// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

/**
 * @fileoverview Atoms for frame handling.
 *
 */


goog.provide('bot.frame');

goog.require('bot');
goog.require('bot.Error');
goog.require('bot.ErrorCode');
goog.require('bot.dom');
goog.require('bot.locators');
goog.require('goog.dom');
goog.require('goog.dom.TagName');


/**
 * @return {!Window} The top window.
 */
bot.frame.defaultContent = function () {
  return bot.getWindow().top;
};


/**
 * @return {!Element} The currently active element.
 */
bot.frame.activeElement = function () {
  return document.activeElement || document.body;
};


/**
 * Gets the parent frame of the specified frame.
 *
 * @param {!Window=} opt_root The window get the parent of.
 *     Defaults to `bot.getWindow()`.
 * @return {!Window} The frame if found, self otherwise.
 */
bot.frame.parentFrame = function (opt_root) {
  var domWindow = opt_root || bot.getWindow();
  return domWindow.parent;
};


/**
 * Returns a reference to the window object corresponding to the given element.
 * Note that the element must be a frame or an iframe.
 *
 * @param {!(HTMLIFrameElement|HTMLFrameElement)} element The iframe or frame
 *     element.
 * @return {Window} The window reference for the given iframe or frame element.
 */
bot.frame.getFrameWindow = function (element) {
  if (bot.frame.isFrame_(element)) {
    var frame = /** @type {HTMLFrameElement|HTMLIFrameElement} */ (element);
    return goog.dom.getFrameContentWindow(frame);
  }
  throw new bot.Error(bot.ErrorCode.NO_SUCH_FRAME,
    "The given element isn't a frame or an iframe.");
};


/**
 * Returns whether an element is a frame (or iframe).
 *
 * @param {!Element} element The element to check.
 * @return {boolean} Whether the element is a frame (or iframe).
 * @private
 */
bot.frame.isFrame_ = function (element) {
  return bot.dom.isElement(element, goog.dom.TagName.FRAME) ||
    bot.dom.isElement(element, goog.dom.TagName.IFRAME);
};


/**
 * Looks for a frame by its name or id (preferring name over id)
 * under the given root. If no frame was found, we look for an
 * iframe by name or id.
 *
 * @param {(string|number)} nameOrId The frame's name, the frame's id, or the
 *     index of the frame in the containing window.
 * @param {!Window=} opt_root The window to perform the search under.
 *     Defaults to `bot.getWindow()`.
 * @return {Window} The window if found, null otherwise.
 */
bot.frame.findFrameByNameOrId = function (nameOrId, opt_root) {
  var domWindow = opt_root || bot.getWindow();

  // Lookup frame by name
  var numFrames = domWindow.frames.length;
  for (var i = 0; i < numFrames; i++) {
    var frame = domWindow.frames[i];
    var frameElement = frame.frameElement || frame;
    if (frameElement.name == nameOrId) {
      // This is needed because Safari 4 returns
      // an HTMLFrameElement instead of a Window object.
      if (frame.document) {
        return frame;
      } else {
        return goog.dom.getFrameContentWindow(frame);
      }
    }
  }

  // Lookup frame by id
  var elements = bot.locators.findElements({ id: nameOrId }, domWindow.document);
  for (var i = 0; i < elements.length; i++) {
    var frameElement = elements[i];
    if (frameElement && bot.frame.isFrame_(frameElement)) {
      return goog.dom.getFrameContentWindow(frameElement);
    }
  }
  return null;
};


/**
 * Looks for a frame by its index under the given root.
 *
 * @param {number} index The frame's index.
 * @param {!Window=} opt_root The window to perform
 *     the search under. Defaults to `bot.getWindow()`.
 * @return {Window} The frame if found, null otherwise.
 */
bot.frame.findFrameByIndex = function (index, opt_root) {
  var domWindow = opt_root || bot.getWindow();
  return domWindow.frames[index] || null;
};


/**
 * Gets the index of a frame in the given window. Note that the element must
 * be a frame or an iframe.
 *
 * @param {!(HTMLIFrameElement|HTMLFrameElement)} element The iframe or frame
 *     element.
 * @param {!Window=} opt_root The window to perform the search under. Defaults
 *     to `bot.getWindow()`.
 * @return {?number} The index of the frame if found, null otherwise.
 */
bot.frame.getFrameIndex = function (element, opt_root) {
  try {
    var elementWindow = element.contentWindow;
  } catch (e) {
    // Happens in IE{7,8} if a frame doesn't have an enclosing frameset.
    return null;
  }

  if (!bot.frame.isFrame_(element)) {
    return null;
  }

  var domWindow = opt_root || bot.getWindow();
  for (var i = 0; i < domWindow.frames.length; i++) {
    if (elementWindow == domWindow.frames[i]) {
      return i;
    }
  }
  return null;
};