// AJAX Plugin
// Docs Here:
// http://jquery.com/docs/ajax/

/**
 * Load HTML from a remote file and inject it into the DOM
 */
jQuery.fn.loadIfModified = function( url, params, callback ) {
	this.load( url, params, callback, 1 );
};

jQuery.fn.load = function( url, params, callback, ifModified ) {
	if ( url.constructor == Function )
		return this.bind("load", url);

	callback = callback || function(){};

	// Default to a GET request
	var type = "GET";

	// If the second parameter was provided
	if ( params ) {
		// If it's a function
		if ( params.constructor == Function ) {
			// We assume that it's the callback
			callback = params;
			params = null;
			
		// Otherwise, build a param string
		} else {
			params = jQuery.param( params );
			type = "POST";
		}
	}
	
	var self = this;
	
	// Request the remote document
	jQuery.ajax( type, url, params,function(res, status){
		
		if ( status == "success" || !ifModified && status == "notmodified" ) {
			// Inject the HTML into all the matched elements
			self.html(res.responseText).each( callback, [res.responseText, status] );
			
			// Execute all the scripts inside of the newly-injected HTML
			$("script", self).each(function(){
				if ( this.src )
					$.getScript( this.src );
				else
					eval.call( window, this.text || this.textContent || this.innerHTML || "" );
			});
		} else
			callback.apply( self, [res.responseText, status] );

	}, ifModified);
	
	return this;
};

// If IE is used, create a wrapper for the XMLHttpRequest object
if ( jQuery.browser.msie )
	XMLHttpRequest = function(){
		return new ActiveXObject(
			navigator.userAgent.indexOf("MSIE 5") >= 0 ?
			"Microsoft.XMLHTTP" : "Msxml2.XMLHTTP"
		);
	};

// Attach a bunch of functions for handling common AJAX events
new function(){
	var e = "ajaxStart,ajaxStop,ajaxComplete,ajaxError,ajaxSuccess".split(',');
	
	for ( var i = 0; i < e.length; i++ ) new function(){
		var o = e[i];
		jQuery.fn[o] = function(f){
			return this.bind(o, f);
		};
	};
};

jQuery.extend({

	/**
	 * Load a remote page using a GET request
	 */
	get: function( url, data, callback, type, ifModified ) {
		if ( data.constructor == Function ) {
			type = callback;
			callback = data;
			data = null;
		}
		
		if ( data ) url += "?" + jQuery.param(data);
		
		// Build and start the HTTP Request
		jQuery.ajax( "GET", url, null, function(r, status) {
			if ( callback ) callback( jQuery.httpData(r,type), status );
		}, ifModified);
	},

	getIfModified: function( url, data, callback, type ) {
		jQuery.get(url, data, callback, type, 1);
	},

	getScript: function( url, data, callback ) {
		jQuery.get(url, data, callback, "script");
	},
	
	/**
	 * Load a remote page using a POST request.
	 */
	post: function( url, data, callback, type ) {
		// Build and start the HTTP Request
		jQuery.ajax( "POST", url, jQuery.param(data), function(r, status) {
			if ( callback ) callback( jQuery.httpData(r,type), status );
		});
	},
	
	// timeout (ms)
	timeout: 0,

	ajaxTimeout: function(timeout) {
		jQuery.timeout = timeout;
	},

	// Last-Modified header cache for next request
	lastModified: {},
	
	/**
	 * A common wrapper for making XMLHttpRequests
	 */
	ajax: function( type, url, data, ret, ifModified ) {
		// If only a single argument was passed in,
		// assume that it is a object of key/value pairs
		if ( !url ) {
			ret = type.complete;
			var success = type.success;
			var error = type.error;
			data = type.data;
			url = type.url;
			type = type.type;
		}
		
		// Watch for a new set of requests
		if ( ! jQuery.active++ )
			jQuery.event.trigger( "ajaxStart" );
	
		// Create the request object
		var xml = new XMLHttpRequest();
	
		// Open the socket
		xml.open(type || "GET", url, true);
		
		// Set the correct header, if data is being sent
		if ( data )
			xml.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
		
		// Set the If-Modified-Since header, if ifModified mode.
		if ( ifModified )
			xml.setRequestHeader("If-Modified-Since",
				jQuery.lastModified[url] || "Thu, 01 Jan 1970 00:00:00 GMT" );
		
		// Set header so calling script knows that it's an XMLHttpRequest
		xml.setRequestHeader("X-Requested-With", "XMLHttpRequest");
	
		// Make sure the browser sends the right content length
		if ( xml.overrideMimeType )
			xml.setRequestHeader("Connection", "close");
		
		// Wait for a response to come back
		var onreadystatechange = function(istimeout){
			// The transfer is complete and the data is available, or the request timed out
			if ( xml && (xml.readyState == 4 || istimeout) ) {
				var status = jQuery.httpSuccess( xml ) && !istimeout ?
					ifModified && jQuery.httpNotModified( xml, url ) ? "notmodified" : "success" : "error";
				
				// Make sure that the request was successful or notmodified
				if ( status != "error" ) {
					// Cache Last-Modified header, if ifModified mode.
					var modRes = xml.getResponseHeader("Last-Modified");
					if ( ifModified && modRes ) jQuery.lastModified[url] = modRes;
					
					// If a local callback was specified, fire it
					if ( success ) success( xml, status );
					
					// Fire the global callback
					jQuery.event.trigger( "ajaxSuccess" );
				
				// Otherwise, the request was not successful
				} else {
					// If a local callback was specified, fire it
					if ( error ) error( xml, status );
					
					// Fire the global callback
					jQuery.event.trigger( "ajaxError" );
				}
				
				// The request was completed
				jQuery.event.trigger( "ajaxComplete" );
				
				// Handle the global AJAX counter
				if ( ! --jQuery.active )
					jQuery.event.trigger( "ajaxStop" );
	
				// Process result
				if ( ret ) ret(xml, status);
				
				// Stop memory leaks
				xml.onreadystatechange = function(){};
				xml = null;
				
			}
		};
		xml.onreadystatechange = onreadystatechange;
		
		// Timeout checker
		if(jQuery.timeout > 0)
			setTimeout(function(){
				// Check to see if the request is still happening
				if (xml) {
					// Cancel the request
					xml.abort();

					// for Opera. Opera does't call onreadystatechange when aborted.
					if (xml) onreadystatechange(1);

					// Clear from memory
					xml = null;
				}
			}, jQuery.timeout);
		
		// Send the data
		xml.send(data);
	},
	
	// Counter for holding the number of active queries
	active: 0,
	
	// Determines if an XMLHttpRequest was successful or not
	httpSuccess: function(r) {
		try {
			return r.status ?
				( r.status >= 200 && r.status < 300 ) || r.status == 304 :
				location.protocol == "file:";
		} catch(e){}

		return false;
	},

	// Determines if an XMLHttpRequest returns NotModified
	httpNotModified: function(xml, url) {
		try {
			var xmlRes = xml.getResponseHeader("Last-Modified");

			// Firefox always returns 200. check Last-Modified date
			if( xml.status == 304 || xmlRes == jQuery.lastModified[url]  ) return true;
		} catch(e){}

		return false;
	},
	
	// Get the data out of an XMLHttpRequest.
	// Return parsed XML if content-type header is "xml" and type is "xml" or omitted,
	// otherwise return plain text.
	httpData: function(r,type) {
		var ct = r.getResponseHeader("content-type");
		var data = ( !type || type == "xml" ) && ct && ct.indexOf("xml") >= 0;
		data = data ? r.responseXML : r.responseText;

		// If the type is "script", eval it
		if ( type == "script" ) eval.call( window, data );

		return data;
	},
	
	// Serialize an array of form elements or a set of
	// key/values into a query string
	param: function(a) {
		var s = [];
		
		// If an array was passed in, assume that it is an array
		// of form elements
		if ( a.constructor == Array ) {
			// Serialize the form elements
			for ( var i = 0; i < a.length; i++ )
				s.push( a[i].name + "=" + encodeURIComponent( a[i].value ) );
			
		// Otherwise, assume that it's an object of key/value pairs
		} else {
			// Serialize the key/values
			for ( var j in a )
				s.push( j + "=" + encodeURIComponent( a[j] ) );
		}
		
		// Return the resulting serialization
		return s.join("&");
	}

});