(function($){

$.idleTimeout = function(element, resume, options){

// overwrite $.idleTimeout.options with the results of $.extend. Allows you to write and a callback then call it from
// from a jQuery UI button or something
options = $.idleTimeout.options = $.extend({}, $.idleTimeout.options, options);

var IdleTimeout = {
init: function(){
var self = this;

this.warning = $(element);
this.resume = $(resume);
this.countdownOpen = false;
this.failedRequests = options.failedRequests;
this._startTimer();

// start the idle timer
$.idleTimer(options.idleAfter * 1000);

// once the user becomes idle
$(document).bind("idle.idleTimer", function(){

// if the user is idle and a countdown isn't already running
if( $.data(document, 'idleTimer') === 'idle' && !self.countdownOpen ){
self._stopTimer();
self.countdownOpen = true;
self._idle();
}
});

// bind continue link
this.resume.bind("click", function(e){
e.preventDefault();

window.clearInterval(self.countdown); // stop the countdown
self.countdownOpen = false; // stop countdown
self._startTimer(); // start up the timer again
options.onResume.call( self.warning ); // call the resume callback
});
},

_idle: function(){
var self = this,
warning = this.warning[0],
counter = options.warningLength;

// fire the onIdle function
options.onIdle.call(warning);

// set inital value in the countdown placeholder
options.onCountdown.call(warning, counter);

// create a timer that runs every second
this.countdown = window.setInterval(function(){
counter -= 1;

if(counter === 0){
window.clearInterval(self.countdown);
options.onTimeout.call(warning);
} else {
options.onCountdown.call(warning, counter);
}

}, 1000);
},

_startTimer: function(){
this.timer = setTimeout(
$.proxy(this._keepAlive, this),
options.pollingInterval * 1000
);
},

_stopTimer: function(){
// reset the failed requests counter
this.failedRequests = options.failedRequests;
clearTimeout(this.timer);
},

_keepAlive: function(){
var self = this;

// if too many requests failed, abort
if( !this.failedRequests ){
this._stopTimer();
options.onAbort.call( this.warning[0] );
return;
}

$.ajax({
timeout: options.AJAXTimeout,
url: options.keepAliveURL,
error: function(){
self.failedRequests--;
self._startTimer();
},
success: function(response){
if($.trim(response) !== options.serverResponseEquals){
self.failedRequests--;
}

self._startTimer();
}
});
}
};

// run this thang
IdleTimeout.init();
};

$.idleTimeout.options = {
// number of seconds after user is idle to show the warning
warningLength: 30,

// url to call to keep the session alive while the user is active
keepAliveURL: "",

// the response from keepAliveURL must equal this text:
serverResponseEquals: "OK",

// user is considered idle after this many seconds. 10 minutes default
idleAfter: 600,

// a polling request will be sent to the server every X seconds
pollingInterval: 60,

// number of failed polling requests until we abort this script
failedRequests: 5,

// the $.ajax timeout in MILLISECONDS!
AJAXTimeout: 250,

/*
Callbacks
"this" refers to the element found by the first selector passed to $.idleTimeout.
*/
// callback to fire when the session times out
onTimeout: function(){},

// fires when the user becomes idle
onIdle: function(){},

// fires during each second of warningLength
onCountdown: function(){},

// fires when the user resumes the session
onResume: function(){},

// callback to fire when the script is aborted due to too many failed requests
onAbort: function(){}
};

})(jQuery);