import { Promise } from 'es6-promise';
import { parse as parseHeaders } from 'get-headers'
import Response from '../response';
import Headers from '../headers';

/**
 @module http/browser
 */

const httpBrowser = (request) => {

  return new Promise((resolve, reject) => {

    const req = new XMLHttpRequest();
    let timer;

    req.open(request.method, request.url, true);

    _.map(request.headers.map, (value, key) => {

      req.setRequestHeader(key, value.join(','))

    });

    req.send(request._bodyInit);

    req.addEventListener('load', () => {

      const headers = new Headers(parseHeaders(req.getAllResponseHeaders()));
      const urlList = req.responseURL && request.url === decodeURI(req.responseURL) ? [
        request.url
      ] : [
        request.url,
        decodeURI(req.responseURL)
      ] ;

      if (request.timeout)
        clearTimeout(timer);

      return resolve(new Response(req.responseText, {
        urlList,
        status: req.status,
        statusText: req.statusText,
        headers,
      }));

    });

    if (request.timeout) {

      timer = setTimeout(() => {

        req.abort();

        return reject(new Error('Fetch timeout exceeded'))

      }, request.timeout);
    }

  })

};

export default httpBrowser;