/*
 * build with:
 *   gcc -o bitmap bitmap.c
 * or maybe you'd prefer:
 *   g++ -o bitmap bitmap.c
 * I really don't care, it'll work in anything:
 *   clang -o bitmap bitmap.c
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct sprite {
	uint16_t width;
	uint16_t height;
	uint32_t * bitmap;
	uint32_t * masks;
	uint32_t blank;
	uint8_t  alpha;
} sprite_t;

#define _RED(color) ((color & 0x00FF0000) / 0x10000)
#define _GRE(color) ((color & 0x0000FF00) / 0x100)
#define _BLU(color) ((color & 0x000000FF) / 0x1)
#define _ALP(color) ((color & 0xFF000000) / 0x1000000)

void load_sprite(sprite_t * sprite, char * filename) {
	/* Open the requested binary */
	FILE * image = fopen(filename, "r");
	size_t image_size= 0;

	fseek(image, 0, SEEK_END);
	image_size = ftell(image);
	fseek(image, 0, SEEK_SET);

	/* Alright, we have the length */
	char * bufferb = (char *)malloc(image_size);
	fread(bufferb, image_size, 1, image);
	uint16_t x = 0; /* -> 212 */
	uint16_t y = 0; /* -> 68 */
	/* Get the width / height of the image */
	signed int *bufferi = (signed int *)((uintptr_t)bufferb + 2);
	uint32_t width  = bufferi[4];
	uint32_t height = bufferi[5];
	uint16_t bpp    = bufferi[6] / 0x10000;
	uint32_t row_width = (bpp * width + 31) / 32 * 4;
	/* Skip right to the important part */
	size_t i = bufferi[2];

	sprite->width = width;
	sprite->height = height;
	sprite->bitmap = (uint32_t *)malloc(sizeof(uint32_t) * width * height);

	for (y = 0; y < height; ++y) {
		for (x = 0; x < width; ++x) {
			if (i > image_size) return;
			/* Extract the color */
			uint32_t color;
			if (bpp == 24) {
				color =	(bufferb[i   + 3 * x] & 0xFF) +
						(bufferb[i+1 + 3 * x] & 0xFF) * 0x100 +
						(bufferb[i+2 + 3 * x] & 0xFF) * 0x10000;
			} else if (bpp == 32) {
				color =	(bufferb[i   + 4 * x] & 0xFF) * 0x1000000 +
						(bufferb[i+1 + 4 * x] & 0xFF) * 0x100 +
						(bufferb[i+2 + 4 * x] & 0xFF) * 0x10000 +
						(bufferb[i+3 + 4 * x] & 0xFF) * 0x1;
			}
			/* Set our point */
			sprite->bitmap[(height - y - 1) * width + x] = color;
		}
		i += row_width;
	}
	free(bufferb);
}

int main(int argc, char * argv[]) {
	int x = 0, y = 0;
	sprite_t sprite;
	load_sprite(&sprite, argv[1]);
	uint32_t color = sprite.bitmap[y * sprite.width + x];
	char red   = _RED(color);
	char blue  = _BLU(color);
	char green = _GRE(color);
	free(sprite.bitmap);
	printf("(%d,%d) = #%02X%02X%02X\n", x, y, red, blue, green);
	return 0;
}