/**
 * AtlantisEngine.js a lightweight JavaScript game engine.
 *
 * @module Atlantis
 * @submodule Framework
 * @namespace Atlantis
 */

var Atlantis = window.Atlantis || {};

/**
* Create a game time object who's responsible to get time informations.
* @constructor
* @class GameTime
*/
Atlantis.GameTime = function () {
    this.reset();
};

/**
* Reset the game timer.
* @method reset
*/
Atlantis.GameTime.prototype.reset = function () {
    this.elapsedTime = 0;
    this.totalGameTime = 0;
    this.currentTime = +new Date();
    this.fps = 0;
};

/**
* Update the game time.
* @method update
*/
Atlantis.GameTime.prototype.update = function () {
    var now = +new Date();
    this.elapsedTime = now - this.currentTime;
    this.totalGameTime += this.elapsedTime;
    this.fps = 1000 / (now - this.currentTime);
    this.currentTime = now;
};

/**
* Gets the elapsed time since last frame.
* @method getElapsedTime
* @return {Number} The elapsed time since last frame.
*/
Atlantis.GameTime.prototype.getElapsedTime = function () {
    return this.elapsedTime;
};

/**
* Gets the total elapsed time since the begining.
* @method getTotalGameTime
* @return {Number} The total elapsed time.
*/
Atlantis.GameTime.prototype.getTotalGameTime = function () {
    return this.totalGameTime;
};

/**
 * Gets the current FPS indice.
 * @method getFPS
 * @return {Number} Return the current FPS.
 */
Atlantis.GameTime.prototype.getFPS = function () {
    return this.fps;
};