(function (settings) {

  var pymParent;

  // Coordinates coming from browser-based geolocation.
  var geoLocation;

  var appendQuery = function appendQuery(url, query) {
    if (0 === query.length) {
      return url;
    }
    if ('?' == query.charAt(0)) {
      query = query.substring(1);
    }
    var separator = (-1 !== url.indexOf('?')) ? '&' : '?';
    return url + separator + query;
  };

  var shouldLoadThankYouPage = function() {
    var queryParams = window.location.search.substr(1).split('&').reduce(function (q, query) {
      var chunks = query.split('=');
      var key = chunks[0];
      var value = chunks[1];
      return (q[key] = value, q);
    }, {});
    return queryParams['nm-embed-show-thank-you'] === '1';
  };

  var geoLocationSuccess = function (position) {
    // Store geolocation for retrieval by the listener.
    geoLocation = position;
    // Trigger an event for the listener to react to if
    // we manage to load coordinates.
    const event = new Event('parent-geo');
    window.dispatchEvent(event);
  }

  var geoLocationError = function () {
    geoLocation = null;
  }

  var geoLocationCheck = function () {
    // Attempt to get coordinates.
    navigator.geolocation.getCurrentPosition(geoLocationSuccess, geoLocationError);
    // Add listiner to send message to child if we get a result.
    window.addEventListener("parent-geo", function(e, latLong) {
      latLong = geoLocation.coords.latitude + ':' + geoLocation.coords.longitude;
      pymParent.sendMessage('parent-geo-coords', latLong);
    });
  }

  var firstScriptElement = document.getElementsByTagName('script')[0];

  if (settings.share_progress_js_url) {
    var scriptElementSP = document.createElement('script');
    scriptElementSP.async = 1;
    scriptElementSP.src = settings.share_progress_js_url;
    firstScriptElement.parentNode.insertBefore(scriptElementSP,firstScriptElement);
  }

  if (settings.nm_analytics_js_url) {
    var scriptElementNMA = document.createElement('script');
    scriptElementNMA.async = 1;
    scriptElementNMA.src = settings.nm_analytics_js_url;
    firstScriptElement.parentNode.insertBefore(scriptElementNMA,firstScriptElement);
  }

  if (settings.pym_lib_url) {
    var scriptElement = document.createElement('script');
    scriptElement.async = 1;
    scriptElement.src = settings.pym_lib_url;
    scriptElement.type = "application/javascript";
    firstScriptElement.parentNode.insertBefore(scriptElement,firstScriptElement);
    scriptElement.onload = function () {
      if (settings.div_id && settings.iframe_url) {
        var url = appendQuery(settings.iframe_url, document.location.search);

        if (shouldLoadThankYouPage() && settings.thank_you_url) {
          url = appendQuery(settings.thank_you_url, document.location.search);
        }

        // Add random iframe ID to subvert safari iframe caching.
        var iframeId = 'nm-' + Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 5) +
    Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 5);
        // Create config object to hold id.
        var pymConfig = {
          id: iframeId,
        };
        // Create pym parent.
        pymParent = new pym.Parent(settings.div_id, url, pymConfig);

        pymParent.onMessage('child-init', function() {
          // Tell child iframe the parent window position as soon as child is
          // ready.
          var partent_offset = window.pageYOffset;
          pymParent.sendMessage('parent-initial-offset', partent_offset);
          // If parent window has scrolled after that, update the offset.
          window.addEventListener("scroll", function() {
            var partent_offset = window.pageYOffset;
            pymParent.sendMessage('parent-initial-offset', partent_offset);
          });
        });

        // Allow child to learn about parent URL, for cases where iframe content has navigated away from original URL with parentUrl parameter.
        pymParent.onMessage('getParentUrl', function() {
          this.sendMessage('parentUrl', encodeURIComponent(window.location.href));
        });

        // pym.js sets the iframe height via the HTML "height" attribute, which
        // can get overridden by (unrelated) CSS rules. So, in addition, we also
        // set the CSS "height" property directly on the iframe, which in turn
        // overrides any CSS applied via rules.
        pymParent.onMessage('height', function(message) {
          var height = parseInt(message);
          if ('style' in this.iframe) {
            if ('height' in this.iframe.style) {
              this.iframe.style.height = height + 'px';
            }
          }
        });

        // Custom message: scrollParentToTop.
        // This is to allow children iframe setup parent position.
        pymParent.onMessage('scrollParentBack', function(pageYOffset) {
          window.scrollTo(0, pageYOffset);
        });

        // If we have an addressfield as a key component then try
        // to get address via browser location detection.
        if (settings.address_key) {
          // Don't do this for ff.

          // Disable this universally for now.
          // isFirefox = navigator.userAgent.indexOf("Firefox") != -1;
          // if (!isFirefox) {
          //   if (navigator.geolocation) {
          //     // Wait 2 few seconds before attempting as page needs
          //     // to load.
          //     timeoutID = window.setTimeout(geoLocationCheck, 2000);
          //   }
          // }
        }
      }
    };
  }

  if (settings.font_url) {
    var head = document.head || document.getElementsByTagName('head')[0],
        link = document.createElement('link');
    link.setAttribute('rel', 'stylesheet');
    link.setAttribute('type', 'text/css');
    link.setAttribute('href', settings.font_url);
    head.appendChild(link);
  }

  // Do not append anything after the closing parenthesis!
})({
    "pym_lib_url": "https://blog.apps.npr.org/pym.js/dist/pym.v1.min.js",
    "share_progress_js_url": "",
    "div_id": "newmode-embed-14660-40026",
    "iframe_url": "//act.newmode.net/nm-letter/14660/40026",
    "font_url": "",
    "thank_you_url": "https://act.newmode.net/node/40026/done",
    "address_key": false
});