// 认证令牌模型 — 匹配后端 LoginResp
//
// 管理访问令牌和刷新令牌，支持自动计算过期时间。
// 令牌通过 flutter_secure_storage 安全持久化（PIPL 合规要求）。

/// 认证令牌 — 包含访问令牌、刷新令牌和过期信息
class AuthToken {
  final String accessToken;
  final String refreshToken;
  final int expiresIn;
  final DateTime expiresAt;

  const AuthToken({
    required this.accessToken,
    required this.refreshToken,
    required this.expiresIn,
    required this.expiresAt,
  });

  /// 令牌是否已过期
  bool get isExpired => DateTime.now().isAfter(expiresAt);

  /// 令牌是否即将过期（5 分钟内）
  bool get isExpiringSoon =>
      DateTime.now().isAfter(expiresAt.subtract(const Duration(minutes: 5)));

  /// 从后端 LoginResp JSON 创建
  factory AuthToken.fromJson(Map<String, dynamic> json) {
    final expiresIn = (json['expires_in'] as int?) ?? 3600;
    return AuthToken(
      accessToken: json['access_token'] as String,
      refreshToken: json['refresh_token'] as String,
      expiresIn: expiresIn,
      expiresAt: DateTime.now().add(Duration(seconds: expiresIn)),
    );
  }

  Map<String, dynamic> toJson() => {
        'access_token': accessToken,
        'refresh_token': refreshToken,
        'expires_in': expiresIn,
        'expires_at': expiresAt.toIso8601String(),
      };

  /// 从持久化存储恢复（使用保存的过期时间）
  factory AuthToken.fromStorage(Map<String, dynamic> json) => AuthToken(
        accessToken: json['access_token'] as String,
        refreshToken: json['refresh_token'] as String,
        expiresIn: (json['expires_in'] as int?) ?? 3600,
        expiresAt: json['expires_at'] != null
            ? DateTime.parse(json['expires_at'] as String)
            : DateTime.now().add(const Duration(hours: 1)),
      );
}