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

USAGE("palette-stream")


static double (*compare)(double x1, double y1, double z1, double a1, double x2, double y2, double z2, double a2);
/* TODO add more formulae: https://en.wikipedia.org/wiki/Color_difference */


static double
distance_xyz(double x1, double y1, double z1, double a1, double x2, double y2, double z2, double a2)
{
	x2 -= x1, x2 *= x2;
	y2 -= y1, y2 *= y2;
	z2 -= z1, z2 *= z2;
	a2 -= a1, a2 *= a2;
	return sqrt(x2 + y2 + z2 + a2);
}


#define PROCESS(TYPE, SUFFIX)\
	static void\
	process_##SUFFIX(struct stream *stream, struct stream *palette, char *pal)\
	{\
		size_t i, j, n, m;\
		size_t palsiz = palette->width * palette->height;\
		size_t best = 0;\
		TYPE x, y, z, a, lx = 0, ly = 0, lz = 0, la = 0;\
		TYPE cx, cy, cz, ca;\
		double distance, best_distance = 0;\
		while (eread_frame(palette, pal)) {\
			m = stream->frame_size;\
			do {\
				n = MIN(stream->ptr, m) / stream->pixel_size;\
				for (i = 0; i < n; i++) {\
					x = ((TYPE *)(stream->buf + i * stream->pixel_size))[0];\
					y = ((TYPE *)(stream->buf + i * stream->pixel_size))[1];\
					z = ((TYPE *)(stream->buf + i * stream->pixel_size))[2];\
					a = ((TYPE *)(stream->buf + i * stream->pixel_size))[3];\
					if ((!i && m == stream->frame_size) || x != lx || y != ly || z != lz || a != la) {\
						for (j = 0; j < palsiz; j++) {\
							cx = ((TYPE *)(pal + j * stream->pixel_size))[0];\
							cy = ((TYPE *)(pal + j * stream->pixel_size))[1];\
							cz = ((TYPE *)(pal + j * stream->pixel_size))[2];\
							ca = ((TYPE *)(pal + j * stream->pixel_size))[3];\
							distance = compare((double)x, (double)y, (double)z, (double)a,\
									   (double)cx, (double)cy, (double)cz, (double)ca);\
							if (!j || distance < best_distance) {\
								best_distance = distance;\
								best = j;\
							}\
						}\
						lx = x, ly = y, lz = z, la = a;\
					}\
					memcpy(stream->buf + i * stream->pixel_size,\
					       pal + best * stream->pixel_size,\
					       stream->pixel_size);\
				}\
				m -= n *= stream->pixel_size;\
				ewriteall(STDOUT_FILENO, stream->buf, n, "<stdout>");\
				memmove(stream->buf, stream->buf + n, stream->ptr -= n);\
			} while (m && eread_stream(stream, SIZE_MAX));\
			if (m)\
				eprintf("%s: incomplete frame\n", stream->file);\
		}\
	}

PROCESS(double, lf)
PROCESS(float, f)


int
main(int argc, char *argv[])
{
	struct stream stream, palette;
	void (*process)(struct stream *stream, struct stream *palette, char *pal);
	char *pal;

	compare = distance_xyz;

	UNOFLAGS(argc != 1);

	eopen_stream(&stream, NULL);
	eopen_stream(&palette, argv[0]);

	if (!strcmp(stream.pixfmt, "xyza"))
		process = process_lf;
	else if (!strcmp(stream.pixfmt, "xyza f"))
		process = process_f;
	else
		eprintf("pixel format %s is not supported, try xyza\n", stream.pixfmt);

	if (strcmp(stream.pixfmt, palette.pixfmt))
		eprintf("videos use incompatible pixel formats\n");

	echeck_dimensions(&stream, WIDTH | HEIGHT, NULL);
	echeck_dimensions(&palette, WIDTH | HEIGHT, NULL);
	pal = emalloc(palette.frame_size);
	fprint_stream_head(stdout, &stream);
	efflush(stdout, "<stdout>");

	process(&stream, &palette, pal);

	free(pal);
	return 0;
}