import 'dart:convert';
import 'package:shared_preferences/shared_preferences.dart';

/// 时间: 2026-03-30
/// 功能: 本地缓存管理器
/// 介绍: 管理应用的本地缓存数据，包括排行榜数据等
/// 最新变化: 新建本地缓存管理器

class LocalCacheManager {
  static final LocalCacheManager _instance = LocalCacheManager._internal();
  factory LocalCacheManager() => _instance;
  LocalCacheManager._internal();

  static const String _preloadEnabledKey = 'preload_enabled';
  static const String _popularListCachePrefix = 'popular_list_cache_';

  /// 获取预加载开关状态
  Future<bool> isPreloadEnabled() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.getBool(_preloadEnabledKey) ?? true;
  }

  /// 设置预加载开关状态
  Future<void> setPreloadEnabled(bool enabled) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setBool(_preloadEnabledKey, enabled);
  }

  /// 缓存排行榜数据
  Future<void> cachePopularList(
    String type,
    List<Map<String, dynamic>> data,
  ) async {
    final prefs = await SharedPreferences.getInstance();
    final key = _popularListCachePrefix + type;
    final jsonData = jsonEncode(data);
    await prefs.setString(key, jsonData);

    final timestampKey = '${key}_timestamp';
    await prefs.setInt(timestampKey, DateTime.now().millisecondsSinceEpoch);
  }

  /// 获取缓存的排行榜数据
  Future<List<Map<String, dynamic>>?> getCachedPopularList(String type) async {
    final prefs = await SharedPreferences.getInstance();
    final key = _popularListCachePrefix + type;
    final jsonData = prefs.getString(key);

    if (jsonData == null) {
      return null;
    }

    try {
      final decoded = jsonDecode(jsonData);
      if (decoded is List) {
        return decoded.cast<Map<String, dynamic>>();
      }
    } catch (e) {
      print('解析缓存数据失败: $e');
    }

    return null;
  }

  /// 获取缓存时间戳
  Future<int?> getCacheTimestamp(String type) async {
    final prefs = await SharedPreferences.getInstance();
    final key = '${_popularListCachePrefix}${type}_timestamp';
    return prefs.getInt(key);
  }

  /// 清除指定类型的缓存
  Future<void> clearCache(String type) async {
    final prefs = await SharedPreferences.getInstance();
    final key = _popularListCachePrefix + type;
    await prefs.remove(key);
    await prefs.remove('${key}_timestamp');
  }

  /// 清除所有排行榜缓存
  Future<void> clearAllPopularCache() async {
    final prefs = await SharedPreferences.getInstance();
    final keys = prefs.getKeys();
    for (final key in keys) {
      if (key.startsWith(_popularListCachePrefix)) {
        await prefs.remove(key);
      }
    }
  }
}