import { ErrorCode } from '../types/error-codes';
import { AppError, type ErrorContext } from './app-error';

type ServiceErrorCode =
  | ErrorCode.INTERNAL_ERROR
  | ErrorCode.SERVICE_UNAVAILABLE
  | ErrorCode.GENERATION_FAILED
  | ErrorCode.EXTERNAL_SERVICE_ERROR;

/**
 * Error for service-level failures (internal errors, external API failures, etc.).
 * HTTP Status: 500 (internal), 502 (external), 503 (unavailable)
 *
 * @example
 * ```typescript
 * // AI generation failed
 * return err(ServiceError.generationFailed('OpenAI', 'Rate limit exceeded', originalError));
 *
 * // External service unavailable
 * return err(ServiceError.unavailable('Payment Service'));
 *
 * // External API error
 * return err(ServiceError.externalError('Stripe', 'Card declined'));
 *
 * // Internal error
 * return err(ServiceError.internal('Failed to process request'));
 * ```
 */
export class ServiceError extends AppError {
  constructor(
    code: ServiceErrorCode,
    message: string,
    cause?: Error,
    context?: ErrorContext
  ) {
    super({ code, message, cause, context });
    this.name = 'ServiceError';
  }

  /**
   * Create an error for AI/content generation failures.
   *
   * @param service - Name of the service (e.g., 'OpenAI', 'Azure OpenAI')
   * @param reason - Why the generation failed
   * @param cause - Original error if available
   */
  static generationFailed(
    service: string,
    reason: string,
    cause?: Error
  ): ServiceError {
    return new ServiceError(
      ErrorCode.GENERATION_FAILED,
      `${service} generation failed: ${reason}`,
      cause,
      { service }
    );
  }

  /**
   * Create an error for a service that is temporarily unavailable.
   *
   * @param service - Name of the unavailable service
   */
  static unavailable(service: string): ServiceError {
    return new ServiceError(
      ErrorCode.SERVICE_UNAVAILABLE,
      `${service} is temporarily unavailable`,
      undefined,
      { service }
    );
  }

  /**
   * Create an error for external API failures.
   *
   * @param service - Name of the external service
   * @param message - Error message or description
   * @param cause - Original error if available
   */
  static externalError(
    service: string,
    message: string,
    cause?: Error
  ): ServiceError {
    return new ServiceError(
      ErrorCode.EXTERNAL_SERVICE_ERROR,
      `${service} error: ${message}`,
      cause,
      { service }
    );
  }

  /**
   * Create an internal server error.
   *
   * @param message - Description of what went wrong
   * @param cause - Original error if available
   */
  static internal(message: string, cause?: Error): ServiceError {
    return new ServiceError(ErrorCode.INTERNAL_ERROR, message, cause);
  }
}