/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

/**
 * Dummy container node used for the root document element.
 */
class RootContainer {
  constructor(markupView, node) {
    this.doc = markupView.doc;
    this.elt = this.doc.createElement("ul");
    // Root container has tree semantics for accessibility.
    this.elt.setAttribute("role", "tree");
    this.elt.setAttribute("tabindex", "0");
    this.elt.setAttribute("aria-dropeffect", "none");
    this.elt.container = this;
    this.children = this.elt;
    this.node = node;
    this.toString = () => "[root container]";
  }

  hasChildren = true;
  expanded = true;
  update() {}
  destroy() {}

  /**
   * If the node has children, return the list of containers for all these children.
   *
   * @return {Array} An array of child containers or null.
   */
  getChildContainers() {
    return [...this.children.children]
      .filter(node => node.container)
      .map(node => node.container);
  }

  /**
   * Set the expanded state of the container node.
   *
   * @param  {boolean} value
   */
  setExpanded() {}

  /**
   * Set an appropriate role of the container's children node.
   */
  setChildrenRole() {}

  /**
   * Set an appropriate DOM tree depth level for a node and its subtree.
   */
  updateLevel() {}

  isSlotted() {
    return false;
  }
}

module.exports = RootContainer;
