/*

 * 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.

 */





jQuery.extend({

	historyCurrentHash: undefined,

	historyCallback: undefined,

	historyIframeSrc: undefined,

	

	historyInit: function(callback, src){

		jQuery.historyCallback = callback;

		if (src) jQuery.historyIframeSrc = src;

		var current_hash = location.hash.replace(/\?.*$/, '');

		

		jQuery.historyCurrentHash = current_hash;

		// if ((jQuery.browser.msie) && (jQuery.browser.version < 8)) {

		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

			jQuery("body").prepend('<iframe id="jQuery_history" style="display: none;"'+

				(jQuery.historyIframeSrc ? ' src="'+jQuery.historyIframeSrc+'"' : '')

				+'></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.browser.msie) && (jQuery.browser.version < 8)) {

		if (jQuery.browser.msie) {

			// 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

			var current_hash = location.hash.replace(/\?.*$/, '');

			if(current_hash != jQuery.historyCurrentHash) {

				jQuery.historyCurrentHash = current_hash;

				jQuery.historyCallback(current_hash.replace(/^#/, ''));

			}

		}

	},

	historyLoad: function(hash){

		var newhash;

		hash = decodeURIComponent(hash.replace(/\?.*$/, ''));

		

		if (jQuery.browser.safari) {

			newhash = hash;

		}

		else {

			newhash = '#' + hash;

			location.hash = newhash;

		}

		jQuery.historyCurrentHash = newhash;

		

		// if ((jQuery.browser.msie) && (jQuery.browser.version < 8)) {

		if (jQuery.browser.msie) {

			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);

		}

	}

});