// https://easings.net/
const c1 = 1.70158
const c2 = c1 * 1.525
const c3 = c1 + 1
const c4 = (2 * Math.PI) / 3
const c5 = (2 * Math.PI) / 4.5

const easings = {
	linear: (x) => x,
	easeInSine: (x) => 1 - Math.cos((x * Math.PI) / 2),
	easeOutSine: (x) => Math.sin((x * Math.PI) / 2),
	easeInOutSine: (x) => -(Math.cos(Math.PI * x) - 1) / 2,
	easeInQuad: (x) => x * x,
	easeOutQuad: (x) => 1 - (1 - x) * (1 - x),
	easeInOutQuad: (x) => x < 0.5 ? 2 * x * x : 1 - Math.pow(-2 * x + 2, 2) / 2,
	easeInCubic: (x) => x * x * x,
	easeOutCubic: (x) => 1 - Math.pow(1 - x, 3),
	easeInOutCubic: (x) => x < 0.5 ? 4 * x * x * x : 1 - Math.pow(-2 * x + 2, 3) / 2,
	easeInQuart: (x) => x * x * x * x,
	easeOutQuart: (x) => 1 - Math.pow(1 - x, 4),
	easeInOutQuart: (x) => x < 0.5 ? 8 * x * x * x * x : 1 - Math.pow(-2 * x + 2, 4) / 2,
	easeInQuint: (x) => x * x * x * x * x,
	easeOutQuint: (x) => 1 - Math.pow(1 - x, 5),
	easeInOutQuint: (x) => x < 0.5 ? 16 * x * x * x * x * x : 1 - Math.pow(-2 * x + 2, 5) / 2,
	easeInExpo: (x) => x === 0 ? 0 : Math.pow(2, 10 * x - 10),
	easeOutExpo: (x) => x === 1 ? 1 : 1 - Math.pow(2, -10 * x),
	easeInOutExpo: (x) => {
		return x === 0
			? 0
			: x === 1
				? 1
				: x < 0.5
					? Math.pow(2, 20 * x - 10) / 2
					: (2 - Math.pow(2, -20 * x + 10)) / 2
	},
	easeInCirc: (x) => 1 - Math.sqrt(1 - Math.pow(x, 2)),
	easeOutCirc: (x) => Math.sqrt(1 - Math.pow(x - 1, 2)),
	easeInOutCirc: (x) => {
		return x < 0.5
			? (1 - Math.sqrt(1 - Math.pow(2 * x, 2))) / 2
			: (Math.sqrt(1 - Math.pow(-2 * x + 2, 2)) + 1) / 2
	},
	easeInBack: (x) => c3 * x * x * x - c1 * x * x,
	easeOutBack: (x) => 1 + c3 * Math.pow(x - 1, 3) + c1 * Math.pow(x - 1, 2),
	easeInOutBack: (x) => {
		return x < 0.5
			? (Math.pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2
			: (Math.pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2
	},
	easeInElastic: (x) => {
		return x === 0
			? 0
			: x === 1
				? 1
				: -Math.pow(2, 10 * x - 10) * Math.sin((x * 10 - 10.75) * c4)
	},
	easeOutElastic: (x) => {
		return x === 0
			? 0
			: x === 1
				? 1
				: Math.pow(2, -10 * x) * Math.sin((x * 10 - 0.75) * c4) + 1
	},
	easeInOutElastic: (x) => {
		return x === 0
			? 0
			: x === 1
				? 1
				: x < 0.5
					? -(Math.pow(2, 20 * x - 10) * Math.sin((20 * x - 11.125) * c5)) / 2
					: (Math.pow(2, -20 * x + 10) * Math.sin((20 * x - 11.125) * c5)) / 2 + 1
	},
	easeInBounce: (x) => 1 - easings.easeOutBounce(1 - x),
	easeOutBounce: (x) => {
		const n1 = 7.5625
		const d1 = 2.75
		if (x < 1 / d1) {
			return n1 * x * x
		} else if (x < 2 / d1) {
			return n1 * (x -= 1.5 / d1) * x + 0.75
		} else if (x < 2.5 / d1) {
			return n1 * (x -= 2.25 / d1) * x + 0.9375
		} else {
			return n1 * (x -= 2.625 / d1) * x + 0.984375
		}
	},
	easeInOutBounce: (x) => {
		return x < 0.5
			? (1 - easings.easeOutBounce(1 - 2 * x)) / 2
			: (1 + easings.easeOutBounce(2 * x - 1)) / 2
	},
}

export default easings