HOME

import URLLocation from './url_location';
import State from './state';
import Socket from '../socket';
import SocketHooks from './socket_hooks';
import Util from '../util';
import Ajax from './ajax';
import HTTPRequest from './http_request';
import Runtime from 'runtime';

var autoIncrement = 1;

class HTTPSocket implements Socket {
  hooks: SocketHooks;
  session: string;
  location: URLLocation;
  readyState: State;
  stream: HTTPRequest;

  onopen: () => void;
  onerror: (error: any) => void;
  onclose: (closeEvent: any) => void;
  onmessage: (message: any) => void;
  onactivity: () => void;

  constructor(hooks: SocketHooks, url: string) {
    this.hooks = hooks;
    this.session = randomNumber(1000) + '/' + randomString(8);
    this.location = getLocation(url);
    this.readyState = State.CONNECTING;
    this.openStream();
  }

  send(payload: any) {
    return this.sendRaw(JSON.stringify([payload]));
  }

  ping() {
    this.hooks.sendHeartbeat(this);
  }

  close(code: any, reason: any) {
    this.onClose(code, reason, true);
  }

  /** For internal use only */
  sendRaw(payload: any): boolean {
    if (this.readyState === State.OPEN) {
      try {
        Runtime.createSocketRequest(
          'POST',
          getUniqueURL(getSendURL(this.location, this.session))
        ).start(payload);
        return true;
      } catch (e) {
        return false;
      }
    } else {
      return false;
    }
  }

  /** For internal use only */
  reconnect() {
    this.closeStream();
    this.openStream();
  }

  /** For internal use only */
  onClose(code, reason, wasClean) {
    this.closeStream();
    this.readyState = State.CLOSED;
    if (this.onclose) {
      this.onclose({
        code: code,
        reason: reason,
        wasClean: wasClean
      });
    }
  }

  private onChunk(chunk) {
    if (chunk.status !== 200) {
      return;
    }
    if (this.readyState === State.OPEN) {
      this.onActivity();
    }

    var payload;
    var type = chunk.data.slice(0, 1);
    switch (type) {
      case 'o':
        payload = JSON.parse(chunk.data.slice(1) || '{}');
        this.onOpen(payload);
        break;
      case 'a':
        payload = JSON.parse(chunk.data.slice(1) || '[]');
        for (var i = 0; i < payload.length; i++) {
          this.onEvent(payload[i]);
        }
        break;
      case 'm':
        payload = JSON.parse(chunk.data.slice(1) || 'null');
        this.onEvent(payload);
        break;
      case 'h':
        this.hooks.onHeartbeat(this);
        break;
      case 'c':
        payload = JSON.parse(chunk.data.slice(1) || '[]');
        this.onClose(payload[0], payload[1], true);
        break;
    }
  }

  private onOpen(options) {
    if (this.readyState === State.CONNECTING) {
      if (options && options.hostname) {
        this.location.base = replaceHost(this.location.base, options.hostname);
      }
      this.readyState = State.OPEN;

      if (this.onopen) {
        this.onopen();
      }
    } else {
      this.onClose(1006, 'Server lost session', true);
    }
  }

  private onEvent(event) {
    if (this.readyState === State.OPEN && this.onmessage) {
      this.onmessage({ data: event });
    }
  }

  private onActivity() {
    if (this.onactivity) {
      this.onactivity();
    }
  }

  private onError(error) {
    if (this.onerror) {
      this.onerror(error);
    }
  }

  private openStream() {
    this.stream = Runtime.createSocketRequest(
      'POST',
      getUniqueURL(this.hooks.getReceiveURL(this.location, this.session))
    );

    this.stream.bind('chunk', chunk => {
      this.onChunk(chunk);
    });
    this.stream.bind('finished', status => {
      this.hooks.onFinished(this, status);
    });
    this.stream.bind('buffer_too_long', () => {
      this.reconnect();
    });

    try {
      this.stream.start();
    } catch (error) {
      Util.defer(() => {
        this.onError(error);
        this.onClose(1006, 'Could not start streaming', false);
      });
    }
  }

  private closeStream() {
    if (this.stream) {
      this.stream.unbind_all();
      this.stream.close();
      this.stream = null;
    }
  }
}

function getLocation(url): URLLocation {
  var parts = /([^\?]*)\/*(\??.*)/.exec(url);
  return {
    base: parts[1],
    queryString: parts[2]
  };
}

function getSendURL(url: URLLocation, session: string): string {
  return url.base + '/' + session + '/xhr_send';
}

function getUniqueURL(url: string): string {
  var separator = url.indexOf('?') === -1 ? '?' : '&';
  return url + separator + 't=' + +new Date() + '&n=' + autoIncrement++;
}

function replaceHost(url: string, hostname: string): string {
  var urlParts = /(https?:\/\/)([^\/:]+)((\/|:)?.*)/.exec(url);
  return urlParts[1] + hostname + urlParts[3];
}

function randomNumber(max: number): number {
  return Runtime.randomInt(max);
}

function randomString(length: number): string {
  var result = [];

  for (var i = 0; i < length; i++) {
    result.push(randomNumber(32).toString(32));
  }

  return result.join('');
}

export default HTTPSocket;