import { ServiceUnavailableException } from '@nestjs/common';

/**
 * Thrown by an engine adapter when an operation fails at the TRANSPORT rather than because the
 * requested resource does not exist: the Chromium page/CDP connection is gone (whatsapp-web.js),
 * the WebSocket dropped (Baileys), or the socket is up but WhatsApp left our query unanswered
 * past a deadline we own. A broad catch that folds this into a not-found result makes a crashed
 * session look like a missing group/channel (404) or a refused invite (400), which is how
 * operators end up debugging the wrong layer.
 *
 * Extends NestJS `ServiceUnavailableException` so it maps to **HTTP 503** through the built-in
 * exception handler — no custom global filter required. Mirrors {@link EngineNotReadyError} (409).
 */
export class EngineTransportError extends ServiceUnavailableException {
  constructor(detail: string) {
    super(detail);
  }
}