#include "common.h"

void usage() {
	fprintf(stderr, "Usage: png_dimensions in.png out.dimensions\n");
}

uint8_t read_dimensions(const char *filename) {
	uint32_t width_px = read_png_width_verbose(filename);
	if (width_px != 40 && width_px != 48 && width_px != 56) {
		fprintf(stderr, "Not a valid width for \"%s\": %" PRIu32 " px\n", filename, width_px);
		exit(1);
	}
	uint8_t width_tiles = (uint8_t)(width_px / 8);
	return (width_tiles << 4) | width_tiles;
}

int main(int argc, char *argv[]) {
	if (argc < 3) {
		usage();
		exit(1);
	}
	uint8_t output_byte = read_dimensions(argv[1]);
	write_u8(argv[2], &output_byte, 1);
	return 0;
}