibFile.resetSupportCache();

    TagLibFile? file;
    try {
      file = await TagLibFile.openAsync(path);
    } catch (e, stackTrace) {
      final diagnostics = await TagLibFile.collectDiagnostics();
      debugPrint('TagLib openAsync threw: $e');
      debugPrint('$stackTrace');
      debugPrint('TagLib diagnostics: $diagnostics');
      rethrow;
    }

    if (file == null) {
      final diagnostics = await TagLibFile.collectDiagnostics();
      debugPrint('TagLib openAsync returned null. diagnostics=$diagnostics');
      setState(() {
        _filePath = null;
        _fileName = null;
        _fileDirectoryPath = null;
        _pickedAudioFile = null;
        _tagLibFile = null;
        _errorMessage =
            'Failed to open file. The audio format may not be supported by TagLib.';
        _hasDirectoryWriteAccess = true;
        _authorizedDirectory = null;
        _isCheckingDirectoryAccess = false;
      });
      return;
    }
    final openedFile = file;

    final sourcePath = pickedAudioFile?.originalPath ?? path;
    final directoryPath = Platform.isIOS && !sourcePath.startsWith('content://')
        ? File(sourcePath).parent.path
        : null;
    AuthorizedDirectory? restoredDirectoryAccess;

    if (Platform.isIOS && directoryPath != null) {
      try {
        restoredDirectoryAccess = await TagLibFile.restoreAuthorizedDirectory(
          directoryPath,
        );
      } catch (e) {
        debugPrint('Failed to restore directory access for $directoryPath: $e');
      }
    }

    if (_authorizedDirectory != null &&
        directoryPath != null &&
        !_isSameDirectoryOrAncestor(
          _authorizedDirectory!.path,
          directoryPath,
        )) {
      await _releaseDirectoryAccess();
    }

    setState(() {
      _filePath = path;
      _pickedAudioFile = pickedAudioFile;
      _fileName =
          name ??
          (path.startsWith('content://')
              ? 'Android Audio File'
              : File(path).path.split(Platform.pathSeparator).last);
      _fileDirectoryPath = directoryPath;
      _tagLibFile = openedFile;
      _errorMessage = null;
      _coverChanged = false;
      _customCoverBytes = openedFile.coverData;
      _customCoverMimeType = openedFile.coverMimeType;
      _hasDirectoryWriteAccess =
          restoredDirectoryAccess != null ||
          !Platform.isIOS ||
          directoryPath == null;
      _authorizedDirectory = restoredDirectoryAccess;
      _isCheckingDirectoryAccess = Platform.isIOS && directoryPath != null;

      titleController.text = openedFile.title;
      artistController.text = openedFile.artist;
      albumController.text = openedFile.album;
      genreController.text = openedFile.genre;
      yearController.text = openedFile.year == 0
          ? ''
          : openedFile.year.toString();
      trackController.text = openedFile.track == 0
          ? ''
          : openedFile.track.toString();
    });

    if (directoryPath != null) {
      final hasAccess = await _checkDirectoryWriteAccess(directoryPath);
      if (!mounted || _filePath != path) return;
      setState(() {
        _hasDirectoryWriteAccess = hasAccess;
        _isCheckingDirectoryAccess = false;
        if (!hasAccess) {
          _errorMessage = '当前原目录没有编辑权限，请先授权该目录。';
        }
      });
    }
  }

  /// Lets the user select an audio file using FilePicker
  Future<void> _pickAudioFile() async {
    try {
      if (Platform.isIOS) {
        final result = await TagLibFile.pickAudioFileForEditing();
        if (result != null) {
          await _loadFile(
            result.path,
            name: result.name,
            pickedAudioFile: result,
          );
        }
        return;
      }

      final result = await FilePicker.pickFiles(type: FileType.audio);

      if (result != null) {
        final file = result.files.single;
        final path = (Platform.isAndroid && file.identifier != null)
            ? file.identifier!
            : file.path;
        if (path != null) {
          await _loadFile(path, name: file.name);
        }
      }
    } catch (e) {
      final diagnostics = await TagLibFile.collectDiagnostics();
      debugPrint('Error picking file: $e');
      debugPrint('TagLib diagnostics during pick: $diagnostics');
      setState(() {
        _errorMessage = 'Error picking file: $e\n$diagnostics';
      });
    }
  }

  Future<bool> _checkDirectoryWriteAccess(String directoryPath) async {
    if (!Platform.isIOS) return true;

    try {
      final directory = Directory(directoryPath);
      if (!await directory.exists()) return false;

      final probeFile = File(
        '${directory.path}${Platform.pathSeparator}.flutter_taglib_write_probe_${DateTime.now().microsecondsSinceEpoch}',
      );
      await probeFile.writeAsBytes(const <int>[], flush: true);
      await probeFile.delete();
      return true;
    } catch (e) {
      debugPrint('Directory access check failed for $directoryPath: $e');
      return false;
    }
  }

  Future<void> _authorizeOriginalDirectory() async {
    if (!Platform.isIOS || _fileDirectoryPath == null) return;

    setState(() {
      _isAuthorizingDirectory = true;
    });

    try {
      final directoryAccess = await TagLibFile.pickAuthorizedDirectory();
      if (directoryAccess == null) return;

      final authorizedPath = directoryAccess.path;
      if (authorizedPath.isEmpty) {
        throw StateError('未能解析授权目录路径。');
      }

      final matchesOriginalDirectory = _isSameDirectoryOrAncestor(
        authorizedPath,
        _fileDirectoryPath!,
      );

      if (!mounted) return;

      if (!matchesOriginalDirectory) {
        final messenger = ScaffoldMessenger.of(context);
        await directoryAccess.dispose();
        messenger.showSnackBar(
          const SnackBar(
            content: Text('请选择当前文件所在的原目录或其上级目录。'),
            backgroundColor: Colors.redAccent,
          ),
        );
        return;
      }

      await _releaseDirectoryAccess();
      if (!mounted) return;
      setState(() {
        _authorizedDirectory = directoryAccess;
        _hasDirectoryWriteAccess = true;
        _isCheckingDirectoryAccess = false;
        _errorMessage = null;
      });

      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('目录授权成功，可以直接保存到原文件。'),
          backgroundColor: Colors.green,
        ),
      );
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('目录授权失败：$e'), backgroundColor: Colors.redAccent),
      );
    } finally {
      if (mounted) {
        setState(() {
          _isAuthorizingDirectory = false;
        });
      }
    }
  }

  bool _isSameDirectoryOrAncestor(
    String candidateDirectory,
    String targetDirectory,
  ) {
    final normalizedCandidate = _normalizeDirectoryPath(candidateDirectory);
    final normalizedTarget = _normalizeDirectoryPath(targetDirectory);

    if (normalizedCandidate == normalizedTarget) {
      return true;
    }

    return normalizedTarget.startsWith(
      '$normalizedCandidate${Platform.pathSeparator}',
    );
  }

  String _normalizeDirectoryPath(String path) {
    var normalized = path.replaceAll('\\', Platform.pathSeparator);
    while (normalized.length > 1 &&
        normalized.endsWith(Platform.pathSeparator)) {
      normalized = normalized.substring(0, normalized.length - 1);
    }
    return normalized;
  }

  Future<void> _releaseDirectoryAccess() async {
    final directoryAccess = _authorizedDirectory;
    if (directoryAccess == null || !Platform.isIOS) return;

    _authorizedDirectory = null;
    try {
      await directoryAccess.dispose();
    } catch (e) {
      debugPrint(
        'Failed to stop accessing directory ${directoryAccess.path}: $e',
      );
    }
  }

  /// Lets the user pick an image file to set as the album cover art
  Future<void> _pickCoverImage() async {
    if (_tagLibFile == null) return;
    try {
      final result = await FilePicker.pickFiles(type: FileType.image);

      if (result != null && result.files.single.path != null) {
        final path = result.files.single.path!;
        final bytes = await File(path).readAsBytes();

        String mimeType = 'image/jpeg';
        if (path.toLowerCase().endsWith('.png')) {
          mimeType = 'image/png';
        } else if (path.toLowerCase().endsWith('.gif')) {
          mimeType = 'image/gif';
        }

        setState(() {
          _customCoverBytes = bytes;
          _customCoverMimeType = mimeType;
          _coverChanged = true;
        });
      }
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Error picking image: $e')));
    }
  }

  /// Removes the cover art
  void _removeCoverImage() {
    setState(() {
      _customCoverBytes = null;
      _customCoverMimeType = null;
      _coverChanged = true;
    });
  }

  /// Saves the updated metadata back to the audio file
  Future<void> _saveChanges() async {
    if (_tagLibFile == null) return;

    setState(() {
      _isSaving = true;
    });

    try {
      // Request write access (handles Android permissions and reopens in read-write mode)
      final hasWriteAccess = await _tagLibFile!.requestWriteAccess();
      if (!hasWriteAccess) {
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Failed to save: Write permission denied.'),
            backgroundColor: Colors.redAccent,
          ),
        );
        setState(() {
          _isSaving = false;
        });
        return;
      }

      // Set updated tag fields
      _tagLibFile!.title = titleController.text;
      _tagLibFile!.artist = artistController.text;
      _tagLibFile!.album = albumController.text;
      _tagLibFile!.genre = genreController.text;
      _tagLibFile!.year = int.tryParse(yearController.text) ?? 0;
      _tagLibFile!.track = int.tryParse(trackController.text) ?? 0;

      // Set cover art if modified
      if (_coverChanged) {
        _tagLibFile!.setCover(
          data: _customCoverBytes,
          mimeType: _customCoverMimeType ?? 'image/jpeg',
        );
      }

      final success = _tagLibFile!.save();

      if (!mounted) return;

      if (success) {
        if (Platform.isIOS &&
            _pickedAudioFile != null &&
            _pickedAudioFile!.needsCommit) {
          await _pickedAudioFile!.commit();
          if (!mounted) return;
        }
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Metadata saved successfully!'),
            backgroundColor: Colors.green,
          ),
        );
        // Reload metadata to confirm it writes/reads correctly
        await _loadFile(
          _tagLibFile!.path,
          name: _fileName,
          pickedAudioFile: _pickedAudioFile,
        );
      } else {
        if (Platform.isIOS && !_hasDirectoryWriteAccess) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text('当前目录没有写权限，请先授权原目录后再保存。'),
              backgroundColor: Colors.redAccent,
            ),
          );
        } else {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text('Failed to save metadata.'),
              backgroundColor: Colors.redAccent,
            ),
          );
        }
      }
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Error saving changes: $e'),
          backgroundColor: Colors.redAccent,
        ),
      );
    } finally {
      setState(() {
        _isSaving = false;
      });
    }
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('TagLib Metadata Editor'),
        backgroundColor: const Color(0xFF1E293B),
        elevation: 0,
        actions: [
          IconButton(
            icon: const Icon(Icons.folder_open),
            tooltip: 'Open Audio File',
            onPressed: _pickAudioFile,
          ),
        ],
      ),
      body: SafeArea(
        child: Column(
          children: [
            // Top banner or warning
            if (_errorMessage != null)
              Container(
                color: Colors.redAccent.withAlpha(51),
                padding: const EdgeInsets.symmetric(
                  vertical: 12,
                  horizontal: 16,
                ),
                width: double.infinity,
                child: Row(
                  children: [
                    const Icon(Icons.error_outline, color: Colors.redAccent),
                    const SizedBox(width: 12),
                    Expanded(
                      child: Text(
                        _errorMessage!,
                        style: const TextStyle(color: Colors.redAccent),
                      ),
                    ),
                  ],
                ),
              ),

            Expanded(
              child: _tagLibFile == null
                  ? _buildEmptyState()
                  : SingleChildScrollView(
                      padding: const EdgeInsets.all(24),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          _buildFileInfoBanner(),
                          const SizedBox(height: 16),
                          _buildDirectoryAuthorizationBanner(),
                          const SizedBox(height: 24),
                          LayoutBuilder(
                            builder: (context, constraints) {
                              if (constraints.maxWidth > 700) {
                                // Side-by-side layout for large screens
                                return Row(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    Expanded(
                                      flex: 2,
                                      child: _buildCoverArtSection(),
                                    ),
                                    const SizedBox(width: 32),
                                    Expanded(
                                      flex: 3,
                                      child: _buildFormSection(),
                                    ),
                                  ],
                                );
                              } else {
                                // Vertical layout for small screens
                                return Column(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    Center(
                                      child: ConstrainedBox(
                                        constraints: const BoxConstraints(
                                          maxWidth: 300,
                                        ),
                                        child: SizedBox(
                                          width: double.infinity,
                                          child: _buildCoverArtSection(),
                                        ),
                                      ),
                                    ),
                                    const SizedBox(height: 32),
                                    _buildFormSection(),
                                  ],
                                );
                              }
                            },
                          ),
                          const SizedBox(height: 24),
                          _buildAudioPropertiesSection(),
                          const SizedBox(
                            height: 100,
                          ), // Padding for the floating save button
                        ],
                      ),
                    ),
            ),
          ],
        ),
      ),
      floatingActionButton: _tagLibFile != null
          ? FloatingActionButton.extended(
              onPressed: _isSaving ? null : _saveChanges,
              backgroundColor: const Color(0xFF6366F1),
              foregroundColor: Colors.white,
              icon: _isSaving
                  ? const SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(
                        color: Colors.white,
                        strokeWidth: 2,
                      ),
                    )
                  : const Icon(Icons.save),
              label: Text(_isSaving ? 'Saving...' : 'Save Changes'),
            )
          : null,
    );
  }

  Widget _buildEmptyState() {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Container(
            padding: const EdgeInsets.all(24),
            decoration: BoxDecoration(
              color: const Color(0xFF1E293B),
              shape: BoxShape.circle,
              border: Border.all(color: const Color(0xFF334155), width: 2),
            ),
            child: Icon(
              Icons.music_note,
              size: 72,
              color: Colors.indigo.shade400,
            ),
          ),
          const SizedBox(height: 24),
          const Text(
            'No Audio File Loaded',
            style: TextStyle(fontSize: 22, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          Text(
            'Select a music file (MP3, FLAC, M4A, WAV, OGG) to view and edit metadata.',
            textAlign: TextAlign.center,
            style: TextStyle(color: Colors.grey.shade400, fontSize: 14),
          ),
          const SizedBox(height: 24),
          ElevatedButton.icon(
            onPressed: _pickAudioFile,
            style: ElevatedButton.styleFrom(
              backgroundColor: const Color(0xFF6366F1),
              foregroundColor: Colors.white,
              padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 14),
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(8),
              ),
            ),
            icon: const Icon(Icons.folder_open),
            label: const Text(
              'Select Audio File',
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildFileInfoBanner() {
    final fileName = _fileName ?? '';
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: const Color(0xFF1E293B),
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: const Color(0xFF334155)),
      ),
      child: LayoutBuilder(
        builder: (context, constraints) {
          final isNarrow = constraints.maxWidth < 520;

          final fileDetails = Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                fileName,
                style: const TextStyle(
                  fontWeight: FontWeight.bold,
                  fontSize: 16,
                ),
                overflow: TextOverflow.ellipsis,
              ),
              const SizedBox(height: 4),
              Text(
                _pickedAudioFile?.originalPath ?? _filePath ?? '',
                style: TextStyle(color: Colors.grey.shade400, fontSize: 12),
                overflow: TextOverflow.fade,
              ),
            ],
          );

          final actionButton = TextButton.icon(
            onPressed: _pickAudioFile,
            icon: const Icon(Icons.swap_horiz, size: 18),
            label: const Text('Change File'),
          );

          if (isNarrow) {
            return Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    Icon(
                      Icons.audio_file,
                      color: Colors.indigo.shade300,
                      size: 28,
                    ),
                    const SizedBox(width: 12),
                    Expanded(child: fileDetails),
                  ],
                ),
                const SizedBox(height: 12),
                Align(alignment: Alignment.centerLeft, child: actionButton),
              ],
            );
          }

          return Row(
            children: [
              Icon(Icons.audio_file, color: Colors.indigo.shade300, size: 28),
              const SizedBox(width: 16),
              Expanded(child: fileDetails),
              const SizedBox(width: 12),
              actionButton,
            ],
          );
        },
      ),
    );
  }

  Widget _buildDirectoryAuthorizationBanner() {
    if (!Platform.isIOS || _fileDirectoryPath == null) {
      return const SizedBox.shrink();
    }

    if (_isCheckingDirectoryAccess) {
      return Container(
        width: double.infinity,
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: const Color(0xFF1E293B),
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: const Color(0xFF334155)),
        ),
        child: const Row(
          children: [
            SizedBox(
              width: 16,
              height: 16,
              child: CircularProgressIndicator(strokeWidth: 2),
            ),
            SizedBox(width: 12),
            Text('正在检查原目录权限...'),
          ],
        ),
      );
    }

    if (_hasDirectoryWriteAccess) {
      return const SizedBox.shrink();
    }

    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: const Color(0xFF3B1D1D),
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: const Color(0xFFB91C1C)),
      ),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Icon(Icons.lock_outline, color: Color(0xFFF87171)),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                const Text(
                  '当前原目录没有编辑权限',
                  style: TextStyle(
                    fontSize: 15,
                    fontWeight: FontWeight.bold,
                    color: Color(0xFFFCA5A5),
                  ),
                ),
                const SizedBox(height: 4),
                Text(
                  '文件所在目录：$_fileDirectoryPath\n先授权这个目录，才能直接保存回原文件。',
                  style: TextStyle(
                    color: Colors.red.shade100,
                    fontSize: 13,
                    height: 1.35,
                  ),
                ),
                const SizedBox(height: 12),
                ElevatedButton.icon(
                  onPressed: _isAuthorizingDirectory
                      ? null
                      : _authorizeOriginalDirectory,
                  style: ElevatedButton.styleFrom(
                    backgroundColor: const Color(0xFFF97316),
                    foregroundColor: Colors.white,
                    padding: const EdgeInsets.symmetric(
                      horizontal: 16,
                      vertical: 12,
                    ),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(8),
                    ),
                  ),
                  icon: _isAuthorizingDirectory
                      ? const SizedBox(
                          width: 16,
                          height: 16,
                          child: CircularProgressIndicator(
                            color: Colors.white,
                            strokeWidth: 2,
                          ),
                        )
                      : const Icon(Icons.folder_shared),
                  label: Text(_isAuthorizingDirectory ? '正在授权...' : '授权原目录'),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildCoverArtSection() {
    return Card(
      elevation: 4,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
      child: Padding(
        padding: const EdgeInsets.all(20),
        child: Column(
          children: [
            // Cover Image
            AspectRatio(
              aspectRatio: 1.0,
              child: Container(
                decoration: BoxDecoration(
                  color: const Color(0xFF0F172A),
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(color: const Color(0xFF334155)),
                ),
                child: _customCoverBytes != null
                    ? ClipRRect(
                        borderRadius: BorderRadius.circular(12),
                        child: Image.memory(
                          _customCoverBytes!,
                          fit: BoxFit.cover,
                        ),
                      )
                    : Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          Icon(
                            Icons.album,
                            size: 80,
                            color: Colors.grey.shade600,
                          ),
                          const SizedBox(height: 12),
                          Text(
                            'No Cover Art',
                            style: TextStyle(
                              color: Colors.grey.shade400,
                              fontSize: 14,
                            ),
                          ),
                        ],
                      ),
              ),
            ),
            const SizedBox(height: 20),
            if (_customCoverBytes != null) ...[
              Text(
                'Mime-Type: ${_customCoverMimeType ?? "Unknown"}',
                style: TextStyle(color: Colors.grey.shade400, fontSize: 12),
              ),
              Text(
                'Size: ${(_customCoverBytes!.length / 1024).toStringAsFixed(1)} KB',
                style: TextStyle(color: Colors.grey.shade400, fontSize: 12),
              ),
              const SizedBox(height: 12),
            ],
            Wrap(
              alignment: WrapAlignment.center,
              spacing: 12,
              runSpacing: 12,
              children: [
                ElevatedButton.icon(
                  onPressed: _pickCoverImage,
                  style: ElevatedButton.styleFrom(
                    backgroundColor: const Color(0xFF334155),
                    foregroundColor: Colors.white,
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(8),
                    ),
                  ),
                  icon: const Icon(Icons.image, size: 18),
                  label: const Text('Change Art'),
                ),
                if (_customCoverBytes != null)
                  OutlinedButton.icon(
                    onPressed: _removeCoverImage,
                    style: OutlinedButton.styleFrom(
                      foregroundColor: Colors.redAccent,
                      side: const BorderSide(color: Colors.redAccent),
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(8),
                      ),
                    ),
                    icon: const Icon(Icons.delete_outline, size: 18),
                    label: const Text('Remove'),
                  ),
              ],
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildFormSection() {
    return Card(
      elevation: 4,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Metadata Info',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
                color: Color(0xFF818CF8),
              ),
            ),
            const Divider(color: Color(0xFF334155), height: 24),
            TextFormField(
              controller: titleController,
              decoration: const InputDecoration(
                labelText: 'Song Title',
                prefixIcon: Icon(Icons.title),
              ),
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: artistController,
              decoration: const InputDecoration(
                labelText: 'Artist',
                prefixIcon: Icon(Icons.person),
              ),
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: albumController,
              decoration: const InputDecoration(
                labelText: 'Album',
                prefixIcon: Icon(Icons.album),
              ),
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: genreController,
              decoration: const InputDecoration(
                labelText: 'Genre',
                prefixIcon: Icon(Icons.category),
              ),
            ),
            const SizedBox(height: 16),
            Row(
              children: [
                Expanded(
                  child: TextFormField(
                    controller: yearController,
                    keyboardType: TextInputType.number,
                    decoration: const InputDecoration(
                      labelText: 'Year',
                      prefixIcon: Icon(Icons.calendar_today),
                    ),
                  ),
                ),
                const SizedBox(width: 16),
                Expanded(
                  child: TextFormField(
                    controller: trackController,
                    keyboardType: TextInputType.number,
                    decoration: const InputDecoration(
                      labelText: 'Track #',
                      prefixIcon: Icon(Icons.music_note),
                    ),
                  ),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildAudioPropertiesSection() {
    if (_tagLibFile == null) return const SizedBox.shrink();

    final props = [
      _AudioPropertyItem(
        label: 'Duration',
        value: _formatDuration(_tagLibFile!.duration),
        icon: Icons.timer_outlined,
      ),
      _AudioPropertyItem(
        label: 'Bitrate',
        value: '${_tagLibFile!.bitrate} kbps',
        icon: Icons.speed_outlined,
      ),
      _AudioPropertyItem(
        label: 'Sample Rate',
        value: '${(_tagLibFile!.sampleRate / 1000).toStringAsFixed(1)} kHz',
        icon: Icons.graphic_eq_outlined,
      ),
      _AudioPropertyItem(
        label: 'Channels',
        value: _tagLibFile!.channels == 2
            ? 'Stereo (2ch)'
            : _tagLibFile!.channels == 1
            ? 'Mono (1ch)'
            : '${_tagLibFile!.channels} ch',
        icon: Icons.hearing_outlined,
      ),
    ];

    return Card(
      elevation: 4,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Technical Properties',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
                color: Color(0xFF34D399),
              ),
            ),
            const Divider(color: Color(0xFF334155), height: 24),
            LayoutBuilder(
              builder: (context, constraints) {
                final isCompact = constraints.maxWidth < 360;

                return GridView.builder(
                  shrinkWrap: true,
                  physics: const NeverScrollableScrollPhysics(),
                  gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
                    maxCrossAxisExtent: isCompact ? constraints.maxWidth : 220,
                    mainAxisExtent: 80,
                    mainAxisSpacing: 16,
                    crossAxisSpacing: 16,
                  ),
                  itemCount: props.length,
                  itemBuilder: (context, index) {
                    final prop = props[index];
                    return Container(
                      padding: const EdgeInsets.symmetric(
                        vertical: 12,
                        horizontal: 16,
                      ),
                      decoration: BoxDecoration(
                        color: const Color(0xFF0F172A),
                        borderRadius: BorderRadius.circular(12),
                        border: Border.all(color: const Color(0xFF334155)),
                      ),
                      child: Row(
                        children: [
                          Icon(
                            prop.icon,
                            color: const Color(0xFF34D399),
                            size: 24,
                          ),
                          const SizedBox(width: 12),
                          Expanded(
                            child: Column(
                              crossAxisAlignment: CrossAxisAlignment.start,
                              mainAxisAlignment: MainAxisAlignment.center,
                              children: [
                                Text(
                                  prop.label,
                                  maxLines: 1,
                                  overflow: TextOverflow.ellipsis,
                                  style: TextStyle(
                                    color: Colors.grey.shade400,
                                    fontSize: 11,
                                  ),
                                ),
                                const SizedBox(height: 2),
                                Text(
                                  prop.value,
                                  maxLines: 1,
                                  overflow: TextOverflow.ellipsis,
                                  style: const TextStyle(
                                    fontWeight: FontWeight.bold,
                                    fontSize: 14,
                                  ),
                                ),
                              ],
                            ),
                          ),
                        ],
                      ),
                    );
                  },
                );
              },
            ),
          ],
        ),
      ),
    );
  }
}

class _AudioPropertyItem {
  final String label;
  final String value;
  final IconData icon;

  _AudioPropertyItem({
    required this.label,
    required this.value,
    required this.icon,
  });
}