#include "colorshop.h"

#define HUE_INIT		0.1f
#define HUE_INCREMENT	0.62f
#define SATURATION		0.99f
#define VALUE			0.99f


static unsigned hsv2rgb(float h, float s, float v)
{
	unsigned hi;
	float r = 0, g = 0, b = 0, p, q, t, f;

	hi = (unsigned)(h * 6.0f);
	f = h * 6.0f - hi;
	p = v * (1.0f - s);
	q = v * (1.0f - f * s);
	t = v * (1.0f - (1.0f - f) * s);

	switch (hi) {
		case 0:
			r = v; g = t; b = p;
			break;
		case 1:
			r = q; g = v; b = p;
			break;
		case 2:
			r = p; g = v; b = t;
			break;
		case 3:
			r = p; g = q; b = v;
			break;
		case 4:
			r = t; g = p; b = v;
			break;
		case 5:
			r = v; g = p; b = q;
			break;
	}

	return ((unsigned)(r * 256) << 16)
	  + ((unsigned)(g * 256) << 8)
	  + (unsigned)(b * 256);
}

ColorShop::ColorShop()
{
	_hueState = HUE_INIT;
}

QColor ColorShop::color()
{
	_hueState += HUE_INCREMENT;
	_hueState -= (int) _hueState;

	return QColor(hsv2rgb(_hueState, SATURATION, VALUE));
}

void ColorShop::reset()
{
	_hueState = HUE_INIT;
}