新增本地自动备份

lib/utils/auto_backup_service.dart

@@ -0,0 +1,216 @@
+import 'dart:async';
+import 'dart:io';
+import 'package:path_provider/path_provider.dart';
+import 'package:path/path.dart' as path;
+import 'package:shared_preferences/shared_preferences.dart';
+import 'backup_service.dart';
+
+/// 自动备份服务 - 定时自动备份到下载目录
+class AutoBackupService {
+  static final AutoBackupService instance = AutoBackupService._init();
+  
+  AutoBackupService._init();
+  
+  Timer? _timer;
+  bool _isRunning = false;
+  
+  static const String _prefsKey = 'auto_backup_enabled';
+  static const String _backupDirName = 'mooknote';
+  static const int _maxBackups = 10;
+  static const Duration _backupInterval = Duration(minutes: 2);
+  
+  /// 是否正在运行
+  bool get isRunning => _isRunning;
+  
+  /// 获取自动备份状态
+  Future<bool> getEnabled() async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.getBool(_prefsKey) ?? false;
+  }
+  
+  /// 设置自动备份状态
+  Future<void> setEnabled(bool enabled) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setBool(_prefsKey, enabled);
+    
+    if (enabled) {
+      await start();
+    } else {
+      await stop();
+    }
+  }
+  
+  /// 启动自动备份
+  Future<void> start() async {
+    if (_isRunning) return;
+    
+    // 立即执行一次备份
+    await _performBackup();
+    
+    // 启动定时器
+    _timer = Timer.periodic(_backupInterval, (_) async {
+      await _performBackup();
+    });
+    
+    _isRunning = true;
+  }
+  
+  /// 停止自动备份
+  Future<void> stop() async {
+    _timer?.cancel();
+    _timer = null;
+    _isRunning = false;
+  }
+  
+  /// 执行备份
+  Future<void> _performBackup() async {
+    try {
+      final backupDir = await _getBackupDirectory();
+      if (backupDir == null) {
+        print('AutoBackup: 无法获取备份目录');
+        return;
+      }
+      
+      // 确保备份目录存在
+      if (!await backupDir.exists()) {
+        await backupDir.create(recursive: true);
+      }
+      
+      // 导出数据
+      final result = await BackupService.instance.exportDataForAutoBackup();
+      
+      if (!result.success) {
+        print('AutoBackup: 导出失败 - ${result.errorMessage}');
+        return;
+      }
+      
+      // 生成备份文件名
+      final fileName = 'auto_backup_${_formatDateTime(DateTime.now())}.zip';
+      final backupFile = File(path.join(backupDir.path, fileName));
+      
+      // 写入备份文件
+      await backupFile.writeAsBytes(result.zipBytes!);
+      
+      print('AutoBackup: 备份成功 - ${backupFile.path}');
+      
+      // 清理旧备份，只保留最新的10个
+      await _cleanupOldBackups(backupDir);
+      
+    } catch (e) {
+      print('AutoBackup: 备份失败 - $e');
+    }
+  }
+  
+  /// 获取备份目录（下载目录/mooknote）
+  Future<Directory?> _getBackupDirectory() async {
+    try {
+      // 尝试获取下载目录
+      Directory? downloadDir;
+      
+      if (Platform.isAndroid) {
+        // Android: 使用外部存储的下载目录
+        final externalDir = await getExternalStorageDirectory();
+        if (externalDir != null) {
+          // 通常路径是 /storage/emulated/0/Android/data/.../files
+          // 我们需要找到真正的下载目录
+          final path = externalDir.path;
+          final downloadPath = path.replaceAll(
+            '/Android/data/${externalDir.uri.pathSegments[externalDir.uri.pathSegments.length - 3]}/files',
+            '/Download',
+          );
+          downloadDir = Directory('$downloadPath/$_backupDirName');
+        }
+      } else if (Platform.isIOS) {
+        // iOS: 使用文档目录
+        final docDir = await getApplicationDocumentsDirectory();
+        downloadDir = Directory('${docDir.path}/$_backupDirName');
+      } else {
+        // 桌面端: 使用下载目录
+        final home = Platform.environment['HOME'] ?? Platform.environment['USERPROFILE'];
+        if (home != null) {
+          downloadDir = Directory('$home/Downloads/$_backupDirName');
+        }
+      }
+      
+      return downloadDir;
+    } catch (e) {
+      print('AutoBackup: 获取备份目录失败 - $e');
+      return null;
+    }
+  }
+  
+  /// 清理旧备份，只保留最新的10个
+  Future<void> _cleanupOldBackups(Directory backupDir) async {
+    try {
+      final files = await backupDir
+          .list()
+          .where((entity) => entity is File && entity.path.endsWith('.zip'))
+          .cast<File>()
+          .toList();
+      
+      // 按修改时间排序（最新的在前）
+      files.sort((a, b) {
+        final aStat = a.statSync();
+        final bStat = b.statSync();
+        return bStat.modified.compareTo(aStat.modified);
+      });
+      
+      // 删除超过10个的旧备份
+      if (files.length > _maxBackups) {
+        for (var i = _maxBackups; i < files.length; i++) {
+          try {
+            await files[i].delete();
+            print('AutoBackup: 删除旧备份 - ${files[i].path}');
+          } catch (e) {
+            print('AutoBackup: 删除旧备份失败 - $e');
+          }
+        }
+      }
+    } catch (e) {
+      print('AutoBackup: 清理旧备份失败 - $e');
+    }
+  }
+  
+  /// 获取备份文件列表
+  Future<List<File>> getBackupFiles() async {
+    try {
+      final backupDir = await _getBackupDirectory();
+      if (backupDir == null || !await backupDir.exists()) {
+        return [];
+      }
+      
+      final files = await backupDir
+          .list()
+          .where((entity) => entity is File && entity.path.endsWith('.zip'))
+          .cast<File>()
+          .toList();
+      
+      // 按修改时间排序（最新的在前）
+      files.sort((a, b) {
+        final aStat = a.statSync();
+        final bStat = b.statSync();
+        return bStat.modified.compareTo(aStat.modified);
+      });
+      
+      return files;
+    } catch (e) {
+      print('AutoBackup: 获取备份列表失败 - $e');
+      return [];
+    }
+  }
+  
+  /// 获取备份目录路径
+  Future<String?> getBackupDirectoryPath() async {
+    final dir = await _getBackupDirectory();
+    return dir?.path;
+  }
+  
+  /// 格式化日期时间用于文件名
+  String _formatDateTime(DateTime dateTime) {
+    return '${dateTime.year}${_pad(dateTime.month)}${_pad(dateTime.day)}_${_pad(dateTime.hour)}${_pad(dateTime.minute)}${_pad(dateTime.second)}';
+  }
+  
+  String _pad(int number) {
+    return number.toString().padLeft(2, '0');
+  }
+}