/**
 * History/Remote - jQuery plugin for enabling history support and bookmarking
 * @requires jQuery v1.0.3
 *
 * http://stilbuero.de/jquery/history/
 *
 * Copyright (c) 2006 Klaus Hartl (stilbuero.de)
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 * Version: 0.2.3
 */

(function($) { // block scope

$.ajaxHistory = new function() {

    var RESET_EVENT = 'historyReset';
    var _currentHash = location.hash;
    var _intervalId = null;
    var _observeHistory; // define outside if/else required by Opera
	var idBlock = '';

    this.update = function() { }; // empty function body for graceful degradation

	this.setBlock = function(block){
		idBlock = block;	
	}
	this.location = function(hash){
		location.hash = hash;	
	}
    // create custom event for state reset
    var _defaultReset = function() {
        $('.remote-output').empty();
    };
    $(document).bind(RESET_EVENT, _defaultReset);
    
    // TODO fix for Safari 3
    // if ($.browser.msie)
    // else if hash != _currentHash
    // else check history length
    if ($.browser.msie) {

        var _historyIframe, initialized = false; // for IE

        // add hidden iframe
        $(function() {
            _historyIframe = $('<iframe style="display: none;"></iframe>').appendTo(document.body).get(0);
            var iframe = _historyIframe.contentWindow.document;
            // create initial history entry
            iframe.open();
            iframe.close();
            if (_currentHash && _currentHash != '#') {
                iframe.location.hash = _currentHash.replace('#', '');
            }
        });

        this.update = function(hash) {
            _currentHash = hash;
            var iframe = _historyIframe.contentWindow.document;
            iframe.open();
            iframe.close();
            iframe.location.hash = hash.replace('#', '');
        };

        _observeHistory = function() {
            var iframe = _historyIframe.contentWindow.document;
            var iframeHash = iframe.location.hash;
            if (iframeHash != _currentHash) {
                _currentHash = iframeHash;
                if (iframeHash && iframeHash != '#') {
                    // order does matter, set location.hash after triggering the click...
                    $(idBlock+'a[@href$="' + iframeHash + '"]').click();
                    location.hash = iframeHash;
                } else if (initialized) {
                    location.hash = '';
                    $(document).trigger(RESET_EVENT);
                }
            }
            initialized = true;
        };

    } else if ($.browser.mozilla || $.browser.opera) {
        this.update = function(hash) {
            _currentHash = hash;
        };

        _observeHistory = function() {
            if (location.hash) {
                if (_currentHash != location.hash) {
                    _currentHash = location.hash;		
                    $(idBlock+' a[@href$="' + _currentHash + '"]').click();
                }
            } else if (_currentHash) {
                _currentHash = '';
                $(document).trigger(RESET_EVENT);
            }
        };

    } else if ($.browser.safari) {

        var _backStack, _forwardStack, _addHistory; // for Safari

        // etablish back/forward stacks
        $(function() {
            _backStack = [];
            _backStack.length = history.length;
            _forwardStack = [];

        });
        var isFirst = false, initialized = false;
        _addHistory = function(hash) {
            _backStack.push(hash);
            _forwardStack.length = 0; // clear forwardStack (true click occured)
            isFirst = false;
        };

        this.update = function(hash) {
            _currentHash = hash;
            _addHistory(_currentHash);
        };

        _observeHistory = function() {
            var historyDelta = history.length - _backStack.length;
            if (historyDelta) { // back or forward button has been pushed
                isFirst = false;
                if (historyDelta < 0) { // back button has been pushed
                    // move items to forward stack
                    for (var i = 0; i < Math.abs(historyDelta); i++) _forwardStack.unshift(_backStack.pop());
                } else { // forward button has been pushed
                    // move items to back stack
                    for (var i = 0; i < historyDelta; i++) _backStack.push(_forwardStack.shift());
                }
                var cachedHash = _backStack[_backStack.length - 1];
                $(idBlock+'a[@href$="' + cachedHash + '"]').click();
                _currentHash = location.hash;
            } else if (_backStack[_backStack.length - 1] == undefined && !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) {
                    $('a[@href$="' + '#' + document.URL.split('#')[1] + '"]').click();
                } else if (initialized) {
                    $(document).trigger(RESET_EVENT);
                }
                isFirst = true;
            }
            initialized = true;
        };

    }

    this.initialize = function(callback) {
        // custom callback to reset app state (no hash in url)
        if (typeof callback == 'function') {
            $(document).unbind(RESET_EVENT, _defaultReset).bind(RESET_EVENT, callback);
        }
        // look for hash in current URL (not Safari)
        if (location.hash && typeof _addHistory == 'undefined') {
            $(idBlock+' a[@href$="' + location.hash + '"]').trigger('click');
        }
        // start observer
        if (_observeHistory && _intervalId == null) {
            _intervalId = setInterval(_observeHistory, 200); // Safari needs at least 200 ms
        }
    };

};


$.fn.remote = function(output, settings, callback) {

    callback = callback || function() {};
    if (typeof settings == 'function') { // shift arguments
        callback = settings;
    }
    
	settings.onBefore = settings.onBefore || function(){};
	
    settings = $.extend({
        hashPrefix: 'remote-'
    }, settings || {});

    var target = $(output).size() && $(output) || $('<div></div>').appendTo('body');
    target.addClass('remote-output');

    return this.each(function(i) {
							  
		var href = this.href;
		if(settings.url != ''){
			if(settings.urlEval){
			href = eval(settings.url);
			} else {
			href = settings.url;				
			}
		}
        var hash = '#' + (this.title && this.title.replace(/\s/g, '_') || settings.hashPrefix + (i + 1)),
            a = this;
        this.href = hash;
        $(this).click(function(e) {
			settings.onBefore.apply(a);							  							   
            // lock target to prevent double loading in Firefox
            if (!target['locked']) {
                // add to history only if true click occured, not a triggered click
                if (e.clientX) {
                    $.ajaxHistory.update(hash);
                }
                target.load(href, function() {
                    target['locked'] = null;
                    callback.apply(a);
                });
            }
        });
    });

};

$.fn.history = function(callback) {
    return this.click(function(e) {        
        // add to history only if true click occured, not a triggered click
        if (e.clientX) {
            $.ajaxHistory.update(this.hash);
        }
        typeof callback == 'function' && callback();
    });
};

})(jQuery);