#include <stdlib.h>
#include <stdint.h>
#include "colors.h"
#include "hsl.h"

// based on: https://github.com/lewisd32/avr-hsl2rgb
xrgb_t hsl2xrgb(const hsl_t cc)
{
	// 0 .. 256*3
	const uint16_t hh = (uint16_t) cc.h * 3;
	const uint8_t hue_mod = hh % 256;

	uint8_t r_temp, g_temp, b_temp;
	if (hh < 256) {
		r_temp = hue_mod ^ 255;
		g_temp = hue_mod;
		b_temp = 0;
	} else if (hh < 512) {
		r_temp = 0;
		g_temp = hue_mod ^ 255;
		b_temp = hue_mod;
	} else if (hh < 768) {
		r_temp = hue_mod;
		g_temp = 0;
		b_temp = hue_mod ^ 255;
	} else {
		r_temp = 0;
		g_temp = 0;
		b_temp = 0;
	}

	const uint8_t inverse_sat = (cc.s ^ 255);

	xrgb_t rgb;

	uint8_t t8;
	uint16_t t16;

#ifdef HSL_LINEAR
	const uint8_t bri = FADE_128[cc.l>>1];
#else
	const uint8_t bri = cc.l;
#endif

	t8 = r_temp;
	t16 = t8 * cc.s + t8;
	t16 = t16 + t8;
	t8 = t16 >> 8;
	t8 = t8 + inverse_sat;
	t16 = t8 * bri;
	t16 = t16 + t8;
	t8 = t16 >> 8;
	rgb.r = t8;

	t8 = g_temp;
	t16 = t8 * cc.s;
	t16 = t16 + t8;
	t8 = t16 >> 8;
	t8 = t8 + inverse_sat;
	t16 = t8 * bri;
	t16 = t16 + t8;
	t8 = t16 >> 8;
	rgb.g = t8;

	t8 = b_temp;
	t16 = t8 * cc.s;
	t16 = t16 + t8;
	t8 = t16 >> 8;
	t8 = t8 + inverse_sat;
	t16 = t8 * bri;
	t16 = t16 + t8;
	t8 = t16 >> 8;
	rgb.b = t8;

	return rgb;
}