/*

 * 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.

 * API rewrite by Lauris Bukšis-Haberkorns

 */



(function($) {



function History()

{

	this._curHash = '';

	this._callback = function(hash){};

};



$.extend(History.prototype, {



	init: function(callback) {

		this._callback = callback;

		this._curHash = location.hash;



		if($.browser.msie) {

			// To stop the callback firing twice during initilization if no hash present

			if (this._curHash == '') {

				this._curHash = '#';

			}



			// add hidden iframe for IE

			$("body").prepend('<iframe id="jQuery_history" style="display: none;"></iframe>');

			var iframe = $("#jQuery_history")[0].contentWindow.document;

			iframe.open();

			iframe.close();

			iframe.location.hash = this._curHash;

		}

		else if ($.browser.safari) {

			// etablish back/forward stacks

			this._historyBackStack = [];

			this._historyBackStack.length = history.length;

			this._historyForwardStack = [];

			this._isFirst = true;

			this._dontCheck = false;

		}

		this._callback(this._curHash.replace(/^#/, ''));

		setInterval(this._check, 100);

	},



	add: function(hash) {

		// This makes the looping function do something

		this._historyBackStack.push(hash);

		

		this._historyForwardStack.length = 0; // clear forwardStack (true click occured)

		this._isFirst = true;

	},

	

	_check: function() {

		if($.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 != $.history._curHash) {

			

				location.hash = current_hash;

				$.history._curHash = current_hash;

				$.history._callback(current_hash.replace(/^#/, ''));

				

			}

		} else if ($.browser.safari) {

			if (!$.history._dontCheck) {

				var historyDelta = history.length - $.history._historyBackStack.length;

				

				if (historyDelta) { // back or forward button has been pushed

					$.history._isFirst = false;

					if (historyDelta < 0) { // back button has been pushed

						// move items to forward stack

						for (var i = 0; i < Math.abs(historyDelta); i++) $.history._historyForwardStack.unshift($.history._historyBackStack.pop());

					} else { // forward button has been pushed

						// move items to back stack

						for (var i = 0; i < historyDelta; i++) $.history._historyBackStack.push($.history._historyForwardStack.shift());

					}

					var cachedHash = $.history._historyBackStack[$.history._historyBackStack.length - 1];

					if (cachedHash != undefined) {

						$.history._curHash = location.hash;

						$.history._callback(cachedHash);

					}

				} else if ($.history._historyBackStack[$.history._historyBackStack.length - 1] == undefined && !$.history._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) {

						$.history._callback(document.URL.split('#')[1]);

					} else {

						$.history._callback('');

					}

					$.history._isFirst = true;

				}

			}

		} else {

			// otherwise, check for location.hash

			var current_hash = location.hash;

			if(current_hash != $.history._curHash) {

				$.history._curHash = current_hash;

				$.history._callback(current_hash.replace(/^#/, ''));

			}

		}

	},



	load: function(hash) {

		var newhash;

		

		if ($.browser.safari) {

			newhash = hash;

		} else {

			newhash = '#' + hash;

			location.hash = newhash;

		}

		this._curHash = newhash;

		

		if ($.browser.msie) {

			var ihistory = $("#jQuery_history")[0]; // TODO: need contentDocument?

			var iframe = ihistory.contentWindow.document;

			iframe.open();

			iframe.close();

			iframe.location.hash = newhash;

			this._callback(hash);

		}

		else if ($.browser.safari) {

			this._dontCheck = true;

			// Manually keep track of the history values for Safari

			this.add(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() {$.history._dontCheck = false;};

			window.setTimeout(fn, 200);

			this._callback(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 {

		  this._callback(hash);

		}

	}

});



$(document).ready(function() {

	$.history = new History(); // singleton instance

});



})(jQuery);