import '../dto/backend.dart';
import '../models/auth.dart';
import '../models/session.dart';
import '../models/two_factor.dart';
import '../models/verification.dart';

abstract final class BackendMapper {
  static AuthResult signup(BackendDTO dto) {
    if (dto.userId.isEmpty) throw const FormatException('Missing user');
    return AuthResult(userId: dto.userId, isSimulated: false);
  }

  static FactorChallenge challenge(BackendDTO dto, String id) {
    if (dto.challengeId.isEmpty || dto.channel != 'email') {
      throw const FactorException(FactorError.unavailable);
    }
    return FactorChallenge(
      id: id,
      purpose: FactorPurpose.login,
      operation: id,
      target: dto.target,
      expiresAt: dto.expiresAt,
      resendAt: dto.resendAt,
    );
  }

  static AuthSession session(BackendDTO dto) {
    if (dto.accessToken.isEmpty || dto.userId.isEmpty) {
      throw const FormatException('Missing session');
    }
    return AuthSession(dto.userId, dto.accessToken, dto.refreshToken);
  }

  static AuthException authFailure(int status, BackendDTO dto) =>
      AuthException(switch (dto.error) {
        'email_in_use' => AuthError.emailInUse,
        'signup_attention_required' => AuthError.signupNeedsAssistance,
        'account_not_verified' => AuthError.accountNotVerified,
        _ when status == 401 => AuthError.invalidCredentials,
        _ when status == 429 => AuthError.factorCooldown,
        _ => AuthError.unavailable,
      });
  static VerificationException verificationFailure(BackendDTO dto) =>
      VerificationException(switch (dto.error) {
        'expired' => VerificationError.expired,
        'invalid' => VerificationError.invalid,
        'signup_attention_required' => VerificationError.needsAssistance,
        _ => VerificationError.internal,
      });
  static FactorException factorFailure(int status, BackendDTO dto) =>
      FactorException(switch (dto.error) {
        'expired' => FactorError.expired,
        'locked' => FactorError.locked,
        'invalid' => FactorError.invalid,
        _ when status == 429 => FactorError.cooldown,
        _ when status == 401 => FactorError.expired,
        _ => FactorError.unavailable,
      });
}