import { CancellationController, TransportRequest } from '../types/transport-request';
import { TransportResponse } from '../types/transport-response';

/**
 * Represents the configuration options for keeping the transport connection alive.
 */
export type TransportKeepAlive = {
  /**
   * The time interval in milliseconds for keeping the connection alive.
   *
   * @default 1000
   */
  keepAliveMsecs?: number;

  /**
   * The maximum number of sockets allowed per host.
   *
   * @default Infinity
   */
  maxSockets?: number;

  /**
   * The maximum number of open and free sockets in the pool per host.
   *
   * @default 256
   */
  maxFreeSockets?: number;

  /**
   * Timeout in milliseconds, after which the `idle` socket will be closed.
   *
   * @default 30000
   */
  timeout?: number;
};

/**
 * This interface is used to send requests to the PubNub API.
 *
 * You can implement this interface for your types or use one of the provided modules to use a
 * transport library.
 *
 * @interface
 */
export interface Transport {
  /**
   * Make request sendable.
   *
   * @param req - The transport request to be processed.
   *
   * @returns - A promise that resolves to a transport response and request cancellation
   * controller (if required).
   */
  makeSendable(req: TransportRequest): [Promise<TransportResponse>, CancellationController | undefined];

  /**
   * Pre-processed request.
   *
   * Transport implementation may pre-process original transport requests before making
   * platform-specific request objects from it.
   *
   * @param req - Transport request provided by the PubNub client.
   *
   * @returns Transport request with updated properties (if it was required).
   */
  request(req: TransportRequest): TransportRequest;
}