const insertAt = function (elm: Element, html: string, index: number) {
  const fragment = createFragment(html);
  if (elm.hasChildNodes() && index < elm.childNodes.length) {
    const target = elm.childNodes[index];
    target.parentNode.insertBefore(fragment, target);
  } else {
    elm.appendChild(fragment);
  }
};

const showCaretContainerBlock = (caretContainer: Element): Element => {
  if (caretContainer && caretContainer.hasAttribute('data-mce-caret')) {
    trimBogusBr(caretContainer);
    caretContainer.removeAttribute('data-mce-caret');
    caretContainer.removeAttribute('data-mce-bogus');
    caretContainer.removeAttribute('style');
    caretContainer.removeAttribute('_moz_abspos');
    return caretContainer;
  }

  return null;
};

const trimBogusBr = (elm: Element): void => {
  const brs = elm.getElementsByTagName('br');
  const lastBr = brs[brs.length - 1];
  if (NodeType.isBogus(lastBr)) {
    lastBr.parentNode.removeChild(lastBr);
  }
};

const getSelectedBlocks = (dom: DOMUtils, rng: Range, startElm?: Element, endElm?: Element): Element[] => {
  let node, root;
  const selectedBlocks = [];

  root = dom.getRoot();
  startElm = dom.getParent(startElm || getStart(root, rng, rng.collapsed), dom.isBlock) as Element;
  endElm = dom.getParent(endElm || getEnd(root, rng, rng.collapsed), dom.isBlock) as Element;

  if (startElm && startElm !== root) {
    selectedBlocks.push(startElm);
  }

  if (startElm && endElm && startElm !== endElm) {
    node = startElm;

    const walker = new TreeWalker(startElm, root);
    while ((node = walker.next()) && node !== endElm) {
      if (dom.isBlock(node)) {
        selectedBlocks.push(node);
      }
    }
  }

  if (endElm && startElm !== endElm && endElm !== root) {
    selectedBlocks.push(endElm);
  }

  return selectedBlocks;
};

    Delay.setEditorTimeout(self, function () {
      const focusedEditor = editorManager.focusedEditor;

      // Still the same editor the blur was outside any editor UI
      if (!isUIElement(self, getActiveElement()) && focusedEditor === self) {
        self.fire('blur', { focusedEditor: null });
        editorManager.focusedEditor = null;
      }
    });

const validInsertion = function (editor: Editor, value: string, parentNode: DomElement) {
  // Should never insert content into bogus elements, since these can
  // be resize handles or similar
  if (parentNode.getAttribute('data-mce-bogus') === 'all') {
    parentNode.parentNode.insertBefore(editor.dom.createFragment(value), parentNode);
  } else {
    // Check if parent is empty or only has one BR element then set the innerHTML of that parent
    const node = parentNode.firstChild;
    const node2 = parentNode.lastChild;
    if (!node || (node === node2 && node.nodeName === 'BR')) {///
      editor.dom.setHTML(parentNode, value);
    } else {
      selectionSetContent(editor, value);
    }
  }
};

const preProcess = function (editor: Editor, node: Element, args) {
  let impl, doc, oldDoc;
  const dom = editor.dom;

  node = node.cloneNode(true) as Element;

  // Nodes needs to be attached to something in WebKit/Opera
  // This fix will make DOM ranges and make Sizzle happy!
  impl = document.implementation;
  if (impl.createHTMLDocument) {
    // Create an empty HTML document
    doc = impl.createHTMLDocument('');

    // Add the element or it's children if it's a body element to the new document
    Tools.each(node.nodeName === 'BODY' ? node.childNodes : [node], function (node) {
      doc.body.appendChild(doc.importNode(node, true));
    });

    // Grab first child or body element for serialization
    if (node.nodeName !== 'BODY') {
      node = doc.body.firstChild;
    } else {
      node = doc.body;
    }

    // set the new document in DOMUtils so createElement etc works
    oldDoc = dom.doc;
    dom.doc = doc;
  }

  Events.firePreProcess(editor, Merger.merge(args, { node }));

  if (oldDoc) {
    dom.doc = oldDoc;
  }

  return node;
};

const create = (editor: Editor, lastRngCell, pasteBinDefaultContent: string) => {
  const dom = editor.dom, body = editor.getBody();
  let pasteBinElm;

  lastRngCell.set(editor.selection.getRng());

  // Create a pastebin
  pasteBinElm = editor.dom.add(getPasteBinParent(editor), 'div', {
    'id': 'mcepastebin',
    'class': 'mce-pastebin',
    'contentEditable': true,
    'data-mce-bogus': 'all',
    'style': 'position: fixed; top: 50%; width: 10px; height: 10px; overflow: hidden; opacity: 0'
  }, pasteBinDefaultContent);

  // Move paste bin out of sight since the controlSelection rect gets displayed otherwise on IE and Gecko
  if (Env.ie || Env.gecko) {
    dom.setStyle(pasteBinElm, 'left', dom.getStyle(body, 'direction', true) === 'rtl' ? 0xFFFF : -0xFFFF);
  }

  // Prevent focus events from bubbeling fixed FocusManager issues
  dom.bind(pasteBinElm, 'beforedeactivate focusin focusout', function (e) {
    e.stopPropagation();
  });

  delegatePasteEvents(editor, pasteBinElm, pasteBinDefaultContent);

  pasteBinElm.focus();
  editor.selection.select(pasteBinElm, true);
};

const exitPreBlock = (editor, direction: HDirection, range: Range): void => {
  let pre, caretPos, newBlock;
  const caretWalker = CaretWalker(editor.getBody());
  const getNextVisualCaretPosition = Fun.curry(getVisualCaretPosition, caretWalker.next);
  const getPrevVisualCaretPosition = Fun.curry(getVisualCaretPosition, caretWalker.prev);

  if (range.collapsed && editor.settings.forced_root_block) {
    pre = editor.dom.getParent(range.startContainer, 'PRE');
    if (!pre) {
      return;
    }

    if (direction === 1) {
      caretPos = getNextVisualCaretPosition(CaretPosition.fromRangeStart(range));
    } else {
      caretPos = getPrevVisualCaretPosition(CaretPosition.fromRangeStart(range));
    }

    if (!caretPos) {
      newBlock = createTextBlock(editor);

      if (direction === 1) {
        editor.$(pre).after(newBlock);
      } else {
        editor.$(pre).before(newBlock);
      }

      editor.selection.select(newBlock, true);
      editor.selection.collapse();
    }
  }
};