"use strict"

function rgb_from_any(color) {
	switch (color.mode) {
	case "rgb": return color
	case "lrgb": return rgb_from_lrgb(color)
	case "oklab": return rgb_from_oklab(color)
	}
}

function lrgb_from_any(color) {
	switch (color.mode) {
	case "rgb": return lrgb_from_rgb(color)
	case "lrgb": return color
	case "oklab": return lrgb_from_oklab(color)
	}
}

function oklab_from_any(color) {
	switch (color.mode) {
	case "rgb": return oklab_from_rgb(color)
	case "lrgb": return oklab_from_lrgb(color)
	case "oklab": return color
	}
}

function format_hex(color) {
	let {r, g, b} = rgb_from_any(color)
	let adj = 1
	r = Math.round(Math.max(0, Math.min(1, r)) * 255)
	g = Math.round(Math.max(0, Math.min(1, g)) * 255)
	b = Math.round(Math.max(0, Math.min(1, b)) * 255)
	let x = (r << 16) | (g << 8) | b
	return "#" + x.toString(16).padStart(6, "0")
}

function parse_hex(str) {
	let x = parseInt(str.substring(1), 16)
	return {
		mode: "rgb",
		r: ((x >> 16) & 255) / 255.0,
		g: ((x >> 8) & 255) / 255.0,
		b: ((x) & 255) / 255.0
	}
}

function lrgb_from_rgb({ r, g, b }) {
	function to_linear(c) {
		let ac = Math.abs(c)
		if (ac < 0.04045)
			return c / 12.92
		return (Math.sign(c) || 1) * Math.pow((ac + 0.055) / 1.055, 2.4)
	}
	return {
		mode: "lrgb",
                r: to_linear(r),
                g: to_linear(g),
                b: to_linear(b)
        }
}

function rgb_from_lrgb({ r, g, b }) {
	function from_linear(c) {
		let ac = Math.abs(c)
		if (ac > 0.0031308)
			return (Math.sign(c) || 1) * (1.055 * Math.pow(ac, 1 / 2.4) - 0.055)
		return c * 12.92
	}
        return {
                mode: "rgb",
                r: from_linear(r),
                g: from_linear(g),
                b: from_linear(b)
	}
}

function oklab_from_lrgb({ r, g, b }) {
	let L = Math.cbrt(0.4122214708 * r + 0.5363325363 * g + 0.0514459929 * b)
        let M = Math.cbrt(0.2119034982 * r + 0.6806995451 * g + 0.1073969566 * b)
        let S = Math.cbrt(0.0883024619 * r + 0.2817188376 * g + 0.6299787005 * b)
        return {
                mode: "oklab",
                l: 0.2104542553 * L + 0.793617785 * M - 0.0040720468 * S,
                a: 1.9779984951 * L - 2.428592205 * M + 0.4505937099 * S,
                b: 0.0259040371 * L + 0.7827717662 * M - 0.808675766 * S
        }
}

function lrgb_from_oklab({ l, a, b }) {
        let L = Math.pow(l + 0.3963377774 * a + 0.2158037573 * b, 3)
        let M = Math.pow(l - 0.1055613458 * a - 0.0638541728 * b, 3)
        let S = Math.pow(l - 0.0894841775 * a - 1.291485548 * b, 3)
        return {
                mode: "lrgb",
                r: +4.0767416621 * L - 3.3077115913 * M + 0.2309699292 * S,
                g: -1.2684380046 * L + 2.6097574011 * M - 0.3413193965 * S,
                b: -0.0041960863 * L - 0.7034186147 * M + 1.707614701 * S
	}
}

function oklab_from_rgb(rgb) {
        return oklab_from_lrgb(lrgb_from_rgb(rgb))
}

function rgb_from_oklab(oklab) {
	return rgb_from_lrgb(lrgb_from_oklab(oklab))
}

if (typeof module === "object")
	module.exports = { format_hex, parse_hex, rgb_from_any, lrgb_from_any, oklab_from_any }