/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
/*
 * Wicket Ajax Support 
 *
 * @author Igor Vaynberg
 * @author Matej Knopp 
 */

if (Function.prototype.bind == null) {
	Function.prototype.bind = function(object) {
		var __method = this;
		return function() {
			return __method.apply(object, arguments);
		}
	}
}

// Wicket Namespace

if (typeof(Wicket) == "undefined")
	Wicket = { };



/**
 * Browser types
 */

Wicket.Browser = { 
	isKHTML: function() {
		return /Konqueror|KHTML/.test(navigator.userAgent) && !/Apple/.test(navigator.userAgent);
	},
	
	isSafari: function() {
		return /KHTML/.test(navigator.userAgent) && /Apple/.test(navigator.userAgent);
	},
	
	isOpera: function() {
		return !Wicket.Browser.isSafari() && typeof(window.opera) != "undefined";
	},

	isIE: function() {
		return !Wicket.Browser.isSafari() && typeof(document.all) != "undefined" && typeof(window.opera) == "undefined";
	},
	
	isIEQuirks: function() {
		// is the browser internet explorer in quirks mode (we could use document.compatMode too)		
		return Wicket.Browser.isIE() && document.documentElement.clientHeight == 0;
	},		
	
	isIELessThan7: function() {
		var index = navigator.userAgent.indexOf("MSIE");
		var version = parseFloat(navigator.userAgent.substring(index + 5));
		return Wicket.Browser.isIE() && version < 7;
	},
	
	isIE7: function() {
		var index = navigator.userAgent.indexOf("MSIE");
		var version = parseFloat(navigator.userAgent.substring(index + 5));
		return Wicket.Browser.isIE() && version >= 7;
	},
	
	isGecko: function() {
		return /Gecko/.test(navigator.userAgent) && !Wicket.Browser.isSafari();
	}
};





/**
 * Events related code
 * Based on code from Mootools (http://mootools.net)
 */

Wicket.Event = {
	idCounter: 0,
	
	getId: function(element) {
		var current = element.getAttribute("id");
		if (typeof(current) == "string" && current.length > 0) {
			return current;
		} else {
			current = "wicket-generated-id-" + Wicket.Event.idCounter++;
			element.setAttribute("id", current);
			return current;
		}
	},
	
	handler: function() {
		var id = this[0];
		var original = this[1];
		var element = Wicket.$(id);
		original.bind(element)();
	},

	// adds an event of specified type to the element
	// also supports the domready event on window
	// domready is event fired when the DOM is complete, but before loading external resources (images, ...)
	add: function(element, type, fn) {
		// is the event domready?
		if (element == window && type == "domready") {
			Wicket.Event.addDomReadyEvent(fn);
		} else {
			if (element.addEventListener){
				element.addEventListener((type == 'mousewheel' && Wicket.Browser.isGecko()) ? 'DOMMouseScroll' : type, fn, false);
			} else {
				if (element == window || element == document)   {
					fn = fn.bind(element);
				}
				else {
					fn = Wicket.Event.handler.bind([Wicket.Event.getId(element), fn]);					
				}				
				// Because of the fn.bind (returning a new function object)
				// you can't detach the event first to be sure that there are no doubles :(
				//element.detachEvent('on'+type, fn);
				element.attachEvent('on'+type, fn);
			}
		}
		return element;
	},
	
	// handlers that will be fired on dom ready event
	domReadyHandlers : new Array(),
	
	// fires the dom ready event and cleanup the handlers
	fireDomReadyHandlers : function() {
		var h = Wicket.Event.domReadyHandlers;
		while (h.length > 0) {
			var c = h.shift();
			c();
		}
		Wicket.Event.domReadyHandlers = null;
	},
	
	// adds the dom ready event 
	addDomReadyEvent : function(fn) {
		// is the window already loaded?
		if (window.loaded)  {
			fn();
		} else if (!window.events || !window.events.domready) {
			// register the handler
			Wicket.Event.domReadyHandlers.push(fn);
		
			// callback
			var domReady = function() {
				if (window.loaded) 
					return;
				window.loaded = true;
				
				// invoke the handlers
				Wicket.Event.fireDomReadyHandlers();
			}.bind(this);
			
			if (document.readyState && (Wicket.Browser.isKHTML() || Wicket.Browser.isSafari())) { 
			  //safari and konqueror don't support the event - simulate it through a timeout
				var domCheck = function() {
					if (document.readyState == "loaded" ||
					    document.readyState == "complete") {
					    domReady();
					} else {
						// dom not yet ready, set timer to check later
						window.setTimeout(domCheck, 10);
					}
				}
				window.setTimeout(domCheck, 10);
			} else if (document.readyState && Wicket.Browser.isIE()) { 
				if (document.getElementById('ie_ready') == null) {
					// for internet explorer we need to load a "dummy" scrip from ::/ to get the 
					// readystatechangeevernt - that means the main page being loaded and now the browser
					// is loading dependencies
					var src = (window.location.protocol == 'https:') ? '\/\/:' : 'javascript:void(0)';
					document.write('<script id="ie_ready" defer src="' + src + '"><\/script>');
					document.getElementById('ie_ready').onreadystatechange = function() {
						if (this.readyState == 'complete') domReady();
					};
				}
			} else { 
				// other browsers
				Wicket.Event.add(document, "DOMContentLoaded", domReady);
			}
		} else {
			window.addEventListener("domready", fn, false);
		}
	}
}