/// 在线会话/设备（对应后端 service.SessionView）。
class DeviceSession {
  final int id;
  final int userId;
  final String username;
  final String realName;
  final String platform;
  final String platformClass;
  final String deviceName;
  final String ip;
  final DateTime? createdAt;
  final DateTime? lastSeenAt;
  final bool online;
  final bool isCurrent;

  const DeviceSession({
    required this.id,
    required this.userId,
    required this.username,
    required this.realName,
    required this.platform,
    required this.platformClass,
    required this.deviceName,
    required this.ip,
    required this.createdAt,
    required this.lastSeenAt,
    required this.online,
    required this.isCurrent,
  });

  factory DeviceSession.fromJson(Map<String, dynamic> json) {
    DateTime? parse(String? s) =>
        (s == null || s.isEmpty) ? null : DateTime.tryParse(s)?.toLocal();
    return DeviceSession(
      id: (json['id'] as num).toInt(),
      userId: (json['user_id'] as num?)?.toInt() ?? 0,
      username: json['username'] as String? ?? '',
      realName: json['real_name'] as String? ?? '',
      platform: json['platform'] as String? ?? '',
      platformClass: json['platform_class'] as String? ?? '',
      deviceName: json['device_name'] as String? ?? '',
      ip: json['ip'] as String? ?? '',
      createdAt: parse(json['created_at'] as String?),
      lastSeenAt: parse(json['last_seen_at'] as String?),
      online: json['online'] as bool? ?? false,
      isCurrent: json['is_current'] as bool? ?? false,
    );
  }

  /// 平台中文显示名。
  String get platformLabel {
    switch (platform) {
      case 'windows':
        return 'Windows';
      case 'macos':
        return 'macOS';
      case 'linux':
        return 'Linux';
      case 'android':
        return 'Android';
      case 'ios':
        return 'iOS';
      case 'web':
        return '网页版';
      default:
        return platform.isEmpty ? '未知' : platform;
    }
  }

  /// 平台类中文显示名。
  String get platformClassLabel {
    switch (platformClass) {
      case 'desktop':
        return '桌面端';
      case 'mobile':
        return '移动端';
      case 'web':
        return '网页端';
      default:
        return platformClass;
    }
  }
}