#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include "engine.h"
#include <inttypes.h>

// TODO: even better compression using zlib or something - or vector graphics

#define MAX_SPRITES 5000
static struct sprite sprites[MAX_SPRITES];
static int numsprites;

struct sprite *get_decompressed_sprite(const unsigned char *spritedata) {
	for(int i = 0; i < numsprites; i++) {
		if(sprites[i].original_data_source == spritedata)
			return &sprites[i];
	}
	struct sprite *s = &sprites[numsprites++];
	s->width = *(uint16_t*)(spritedata + 0);
	s->height = *(uint16_t*)(spritedata + 2);
	s->original_data_source = spritedata;
	spritedata += 4;

	s->pixels = (uint32_t*)malloc(s->width*s->height*4);
	if(!s->pixels) error(1, 0, "get_decompressed_sprite: memory allocation failed");

	for(int channel = 0; channel < 4; channel++) {
		unsigned char *pixels = (unsigned char*)s->pixels;
		pixels += channel;
		unsigned int pixelsleft = s->width * s->height;
		while(pixelsleft > 0) {
			unsigned char control = *spritedata++;
			if(control & 0x80) {
				control &= 0x7f;
				if(control > pixelsleft) error(1, 0, "corrupted compressed sprite A %u > %u", (unsigned int)control, (unsigned int)pixelsleft);
				for(int i = 0; i < control; i++) {
					*pixels = *spritedata++;
					pixels += 4;
				}
				pixelsleft -= control;
			} else {
				uint32_t count;
				if(control == 0) {
					count = *(uint32_t*)spritedata;
					spritedata += 4;
				} else {
					count = control;
				}
				unsigned char value = *spritedata++;
				if(count > pixelsleft) error(1, 0, "corrupted compressed sprite B %u > %u", (unsigned int)count, (unsigned int)pixelsleft);
				for(uint32_t i = 0; i < count; i++) {
					*pixels = value;
					pixels += 4;
				}
				pixelsleft -= count;
			}
		}
	}
	return s;
}