class OtaConfigResp {
  // 单例实例
  static OtaConfigResp? _instance;

  // 单例访问器（增加空安全保护）
  static OtaConfigResp get instance {
    if (_instance == null) {
      throw Exception("User must be initialized first");
    }
    return _instance!;
  }

  // 最终属性（不可变）
  final String? id;
  final String? factory;
  final String? equipmentname;
  final String? systemversion;
  final String? updatepackageaddress;
  // 私有构造函数
  OtaConfigResp._({
    this.id,
    this.factory,
    this.equipmentname,
    this.systemversion,
    this.updatepackageaddress,
  });

  factory OtaConfigResp.fromJson(Map<String, dynamic> json) {
    print("数据获取fronTokenJson${json}");
    // 修复1：安全获取嵌套的 user 字段
    final infoData = json['info'] as Map<String, dynamic>?; // 允许空值

    // 更新单例实例
    return _instance = OtaConfigResp._(
      id: (infoData?['id'] as String?) ?? '',
      factory: (infoData?['factory'] as String?) ?? '',
      equipmentname: (infoData?['equipmentname'] as String?) ?? '',
      systemversion: (infoData?['systemversion'] as String?) ?? '',
      updatepackageaddress:
          (infoData?['updatepackageaddress'] as String?) ?? '',
    );
  }

  // 完整的JSON序列化
  Map<String, dynamic> toJson() => {
        'user': {
          'id': instance.id,
          'factory': instance.factory,
          'equipmentname': instance.equipmentname,
          'systemversion': instance.systemversion,
          'updatepackageaddress': instance.updatepackageaddress,
        }
      };
}