import Logger from 'core/logger';
import TimelineSender from 'core/timeline/timeline_sender';
import * as Collections from 'core/utils/collections';
import Util from 'core/util';
import Runtime from 'runtime';
import TimelineTransport from 'core/timeline/timeline_transport';

var getAgent = function(sender: TimelineSender, useTLS: boolean) {
  return function(data: any, callback: Function) {
    var scheme = 'http' + (useTLS ? 's' : '') + '://';
    var url =
      scheme + (sender.host || sender.options.host) + sender.options.path;
    var query = Collections.buildQueryString(data);

    url += '/' + 2 + '?' + query;

    var xhr = Runtime.createXHR();
    xhr.open('GET', url, true);

    xhr.onreadystatechange = function() {
      if (xhr.readyState === 4) {
        let { status, responseText } = xhr;
        if (status !== 200) {
          Logger.debug(
            `TimelineSender Error: received ${status} from stats.pusher.com`
          );
          return;
        }

        try {
          var { host } = JSON.parse(responseText);
        } catch (e) {
          Logger.debug(`TimelineSenderError: invalid response ${responseText}`);
        }
        if (host) {
          sender.host = host;
        }
      }
    };

    xhr.send();
  };
};

var xhr = {
  name: 'xhr',
  getAgent
};

export default xhr;