xianyan/lib/features/file_transfer/services/cache_manager_service.dart

// ============================================================
// 闲言APP — 缓存管理服务
// 创建时间: 2026-05-09
// 更新时间: 2026-05-09
// 作用: 传输缓存管理 — 缩略图/临时文件/传输记录清理
// 上次更新: 初始版本
// ============================================================

import 'dart:io';

import 'package:path_provider/path_provider.dart';
import 'package:xianyan/core/utils/logger.dart';

import '../database/transfer_database.dart';

class CacheCategory {
  const CacheCategory({
    required this.name,
    required this.emoji,
    required this.directory,
  });

  final String name;
  final String emoji;
  final String directory;
}

class CacheInfo {
  const CacheInfo({
    required this.category,
    required this.size,
    required this.fileCount,
  });

  final CacheCategory category;
  final int size;
  final int fileCount;

  String get sizeText => _formatSize(size);

  static String _formatSize(int bytes) {
    if (bytes < 1024) return '$bytes B';
    if (bytes < 1024 * 1024) return '${(bytes / 1024).toStringAsFixed(1)} KB';
    if (bytes < 1024 * 1024 * 1024)
      return '${(bytes / (1024 * 1024)).toStringAsFixed(1)} MB';
    return '${(bytes / (1024 * 1024 * 1024)).toStringAsFixed(1)} GB';
  }
}

class CacheManagerService {
  CacheManagerService();

  static const List<CacheCategory> categories = [
    CacheCategory(name: '缩略图', emoji: '🖼️', directory: 'thumbnails'),
    CacheCategory(name: '临时文件', emoji: '📁', directory: 'temp'),
    CacheCategory(name: '传输记录', emoji: '📋', directory: 'records'),
    CacheCategory(name: '接收文件', emoji: '📥', directory: 'received'),
  ];

  Future<String> _getBasePath() async {
    final dir = await getApplicationSupportDirectory();
    return '${dir.path}${Platform.pathSeparator}file_transfer';
  }

  Future<Directory> _getCategoryDir(CacheCategory category) async {
    final basePath = await _getBasePath();
    final dir = Directory(
      '$basePath${Platform.pathSeparator}${category.directory}',
    );
    if (!await dir.exists()) {
      await dir.create(recursive: true);
    }
    return dir;
  }

  Future<List<CacheInfo>> getAllCacheInfo() async {
    final infos = <CacheInfo>[];
    for (final category in categories) {
      final info = await getCacheInfo(category);
      infos.add(info);
    }
    return infos;
  }

  Future<CacheInfo> getCacheInfo(CacheCategory category) async {
    try {
      final dir = await _getCategoryDir(category);
      int totalSize = 0;
      int fileCount = 0;

      await for (final entity in dir.list(recursive: true)) {
        if (entity is File) {
          try {
            totalSize += await entity.length();
            fileCount++;
          } catch (_) {}
        }
      }

      return CacheInfo(
        category: category,
        size: totalSize,
        fileCount: fileCount,
      );
    } catch (e) {
      Log.w('CacheManager: Failed to get info for ${category.name}: $e');
      return CacheInfo(category: category, size: 0, fileCount: 0);
    }
  }

  Future<int> getTotalCacheSize() async {
    final infos = await getAllCacheInfo();
    return infos.fold<int>(0, (sum, info) => sum + info.size);
  }

  Future<void> clearCategory(CacheCategory category) async {
    try {
      final dir = await _getCategoryDir(category);
      await for (final entity in dir.list()) {
        if (entity is File) {
          await entity.delete();
        } else if (entity is Directory) {
          await entity.delete(recursive: true);
        }
      }
      Log.i('CacheManager: Cleared ${category.name}');
    } catch (e) {
      Log.e('CacheManager: Failed to clear ${category.name}: $e');
    }
  }

  Future<void> clearAll() async {
    for (final category in categories) {
      await clearCategory(category);
    }
    Log.i('CacheManager: All caches cleared');
  }

  Future<void> cleanOldRecords({int keepDays = 30}) async {
    await TransferDatabase.instance.cleanOldRecords(keepDays);
    Log.i('CacheManager: Old records cleaned (keep $keepDays days)');
  }

  Future<String> getSavePath(String fileName, {String? subDir}) async {
    final basePath = await _getBasePath();
    final dir = subDir != null
        ? '$basePath${Platform.pathSeparator}$subDir'
        : '$basePath${Platform.pathSeparator}received';
    final directory = Directory(dir);
    if (!await directory.exists()) {
      await directory.create(recursive: true);
    }
    return '$dir${Platform.pathSeparator}$fileName';
  }

  Future<String> getThumbnailPath(String fileName) async {
    return await getSavePath(fileName, subDir: 'thumbnails');
  }

  Future<String> getTempPath(String fileName) async {
    return await getSavePath(fileName, subDir: 'temp');
  }
}