/*
* jQuery history plugin
*
* Copyright (c) 2006 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.
*/


jQuery.extend({
   historyCurrentHash: undefined,
   
   historyCallback: undefined,
   
   historyInit: function(callback){
      jQuery.historyCallback = callback;
      var current_hash = location.hash;
      
      jQuery.historyCurrentHash = current_hash;
      if(jQuery.browser.msie) {
         // To stop the callback firing twice during initilization if no hash present
         if (jQuery.historyCurrentHash == '') {
         jQuery.historyCurrentHash = '#';
      }
      
         // add hidden iframe for IE
         $("body").prepend('<iframe id="jQuery_history" style="display: none;"></iframe>');
         var ihistory = $("#jQuery_history")[0];
         var iframe = ihistory.contentWindow.document;
         iframe.open();
         iframe.close();
         iframe.location.hash = current_hash;
      }
      else if ($.browser.safari) {
         // etablish back/forward stacks
         jQuery.historyBackStack = [];
         jQuery.historyBackStack.length = history.length;
         jQuery.historyForwardStack = [];
         
         jQuery.isFirst = true;
      }
      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.browser.msie) {
         // On IE, check for location.hash of iframe
         var ihistory = $("#jQuery_history")[0];
         var iframe = ihistory.contentDocument || ihistory.contentWindow.document;
         var current_hash = iframe.location.hash;
         if(current_hash != jQuery.historyCurrentHash) {
         
            location.hash = current_hash;
            jQuery.historyCurrentHash = current_hash;
            jQuery.historyCallback(current_hash.replace(/^#/, ''));
            
         }
      } else if ($.browser.safari) {
         if (!jQuery.dontCheck) {
            var historyDelta = history.length - jQuery.historyBackStack.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;
                  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 (document.URL.indexOf('#') >= 0) {
                  jQuery.historyCallback(document.URL.split('#')[1]);
               } else {
                  var current_hash = location.hash;
                  jQuery.historyCallback('');
               }
               jQuery.isFirst = true;
            }
         }
      } else {
         // otherwise, check for location.hash
         var current_hash = location.hash;
         if(current_hash != jQuery.historyCurrentHash) {
            jQuery.historyCurrentHash = current_hash;
            jQuery.historyCallback(current_hash.replace(/^#/, ''));
         }
      }
   },
   historyLoad: function(hash){
      var newhash;
      
      if (jQuery.browser.safari) {
         newhash = hash;
      }
      else {
         newhash = '#' + hash;
         location.hash = newhash;
      }
      jQuery.historyCurrentHash = newhash;
      
      if(jQuery.browser.msie) {
         var ihistory = $("#jQuery_history")[0];
         var iframe = ihistory.contentWindow.document;
         iframe.open();
         iframe.close();
         iframe.location.hash = newhash;
         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);
      }
   }
});