export function hexToRGB(H: string) {
	let r = '0',
		g = '0',
		b = '0';
	switch (H.length) {
		case 4:
			r = '0x' + H[1] + H[1];
			g = '0x' + H[2] + H[2];
			b = '0x' + H[3] + H[3];
			break;

		case 7:
			r = '0x' + H[1] + H[2];
			g = '0x' + H[3] + H[4];
			b = '0x' + H[5] + H[6];
			break;

		default:
			r = '0x' + '0' + '0';
			g = '0x' + '0' + '0';
			b = '0x' + '0' + '0';
			break;
	}
	return { r: parseInt(r), g: parseInt(g), b: parseInt(b) };
}
export function hexToHSL(H: string) {
	// Convert hex to RGB first
	const { r, g, b } = hexToRGB(H);
	// Then to HSL
	const intR = r / 255;
	const intG = g / 255;
	const intB = b / 255;
	let cmin = Math.min(intR, intG, intB),
		cmax = Math.max(intR, intG, intB),
		delta = cmax - cmin,
		h = 0,
		s = 0,
		l = 0;

	if (delta === 0) h = 0;
	else if (cmax === intR) h = ((intG - intB) / delta) % 6;
	else if (cmax === intG) h = (intB - intR) / delta + 2;
	else h = (intR - intG) / delta + 4;

	h = Math.round(h * 60);

	if (h < 0) h += 360;

	l = (cmax + cmin) / 2;
	s = delta == 0 ? 0 : delta / (1 - Math.abs(2 * l - 1));
	s = +(s * 100).toFixed(1);
	l = +(l * 100).toFixed(1);
	return { h, s, l };
	// return 'hsl(' + h + ',' + s + '%,' + l + '%)';
}

export function convertChannels(r: number, g: number, b: number, m: number) {
	// Having obtained RGB, convert channels to hex
	let stringR = Math.round((r + m) * 255).toString(16);
	let stringG = Math.round((g + m) * 255).toString(16);
	let stringB = Math.round((b + m) * 255).toString(16);

	// Prepend 0s, if necessary
	if (stringR.length == 1) stringR = '0' + stringR;
	if (stringG.length == 1) stringG = '0' + stringG;
	if (stringB.length == 1) stringB = '0' + stringB;
	return '#' + stringR + stringG + stringB;
}

export function gteAndLt(x: number, y: number, z: number) {
	return x <= y && y < z;
}

export function HSLToHex(h: number, s: number, l: number) {
	const newH = gteAndLt(0, h, 360) ? h : 360;
	const newS = s / 100;
	const newL = l / 100;

	// chroma - color intensity
	const c = (1 - Math.abs(2 * newL - 1)) * newS;
	const x = c * (1 - Math.abs(((newH / 60) % 2) - 1));
	// lightness to match when converting channels
	const m = newL - c / 2;

	switch (true) {
		case gteAndLt(0, newH, 60):
			return convertChannels(c, x, 0, m);
		case gteAndLt(60, newH, 120):
			return convertChannels(x, c, 0, m);
		case gteAndLt(120, newH, 180):
			return convertChannels(0, c, x, m);
		case gteAndLt(180, newH, 240):
			return convertChannels(0, x, c, m);
		case gteAndLt(240, newH, 300):
			return convertChannels(x, 0, c, m);
		case gteAndLt(300, newH, 360):
		default:
			return convertChannels(c, 0, x, m);
	}
}

export function lightOrDark(H: string) {
	const { r, g, b } = hexToRGB(H);

	const hsp = Math.sqrt(0.299 * (r * r) + 0.587 * (g * g) + 0.114 * (b * b));
	// Using the HSP value, determine whether the color is light or dark
	if (hsp > 127.5) {
		return 'light';
	} else {
		return 'dark';
	}
}