/*
 * 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.
 */


function getHash(loc) {
    loc = loc.toString();
    if (loc.indexOf("#") != -1)
        return loc.substring(loc.indexOf("#"));
        else return "";
}

jQuery.extend({
  historyCurrentHash: undefined,

  historyCallback: undefined,

  historyInit: function(callback){
    jQuery.historyCallback = callback;
    var current_hash = getHash(location);

    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(/^#/, ''));
    window.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 = $("#jQuery_history")[0];
      var iframe = ihistory.contentDocument || ihistory.contentWindow.document;
      //var current_hash = iframe.location.hash;
      var current_hash = getHash(iframe.location);
      //$('body').append('current_hash='+current_hash+',jQuery.historyCurrentHash='+jQuery.historyCurrentHash+'<br>');
      if(current_hash != jQuery.historyCurrentHash) {
        location.hash = current_hash;
        jQuery.historyCurrentHash = current_hash;
        jQuery.historyCallback(current_hash.replace(/^#/, ''));
      } else {
        if (location.hash != current_hash) {
            location.hash = current_hash;
        }
      }
    } else if ($.browser.safari) {
      if (!jQuery.dontCheck) {
        var historyDelta = history.length - jQuery.historyBackStack.length;

        /*
          if (typeof jQuery.lastAppend == 'undefined') {
            jQuery.lastAppend = location.hash;
            $('body').append('jQuery.lastAppend='+jQuery.lastAppend);
          }
          if (jQuery.lastAppend != location.hash) {
            jQuery.lastAppend = location.hash;
            $('body').append('jQuery.lastAppend='+jQuery.lastAppend);
          }
          */

        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 = getHash(location);
            cachedHash = getHash(location);
            jQuery.historyCallback(cachedHash.replace(/^#/, ''));
          }
        } else if (jQuery.historyCurrentHash != getHash(location.hash)) {
          var current_hash = getHash(location.hash);
          jQuery.historyCallback(location.hash.replace(/^#/, ''));
        }
      }
    } else {
      // otherwise, check for location.hash
      var current_hash = getHash(location);

      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;
       if ((jQuery.historyCurrentHash == newhash) && (jQuery.dblChk)) {
         return;
       }
      location.hash = newhash;
    }
    jQuery.dblChk = true;
    window.setTimeout(function() {jQuery.dblChk = false}, 200);
    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);
    }

  }
});