import { SshClient } from './classes.sshclient.js';
import type { IProxyRequest } from './types.js';

export class PortProxy {
  constructor(private sshClient = new SshClient()) {}

  public buildArgs(request: IProxyRequest): string[] {
    this.validateLocalForward(request.localForward);
    return this.sshClient.buildSshArgs(request.host, {
      localForwards: [request.localForward],
      extraArgs: ['-N'],
      exitOnForwardFailure: true,
    });
  }

  public async start(request: IProxyRequest): Promise<number> {
    return this.sshClient.spawnInteractive('ssh', this.buildArgs(request));
  }

  private validateLocalForward(localForward: string): void {
    const parts = localForward.split(':');
    if (parts.length < 3) {
      throw new Error('Local forward must look like <localPort>:<remoteHost>:<remotePort>');
    }
  }
}