/* See LICENSE file for copyright and license details. */
#include "common.h"
#ifndef TEST


static void
vconvolute(double *restrict raster, size_t rowsize, size_t width, size_t height, size_t kernelsize, const double *kernel)
{
	size_t y, x, i;

	if (kernelsize == 3 && kernel[0] == kernel[1] && kernel[1] == kernel[2]) {
		raster = &raster[-2 * rowsize];
		for (y = 0; y < height; y++) {
			for (x = 0; x < width; x++)
				raster[x] += raster[1 * rowsize + x];
			for (x = 0; x < width; x++) {
				raster[x] += raster[2 * rowsize + x];
				raster[x] *= kernel[0];
			}
			raster = &raster[rowsize];
		}
		for (x = 0; x < width; x++)
			raster[x] *= kernel[0];
		raster = &raster[rowsize];
		for (x = 0; x < width; x++)
			raster[x] *= kernel[0];

	} else {
		for (y = 0; y < height; y++) {
			for (x = 0; x < width; x++)
				raster[x] *= kernel[0];
			for (i = 1; i < kernelsize; i++)
				for (x = 0; x < width; x++)
					raster[x] = fma(raster[i * rowsize + x], kernel[i], raster[x]);
			raster = &raster[rowsize];
		}
	}
}


static void
hconvolute(double *restrict raster, size_t rowsize, size_t width, size_t height, size_t kernelsize, const double *kernel)
{
	size_t y, x, i;

	if (kernelsize == 3 && kernel[0] == kernel[1] && kernel[1] == kernel[2]) {
		for (y = 0; y < height; y++) {
			for (x = 0; x < width; x++) {
				raster[x - 1] += raster[x];
				raster[x - 2] += raster[x];
				raster[x - 2] *= kernel[0];
			}
			raster[width - 2] *= kernel[0];
			raster[width - 1] *= kernel[0];
			raster = &raster[rowsize];
		}

	} else {
		for (y = 0; y < height; y++) {
			for (x = 0; x < width; x++) {
				raster[x] *= kernel[0];
				for (i = 1; i < kernelsize; i++)
					raster[x] = fma(raster[x + i], kernel[i], raster[x]);
			}
			raster = &raster[rowsize];
		}
	}
}


void
libglitter_redistribute_energy_double(double *restrict raster, size_t rowsize, size_t width, size_t height, /* TODO add man page */
                                      size_t hkernelsize, size_t vkernelsize, const double *hkernel, const double *vkernel)
{
	if (vkernelsize > 1) {
		raster -= (hkernelsize - 1) * rowsize;
		vconvolute(raster, rowsize, width, height, vkernelsize, vkernel);
		height += hkernelsize - 1;
	}
	if (hkernelsize > 1) {
		raster -= hkernelsize - 1;
		hconvolute(raster, rowsize, width, height, hkernelsize, hkernel);
		width += hkernelsize - 1;
	}
}


#else


#define TOLERANCE 0.0001

static int
eq(double a, double b)
{
	double r = a - b;
	return (r < 0 ? -r : r) < TOLERANCE;
}

int
main(void)
{
	return 0; /* TODO add test */
}


#endif