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

USAGE("key-stream")

#define FILE "blind-chroma-key.c"
#include "define-functions.h"

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

	UNOFLAGS(argc != 1);

	eopen_stream(&stream, NULL);
	eopen_stream(&key, 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, key.pixfmt))
		eprintf("videos use incompatible pixel formats\n");

	if (key.width > 2 || key.height > 2 || key.width * key.height != 2)
		eprintf("%s: each frame must contain exactly 2 pixels\n", key.file);

	fprint_stream_head(stdout, &stream);
	efflush(stdout, "<stdout>");
	process(&stream, &key);
	return 0;
}

#else

static void
PROCESS(struct stream *stream, struct stream *key)
{
	size_t i, n, m = 0;
	TYPE x1, y1, z1, a1, a2, variance2, *keyxyza;
	TYPE x, y, z, d;
	do {
		if (!m) {
			m = stream->frame_size;
			while (key->ptr < key->frame_size)
				if (!eread_stream(key, key->frame_size - key->ptr))
					return;
			keyxyza = (TYPE *)(key->buf);
			x1 = keyxyza[0];
			y1 = keyxyza[1];
			z1 = keyxyza[2];
			a1 = keyxyza[3];
			x = x1 - keyxyza[4];
			y = y1 - keyxyza[5];
			z = z1 - keyxyza[6];
			a2 = keyxyza[7];
			variance2 = x * x + y * y + z * z;
			/* TODO add more formulae: https://en.wikipedia.org/wiki/Color_difference */
			if (a2 > a1) {
				a1 = 1 - a1;
				a2 = 1 - a2;
			}
			memmove(key->buf, key->buf + key->frame_size,
				key->ptr -= key->frame_size);
		}
		n = MIN(stream->ptr, m) / stream->pixel_size;
		for (i = 0; i < n; i++) {
			x = ((TYPE *)(stream->buf))[4 * i + 0] - x1;
			y = ((TYPE *)(stream->buf))[4 * i + 1] - y1;
			z = ((TYPE *)(stream->buf))[4 * i + 2] - z1;
			d = x * x + y * y + z * z;
			if (d <= variance2) {
				if (a1 == a2)
					d = 0;
				else
					d = sqrt(d / variance2) * (a1 - a2) + a2;
				((TYPE *)(stream->buf))[4 * i + 3] *= d;
			}
		}
		n *= stream->pixel_size;
		m -= n;
		ewriteall(STDOUT_FILENO, stream->buf, n, "<stdout>");
		memmove(stream->buf, stream->buf + n, stream->ptr -= n);
	} while (eread_stream(stream, SIZE_MAX));
	if (stream->ptr)
		eprintf("%s: incomplete frame\n", stream->file);
}

#endif