import '../../domain/entities/auth_user.dart';

/// Modelo de datos que extiende la entidad [AuthUser].
/// Responsable de serialización/deserialización JSON.
/// En la fase MVP el token se simula localmente (sin llamada real a backend).
class AuthUserModel extends AuthUser {
  const AuthUserModel({
    required super.token,
    required super.email,
    required super.role,
    required super.issuedAt,
    required super.expiresAt,
  });

  factory AuthUserModel.fromJson(Map<String, dynamic> json) {
    return AuthUserModel(
      token: json['token'] as String,
      email: json['email'] as String,
      role: json['role'] as String? ?? 'citizen',
      issuedAt: DateTime.parse(json['issued_at'] as String),
      expiresAt: DateTime.parse(json['expires_at'] as String),
    );
  }

  Map<String, dynamic> toJson() {
    return {
      'token': token,
      'email': email,
      'role': role,
      'issued_at': issuedAt.toIso8601String(),
      'expires_at': expiresAt.toIso8601String(),
    };
  }

  /// Crea un token JWT simulado para la fase MVP.
  /// En producción este token vendría del backend con firma RS256.
  factory AuthUserModel.simulatedJwt({
    required String email,
    required String role,
  }) {
    final now = DateTime.now();
    // Header.Payload.Signature — simulado con base64 simple
    final header = 'eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9';
    final payloadRaw =
        '{"sub":"usr_${email.hashCode.abs()}","email":"$email","role":"$role",'
        '"iat":${now.millisecondsSinceEpoch},'
        '"exp":${now.add(const Duration(hours: 8)).millisecondsSinceEpoch},'
        '"iss":"waste-notify-mvp"}';
    // ignore: deprecated_member_use
    final payload = _base64UrlEncode(payloadRaw);
    const signature = 'SIMULATED_SIGNATURE_MVP';

    return AuthUserModel(
      token: '$header.$payload.$signature',
      email: email,
      role: role,
      issuedAt: now,
      expiresAt: now.add(const Duration(hours: 8)),
    );
  }

  static String _base64UrlEncode(String input) {
    final bytes = input.codeUnits;
    final encoded = bytes
        .map((b) => b.toRadixString(16).padLeft(2, '0'))
        .join();
    return encoded.substring(0, encoded.length > 64 ? 64 : encoded.length);
  }
}