!(async function () {
  const regexp = /https:\/\/github.com\/github\/([^\/]*)\/pull\/\d*\/files/;

  if (!window.location.href.match(regexp)) {
    window.alert("You're not on a PR 'Files changed' page. 🙃");
    return
  }

  let conversation_url = window.location.href.replace(/files.*/g, "");

  // get the preview deployment URL by loading the 'Conversation' page, and searching for the 'View deployment' link
  let deployment_url = await fetch(conversation_url)
    .then(function (response) {
      return response.text();
    })
    .then(function (html) {
      // Convert the HTML string into a document object
      var parser = new DOMParser();
      var doc = parser.parseFromString(html, "text/html");

      var elements = doc.getElementsByClassName("TimelineItem");
      // Find the element that is a link that contains the text "View deployment"
      for (var i = 0; i < elements.length; i++) {
        var element = elements[i];
        var links = element.getElementsByTagName("a");
        for (var j = 0; j < links.length; j++) {
          var link = links[j];
          if (link.innerText.match(/View deployment/)) {
            // Get the href of the link
            var deployment_url = link.getAttribute("href");
          }
        }
      }
      // This should return the last link that contains the text "View deployment" (there might be multiple ones if there are multiple deployments)
      return deployment_url;
    });
  if (deployment_url == null) {
    window.alert("No preview deployment found! 😭");
    return;
  }
  // strip any trailing slash from deployment_url
  deployment_url = deployment_url.replace(/\/$/, "");

  var url_fpt = deployment_url + "/en";
  var url_ghec = deployment_url + "/en/enterprise-cloud@latest";
  var url_ghes = deployment_url + "/en/enterprise-server@latest";
  var url_ae = deployment_url + "/en/github-ae@latest";
  var fpt = "FPT";
  var ghes = "GHES";
  var ghec = "GHEC";
  var ae = "AE";

  const file_info = document.querySelectorAll("div.file-info");
  for (var i = 0; i < file_info.length; i++) {
    var link = file_info[i].querySelector("a").title;
    if (link.search("data/") === 0) {
      continue;
    } else {
      var regex = /\.md$/;
      var markdownfile = link.search(regex) >= 0;
      if (markdownfile) {
        console.log("link: " + link);
        link = link.replace(regex, "");
        link = link.replace(/^content/, "");
        link = link.replace(/\/index/, "");
        var span = document.createElement("SPAN");
        span.style.fontFamily =
          "-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif";
        span.innerHTML = "&nbsp; View: ";

        span = addLink(span, fpt, url_fpt + link);
        span.innerHTML += " / ";
        span = addLink(span, ghec, url_ghec + link);
        span.innerHTML += " / ";
        span = addLink(span, ghes, url_ghes + link);
        span.innerHTML += " / ";
        span = addLink(span, ae, url_ae + link);

        file_info[i].appendChild(span);
      }
    }
  }

  function addLink(span, link_name, link_href) {
    var anchor = document.createElement("A");
    anchor.innerHTML = link_name;
    anchor.href = link_href;
    anchor.target = "_blank";
    span.appendChild(anchor);
    return span;
  }
})();