WINDOW_CONTENTS = window.location.href.split("/");

function currentVersion() {
  if (WINDOW_CONTENTS.includes("$web") && WINDOW_CONTENTS.length > 5) {
    return WINDOW_CONTENTS[6];
  } else {
    return "";
  }
}

function currentPackage() {
  if (WINDOW_CONTENTS.includes("$web") && WINDOW_CONTENTS.length > 5) {
    return WINDOW_CONTENTS[5];
  } else {
    return "";
  }
}

function httpGetAsync(targetUrl, callback) {
  var xmlHttp = new XMLHttpRequest();
  xmlHttp.onreadystatechange = function() {
    if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
      callback(xmlHttp.responseText);
  };
  xmlHttp.open("GET", targetUrl, true); // true for asynchronous
  xmlHttp.send(null);
}

function showSelectors(selectors) {
  selectors.forEach(function(item, index) {
    $(item).show();
  });
}

function hideSelectors(selectors) {
  selectors.forEach(function(item, index) {
    $(item).hide();
  });
}

function populateOptions(optionSelector, otherSelectors) {
  if (currentPackage()) {
    var versionRequestUrl =
      "https://azuresdkdocs.blob.core.windows.net/$web?restype=container&comp=list&prefix=" +
      SELECTED_LANGUAGE +
      "/" +
      currentPackage() +
      "/versions/";

    httpGetAsync(versionRequestUrl, function(responseText) {
      if (responseText) {
        data_stored = responseText;

        parser = new DOMParser();
        xmlDoc = parser.parseFromString(responseText, "text/xml");

        nameElements = Array.from(xmlDoc.getElementsByTagName("Name"));
        options = [];

        for (var i in nameElements) {
          options.push(nameElements[i].textContent.split("/")[3]);
        }

        populateVersionDropDown(optionSelector, options);
        showSelectors(otherSelectors);

        $(optionSelector).change(function() {
          targetVersion = $(this).val();

          url = WINDOW_CONTENTS.slice();
          url[6] = targetVersion;
          window.location.href = url.join("/");
        });
      }
    });
  }
}

function populateVersionDropDown(selector, values) {
  var select = $(selector);

  $("option", select).remove();

  $.each(values, function(index, text) {
    $("<option/>", { value: text, text: text }).appendTo(select);
  });
  select.val(currentVersion());
}

function getPackageUrl(language, package, version) {
  return (
    "https://azuresdkdocs.blob.core.windows.net/$web/" +
    language +
    "/" +
    package +
    "/" +
    version +
    "/index.html"
  );
}

function populateIndexList(selector, packageName) {
  url =
    "https://azuresdkdocs.blob.core.windows.net/$web?restype=container&comp=list&prefix=" +
    SELECTED_LANGUAGE +
    "/" +
    packageName +
    "/versions/";

  httpGetAsync(url, function(responseText) {
    if (responseText) {
      parser = new DOMParser();
      xmlDoc = parser.parseFromString(responseText, "text/xml");

      nameElements = Array.from(xmlDoc.getElementsByTagName("Name"));
      options = [];

      for (var i in nameElements) {
        options.push(nameElements[i].textContent.split("/")[3]);
      }

      for (var i in options) {
        $(selector).append(
          '<li><a target="new" href="' +
            getPackageUrl(SELECTED_LANGUAGE, packageName, options[i]) +
            '">' +
            options[i] +
            "</a></li>"
        );
      }
    } else {
      $(selector).append(
        "<li>No discovered versions present in blob storage.</li>"
      );
    }
  });
}

// language specific
SELECTED_LANGUAGE = "javascript";
populateOptions("#versionSelector", [
  "#versionSelector",
  "#versionSelectorHeader"
]);