flutter_appfx/lib/utils/deviceUuid.dart

// device_info_plus 中 androidInfo.androidId 被移除，无法获取跨应用的设备唯一标识
// 为了代码一致性，iOS 端也不使用 iosInfo.identifierForVendor
// 统一使用 uuid.dart 来随机生成

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

class DeviceUuid {
  static const String _uuidKey = 'device_uuid';
  static String? _cachedUuid;

  // 获取或创建 UUID
  static Future<String> getUuid() async {
    if (_cachedUuid != null) {
      return _cachedUuid!;
    }

    final prefs = await SharedPreferences.getInstance();
    String? storedUuid = prefs.getString(_uuidKey);

    if (storedUuid == null || storedUuid.isEmpty) {
      storedUuid = _generateAndStoreUuid(prefs);
    }

    _cachedUuid = storedUuid;
    return storedUuid;
  }

  // 生成并存储新的 UUID
  static String _generateAndStoreUuid(SharedPreferences prefs) {
    final newUuid = const Uuid().v4();
    prefs.setString(_uuidKey, newUuid);
    return newUuid;
  }

  // 重置 UUID（用户选择重置隐私时使用）
  static Future<String> resetUuid() async {
    final prefs = await SharedPreferences.getInstance();
    _cachedUuid = null;
    return _generateAndStoreUuid(prefs);
  }

  // 检查是否已有 UUID
  static Future<bool> hasUuid() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.containsKey(_uuidKey);
  }

  // 清除 UUID（用户注销时）
  static Future<void> clearUuid() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.remove(_uuidKey);
    _cachedUuid = null;
  }
}