/*
 * jQuery history plugin
 * 
 * sample page: http://www.mikage.to/jquery/jquery_history.html
 *
 * Copyright (c) 2006-2009 Taku Sano (Mikage Sawatari)
 * Licensed under the MIT License:
 *   http://www.opensource.org/licenses/mit-license.php
 *
 * Modified by Lincoln Cooper to add Safari support and only call the callback once during initialization
 * for msie when no initial hash supplied.
 * 
 * Modified by Joe Lencioni (http://shiftingpixel.com) to fix Firefox hash bug.
 */


jQuery.extend({
 historyCurrentHash: undefined,
 historyCallback: undefined,
 historyIframeSrc: undefined,
 historyNeedIframe: jQuery.browser.msie && (jQuery.browser.version < 8 || document.documentMode < 8),
 
 historyInit: function(callback, src){
  jQuery.historyCallback = callback;
  if (src) jQuery.historyIframeSrc = src;
  
  if (location.hash == '')
   var current_hash = '#';
  else
  {
   var current_hash = location.href.replace(/.*?#/, '#');
   current_hash = current_hash.replace(/\?.*$/, '');
  }
  
  jQuery.historyCurrentHash = current_hash;
  if (jQuery.historyNeedIframe) {
   // To stop the callback firing twice during initilization if no hash present
   if (jQuery.historyCurrentHash == '') {
    jQuery.historyCurrentHash = '#';
   }
  
   // add hidden iframe for IE
   jQuery("body").prepend('<iframe id="jQuery_history" style="display: none;"'+
    ' src="javascript:false;"></iframe>'
   );
   var ihistory = jQuery("#jQuery_history")[0];
   var iframe = ihistory.contentWindow.document;
   iframe.open();
   iframe.close();
   iframe.location.hash = current_hash;
  }
  else if (jQuery.browser.safari) {
   // etablish back/forward stacks
   jQuery.historyBackStack = [];
   jQuery.historyBackStack.length = history.length;
   jQuery.historyForwardStack = [];
   jQuery.lastHistoryLength = history.length;
   
   jQuery.isFirst = true;
  }
  if(current_hash)
   jQuery.historyCallback(current_hash.replace(/^#/, ''));
  setInterval(jQuery.historyCheck, 100);
 },
 
 historyAddHistory: function(hash) {
  // This makes the looping function do something
  jQuery.historyBackStack.push(hash);
  
  jQuery.historyForwardStack.length = 0; // clear forwardStack (true click occured)
  this.isFirst = true;
 },
 
 historyCheck: function(){
  if (jQuery.historyNeedIframe) {
   // On IE, check for location.hash of iframe
   var ihistory = jQuery("#jQuery_history")[0];
   var iframe = ihistory.contentDocument || ihistory.contentWindow.document;
   var current_hash = iframe.location.hash.replace(/\?.*$/, '');
   if(current_hash != jQuery.historyCurrentHash) {
   
    location.hash = current_hash;
    jQuery.historyCurrentHash = current_hash;
    jQuery.historyCallback(current_hash.replace(/^#/, ''));
    
   }
  } else if (jQuery.browser.safari) {
   if(jQuery.lastHistoryLength == history.length && jQuery.historyBackStack.length > jQuery.lastHistoryLength) {
    jQuery.historyBackStack.shift();
   }
   if (!jQuery.dontCheck) {
    var historyDelta = history.length - jQuery.historyBackStack.length;
    jQuery.lastHistoryLength = history.length;
    
    if (historyDelta) { // back or forward button has been pushed
     jQuery.isFirst = false;
     if (historyDelta < 0) { // back button has been pushed
      // move items to forward stack
      for (var i = 0; i < Math.abs(historyDelta); i++) jQuery.historyForwardStack.unshift(jQuery.historyBackStack.pop());
     } else { // forward button has been pushed
      // move items to back stack
      for (var i = 0; i < historyDelta; i++) jQuery.historyBackStack.push(jQuery.historyForwardStack.shift());
     }
     var cachedHash = jQuery.historyBackStack[jQuery.historyBackStack.length - 1];
     if (cachedHash != undefined) {
      jQuery.historyCurrentHash = location.hash.replace(/\?.*$/, '');
      jQuery.historyCallback(cachedHash);
     }
    } else if (jQuery.historyBackStack[jQuery.historyBackStack.length - 1] == undefined && !jQuery.isFirst) {
     // back button has been pushed to beginning and URL already pointed to hash (e.g. a bookmark)
     // document.URL doesn't change in Safari
     if (location.hash) {
      var current_hash = location.hash;
      jQuery.historyCallback(location.hash.replace(/^#/, ''));
     } else {
      var current_hash = '';
      jQuery.historyCallback('');
     }
     jQuery.isFirst = true;
    }
   }
  } else {
   // otherwise, check for location.hash
   
   if (location.hash == '')
    var current_hash = '#';
   else
   {
    var current_hash = location.href.replace(/.*?#/, '#');
    current_hash = current_hash.replace(/\?.*$/, '');
   }
   
   if(current_hash != jQuery.historyCurrentHash) {
    jQuery.historyCurrentHash = current_hash;
    jQuery.historyCallback(current_hash.replace(/^#/, ''));
   }
  }
 },
 historyLoad: function(hash,parameter_hash){
 //alert(parameter_hash);
  var newhash;
  hash = decodeURIComponent(hash.replace(/\?.*$/, ''));
  
  if (jQuery.browser.safari) {
   newhash = hash;
  }
  else {
   newhash = '#' + hash;
   location.hash = newhash;
  }
  jQuery.historyCurrentHash = newhash;
  
  if (jQuery.historyNeedIframe) {
   var ihistory = jQuery("#jQuery_history")[0];
   var iframe = ihistory.contentWindow.document;
   iframe.open();
   iframe.close();
   iframe.location.hash = newhash;
   jQuery.lastHistoryLength = history.length;
   jQuery.historyCallback(hash);
  }
  else if (jQuery.browser.safari) {
   jQuery.dontCheck = true;
   // Manually keep track of the history values for Safari
   this.historyAddHistory(hash);
   
   // Wait a while before allowing checking so that Safari has time to update the "history" object
   // correctly (otherwise the check loop would detect a false change in hash).
   var fn = function() {jQuery.dontCheck = false;};
   window.setTimeout(fn, 200);
   jQuery.historyCallback(hash);
   // N.B. "location.hash=" must be the last line of code for Safari as execution stops afterwards.
   //      By explicitly using the "location.hash" command (instead of using a variable set to "location.hash") the
   //      URL in the browser and the "history" object are both updated correctly.
   location.hash = newhash;
  }
  else {
    jQuery.historyCallback(hash);
  }
 }
});