// ==UserScript==
// @name           多列书签
// @include        main
// ==/UserScript==
location.href.startsWith('chrome://browser/content/browser.x') && (() => {
  //按顺序从两列开始
  const column = [
    ['2列显示的书签文件夹名称1', '2列名称2', '2列名称3', '2列名称4'],
    ['3列显示的书签文件夹名称1', '3列名称2'],
    ['4列显示的书签文件夹名称1', '4列名称2'],
    //...由此类推
  ];

  const BOOKMARK_WIDTH = 180; // 书签宽度
  const MARGIN_RIGHT = 5;
  const sss = Cc["@mozilla.org/content/style-sheet-service;1"].getService(Ci.nsIStyleSheetService);
  sss.loadAndRegisterSheet(Services.io.newURI("data:text/css," + encodeURIComponent(`
  @-moz-document url("chrome://browser/content/browser.xhtml"){
    #PlacesToolbarItems menuitem.bookmark-item .menu-accel-container {
      display: none !important;
    }
    ${column.map(c => {
      return c.length ? `#PlacesToolbarItems .bookmark-item[container="true"]:is(
        ${c.map(i => `[label=${JSON.stringify(i)}]`).join(', ')}
      ) > menupopup > :is(menuitem, menu, menuseparator) {
        min-width: ${BOOKMARK_WIDTH}px !important;
        max-width: ${BOOKMARK_WIDTH}px !important;
        margin-right: ${MARGIN_RIGHT}px !important;
      }` : '';
    }).join('\n')}
  }`), null, null), sss.USER_SHEET);

  function _getScrollableElements () {
    let nodes = this.children;
    if(nodes.length == 1 && nodes[0].className === 'scrollbox-innerbox') {
      nodes = nodes[0].children;
    }
    if (nodes.length == 1) {
      let node = nodes[0];
      if (node.localName == 'children' &&
          node.namespaceURI == 'http://www.mozilla.org/xbl') {
        nodes = document.getBindingParent(this).children;
      } else if (node.localName == 'slot' &&
                 node.namespaceURI == 'http://www.w3.org/1999/xhtml') {
        nodes = node.getRootNode().host.children;
      }
    }

    return Array.prototype.filter.call(nodes, this._canScrollToElement, this);
  }
  const PlacesToolbarItems = document.getElementById('PlacesToolbarItems');
  PlacesToolbarItems.addEventListener('popupshowing', (event) => {
    const menupopup = event.target;
    if(menupopup._isInitMultipledBM) return;
    const title = menupopup.parentNode &&
      menupopup.parentNode._placesNode &&
      menupopup.parentNode._placesNode.title;
    menupopup._isInitMultipledBM = true;
    let col = -1;
    if(!title || !menupopup.shadowRoot || (col = column.findIndex(c => {
      return c.indexOf(title) > -1;
    })) === -1) return;
    col += 2;

    const markup = `<html:style>
      arrowscrollbox::part(scrollbox), /*bug 1514926*/
      scrollbox.arrowscrollbox-scrollbox{
        overflow-y: auto !important;
      }
      arrowscrollbox > .scrollbox-innerbox{
        display:grid !important;
        grid-template-columns: repeat(${col}, 1fr);
      }
      </html:style>${menupopup.markup.replace(
      /<html:slot\/>|<html:slot><\/html:slot>/,
      '<box class="scrollbox-innerbox" orient="vertical" pack="start" smoothscroll="false" flex="1">$&</box>'
    )}`;

    let count = menupopup.shadowRoot.childElementCount;
    menupopup.shadowRoot.prepend(MozXULElement.parseXULToFragment(markup));
    while(count--) menupopup.shadowRoot.lastElementChild.remove();
    const arrowscrollbox = menupopup.shadowRoot.querySelector('arrowscrollbox');
    if(arrowscrollbox && arrowscrollbox._getScrollableElements) {
      arrowscrollbox._getScrollableElements = _getScrollableElements.bind(arrowscrollbox);
    }

    if(menupopup.__indicatorBar){
      menupopup.__indicatorBar = null;
      menupopup._scrollBox = null;
    }else{
      menupopup._indicatorBar = menupopup.shadowRoot.querySelector(
        '[part="drop-indicator-bar"]'
      );
      menupopup._scrollBox = menupopup.shadowRoot.querySelector(
        'arrowscrollbox'
      );
    }

  }, true);
})();