import type { ArgumentsHost } from '@nestjs/common';

import type { ITransport } from '../types';

/**
 * This class is used to detect current protocol (transport type).
 * Mostly used in global enhancers to decide: "to work of not to work"
 */
export class ProtocolDetector {
  constructor(private transports: ITransport[]) {}

  /**
   * Detects transport's protocol by ArgumentHost (context)
   */
  getProtocol(context: ArgumentsHost): string | undefined {
    return this.getTransport(context)?.getProtocol();
  }

  /**
   * Checks that transport's protocol matches the provided one.
   * (just convenience method)
   */
  matchProtocol(context: ArgumentsHost, protocol: string): boolean {
    return this.getProtocol(context) === protocol;
  }

  private getTransport(context: ArgumentsHost): ITransport | undefined {
    return this.transports.findLast((x) => x.matchByContext(context));
  }
}