Tween = {};
Tween.activeTweens = [];
Tween.idCounter = 0;
Tween.create = (obj, targetProperties, duration, easing, completedCallback) => {
	let singleTween = {};
	singleTween.id = ++Tween.idCounter;
	singleTween.obj = obj;
	singleTween.objStart = {};
	singleTween.objTarget = targetProperties;
	Tween.saveProperties(singleTween.objStart, obj, targetProperties);
	singleTween.startTime = new Date().getTime();
	singleTween.endTime = singleTween.startTime + duration;
	singleTween.easing = easing;
	singleTween.completedCallback = completedCallback;
	Tween.activeTweens.push(singleTween);
	return singleTween.id;
};
Tween.cancel = (tweenId) => {
	let tween = Tween.activeTweens.find(tween => tweenId == tween.id);
	if (tween) {
		let index = Tween.activeTweens.indexOf(tween);
		Tween.activeTweens.splice(index, 1);
		return tween;
	}
};
Tween.stop = (tweenId) => {
	let tween = Tween.cancel(tweenId);
	tween.completedCallback();
	return tween;
};
Tween.saveProperties = (singleTweenStart, obj, targetProperties) => {
	for (let property in targetProperties) {
		let startValue = obj[property];
		if (typeof startValue == "object") {
			singleTweenStart[property] = {};
			Tween.saveProperties(singleTweenStart[property], obj[property], targetProperties[property]);
			continue;
		}
		singleTweenStart[property] = startValue;
	}
}
Tween.update = () => {
	let completed = [];
	for (let i = 0; i < Tween.activeTweens.length; i++) {
		let singleTween = Tween.activeTweens[i];
		if (Tween.updateSingleTween(singleTween) == 1) {
			completed.push(singleTween);
		}
	}

	for (let i = 0; i < completed.length; i++) {
		let singleTween = completed[i];
		singleTween.completedCallback();
		let foundIndex = Tween.activeTweens.indexOf(singleTween);
		if (foundIndex != -1) {
			Tween.activeTweens.splice(foundIndex, 1);
		}
	}
};
Tween.updateSingleTween = (singleTween) => {
	let currentTime = new Date().getTime();
	let runTime = currentTime - singleTween.startTime;
	let duration = singleTween.endTime - singleTween.startTime;
	let percentageComplete = Math.min(1, runTime / duration);
	let valueToUpdate = singleTween.easing(percentageComplete);
	Tween.updateProperties(singleTween.obj, singleTween.objStart, singleTween.objTarget, valueToUpdate);
	return percentageComplete;
}

Tween.updateProperties = (obj, objStart, objTarget, valueToUpdate) => {
	for (let property in objStart) {
		let startValue = objStart[property];
		if (typeof startValue == "object") {
			Tween.updateProperties(obj[property], objStart[property], objTarget[property], valueToUpdate);
			continue;
		}
		let endValue = objTarget[property];
		let delta = endValue - startValue;
		obj[property] = startValue + (delta * valueToUpdate);
	}
};

Tween.Easing = {};

Tween.Easing.Linear = {};
Tween.Easing.Linear.EaseNone = (percentageComplete) => percentageComplete;

Tween.Easing.Quadratic = {};
Tween.Easing.Quadratic.EaseIn = (percentageComplete) => percentageComplete * percentageComplete;
Tween.Easing.Quadratic.EaseOut = (percentageComplete) => -percentageComplete * (percentageComplete - 2);
Tween.Easing.Quadratic.EaseInOut = (percentageComplete) => {
	if ((percentageComplete *= 2) < 1) return 0.5 * percentageComplete * percentageComplete;
	return - 0.5 * (--percentageComplete * (percentageComplete - 2) - 1);
};
Tween.Easing.Cubic = {};
Tween.Easing.Cubic.EaseIn = (percentageComplete) => percentageComplete * percentageComplete * percentageComplete;
Tween.Easing.Cubic.EaseOut = (percentageComplete) => --percentageComplete * percentageComplete * percentageComplete + 1;
Tween.Easing.Cubic.EaseInOut = (percentageComplete) => {
	if ((percentageComplete *= 2) < 1) return 0.5 * percentageComplete * percentageComplete * percentageComplete;
	return 0.5 * ((percentageComplete -= 2) * percentageComplete * percentageComplete + 2);
};
Tween.Easing.Quartic = {};
Tween.Easing.Quartic.EaseIn = (percentageComplete) => percentageComplete * percentageComplete * percentageComplete * percentageComplete;
Tween.Easing.Quartic.EaseOut = (percentageComplete) => -(--percentageComplete * percentageComplete * percentageComplete * percentageComplete - 1);
Tween.Easing.Quartic.EaseInOut = (percentageComplete) => {
	if ((percentageComplete *= 2) < 1) return 0.5 * percentageComplete * percentageComplete * percentageComplete * percentageComplete;
	return - 0.5 * ((percentageComplete -= 2) * percentageComplete * percentageComplete * percentageComplete - 2);
};
Tween.Easing.Quintic = {};
Tween.Easing.Quintic.EaseIn = (percentageComplete) => percentageComplete * percentageComplete * percentageComplete * percentageComplete * percentageComplete;
Tween.Easing.Quintic.EaseOut = (percentageComplete) => (percentageComplete = percentageComplete - 1) * percentageComplete * percentageComplete * percentageComplete * percentageComplete + 1;
Tween.Easing.Quintic.EaseInOut = (percentageComplete) => {
	if ((percentageComplete *= 2) < 1) return 0.5 * percentageComplete * percentageComplete * percentageComplete * percentageComplete * percentageComplete;
	return 0.5 * ((percentageComplete -= 2) * percentageComplete * percentageComplete * percentageComplete * percentageComplete + 2);
};
Tween.Easing.Sinusoidal = {};
Tween.Easing.Sinusoidal.EaseIn = (percentageComplete) => -Math.cos(percentageComplete * Math.PI / 2) + 1;
Tween.Easing.Sinusoidal.EaseOut = (percentageComplete) => Math.sin(percentageComplete * Math.PI / 2);
Tween.Easing.Sinusoidal.EaseInOut = (percentageComplete) => -0.5 * (Math.cos(Math.PI * percentageComplete) - 1);
Tween.Easing.Exponential = {};
Tween.Easing.Exponential.EaseIn = (percentageComplete) => {
	return percentageComplete == 0 ? 0 : Math.pow(2, 10 * (percentageComplete - 1));
};

Tween.Easing.Exponential.EaseOut = (percentageComplete) => {
	return percentageComplete == 1 ? 1 : - Math.pow(2, - 10 * percentageComplete) + 1;
};

Tween.Easing.Exponential.EaseInOut = (percentageComplete) => {
	if (percentageComplete == 0) return 0;
	if (percentageComplete == 1) return 1;
	if ((percentageComplete *= 2) < 1) return 0.5 * Math.pow(2, 10 * (percentageComplete - 1));
	return 0.5 * (- Math.pow(2, - 10 * (percentageComplete - 1)) + 2);
};
Tween.Easing.Circular = {};
Tween.Easing.Circular.EaseIn = (percentageComplete) => -(Math.sqrt(1 - percentageComplete * percentageComplete) - 1);
Tween.Easing.Circular.EaseOut = (percentageComplete) => Math.sqrt(1 - (--percentageComplete * percentageComplete));
Tween.Easing.Circular.EaseInOut = (percentageComplete) => {
	if ((percentageComplete /= 0.5) < 1) return - 0.5 * (Math.sqrt(1 - percentageComplete * percentageComplete) - 1);
	return 0.5 * (Math.sqrt(1 - (percentageComplete -= 2) * percentageComplete) + 1);
};
Tween.Easing.Elastic = {};
Tween.Easing.Elastic.EaseIn = (percentageComplete) => {
	var s, a = 0.1, p = 0.4;
	if (percentageComplete == 0) return 0; if (percentageComplete == 1) return 1; if (!p) p = 0.3;
	if (!a || a < 1) { a = 1; s = p / 4; }
	else s = p / (2 * Math.PI) * Math.asin(1 / a);
	return - (a * Math.pow(2, 10 * (percentageComplete -= 1)) * Math.sin((percentageComplete - s) * (2 * Math.PI) / p));
};

Tween.Easing.Elastic.EaseOut = (percentageComplete) => {
	var s, a = 0.1, p = 0.4;
	if (percentageComplete == 0) return 0; if (percentageComplete == 1) return 1; if (!p) p = 0.3;
	if (!a || a < 1) { a = 1; s = p / 4; }
	else s = p / (2 * Math.PI) * Math.asin(1 / a);
	return (a * Math.pow(2, - 10 * percentageComplete) * Math.sin((percentageComplete - s) * (2 * Math.PI) / p) + 1);
};

Tween.Easing.Elastic.EaseInOut = (percentageComplete) => {
	var s, a = 0.1, p = 0.4;
	if (percentageComplete == 0) return 0; if (percentageComplete == 1) return 1; if (!p) p = 0.3;
	if (!a || a < 1) { a = 1; s = p / 4; }
	else s = p / (2 * Math.PI) * Math.asin(1 / a);
	if ((percentageComplete *= 2) < 1) return - 0.5 * (a * Math.pow(2, 10 * (percentageComplete -= 1)) * Math.sin((percentageComplete - s) * (2 * Math.PI) / p));
	return a * Math.pow(2, -10 * (percentageComplete -= 1)) * Math.sin((percentageComplete - s) * (2 * Math.PI) / p) * 0.5 + 1;
};
Tween.Easing.Back = {};
Tween.Easing.Back.EaseIn = (percentageComplete) => {
	var s = 1.70158;
	return percentageComplete * percentageComplete * ((s + 1) * percentageComplete - s);
};

Tween.Easing.Back.EaseOut = (percentageComplete) => {
	var s = 1.70158;
	return (percentageComplete = percentageComplete - 1) * percentageComplete * ((s + 1) * percentageComplete + s) + 1;
};

Tween.Easing.Back.EaseInOut = (percentageComplete) => {
	var s = 1.70158 * 1.525;
	if ((percentageComplete *= 2) < 1) return 0.5 * (percentageComplete * percentageComplete * ((s + 1) * percentageComplete - s));
	return 0.5 * ((percentageComplete -= 2) * percentageComplete * ((s + 1) * percentageComplete + s) + 2);
};
Tween.Easing.Bounce = {};
Tween.Easing.Bounce.EaseIn = (percentageComplete) => 1 - Tween.Easing.Bounce.EaseOut(1 - percentageComplete);
Tween.Easing.Bounce.EaseOut = (percentageComplete) => {
	if ((percentageComplete /= 1) < (1 / 2.75)) {
		return 7.5625 * percentageComplete * percentageComplete;
	} else if (percentageComplete < (2 / 2.75)) {
		return 7.5625 * (percentageComplete -= (1.5 / 2.75)) * percentageComplete + 0.75;
	} else if (percentageComplete < (2.5 / 2.75)) {
		return 7.5625 * (percentageComplete -= (2.25 / 2.75)) * percentageComplete + 0.9375;
	} else {
		return 7.5625 * (percentageComplete -= (2.625 / 2.75)) * percentageComplete + 0.984375;
	}
};
Tween.Easing.Bounce.EaseInOut = (percentageComplete) => {
	if (percentageComplete < 0.5) return Tween.Easing.Bounce.EaseIn(percentageComplete * 2) * 0.5;
	return Tween.Easing.Bounce.EaseOut(percentageComplete * 2 - 1) * 0.5 + 0.5;
};