//Throbber class

//The constructor requires the div with the throbber, and 

//the css classes used by the div when active and inactive.

function Throbber(div, active, inactive) {

	var me = this; //Just to use me instead of this

	

	//Function to activate the trobler

	me.activate = function() {

		var aux = document.getElementById(div);

		aux.setAttribute("class", active);

		aux.setAttribute("className", active); //IE sucks

	};

	

	//Function to inactivate the trobler

	me.close = function() {

		var aux = document.getElementById(div);

		aux.setAttribute("class", inactive);

		aux.setAttribute("className", inactive); //IE sucks

	};

	

}



//Semaphore class

function Semaphore() {

	var me = this; //Just to use me instead of this if a recursived function is used

	

	var status = true; //The green or red light

	me.using = 0;

	

	//Function to set green

	me.setGreen = function() {

		status = true;

	};

	

	//Is green?

	me.isGreen = function() {

		return status;

	};

	

	//Function to set red

	me.setRed = function() {

		status = false;

	};

	

	//Is red?

	me.isRed = function() {

		return !status;

	};

	

}



//Minimax Class

//Read the answer of an URL and write the contents into a 'div'

function minimax(url, div) {	

	var me = this; //Just to use me instead of this if a recursived function is used



	//The semaphore to wait if other ajax call from the same instance have been called

	me.semaphore = false;

	var haveSemaphore = false;

	

	//The throbber to indicate we are doing someting.

	var throbber=false;

	var haveThrobber=false;

	

	//The default function to attend the event

	var set_func = function () {

		//Do we have wath we need?

		if (me.xhr.readyState == 4 && me.xhr.status==200 ) {

			var text=me.xhr.responseText;

			if(haveSemaphore) { semaphore.setGreen(); }

			if(haveThrobber) { throbber.close(); }

			if(div) { document.getElementById(div).innerHTML=text; }

		}

	};

	

	//Sets the default function

	var func = set_func;

	

	//Just to declare the XMLHttpRequest

	me.xhr = false;

	

	//Function to create a XMLHttpRequest, we need this any time we start a new request

	var startXhr=function() {

	

		if (window.XMLHttpRequest) { // It it's Mozilla, Safari etc

			me.xhr = new XMLHttpRequest();

		} else { 

			if (window.ActiveXObject) { // if it's IE

				try {

					me.xhr = new ActiveXObject('Microsoft.XMLHTTP');

				} catch (e) { // if it's and old version

					try {

						me.xhr = new ActiveXObject('Msxml2.XMLHTTP');

					} catch (f){}

				}

			} else {

				return false;

			}

		}

		

		//Event handler when get the answer

		me.xhr.onreadystatechange = func;

		return true;

		

	};

	

	//Function to set another div

	me.setDiv = function(div_x) {

		div=div_x;

	};

	

	//Function to set the event handler

	me.setFunc = function(func_x) {

		func = func_x;

	};

	

	//Function to reset the event handler

	me.resetFunc = function() {

		func = set_func;

	};

	

	//Function to declare the semaphore

	me.setSemaphore = function(aux_semaphore) {

		haveSemaphore = true;

		semaphore=aux_semaphore;

		semaphore.setGreen();

		semaphore.using++;

	};

	

	//Function to declare the throbber

	me.setThrobber = function(tdiv,on,off) {

		throbber=new Throbber(tdiv,on,off);

		haveThrobber = true;

	};

	

	//For compatibility with the old gramatical error

	//Trobbler - Throbber

	me.setTrobbler = function(tdiv,on,off) {

		throbber=new Throbber(tdiv,on,off);

		haveThrobber = true;

	};

	

	//Function to inactivate the throbber

	me.closeThrobber = function() {

		if(haveThrobber) { throbber.close(); }

	};

	

	//Function to activate the throbber

	me.activateThrobber = function() {

		if(haveThrobber) { throbber.activate(); }

	};

	

	me.get = function () {

		if(haveThrobber) { throbber.activate(); }

		//If we dont't have a semaphore or it is green, call the post.

		//Else, request another get in 1 second, for we are doing 

		//something and the result from the other process would be 

		//older than ours

		if( !haveSemaphore || semaphore.isGreen()) {

			/* Explorer only accepts POST requests */

			if(haveSemaphore) { semaphore.setRed(); }

			startXhr();

			me.xhr.open('POST', url, true);

			me.xhr.send(null);

		} else { 

			setTimeout(function (){ me.get(); }, 300);

		}

	};

	

	me.post = function (post_x) {

		if(haveThrobber) { throbber.activate(); }		

		//If we dont't have a semaphore or it is green, call the post.

		//Else, request another get in 1 second, for we are doing 

		//something and the result from the other process would be 

		//older than ours

		if( !haveSemaphore || semaphore.isGreen() ) {

			post_x=post_x.replace(/\&/g, '&');

			if(haveSemaphore) { semaphore.setRed(); }

			startXhr();

			me.xhr.open('POST', url);

			me.xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

			me.xhr.send(post_x);

		} else { 

			setTimeout(function (){ me.post(post_x); }, 300);

		}

	};

	

}