// Copyright 2008 Google Inc.
// 
// Licensed 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 AxsJAX to enhance accessibility
 * of Skel. 
 *
 * This is a skeleton AxsJAX script - when you start using it,
 * you should do a global replace of "axsSkel" with 
 * "axsWhateverYourAppNameIs" and update this fileoverview.
 *
 * @author clchen@google.com (Charles L. Chen)
 */
// create namespace
var axsSkel = {};

//These are strings to be spoken to the user
axsSkel.HELP = 'The following shortcut keys are available. ';
axsSkel.ARTICLES_LOADED_STRING = 'Articles loaded.';
axsSkel.ITEM_STARRED_STRING = 'Star added.';
axsSkel.ITEM_UNSTARRED_STRING = 'Star removed.';


/**
 * The AxsJAX object that will do the tickling and speaking.
 * @type AxsJAX?
 */
axsSkel.axsJAXObj = null;
/**
 * The AxsNav object that will handle navigation.
 * @type AxsNav?
 */
axsSkel.axsNavObj = null;

/**
 * The AxsLens object that will magnify content.
 * @type AxsLens?
 */
axsSkel.axsLensObj = null;

/**
 * The magnification factor for the AxsLens object.
 * @type number
 */
axsSkel.magSize = 1.5;

axsSkel.init = function(){
  axsSkel.axsJAXObj = new AxsJAX(true);
  axsSkel.axsNavObj = new AxsNav(axsSkel.axsJAXObj);

  //Add event listeners
  document.addEventListener('DOMNodeInserted', axsSkel.nodeInsertedHandler, true);
  document.addEventListener('DOMAttrModified', axsSkel.attrModifiedHandler, true);
  document.addEventListener('keypress', axsSkel.keyHandler, true);
  
  var cnrString = "";

  axsSkel.axsNavObj.navInit(cnrString, null);

  axsSkel.axsLensObj = new AxsLens(axsSkel.axsJAXObj);
  axsSkel.axsNavObj.setLens(axsSkel.axsLensObj);
  axsSkel.axsLensObj.setMagnification(axsSkel.magSize);
};

axsSkel.nodeInsertedHandler = function(evt){
  var target = evt.target;
  // If the target node is something that should
  // be spoken, speak it here.
};

axsSkel.attrModifiedHandler = function(evt){
  var attrib = evt.attrName;
  var newVal = evt.newValue;
  var oldVal = evt.prevValue;
  var target = evt.target;
  // If the target node is something that should
  // be spoken, speak it here.
  if ( (attrib == 'class') && 
       (oldVal.indexOf('cursor') == -1) &&
       (newVal.indexOf('cursor') != -1) ){
    axsSkel.axsJAXObj.speakNode(target);
  }
  if ( (attrib == 'id') && 
       (oldVal.indexOf('current-entry') == -1) &&
       (newVal.indexOf('current-entry') != -1) ){
    axsSkel.axsJAXObj.speakNode(target);
  }   
  if( (target.id == 'viewer-box') &&
      (attrib == 'class') &&
      (oldVal.indexOf('hidden') != -1) &&
      (newVal.indexOf('hidden') == -1)  ){
    axsSkel.axsJAXObj.speakTextViaNode(axsSkel.ARTICLES_LOADED_STRING);
  }
  if( (attrib == 'class') &&
      (oldVal.indexOf('item-star-active') == -1) &&
	  (newVal.indexOf('item-star-active') != -1) ){
    axsSkel.axsJAXObj.speakTextViaNode(axsSkel.ITEM_STARRED_STRING);
  }
  if( (attrib == 'class') &&
      (oldVal.indexOf('item-star-active') != -1) &&
	  (newVal.indexOf('item-star-active') == -1) ){
    axsSkel.axsJAXObj.speakTextViaNode(axsSkel.ITEM_UNSTARRED_STRING);
  }
  
};


axsSkel.keyHandler = function(evt){
  //If Ctrl is held, it must be for some AT. 
  if (evt.ctrlKey) return true;
  
  if (evt.keyCode == 27){ // ESC
    axsSkel.axsJAXObj.lastFocusedNode.blur();
    return false;
  }

  if (axsSkel.axsJAXObj.inputFocused) return true;
  
  var command =  axsSkel.keyCodeMap[evt.keyCode] ||
                 axsSkel.charCodeMap[evt.charCode];

  if (command)  return  command();
  return true;
  
};

axsSkel.keyCodeMap = {
  // Map additional keyboard behavior that involves key codes here
};

axsSkel.charCodeMap = {
  // Map additional keyboard behavior that involves char codes here
  63 : function () {
         var helpStr = axsSkel.HELP +
                       axsSkel.axsNavObj.localHelpString() +
					   axsSkel.axsNavObj.globalHelpString();
         axsSkel.axsJAXObj.speakTextViaNode(helpStr);
	     return false;
       }
};

axsSkel.init();