import { createServer, Server as HttpServer } from "http";
import { Server, AttachOptions, ServerOptions } from "./server";
import transports from "./transports/index";
import * as parser from "engine.io-parser";

export { Server, transports, listen, attach, parser };
export type {
  AttachOptions,
  ServerOptions,
  BaseServer,
  ErrorCallback,
} from "./server";
export { uServer } from "./userver";
export { Socket } from "./socket";
export { Transport } from "./transport";
export const protocol = parser.protocol;

/**
 * Creates an http.Server exclusively used for WS upgrades, and starts listening.
 *
 * @param port
 * @param options
 * @param listenCallback - callback for http.Server.listen()
 * @return engine.io server
 */

function listen(
  port: number,
  options?: AttachOptions & ServerOptions,
  listenCallback?: () => void,
): Server {
  if ("function" === typeof options) {
    listenCallback = options;
    options = {};
  }

  const server = createServer(function (req, res) {
    res.writeHead(501);
    res.end("Not Implemented");
  });

  // create engine server
  const engine = attach(server, options);
  engine.httpServer = server;

  server.listen(port, listenCallback);

  return engine;
}

/**
 * Captures upgrade requests for a http.Server.
 *
 * @param server
 * @param options
 * @return engine.io server
 */

function attach(
  server: HttpServer,
  options: AttachOptions & ServerOptions,
): Server {
  const engine = new Server(options);
  engine.attach(server, options);
  return engine;
}