/**
 * @file
 * Some basic behaviors and utility functions for Views UI.
 */

(function ($, Drupal, drupalSettings) {
  /**
   * @namespace
   */
  Drupal.viewsUi = {};

  /**
   * Improve the user experience of the views edit interface.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches toggling of SQL rewrite warning on the corresponding checkbox.
   */
  Drupal.behaviors.viewsUiEditView = {
    attach() {
      // Only show the SQL rewrite warning when the user has chosen the
      // corresponding checkbox.
      $('[data-drupal-selector="edit-query-options-disable-sql-rewrite"]').on(
        'click',
        () => {
          $('.sql-rewrite-warning').toggleClass('js-hide');
        },
      );
    },
  };

  /**
   * In the add view wizard, use the view name to prepopulate form fields such
   * as page title and menu link.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches behavior for prepopulating page title and menu links, based on
   *   view name.
   */
  Drupal.behaviors.viewsUiAddView = {
    attach(context) {
      const $context = $(context);
      // Set up regular expressions to allow only numbers, letters, and dashes.
      const exclude = new RegExp('[^a-z0-9\\-]+', 'g');
      const replace = '-';
      let suffix;

      // The page title, block title, and menu link fields can all be
      // prepopulated with the view name - no regular expression needed.
      const $fields = $context.find(
        '[id^="edit-page-title"], [id^="edit-block-title"], [id^="edit-page-link-properties-title"]',
      );
      if ($fields.length) {
        if (!this.fieldsFiller) {
          this.fieldsFiller = new Drupal.viewsUi.FormFieldFiller($fields);
        } else {
          // After an AJAX response, this.fieldsFiller will still have event
          // handlers bound to the old version of the form fields (which don't
          // exist anymore). The event handlers need to be unbound and then
          // rebound to the new markup. Note that jQuery.live is difficult to
          // make work in this case because the IDs of the form fields change
          // on every AJAX response.
          this.fieldsFiller.rebind($fields);
        }
      }

      // Prepopulate the path field with a URLified version of the view name.
      const $pathField = $context.find('[id^="edit-page-path"]');
      if ($pathField.length) {
        if (!this.pathFiller) {
          this.pathFiller = new Drupal.viewsUi.FormFieldFiller(
            $pathField,
            exclude,
            replace,
          );
        } else {
          this.pathFiller.rebind($pathField);
        }
      }

      // Populate the RSS feed field with a URLified version of the view name,
      // and an .xml suffix (to make it unique).
      const $feedField = $context.find(
        '[id^="edit-page-feed-properties-path"]',
      );
      if ($feedField.length) {
        if (!this.feedFiller) {
          suffix = '.xml';
          this.feedFiller = new Drupal.viewsUi.FormFieldFiller(
            $feedField,
            exclude,
            replace,
            suffix,
          );
        } else {
          this.feedFiller.rebind($feedField);
        }
      }
    },
  };

  /**
   * Constructor for the {@link Drupal.viewsUi.FormFieldFiller} object.
   *
   * Prepopulates a form field based on the view name.
   *
   * @constructor
   *
   * @param {jQuery} $target
   *   A jQuery object representing the form field or fields to prepopulate.
   * @param {boolean} [exclude=false]
   *   A regular expression representing characters to exclude from
   *   the target field.
   * @param {string} [replace='']
   *   A string to use as the replacement value for disallowed characters.
   * @param {string} [suffix='']
   *   A suffix to append at the end of the target field content.
   */
  Drupal.viewsUi.FormFieldFiller = function (
    $target,
    exclude,
    replace,
    suffix,
  ) {
    /**
     *
     * @type {jQuery}
     */
    this.source = $('#edit-label');

    /**
     *
     * @type {jQuery}
     */
    this.target = $target;

    /**
     *
     * @type {boolean}
     */
    this.exclude = exclude || false;

    /**
     *
     * @type {string}
     */
    this.replace = replace || '';

    /**
     *
     * @type {string}
     */
    this.suffix = suffix || '';

    // Create bound versions of this instance's object methods to use as event
    // handlers. This will let us easily unbind those specific handlers later
    // on. NOTE: jQuery.proxy will not work for this because it assumes we want
    // only one bound version of an object method, whereas we need one version
    // per object instance.
    const self = this;

    /**
     * Populate the target form field with the altered source field value.
     *
     * @return {*}
     *   The result of the _populate call, which should be undefined.
     */
    this.populate = function () {
      return self._populate.call(self);
    };

    /**
     * Stop prepopulating the form fields.
     *
     * @return {*}
     *   The result of the _unbind call, which should be undefined.
     */
    this.unbind = function () {
      return self._unbind.call(self);
    };

    this.bind();
    // Object constructor; no return value.
  };

  $.extend(
    Drupal.viewsUi.FormFieldFiller.prototype,
    /** @lends Drupal.viewsUi.FormFieldFiller# */ {
      /**
       * Bind the form-filling behavior.
       */
      bind() {
        this.unbind();
        // Populate the form field when the source changes.
        this.source.on('keyup.viewsUi change.viewsUi', this.populate);
        // Quit populating the field as soon as it gets focus.
        this.target.on('focus.viewsUi', this.unbind);
      },

      /**
       * Get the source form field value as altered by the passed-in parameters.
       *
       * @return {string}
       *   The source form field value.
       */
      getTransliterated() {
        let from = this.source.length ? this.source[0].value : '';
        if (this.exclude) {
          from = from.toLowerCase().replace(this.exclude, this.replace);
        }
        return from;
      },

      /**
       * Populate the target form field with the altered source field value.
       */
      _populate() {
        const transliterated = this.getTransliterated();
        const suffix = this.suffix;
        this.target.each(function (i) {
          // Ensure that the maxlength is not exceeded by prepopulating the field.
          const maxlength = $(this).attr('maxlength') - suffix.length;
          this.value = transliterated.substr(0, maxlength) + suffix;
        });
      },

      /**
       * Stop prepopulating the form fields.
       */
      _unbind() {
        this.source.off('keyup.viewsUi change.viewsUi', this.populate);
        this.target.off('focus.viewsUi', this.unbind);
      },

      /**
       * Bind event handlers to new form fields, after they're replaced via Ajax.
       *
       * @param {jQuery} $fields
       *   Fields to rebind functionality to.
       */
      rebind($fields) {
        this.target = $fields;
        this.bind();
      },
    },
  );

  /**
   * Adds functionality for the add item form.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches the functionality in {@link Drupal.viewsUi.AddItemForm} to the
   *   forms in question.
   */
  Drupal.behaviors.addItemForm = {
    attach(context) {
      const $context = $(context);
      let $form = $context;
      // The add handler form may have an id of views-ui-add-handler-form--n.
      if (!$context.is('form[id^="views-ui-add-handler-form"]')) {
        $form = $context.find('form[id^="views-ui-add-handler-form"]');
      }
      if (once('views-ui-add-handler-form', $form).length) {
        // If we have an unprocessed views-ui-add-handler-form, let's
        // instantiate.
        new Drupal.viewsUi.AddItemForm($form);
      }
    },
  };

  /**
   * Constructs a new AddItemForm.
   *
   * @constructor
   *
   * @param {jQuery} $form
   *   The form element used.
   */
  Drupal.viewsUi.AddItemForm = function ($form) {
    /**
     *
     * @type {jQuery}
     */
    this.$form = $form;
    this.$form
      .find('.views-filterable-options :checkbox')
      .on('click', $.proxy(this.handleCheck, this));

    /**
     * Find the wrapper of the displayed text.
     */
    this.$selected_div = this.$form.find('.views-selected-options').parent();
    this.$selected_div.hide();

    /**
     *
     * @type {Array}
     */
    this.checkedItems = [];
  };

  /**
   * Handles a checkbox check.
   *
   * @param {jQuery.Event} event
   *   The event triggered.
   */
  Drupal.viewsUi.AddItemForm.prototype.handleCheck = function (event) {
    const $target = $(event.target);
    const label = $target.closest('td').next().html().trim();
    // Add/remove the checked item to the list.
    if ($target.is(':checked')) {
      this.$selected_div.show().css('display', 'block');
      this.checkedItems.push(label);
    } else {
      const position = $.inArray(label, this.checkedItems);
      // Delete the item from the list and make sure that the list doesn't have
      // undefined items left.
      for (let i = 0; i < this.checkedItems.length; i++) {
        if (i === position) {
          this.checkedItems.splice(i, 1);
          i--;
          break;
        }
      }
      // Hide it again if none item is selected.
      if (this.checkedItems.length === 0) {
        this.$selected_div.hide();
      }
    }
    this.refreshCheckedItems();
  };

  /**
   * Refresh the display of the checked items.
   */
  Drupal.viewsUi.AddItemForm.prototype.refreshCheckedItems = function () {
    // Perhaps we should precache the text div, too.
    this.$selected_div
      .find('.views-selected-options')
      .html(this.checkedItems.join(', '))
      .trigger('dialogContentResize');
  };

  /**
   * The input field items that add displays must be rendered as `<input>`
   * elements. The following behavior detaches the `<input>` elements from the
   * DOM, wraps them in an unordered list, then appends them to the list of
   * tabs.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Fixes the input elements needed.
   */
  Drupal.behaviors.viewsUiRenderAddViewButton = {
    attach(context) {
      // Build the add display menu and pull the display input buttons into it.
      const menu = once(
        'views-ui-render-add-view-button',
        '#views-display-menu-tabs',
        context,
      );
      if (!menu.length) {
        return;
      }
      const $menu = $(menu);

      const $addDisplayDropdown = $(
        `<li class="add"><a href="#"><span class="icon add"></span>${Drupal.t(
          'Add',
        )}</a><ul class="action-list" style="display:none;"></ul></li>`,
      );
      const $displayButtons = $menu.nextAll('input.add-display').detach();
      $displayButtons
        .appendTo($addDisplayDropdown.find('.action-list'))
        .wrap('<li>')
        .parent()
        .eq(0)
        .addClass('first')
        .end()
        .eq(-1)
        .addClass('last');
      $displayButtons.each(function () {
        const $this = $(this);
        this.value = $this.attr('data-drupal-dropdown-label');
      });
      $addDisplayDropdown.appendTo($menu);

      // Add the click handler for the add display button.
      $menu.find('li.add > a').on('click', function (event) {
        event.preventDefault();
        const $trigger = $(this);
        Drupal.behaviors.viewsUiRenderAddViewButton.toggleMenu($trigger);
      });
      // Add a mouseleave handler to close the dropdown when the user mouses
      // away from the item. We use mouseleave instead of mouseout because
      // the user is going to trigger mouseout when moving away from the trigger
      // link to the sub menu items.
      // We use the live binder because the open class on this item will be
      // toggled on and off and we want the handler to take effect in the cases
      // that the class is present, but not when it isn't.
      $('li.add', $menu).on('mouseleave', function (event) {
        const $this = $(this);
        const $trigger = $this.children('a[href="#"]');
        if ($this.children('.action-list').is(':visible')) {
          Drupal.behaviors.viewsUiRenderAddViewButton.toggleMenu($trigger);
        }
      });
    },
  };

  /**
   * Toggle menu visibility.
   *
   * @param {jQuery} $trigger
   *   The element where the toggle was triggered.
   *
   *
   * @note [@jessebeach] I feel like the following should be a more generic
   *   function and not written specifically for this UI, but I'm not sure
   *   where to put it.
   */
  Drupal.behaviors.viewsUiRenderAddViewButton.toggleMenu = function ($trigger) {
    $trigger.parent().toggleClass('open');
    $trigger.next().slideToggle('fast');
  };

  /**
   * Add search options to the views ui.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches {@link Drupal.viewsUi.OptionsSearch} to the views ui filter
   *   options.
   */
  Drupal.behaviors.viewsUiSearchOptions = {
    attach(context) {
      const $context = $(context);
      let $form = $context;
      // The add handler form may have an id of views-ui-add-handler-form--n.
      if (!$context.is('form[id^="views-ui-add-handler-form"]')) {
        $form = $context.find('form[id^="views-ui-add-handler-form"]');
      }
      // Make sure we don't add more than one event handler to the same form.
      if (once('views-ui-filter-options', $form).length) {
        new Drupal.viewsUi.OptionsSearch($form);
      }
    },
  };

  /**
   * Constructor for the viewsUi.OptionsSearch object.
   *
   * The OptionsSearch object filters the available options on a form according
   * to the user's search term. Typing in "taxonomy" will show only those
   * options containing "taxonomy" in their label.
   *
   * @constructor
   *
   * @param {jQuery} $form
   *   The form element.
   */
  Drupal.viewsUi.OptionsSearch = function ($form) {
    /**
     *
     * @type {jQuery}
     */
    this.$form = $form;

    // Click on the title checks the box.
    this.$form.on('click', 'td.title', (event) => {
      const $target = $(event.currentTarget);
      $target.closest('tr').find('input').trigger('click');
    });

    const searchBoxSelector =
      '[data-drupal-selector="edit-override-controls-options-search"]';
    const controlGroupSelector =
      '[data-drupal-selector="edit-override-controls-group"]';
    this.$form.on(
      'formUpdated',
      `${searchBoxSelector},${controlGroupSelector}`,
      $.proxy(this.handleFilter, this),
    );

    this.$searchBox = this.$form.find(searchBoxSelector);
    this.$controlGroup = this.$form.find(controlGroupSelector);

    /**
     * Get a list of option labels and their corresponding divs and maintain it
     * in memory, so we have as little overhead as possible at keyup time.
     */
    this.options = this.getOptions(this.$form.find('.filterable-option'));

    // Trap the ENTER key in the search box so that it doesn't submit the form.
    this.$searchBox.on('keypress', (event) => {
      if (event.which === 13) {
        event.preventDefault();
      }
    });
  };

  $.extend(
    Drupal.viewsUi.OptionsSearch.prototype,
    /** @lends Drupal.viewsUi.OptionsSearch# */ {
      /**
       * Assemble a list of all the filterable options on the form.
       *
       * @param {jQuery} $allOptions
       *   A jQuery object representing the rows of filterable options to be
       *   shown and hidden depending on the user's search terms.
       *
       * @return {Array}
       *   An array of all the filterable options.
       */
      getOptions($allOptions) {
        let $title;
        let $description;
        let $option;
        const options = [];
        const length = $allOptions.length;
        for (let i = 0; i < length; i++) {
          $option = $($allOptions[i]);
          $title = $option.find('.title');
          $description = $option.find('.description');
          options[i] = {
            // Search on the lowercase version of the title text + description.
            searchText: `${$title[0].textContent.toLowerCase()} ${$description[0].textContent.toLowerCase()}
              .toLowerCase()}`,
            // Maintain a reference to the jQuery object for each row, so we don't
            // have to create a new object inside the performance-sensitive keyup
            // handler.
            $div: $option,
          };
        }
        return options;
      },

      /**
       * Filter handler for the search box and type select that hides or shows the relevant
       * options.
       *
       * @param {jQuery.Event} event
       *   The formUpdated event.
       */
      handleFilter(event) {
        // Determine the user's search query. The search text has been converted
        // to lowercase.
        const search = this.$searchBox[0].value.toLowerCase();
        const words = search.split(' ');
        // Get selected Group
        const group = this.$controlGroup[0].value;

        // Search through the search texts in the form for matching text.
        this.options.forEach((option) => {
          function hasWord(word) {
            return option.searchText.indexOf(word) !== -1;
          }

          let found = true;
          // Each word in the search string has to match the item in order for the
          // item to be shown.
          if (search) {
            found = words.every(hasWord);
          }
          if (found && group !== 'all') {
            found = option.$div.hasClass(group);
          }

          option.$div.toggle(found);
        });

        // Adapt dialog to content size.
        $(event.target).trigger('dialogContentResize');
      },
    },
  );

  /**
   * Preview functionality in the views edit form.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches the preview functionality to the view edit form.
   */
  Drupal.behaviors.viewsUiPreview = {
    attach(context) {
      // Only act on the edit view form.
      const $contextualFiltersBucket = $(context).find(
        '.views-display-column .views-ui-display-tab-bucket.argument',
      );
      if ($contextualFiltersBucket.length === 0) {
        return;
      }

      // If the display has no contextual filters, hide the form where you
      // enter the contextual filters for the live preview. If it has contextual
      // filters, show the form.
      const $contextualFilters = $contextualFiltersBucket.find(
        '.views-display-setting a',
      );
      if ($contextualFilters.length) {
        $('#preview-args').parent().show();
      } else {
        $('#preview-args').parent().hide();
      }

      // Executes an initial preview.
      if (
        $(once('edit-displays-live-preview', '#edit-displays-live-preview')).is(
          ':checked',
        )
      ) {
        $(once('edit-displays-live-preview', '#preview-submit')).trigger(
          'click',
        );
      }
    },
  };

  /**
   * Improve the UI of the rearrange filters dialog box.
   *
   * @constructor
   *
   * @param {jQuery} $table
   *   The table in the filter form.
   * @param {jQuery} $operator
   *   The filter groups operator element.
   */
  Drupal.viewsUi.RearrangeFilterHandler = function ($table, $operator) {
    /**
     * Keep a reference to the `<table>` being altered and to the div containing
     * the filter groups operator dropdown (if it exists).
     */
    this.table = $table;

    /**
     *
     * @type {jQuery}
     */
    this.operator = $operator;

    /**
     *
     * @type {boolean}
     */
    this.hasGroupOperator = this.operator.length > 0;

    /**
     * Keep a reference to all draggable rows within the table.
     *
     * @type {jQuery}
     */
    this.draggableRows = $table.find('.draggable');

    /**
     * Keep a reference to the buttons for adding and removing filter groups.
     *
     * @type {jQuery}
     */
    this.addGroupButton = $('#views-add-group');

    /**
     * @type {jQuery}
     */
    this.removeGroupButtons = $table.find('.views-remove-group');

    // Add links that duplicate the functionality of the (hidden) add and remove
    // buttons.
    this.insertAddRemoveFilterGroupLinks();

    // When there is a filter groups operator dropdown on the page, create
    // duplicates of the dropdown between each pair of filter groups.
    if (this.hasGroupOperator) {
      /**
       * @type {jQuery}
       */
      this.dropdowns = this.duplicateGroupsOperator();
      this.syncGroupsOperators();
    }

    // Add methods to the tableDrag instance to account for operator cells
    // (which span multiple rows), the operator labels next to each filter
    // (e.g., "And" or "Or"), the filter groups, and other special aspects of
    // this tableDrag instance.
    this.modifyTableDrag();

    // Initialize the operator labels (e.g., "And" or "Or") that are displayed
    // next to the filters in each group, and bind a handler so that they change
    // based on the values of the operator dropdown within that group.
    this.redrawOperatorLabels();
    $(
      once(
        'views-rearrange-filter-handler',
        $table.find('.views-group-title select'),
      ),
    ).on(
      'change.views-rearrange-filter-handler',
      $.proxy(this, 'redrawOperatorLabels'),
    );

    // Bind handlers so that when a "Remove" link is clicked, we:
    // - Update the rowspans of cells containing an operator dropdown (since
    //   they need to change to reflect the number of rows in each group).
    // - Redraw the operator labels next to the filters in the group (since the
    //   filter that is currently displayed last in each group is not supposed
    //   to have a label display next to it).
    $(
      once(
        'views-rearrange-filter-handler',
        $table.find('a.views-groups-remove-link'),
      ),
    )
      .on(
        'click.views-rearrange-filter-handler',
        $.proxy(this, 'updateRowspans'),
      )
      .on(
        'click.views-rearrange-filter-handler',
        $.proxy(this, 'redrawOperatorLabels'),
      );
  };

  $.extend(
    Drupal.viewsUi.RearrangeFilterHandler.prototype,
    /** @lends Drupal.viewsUi.RearrangeFilterHandler# */ {
      /**
       * Insert links that allow filter groups to be added and removed.
       */
      insertAddRemoveFilterGroupLinks() {
        // Insert a link for adding a new group at the top of the page, and make
        // it match the action link styling used in a typical page.html.twig.
        // Since Drupal does not provide a theme function for this markup this is
        // the best we can do.
        $(
          once(
            'views-rearrange-filter-handler',
            // When the link is clicked, dynamically click the hidden form
            // button for adding a new filter group.
            $(
              `<ul class="action-links"><li><a id="views-add-group-link" href="#">${this.addGroupButton[0].value}</a></li></ul>`,
            ).prependTo(this.table.parent()),
          ),
        )
          .find('#views-add-group-link')
          .on(
            'click.views-rearrange-filter-handler',
            $.proxy(this, 'clickAddGroupButton'),
          );

        // Find each (visually hidden) button for removing a filter group and
        // insert a link next to it.
        const length = this.removeGroupButtons.length;
        let i;
        for (i = 0; i < length; i++) {
          const $removeGroupButton = $(this.removeGroupButtons[i]);
          const buttonId = $removeGroupButton.attr('id');
          $(
            once(
              'views-rearrange-filter-handler',
              // When the link is clicked, dynamically click the corresponding form
              // button.
              $(
                `<a href="#" class="views-remove-group-link">${Drupal.t(
                  'Remove group',
                )}</a>`,
              ).insertBefore($removeGroupButton),
            ),
          ).on(
            'click.views-rearrange-filter-handler',
            { buttonId },
            $.proxy(this, 'clickRemoveGroupButton'),
          );
        }
      },

      /**
       * Dynamically click the button that adds a new filter group.
       *
       * @param {jQuery.Event} event
       *   The event triggered.
       */
      clickAddGroupButton(event) {
        this.addGroupButton.trigger('mousedown');
        event.preventDefault();
      },

      /**
       * Dynamically click a button for removing a filter group.
       *
       * @param {jQuery.Event} event
       *   Event being triggered, with event.data.buttonId set to the ID of the
       *   form button that should be clicked.
       */
      clickRemoveGroupButton(event) {
        this.table.find(`#${event.data.buttonId}`).trigger('mousedown');
        event.preventDefault();
      },

      /**
       * Move the groups operator so that it's between the first two groups, and
       * duplicate it between any subsequent groups.
       *
       * @return {jQuery}
       *   An operator element.
       */
      duplicateGroupsOperator() {
        let newRow;
        let titleRow;

        const titleRows = once(
          'duplicateGroupsOperator',
          'tr.views-group-title',
        );

        if (!titleRows.length) {
          return this.operator;
        }

        // Get rid of the explanatory text around the operator; its placement is
        // explanatory enough.
        this.operator
          .find('label')
          .add('div.description')
          .addClass('visually-hidden');
        this.operator.find('select').addClass('form-select');

        // Keep a list of the operator dropdowns, so we can sync their behavior
        // later.
        const dropdowns = this.operator;

        // Move the operator to a new row just above the second group.
        titleRow = $('tr#views-group-title-2');
        newRow = $(
          '<tr class="filter-group-operator-row"><td colspan="5"></td></tr>',
        );
        newRow.find('td').append(this.operator);
        newRow.insertBefore(titleRow);
        const length = titleRows.length;
        // Starting with the third group, copy the operator to a new row above the
        // group title.
        for (let i = 2; i < length; i++) {
          titleRow = $(titleRows[i]);
          // Make a copy of the operator dropdown and put it in a new table row.
          const fakeOperator = this.operator.clone();
          fakeOperator.attr('id', '');
          newRow = $(
            '<tr class="filter-group-operator-row"><td colspan="5"></td></tr>',
          );
          newRow.find('td').append(fakeOperator);
          newRow.insertBefore(titleRow);
          dropdowns.add(fakeOperator);
        }

        return dropdowns;
      },

      /**
       * Make the duplicated groups operators change in sync with each other.
       */
      syncGroupsOperators() {
        if (this.dropdowns.length < 2) {
          // We only have one dropdown (or none at all), so there's nothing to
          // sync.
          return;
        }

        this.dropdowns.on('change', $.proxy(this, 'operatorChangeHandler'));
      },

      /**
       * Click handler for the operators that appear between filter groups.
       *
       * Forces all operator dropdowns to have the same value.
       *
       * @param {jQuery.Event} event
       *   The event triggered.
       */
      operatorChangeHandler(event) {
        const $target = $(event.target);
        const operators = this.dropdowns.find('select').not($target);

        // Change the other operators to match this new value.
        operators.each(function (index, item) {
          item.value = $target[0].value;
        });
      },

      /**
       * @method
       */
      modifyTableDrag() {
        const tableDrag = Drupal.tableDrag['views-rearrange-filters'];
        const filterHandler = this;

        /**
         * Override the row.onSwap method from tabledrag.js.
         *
         * When a row is dragged to another place in the table, several things
         * need to occur.
         * - The row needs to be moved so that it's within one of the filter
         * groups.
         * - The operator cells that span multiple rows need their rowspan
         * attributes updated to reflect the number of rows in each group.
         * - The operator labels that are displayed next to each filter need to
         * be redrawn, to account for the row's new location.
         */
        tableDrag.row.prototype.onSwap = function () {
          if (filterHandler.hasGroupOperator) {
            // Make sure the row that just got moved (this.group) is inside one
            // of the filter groups (i.e. below an empty marker row or a
            // draggable). If it isn't, move it down one.
            const thisRow = $(this.group);
            const previousRow = thisRow.prev('tr');
            if (
              previousRow.length &&
              !previousRow.hasClass('group-message') &&
              !previousRow.hasClass('draggable')
            ) {
              // Move the dragged row down one.
              const next = thisRow.next();
              if (next.is('tr')) {
                this.swap('after', next);
              }
            }
            filterHandler.updateRowspans();
          }
          // Redraw the operator labels that are displayed next to each filter, to
          // account for the row's new location.
          filterHandler.redrawOperatorLabels();
        };

        /**
         * Override the onDrop method from tabledrag.js.
         */
        tableDrag.onDrop = function () {
          // If the tabledrag change marker (i.e., the "*") has been inserted
          // inside a row after the operator label (i.e., "And" or "Or")
          // rearrange the items so the operator label continues to appear last.
          const changeMarker = $(this.oldRowElement).find('.tabledrag-changed');
          if (changeMarker.length) {
            // Search for occurrences of the operator label before the change
            // marker, and reverse them.
            const operatorLabel = changeMarker.prevAll('.views-operator-label');
            if (operatorLabel.length) {
              operatorLabel.insertAfter(changeMarker);
            }
          }

          // Make sure the "group" dropdown is properly updated when rows are
          // dragged into an empty filter group. This is borrowed heavily from
          // the block.js implementation of tableDrag.onDrop().
          const groupRow = $(this.rowObject.element)
            .prevAll('tr.group-message')
            .get(0);
          const groupName = groupRow.className.replace(
            /([^ ]+[ ]+)*group-([^ ]+)-message([ ]+[^ ]+)*/,
            '$2',
          );
          const groupField = $(
            'select.views-group-select',
            this.rowObject.element,
          );
          if (!groupField.is(`.views-group-select-${groupName}`)) {
            const oldGroupName = groupField
              .attr('class')
              .replace(
                /([^ ]+[ ]+)*views-group-select-([^ ]+)([ ]+[^ ]+)*/,
                '$2',
              );
            groupField
              .removeClass(`views-group-select-${oldGroupName}`)
              .addClass(`views-group-select-${groupName}`);
            groupField[0].value = groupName;
          }
        };
      },

      /**
       * Redraw the operator labels that are displayed next to each filter.
       */
      redrawOperatorLabels() {
        for (let i = 0; i < this.draggableRows.length; i++) {
          // Within the row, the operator labels are displayed inside the first
          // table cell (next to the filter name).
          const $draggableRow = $(this.draggableRows[i]);
          const $firstCell = $draggableRow.find('td').eq(0);
          if ($firstCell.length) {
            // The value of the operator label ("And" or "Or") is taken from the
            // first operator dropdown we encounter, going backwards from the
            // current row. This dropdown is the one associated with the current
            // row's filter group.
            const operatorValue = $draggableRow
              .prevAll('.views-group-title')
              .find('option:selected')
              .html();
            const operatorLabel = `<span class="views-operator-label">${operatorValue}</span>`;
            // If the next visible row after this one is a draggable filter row,
            // display the operator label next to the current row. (Checking for
            // visibility is necessary here since the "Remove" links hide the
            // removed row but don't actually remove it from the document).
            const $nextRow = $draggableRow.nextAll(':visible').eq(0);
            const $existingOperatorLabel = $firstCell.find(
              '.views-operator-label',
            );
            if ($nextRow.hasClass('draggable')) {
              // If an operator label was already there, replace it with the new
              // one.
              if ($existingOperatorLabel.length) {
                $existingOperatorLabel.replaceWith(operatorLabel);
              }
              // Otherwise, append the operator label to the end of the table
              // cell.
              else {
                $firstCell.append(operatorLabel);
              }
            }
            // If the next row doesn't contain a filter, then this is the last row
            // in the group. We don't want to display the operator there (since
            // operators should only display between two related filters, e.g.
            // "filter1 AND filter2 AND filter3"). So we remove any existing label
            // that this row has.
            else {
              $existingOperatorLabel.remove();
            }
          }
        }
      },

      /**
       * Update the rowspan attribute of each cell containing an operator
       * dropdown.
       */
      updateRowspans() {
        let $row;
        let $currentEmptyRow;
        let draggableCount;
        let $operatorCell;
        const rows = $(this.table).find('tr');
        const length = rows.length;
        for (let i = 0; i < length; i++) {
          $row = $(rows[i]);
          if ($row.hasClass('views-group-title')) {
            // This row is a title row.
            // Keep a reference to the cell containing the dropdown operator.
            $operatorCell = $row.find('td.group-operator');
            // Assume this filter group is empty, until we find otherwise.
            draggableCount = 0;
            $currentEmptyRow = $row.next('tr');
            $currentEmptyRow
              .removeClass('group-populated')
              .addClass('group-empty');
            // The cell with the dropdown operator should span the title row and
            // the "this group is empty" row.
            $operatorCell.attr('rowspan', 2);
          } else if ($row.hasClass('draggable') && $row.is(':visible')) {
            // We've found a visible filter row, so we now know the group isn't
            // empty.
            draggableCount++;
            $currentEmptyRow
              .removeClass('group-empty')
              .addClass('group-populated');
            // The operator cell should span all draggable rows, plus the title.
            $operatorCell.attr('rowspan', draggableCount + 1);
          }
        }
      },
    },
  );

  /**
   * Add a select all checkbox, which checks each checkbox at once.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches select all functionality to the views filter form.
   */
  Drupal.behaviors.viewsFilterConfigSelectAll = {
    attach(context) {
      const selectAll = once(
        'filterConfigSelectAll',
        '.js-form-item-options-value-all',
        context,
      );

      if (selectAll.length) {
        const $selectAll = $(selectAll);
        const $selectAllCheckbox = $selectAll.find('input[type=checkbox]');
        const $checkboxes = $selectAll
          .closest('.form-checkboxes')
          .find(
            '.js-form-type-checkbox:not(.js-form-item-options-value-all) input[type="checkbox"]',
          );
        // Show the select all checkbox.
        $selectAll.show();
        $selectAllCheckbox.on('click', function () {
          // Update all checkbox beside the select all checkbox.
          $checkboxes.prop('checked', $(this).is(':checked'));
        });

        // Uncheck the select all checkbox if any of the others are unchecked.
        $checkboxes.on('click', function () {
          if ($(this).is('checked') === false) {
            $selectAllCheckbox.prop('checked', false);
          }
        });
      }
    },
  };

  /**
   * Remove icon class from elements that are themed as buttons or dropbuttons.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Removes the icon class from certain views elements.
   */
  Drupal.behaviors.viewsRemoveIconClass = {
    attach(context) {
      $(once('dropbutton-icon', '.dropbutton', context))
        .find('.icon')
        .removeClass('icon');
    },
  };

  /**
   * Change "Expose filter" buttons into checkboxes.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Changes buttons into checkboxes via {@link Drupal.viewsUi.Checkboxifier}.
   */
  Drupal.behaviors.viewsUiCheckboxify = {
    attach(context, settings) {
      const buttons = once(
        'views-ui-checkboxify',
        '[data-drupal-selector="edit-options-expose-button-button"], [data-drupal-selector="edit-options-group-button-button"]',
      ).forEach((button) => new Drupal.viewsUi.Checkboxifier(button));
    },
  };

  /**
   * Change the default widget to select the default group according to the
   * selected widget for the exposed group.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Changes the default widget based on user input.
   */
  Drupal.behaviors.viewsUiChangeDefaultWidget = {
    attach(context) {
      const $context = $(context);

      function changeDefaultWidget(event) {
        if ($(event.target).prop('checked')) {
          $context.find('input.default-radios').parent().hide();
          $context.find('td.any-default-radios-row').parent().hide();
          $context.find('input.default-checkboxes').parent().show();
        } else {
          $context.find('input.default-checkboxes').parent().hide();
          $context.find('td.any-default-radios-row').parent().show();
          $context.find('input.default-radios').parent().show();
        }
      }

      // Update on widget change.
      $context
        .find('input[name="options[group_info][multiple]"]')
        .on('change', changeDefaultWidget)
        // Update the first time the form is rendered.
        .trigger('change');
    },
  };

  /**
   * Attaches expose filter button to a checkbox that triggers its click event.
   *
   * @constructor
   *
   * @param {Element} button
   *   The DOM object representing the button to be checkboxified.
   */
  Drupal.viewsUi.Checkboxifier = function (button) {
    this.$button = $(button);
    this.$parent = this.$button.parent('div.views-expose, div.views-grouped');
    this.$input = this.$parent.find('input:checkbox, input:radio');
    // Hide the button and its description.
    this.$button.hide();
    this.$parent.find('.exposed-description, .grouped-description').hide();

    this.$input.on('click', $.proxy(this, 'clickHandler'));
  };

  /**
   * When the checkbox is checked or unchecked, simulate a button press.
   *
   * @param {jQuery.Event} e
   *   The event triggered.
   */
  Drupal.viewsUi.Checkboxifier.prototype.clickHandler = function (e) {
    this.$button.trigger('click').trigger('submit');
  };

  /**
   * Change the Apply button text based upon the override select state.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches behavior to change the Apply button according to the current
   *   state.
   */
  Drupal.behaviors.viewsUiOverrideSelect = {
    attach(context) {
      once(
        'views-ui-override-button-text',
        '[data-drupal-selector="edit-override-dropdown"]',
        context,
      ).forEach((dropdown) => {
        // Closures! :(
        const $context = $(context);
        const submit = context.querySelector('[id^=edit-submit]');
        const oldValue = submit ? submit.value : '';

        $(once('views-ui-override-button-text', submit)).on(
          'mouseup',
          function () {
            this.value = oldValue;
            return true;
          },
        );

        $(dropdown)
          .on('change', function () {
            if (!submit) {
              return;
            }
            if (this.value === 'default') {
              submit.value = Drupal.t('Apply (all displays)');
            } else if (this.value === 'default_revert') {
              submit.value = Drupal.t('Revert to default');
            } else {
              submit.value = Drupal.t('Apply (this display)');
            }
            const $dialog = $context.closest('.ui-dialog-content');
            $dialog.trigger('dialogButtonsChange');
          })
          .trigger('change');
      });
    },
  };

  /**
   * Functionality for the remove link in the views UI.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches behavior for the remove view and remove display links.
   */
  Drupal.behaviors.viewsUiHandlerRemoveLink = {
    attach(context) {
      const $context = $(context);
      // Handle handler deletion by looking for the hidden checkbox and hiding
      // the row.
      $(once('views', 'a.views-remove-link', context)).on(
        'click',
        function (event) {
          const id = $(this).attr('id').replace('views-remove-link-', '');
          $context.find(`#views-row-${id}`).hide();
          $context.find(`#views-removed-${id}`).prop('checked', true);
          event.preventDefault();
        },
      );

      // Handle display deletion by looking for the hidden checkbox and hiding
      // the row.
      $(once('display', 'a.display-remove-link', context)).on(
        'click',
        function (event) {
          const id = $(this).attr('id').replace('display-remove-link-', '');
          $context.find(`#display-row-${id}`).hide();
          $context.find(`#display-removed-${id}`).prop('checked', true);
          event.preventDefault();
        },
      );
    },
  };

  /**
   * Rearranges the filters.
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attach handlers to make it possible to rearrange the filters in the form
   *   in question.
   *   @see Drupal.viewsUi.RearrangeFilterHandler
   */
  Drupal.behaviors.viewsUiRearrangeFilter = {
    attach(context) {
      // Only act on the rearrange filter form.
      if (
        typeof Drupal.tableDrag === 'undefined' ||
        typeof Drupal.tableDrag['views-rearrange-filters'] === 'undefined'
      ) {
        return;
      }
      const table = once(
        'views-rearrange-filters',
        '#views-rearrange-filters',
        context,
      );
      const operator = once(
        'views-rearrange-filters',
        '.js-form-item-filter-groups-operator',
        context,
      );
      if (table.length) {
        new Drupal.viewsUi.RearrangeFilterHandler($(table), $(operator));
      }
    },
  };
})(jQuery, Drupal, drupalSettings);
