(window => {
  const noTrack = window.localStorage.getItem("noTrack");

  const {
    screen: {width, height},
    navigator: {language},
    location: {hostname, pathname, search},
    document: {referrer}
  } = window;

  const website = "4f6fd0ae-646a-4946-a9da-7aad63284e48";
  const root = "https://fmg-stats.herokuapp.com";
  const screen = `${width}x${height}`;
  const url = `${pathname}${search}`;

  const post = (url, data) => {
    const req = new XMLHttpRequest();
    req.open("POST", url, true);
    req.setRequestHeader("Content-Type", "application/json");
    req.send(JSON.stringify(data));
  };

  const collect = (type, params) => {
    if (noTrack) return;

    const payload = {website, hostname, screen, language, cache: false};
    Object.keys(params).forEach(key => {
      payload[key] = params[key];
    });

    post(`${root}/api/collect`, {type, payload});
  };

  collect("pageview", {url, referrer});
  window.track = (event_type = "reach", event_value = "") => collect("event", {event_type, event_value, url});
})(window);