// JavaScript Document

/*
Script: Ajax.js
		Contains the <Ajax> class. Also contains methods to generate querystings from forms and Objects.

Credits:
		Loosely based on the version from prototype.js <http://prototype.conio.net>

License:
		MIT-style license.
*/

/*
Class: Ajax
		An Ajax class, For all your asynchronous needs. Inherits methods, properties and options from <XHR>.

Arguments:
		url - the url pointing to the server-side script.
		options - optional, an object containing options.

Options:
		data - you can write parameters here. Can be a querystring, an object or a Form element.
		onComplete - function to execute when the ajax request completes.
		update - $(element) to insert the response text of the XHR into, upon completion of the request.
		evalScripts - boolean; default is false. Execute scripts in the response text onComplete. When the response is javascript the whole response is evaluated.
		evalResponse - boolean; default is false. Force global evalulation of the whole response, no matter what content-type it is.

Example:
		>var myAjax = new Ajax(url, {method: 'get'}).request();
*/
	
	var Ajax = XHR.extend({
	
	        options: {
	                data: null,
	                update: null,
	                onComplete: Class.empty,
	                evalScripts: false,
	                evalResponse: false
	        },
	
	        initialize: function(url, options){
	                this.addEvent('onSuccess', this.onComplete);
	                this.setOptions(options);
	                this.options.data = this.options.data || this.options.postBody;
	                if (!['post', 'get'].contains(this.options.method)){
	                        this._method = '_method=' + this.options.method;
	                        this.options.method = 'post';
	                }
	                this.parent();
	                this.setHeader('X-Requested-With', 'XMLHttpRequest');
	                this.setHeader('Accept', 'text/javascript, text/html, application/xml, text/xml, */*');
	                this.url = url;
	        },
	
	        onComplete: function(){
	                if (this.options.update) $(this.options.update).empty().setHTML(this.response.text);
	                if (this.options.evalScripts || this.options.evalResponse) this.evalScripts();
	                this.fireEvent('onComplete', [this.response.text, this.response.xml], 20);
	        },
	
	        /*
	        Property: request
	                Executes the ajax request.
	
	        Example:
	                >var myAjax = new Ajax(url, {method: 'get'});
	                >myAjax.request();
	
	                OR
	
	                >new Ajax(url, {method: 'get'}).request();
	        */
	
	        request: function(data){
	                data = data || this.options.data;
	                switch($type(data)){
	                        case 'element': data = $(data).toQueryString(); break;
	                        case 'object': data = Object.toQueryString(data);
	                }
	                if (this._method) data = (data) ? [this._method, data].join('&') : this._method;
	                return this.send(this.url, data);
	        },
	
	        /*
	        Property: evalScripts
	                Executes scripts in the response text
	        */
	
	        evalScripts: function(){
	                if (this.options.evalResponse || /(ecma|java)script/.test(this.getHeader('Content-type'))) var scripts = this.response.text;
	                else {
	                        var script, scripts = [], regexp = /<script[^>]*>([\s\S]*?)<\/script>/gi;
	                        while ((script = regexp.exec(this.response.text))) scripts.push(script[1]);
	                        scripts = scripts.join('\n');
	                }
	                if (scripts) (window.execScript) ? window.execScript(scripts) : window.setTimeout(scripts, 0);
	        },
	
	        /*
	        Property: getHeader
	                Returns the given response header or null
	        */
	
	        getHeader: function(name) {
	                try {return this.transport.getResponseHeader(name);} catch(e){};
	                return null;
	        }
	
	});
	
	/* Section: Object related Functions */
	
	/*
	Function: Object.toQueryString
	        Generates a querystring from key/pair values in an object
	
	Arguments:
	        source - the object to generate the querystring from.
	
	Returns:
	        the query string.
	
	Example:
	        >Object.toQueryString({apple: "red", lemon: "yellow"}); //returns "apple=red&lemon=yellow"
	*/
	
	Object.toQueryString = function(source){
	        var queryString = [];
	        for (var property in source) queryString.push(encodeURIComponent(property) + '=' + encodeURIComponent(source[property]));
	        return queryString.join('&');
	};
	
	/*
	Class: Element
	        Custom class to allow all of its methods to be used with any DOM element via the dollar function <$>.
	*/
	
	Element.extend({
	
	        /*
	        Property: send
	                Sends a form with an ajax post request
	
	        Arguments:
	                options - option collection for ajax request. See <Ajax> for the options list.
	
	        Returns:
	                The Ajax Class Instance
	
	        Example:
	                (start code)
	                <form id="myForm" action="submit.php">
	                <input name="email" value="bob@bob.com">
	                <input name="zipCode" value="90210">
	                </form>
	                <script>
	                $('myForm').send()
	                </script>
	                (end)
	        */
	
	        send: function(options){
	                return new Ajax(this.getProperty('action'), $merge({postBody: this.toQueryString()}, options, {method: 'post'})).request();
	        }
	
	});