#include <stdio.h>
#include <libplum.h>

int main(int const argc, char *const *const argv) {
	if (argc < 3) {
		fprintf(stderr, "usage: %s <OUT.png> <IN.png>...\n", argv[0]);
		return 1;
	}
	unsigned error;
	struct plum_image *outimage = plum_new_image();
	outimage->type = PLUM_IMAGE_PNG;
	outimage->color_format = PLUM_COLOR_32;
	outimage->frames = 1;
	outimage->width = 128;
	if (argc == 3) {
		struct plum_image *inimage = plum_load_image(argv[2], PLUM_MODE_FILENAME, PLUM_COLOR_32, &error);
		if (inimage == NULL) {
			printf("%s: read error (%s)\n", argv[2], plum_get_error_text(error));
			return 1;
		}
		outimage->height = inimage->height / 4;
		outimage->data = plum_malloc(outimage, plum_pixel_buffer_size(outimage));
		for (int i = 0; i < inimage->height / 32; i++) {
			int const toy = i * outimage->width * 8;
			for (int j = 0; j < 16; j++) {
				int const tox = j * 8;
				int const tiy = ((int [16]) {0, 0, 1, 3, 3, 3, 0, 2, 0, 2, 1, 1, 1, 3, 2, 2}[j]) * 8 + inimage->width * 32 * i;
				int const tix = ((int [16]) {0, 3, 0, 3, 0, 1, 2, 3, 1, 0, 3, 2, 1, 2, 1, 2}[j]) * 8 * inimage->width;
				for (int py = 0; py < 8; py++) {
					int const poy = py * outimage->width;
					int const piy = py * inimage->width;
					for (int px = 0; px < 8; px++) {
						outimage->data32[toy + tox + poy + px] = inimage->data32[tiy + tix + piy + px];
					}
				}
			}
		}
		plum_destroy_image(inimage);
		
	} else {
		outimage->height = (argc - 2) * 8;
		outimage->data = plum_malloc(outimage, plum_pixel_buffer_size(outimage));
		
		for (int i = 2; i < argc; i++) {
			struct plum_image *inimage = plum_load_image(argv[i], PLUM_MODE_FILENAME, PLUM_COLOR_32, &error);
			if (inimage == NULL) {
				printf("%s: read error (%s)\n", argv[i], plum_get_error_text(error));
				return 1;
			}
			int const toy = (i - 2) * outimage->width * 8;
			for (int j = 0; j < 16; j++) {
				int const tox = j * 8;
				int const tiy = ((int [16]) {0, 0, 1, 3, 3, 3, 0, 2, 0, 2, 1, 1, 1, 3, 2, 2}[j]) * 8;
				int const tix = ((int [16]) {0, 3, 0, 3, 0, 1, 2, 3, 1, 0, 3, 2, 1, 2, 1, 2}[j]) * 8 * inimage->width;
				for (int py = 0; py < 8; py++) {
					int const poy = py * outimage->width;
					int const piy = py * inimage->width;
					for (int px = 0; px < 8; px++) {
						outimage->data32[toy + tox + poy + px] = inimage->data32[tiy + tix + piy + px];
					}
				}
			}
			plum_destroy_image(inimage);
		}
	}
	plum_store_image(outimage, argv[1], PLUM_MODE_FILENAME, &error);
	if (error) {
		printf("%s: write error (%s)\n", argv[1], plum_get_error_text(error));
		return 1;
	}
	plum_destroy_image(outimage);
	return 0;
}