/**
 * Implementation of the openIframe Ajax command.
 *
 * This command uses the default openDialog command to initialize a dialog. It
 * then attaches event listeners to the iframe and window to handle closing and
 * resizing the dialog.
 */
(function ($, Drupal) {
  Drupal.AjaxCommands.prototype.openIframe = function (ajax, response, status) {
    Drupal.AjaxCommands.prototype.openDialog(ajax, response, status)
    this.openIframe.initialResize(ajax.wrapper)
    this.openIframe.focusIframe(ajax.wrapper)
    this.openIframe.initMessageListener()
    Drupal.AjaxCommands.prototype.openIframe._scrollPosition = window.scrollY
  };

  /**
   * Set the size of the dialog to fill most of the viewport.
   */
  Drupal.AjaxCommands.prototype.openIframe.initialResize = function (wrapper) {
    var dialog = $('#' + wrapper)
    var dialogHeight = window.innerHeight - 180
    var dialogWidth = window.innerWidth - 180
    dialog.dialog('option', 'height', dialogHeight)
    dialog.dialog('option', 'width', dialogWidth)
  }

  /**
   * Try to focus the window of the iframe.
   */
  Drupal.AjaxCommands.prototype.openIframe.focusIframe = function (wrapper) {
    try {
      var dialog = $('#' + wrapper)
      var iframe = $(dialog).find('iframe')
      $(iframe).on('load', function() {
        this.contentWindow.focus()
      })
    } catch(e) {}
  }

  /**
   * Attaches a message event listener to the window.
   *
   * The loaded document in the iframe will redirect to a special route, which
   * uses postMessage to send a message to the parent. This means we can
   * trigger a rebuild of the layout, which in return will close the dialog.
   */
  Drupal.AjaxCommands.prototype.openIframe.initMessageListener = function () {
    if (this._isInitialized) {
      return
    }

    this._isInitialized = true

    window.addEventListener("message", function (e) {
      if (e.data === 'LBIM_REDIRECT') {
        $('#edit-rebuild-layout').trigger('click')
      }
    }, false);
  }

  // Stores the last scroll position before rebuild happened.
  Drupal.AjaxCommands.prototype.openIframe._scrollPosition = 0

  /**
   * Scrolls to the position before the layout rebuild was triggered.
   *
   * The scroll only happens if the delta between then and now is above a
   * certain threshold. This prevents unnecessary scrolling.
   */
  Drupal.AjaxCommands.prototype.scrollToBlock = function () {
    var scrollY = Drupal.AjaxCommands.prototype.openIframe._scrollPosition
    if (scrollY) {
      window.setTimeout(function() {
        if (Math.abs(window.scrollY - scrollY) > 300) {
          window.scrollTo(0, scrollY)
        }
        Drupal.AjaxCommands.prototype.openIframe._scrollPosition = 0
      }, 200)
    }
  };
})(jQuery, Drupal);