/*
 * Copyright (C) 2007 Apple Inc.  All rights reserved.
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Contains diff method based on Javascript Diff Algorithm By John Resig
 * http://ejohn.org/files/jsdiff.js (released under the MIT license).
 */
/**
 * @param {number} offset
 * @param {string} stopCharacters
 * @param {!Node} stayWithinNode
 * @param {string=} direction
 * @return {!Range}
 */
Node.prototype.rangeOfWord = function(offset, stopCharacters, stayWithinNode, direction) {
  let startNode;
  let startOffset = 0;
  let endNode;
  let endOffset = 0;

  if (!stayWithinNode)
    stayWithinNode = this;

  if (!direction || direction === 'backward' || direction === 'both') {
    let node = this;
    while (node) {
      if (node === stayWithinNode) {
        if (!startNode)
          startNode = stayWithinNode;
        break;
      }

      if (node.nodeType === Node.TEXT_NODE) {
        const start = (node === this ? (offset - 1) : (node.nodeValue.length - 1));
        for (let i = start; i >= 0; --i) {
          if (stopCharacters.indexOf(node.nodeValue[i]) !== -1) {
            startNode = node;
            startOffset = i + 1;
            break;
          }
        }
      }

      if (startNode)
        break;

      node = node.traversePreviousNode(stayWithinNode);
    }

    if (!startNode) {
      startNode = stayWithinNode;
      startOffset = 0;
    }
  } else {
    startNode = this;
    startOffset = offset;
  }

  if (!direction || direction === 'forward' || direction === 'both') {
    let node = this;
    while (node) {
      if (node === stayWithinNode) {
        if (!endNode)
          endNode = stayWithinNode;
        break;
      }

      if (node.nodeType === Node.TEXT_NODE) {
        const start = (node === this ? offset : 0);
        for (let i = start; i < node.nodeValue.length; ++i) {
          if (stopCharacters.indexOf(node.nodeValue[i]) !== -1) {
            endNode = node;
            endOffset = i;
            break;
          }
        }
      }

      if (endNode)
        break;

      node = node.traverseNextNode(stayWithinNode);
    }

    if (!endNode) {
      endNode = stayWithinNode;
      endOffset = stayWithinNode.nodeType === Node.TEXT_NODE ? stayWithinNode.nodeValue.length :
                                                               stayWithinNode.childNodes.length;
    }
  } else {
    endNode = this;
    endOffset = offset;
  }

  const result = this.ownerDocument.createRange();
  result.setStart(startNode, startOffset);
  result.setEnd(endNode, endOffset);

  return result;
};

/**
 * @param {!Node=} stayWithin
 * @return {?Node}
 */
Node.prototype.traverseNextTextNode = function(stayWithin) {
  let node = this.traverseNextNode(stayWithin);
  if (!node)
    return null;
  const nonTextTags = {'STYLE': 1, 'SCRIPT': 1};
  while (node && (node.nodeType !== Node.TEXT_NODE || nonTextTags[node.parentElement.nodeName]))
    node = node.traverseNextNode(stayWithin);

  return node;
};

/**
 * @param {number|undefined} x
 * @param {number|undefined} y
 * @param {!Element=} relativeTo
 */
Element.prototype.positionAt = function(x, y, relativeTo) {
  let shift = {x: 0, y: 0};
  if (relativeTo)
    shift = relativeTo.boxInWindow(this.ownerDocument.defaultView);

  if (typeof x === 'number')
    this.style.setProperty('left', (shift.x + x) + 'px');
  else
    this.style.removeProperty('left');

  if (typeof y === 'number')
    this.style.setProperty('top', (shift.y + y) + 'px');
  else
    this.style.removeProperty('top');

  if (typeof x === 'number' || typeof y === 'number')
    this.style.setProperty('position', 'absolute');
  else
    this.style.removeProperty('position');
};

/**
 * @return {boolean}
 */
Element.prototype.isScrolledToBottom = function() {
  // This code works only for 0-width border.
  // The scrollTop, clientHeight and scrollHeight are computed in double values internally.
  // However, they are exposed to javascript differently, each being either rounded (via
  // round, ceil or floor functions) or left intouch.
  // This adds up a total error up to 2.
  return Math.abs(this.scrollTop + this.clientHeight - this.scrollHeight) <= 2;
};

/**
 * @param {!Array.<string>} nameArray
 * @return {?Node}
 */
Node.prototype.enclosingNodeOrSelfWithNodeNameInArray = function(nameArray) {
  for (let node = this; node && node !== this.ownerDocument; node = node.parentNodeOrShadowHost()) {
    for (let i = 0; i < nameArray.length; ++i) {
      if (node.nodeName.toLowerCase() === nameArray[i].toLowerCase())
        return node;
    }
  }
  return null;
};

/**
 * @param {string} nodeName
 * @return {?Node}
 */
Node.prototype.enclosingNodeOrSelfWithNodeName = function(nodeName) {
  return this.enclosingNodeOrSelfWithNodeNameInArray([nodeName]);
};

/**
 * @param {string} className
 * @param {!Element=} stayWithin
 * @return {?Element}
 */
Node.prototype.enclosingNodeOrSelfWithClass = function(className, stayWithin) {
  return this.enclosingNodeOrSelfWithClassList([className], stayWithin);
};

/**
 * @param {!Array.<string>} classNames
 * @param {!Element=} stayWithin
 * @return {?Element}
 */
Node.prototype.enclosingNodeOrSelfWithClassList = function(classNames, stayWithin) {
  for (let node = this; node && node !== stayWithin && node !== this.ownerDocument;
       node = node.parentNodeOrShadowHost()) {
    if (node.nodeType === Node.ELEMENT_NODE) {
      let containsAll = true;
      for (let i = 0; i < classNames.length && containsAll; ++i) {
        if (!node.classList.contains(classNames[i]))
          containsAll = false;
      }
      if (containsAll)
        return /** @type {!Element} */ (node);
    }
  }
  return null;
};

/**
 * @return {?Element}
 */
Node.prototype.parentElementOrShadowHost = function() {
  if (this.nodeType === Node.DOCUMENT_FRAGMENT_NODE && this.host)
    return /** @type {!Element} */ (this.host);
  const node = this.parentNode;
  if (!node)
    return null;
  if (node.nodeType === Node.ELEMENT_NODE)
    return /** @type {!Element} */ (node);
  if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE)
    return /** @type {!Element} */ (node.host);
  return null;
};

/**
 * @return {?Node}
 */
Node.prototype.parentNodeOrShadowHost = function() {
  if (this.parentNode)
    return this.parentNode;
  if (this.nodeType === Node.DOCUMENT_FRAGMENT_NODE && this.host)
    return this.host;
  return null;
};

/**
 * @return {?Selection}
 */
Node.prototype.getComponentSelection = function() {
  let parent = this.parentNode;
  while (parent && parent.nodeType !== Node.DOCUMENT_FRAGMENT_NODE)
    parent = parent.parentNode;
  return parent instanceof ShadowRoot ? parent.getSelection() : this.window().getSelection();
};

/**
 * @return {boolean}
 */
Node.prototype.hasSelection = function() {
  // TODO(luoe): use contains(node, {includeShadow: true}) when it is fixed for shadow dom.
  if (this instanceof Element) {
    const slots = this.querySelectorAll('slot');
    for (const slot of slots) {
      if (Array.prototype.some.call(slot.assignedNodes(), node => node.hasSelection()))
        return true;
    }
  }

  const selection = this.getComponentSelection();
  if (selection.type !== 'Range')
    return false;
  return selection.containsNode(this, true) || selection.anchorNode.isSelfOrDescendant(this) ||
      selection.focusNode.isSelfOrDescendant(this);
};

/**
 * @return {!Window}
 */
Node.prototype.window = function() {
  return /** @type {!Window} */ (this.ownerDocument.defaultView);
};

Element.prototype.removeChildren = function() {
  if (this.firstChild)
    this.textContent = '';
};

/**
 * @param {string} tagName
 * @param {string=} customElementType
 * @return {!Element}
 * @suppress {checkTypes}
 * @suppressGlobalPropertiesCheck
 */
function createElement(tagName, customElementType) {
  return document.createElement(tagName, {is: customElementType});
}

/**
 * @param {number|string} data
 * @return {!Text}
 * @suppressGlobalPropertiesCheck
 */
function createTextNode(data) {
  return document.createTextNode(data);
}

/**
 * @param {string} elementName
 * @param {string=} className
 * @param {string=} customElementType
 * @suppress {checkTypes}
 * @return {!Element}
 */
Document.prototype.createElementWithClass = function(elementName, className, customElementType) {
  const element = this.createElement(elementName, {is: customElementType});
  if (className)
    element.className = className;
  return element;
};

/**
 * @param {string} elementName
 * @param {string=} className
 * @param {string=} customElementType
 * @return {!Element}
 * @suppressGlobalPropertiesCheck
 */
function createElementWithClass(elementName, className, customElementType) {
  return document.createElementWithClass(elementName, className, customElementType);
}

/**
 * @param {string} childType
 * @param {string=} className
 * @return {!Element}
 */
Document.prototype.createSVGElement = function(childType, className) {
  const element = this.createElementNS('http://www.w3.org/2000/svg', childType);
  if (className)
    element.setAttribute('class', className);
  return element;
};

/**
 * @param {string} childType
 * @param {string=} className
 * @return {!Element}
 * @suppressGlobalPropertiesCheck
 */
function createSVGElement(childType, className) {
  return document.createSVGElement(childType, className);
}

/**
 * @return {!DocumentFragment}
 * @suppressGlobalPropertiesCheck
 */
function createDocumentFragment() {
  return document.createDocumentFragment();
}

/**
 * @param {string} elementName
 * @param {string=} className
 * @param {string=} customElementType
 * @return {!Element}
 */
Element.prototype.createChild = function(elementName, className, customElementType) {
  const element = this.ownerDocument.createElementWithClass(elementName, className, customElementType);
  this.appendChild(element);
  return element;
};

DocumentFragment.prototype.createChild = Element.prototype.createChild;

/**
 * @param {string} text
 * @return {!Text}
 */
Element.prototype.createTextChild = function(text) {
  const element = this.ownerDocument.createTextNode(text);
  this.appendChild(element);
  return element;
};

DocumentFragment.prototype.createTextChild = Element.prototype.createTextChild;

/**
 * @param {...string} var_args
 */
Element.prototype.createTextChildren = function(var_args) {
  for (let i = 0, n = arguments.length; i < n; ++i)
    this.createTextChild(arguments[i]);
};

DocumentFragment.prototype.createTextChildren = Element.prototype.createTextChildren;

/**
 * @return {number}
 */
Element.prototype.totalOffsetLeft = function() {
  return this.totalOffset().left;
};

/**
 * @return {number}
 */
Element.prototype.totalOffsetTop = function() {
  return this.totalOffset().top;
};

/**
 * @return {!{left: number, top: number}}
 */
Element.prototype.totalOffset = function() {
  const rect = this.getBoundingClientRect();
  return {left: rect.left, top: rect.top};
};

/**
 * @param {string} childType
 * @param {string=} className
 * @return {!Element}
 */
Element.prototype.createSVGChild = function(childType, className) {
  const child = this.ownerDocument.createSVGElement(childType, className);
  this.appendChild(child);
  return child;
};

/**
 * @unrestricted
 */
var AnchorBox = class {  // eslint-disable-line
  /**
   * @param {number=} x
   * @param {number=} y
   * @param {number=} width
   * @param {number=} height
   */
  constructor(x, y, width, height) {
    this.x = x || 0;
    this.y = y || 0;
    this.width = width || 0;
    this.height = height || 0;
  }

  /**
   * @param {number} x
   * @param {number} y
   * @return {boolean}
   */
  contains(x, y) {
    return x >= this.x && x <= this.x + this.width && y >= this.y && y <= this.y + this.height;
  }
};

/**
 * @param {!AnchorBox} box
 * @return {!AnchorBox}
 */
AnchorBox.prototype.relativeTo = function(box) {
  return new AnchorBox(this.x - box.x, this.y - box.y, this.width, this.height);
};

/**
 * @param {!Element} element
 * @return {!AnchorBox}
 */
AnchorBox.prototype.relativeToElement = function(element) {
  return this.relativeTo(element.boxInWindow(element.ownerDocument.defaultView));
};

/**
 * @param {?AnchorBox} anchorBox
 * @return {boolean}
 */
AnchorBox.prototype.equals = function(anchorBox) {
  return !!anchorBox && this.x === anchorBox.x && this.y === anchorBox.y && this.width === anchorBox.width &&
      this.height === anchorBox.height;
};

/**
 * @param {?Window=} targetWindow
 * @return {!AnchorBox}
 */
Element.prototype.boxInWindow = function(targetWindow) {
  targetWindow = targetWindow || this.ownerDocument.defaultView;

  const anchorBox = new AnchorBox();
  let curElement = this;
  let curWindow = this.ownerDocument.defaultView;
  while (curWindow && curElement) {
    anchorBox.x += curElement.totalOffsetLeft();
    anchorBox.y += curElement.totalOffsetTop();
    if (curWindow === targetWindow)
      break;
    curElement = curWindow.frameElement;
    curWindow = curWindow.parent;
  }

  anchorBox.width = Math.min(this.offsetWidth, targetWindow.innerWidth - anchorBox.x);
  anchorBox.height = Math.min(this.offsetHeight, targetWindow.innerHeight - anchorBox.y);
  return anchorBox;
};

/**
 * @param {boolean=} preventDefault
 */
Event.prototype.consume = function(preventDefault) {
  this.stopImmediatePropagation();
  if (preventDefault)
    this.preventDefault();
  this.handled = true;
};

/**
 * @param {number=} start
 * @param {number=} end
 * @return {!Text}
 */
Text.prototype.select = function(start, end) {
  start = start || 0;
  end = end || this.textContent.length;

  if (start < 0)
    start = end + start;

  const selection = this.getComponentSelection();
  selection.removeAllRanges();
  const range = this.ownerDocument.createRange();
  range.setStart(this, start);
  range.setEnd(this, end);
  selection.addRange(range);
  return this;
};

/**
 * @return {?number}
 */
Element.prototype.selectionLeftOffset = function() {
  // Calculate selection offset relative to the current element.

  const selection = this.getComponentSelection();
  if (!selection.containsNode(this, true))
    return null;

  let leftOffset = selection.anchorOffset;
  let node = selection.anchorNode;

  while (node !== this) {
    while (node.previousSibling) {
      node = node.previousSibling;
      leftOffset += node.textContent.length;
    }
    node = node.parentNodeOrShadowHost();
  }

  return leftOffset;
};

/**
 * @param {...!Node} var_args
 */
Node.prototype.appendChildren = function(var_args) {
  for (let i = 0, n = arguments.length; i < n; ++i)
    this.appendChild(arguments[i]);
};

/**
 * @return {string}
 */
Node.prototype.deepTextContent = function() {
  return this.childTextNodes()
      .map(function(node) {
        return node.textContent;
      })
      .join('');
};

/**
 * @return {!Array.<!Node>}
 */
Node.prototype.childTextNodes = function() {
  let node = this.traverseNextTextNode(this);
  const result = [];
  const nonTextTags = {'STYLE': 1, 'SCRIPT': 1};
  while (node) {
    if (!nonTextTags[node.parentElement.nodeName])
      result.push(node);
    node = node.traverseNextTextNode(this);
  }
  return result;
};

/**
 * @param {?Node} node
 * @return {boolean}
 */
Node.prototype.isAncestor = function(node) {
  if (!node)
    return false;

  let currentNode = node.parentNodeOrShadowHost();
  while (currentNode) {
    if (this === currentNode)
      return true;
    currentNode = currentNode.parentNodeOrShadowHost();
  }
  return false;
};

/**
 * @param {?Node} descendant
 * @return {boolean}
 */
Node.prototype.isDescendant = function(descendant) {
  return !!descendant && descendant.isAncestor(this);
};

/**
 * @param {?Node} node
 * @return {boolean}
 */
Node.prototype.isSelfOrAncestor = function(node) {
  return !!node && (node === this || this.isAncestor(node));
};

/**
 * @param {?Node} node
 * @return {boolean}
 */
Node.prototype.isSelfOrDescendant = function(node) {
  return !!node && (node === this || this.isDescendant(node));
};

/**
 * @param {!Node=} stayWithin
 * @return {?Node}
 */
Node.prototype.traverseNextNode = function(stayWithin) {
  if (this.shadowRoot)
    return this.shadowRoot;

  const distributedNodes = this instanceof HTMLSlotElement ? this.assignedNodes() : [];

  if (distributedNodes.length)
    return distributedNodes[0];

  if (this.firstChild)
    return this.firstChild;

  let node = this;
  while (node) {
    if (stayWithin && node === stayWithin)
      return null;

    const sibling = nextSibling(node);
    if (sibling)
      return sibling;

    node = node.assignedSlot || node.parentNodeOrShadowHost();
  }

  /**
   * @param {!Node} node
   * @return {?Node}
   */
  function nextSibling(node) {
    if (!node.assignedSlot)
      return node.nextSibling;
    const distributedNodes = node.assignedSlot.assignedNodes();

    const position = Array.prototype.indexOf.call(distributedNodes, node);
    if (position + 1 < distributedNodes.length)
      return distributedNodes[position + 1];
    return null;
  }

  return null;
};

/**
 * @param {!Node=} stayWithin
 * @return {?Node}
 */
Node.prototype.traversePreviousNode = function(stayWithin) {
  if (stayWithin && this === stayWithin)
    return null;
  let node = this.previousSibling;
  while (node && node.lastChild)
    node = node.lastChild;
  if (node)
    return node;
  return this.parentNodeOrShadowHost();
};

/**
 * @param {*} text
 * @param {string=} placeholder
 * @return {boolean} true if was truncated
 */
Node.prototype.setTextContentTruncatedIfNeeded = function(text, placeholder) {
  // Huge texts in the UI reduce rendering performance drastically.
  // Moreover, Blink/WebKit uses <unsigned short> internally for storing text content
  // length, so texts longer than 65535 are inherently displayed incorrectly.
  const maxTextContentLength = 10000;

  if (typeof text === 'string' && text.length > maxTextContentLength) {
    this.textContent = typeof placeholder === 'string' ? placeholder : text.trimMiddle(maxTextContentLength);
    return true;
  }

  this.textContent = text;
  return false;
};

/**
 * @return {?Node}
 */
Event.prototype.deepElementFromPoint = function() {
  // Some synthetic events have zero coordinates which lead to a wrong element. Better return nothing in this case.
  if (!this.which && !this.pageX && !this.pageY && !this.clientX && !this.clientY && !this.movementX && !this.movementY)
    return null;
  const root = this.target && this.target.getComponentRoot();
  return root ? root.deepElementFromPoint(this.pageX, this.pageY) : null;
};

/**
 * @param {number} x
 * @param {number} y
 * @return {?Node}
 */
Document.prototype.deepElementFromPoint = function(x, y) {
  let container = this;
  let node = null;
  while (container) {
    const innerNode = container.elementFromPoint(x, y);
    if (!innerNode || node === innerNode)
      break;
    node = innerNode;
    container = node.shadowRoot;
  }
  return node;
};

DocumentFragment.prototype.deepElementFromPoint = Document.prototype.deepElementFromPoint;

/**
 * @return {?Element}
 */
Document.prototype.deepActiveElement = function() {
  let activeElement = this.activeElement;
  while (activeElement && activeElement.shadowRoot && activeElement.shadowRoot.activeElement)
    activeElement = activeElement.shadowRoot.activeElement;
  return activeElement;
};

DocumentFragment.prototype.deepActiveElement = Document.prototype.deepActiveElement;

/**
 * @return {boolean}
 */
Element.prototype.hasFocus = function() {
  const root = this.getComponentRoot();
  return !!root && this.isSelfOrAncestor(root.activeElement);
};

/**
 * @return {?Document|?DocumentFragment}
 */
Node.prototype.getComponentRoot = function() {
  let node = this;
  while (node && node.nodeType !== Node.DOCUMENT_FRAGMENT_NODE && node.nodeType !== Node.DOCUMENT_NODE)
    node = node.parentNode;
  return /** @type {?Document|?DocumentFragment} */ (node);
};

/**
 * @param {!Event} event
 * @return {boolean}
 */
function isEnterKey(event) {
  // Check if in IME.
  return event.keyCode !== 229 && event.key === 'Enter';
}

/**
 * @param {!Event} event
 * @return {boolean}
 */
function isEscKey(event) {
  return event.keyCode === 27;
}