#include <dpa-qoi.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>

void bitmap_header(FILE* file, const uint32_t w, const uint32_t h){
  const size_t ims = sizeof(uint8_t[h][w][4]);
  const uint8_t header[54] = {
    'B','M', (sizeof(header)+ims),(sizeof(header)+ims)>>8,(sizeof(header)+ims)>>16,(sizeof(header)+ims)>>24, 0,0,0,0, sizeof(header),sizeof(header)>>8,sizeof(header)>>16,sizeof(header)>>24,
    40,0,0,0, w,w>>8,w>>16,w>>24, h,h>>8,h>>16,h>>24, 1,0, 32,0, 0,0,0,0, ims,ims>>8,ims>>16,ims>>24, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0
  };
  fwrite(header, 1, sizeof(header), file);
}

bool qoi_to_bmp(const unsigned char* a){
  if(!qoi_check_magic(a))
    return false;
  uint32_t width = qoi_get_width(a);
  uint32_t height = qoi_get_height(a);
  struct qoi_decoder qoi = QOI_DECODER_INIT(a);
  bitmap_header(stdout, width, height);
  unsigned char buf[16*4] = {0};
  size_t length = (size_t)width*height*4;
  while(true){
    qoi_decode(&qoi, sizeof(buf)/4, buf);
    if(length < sizeof(buf))
      break;
    fwrite(buf, 1, sizeof(buf), stdout);
    length -= sizeof(buf);
  }
  fwrite(buf, 1, length, stdout);
  fclose(stdout);
  return true;
}

int main(int argc, char *argv[]){
  if(argc != 1){
    fprintf(stderr, "usage: %s <image.qoi >image.bmp\n", argv[0]);
    return 1;
  }
  struct stat sb;
  if(fstat(0, &sb) == -1){
    perror("fstat");
    return 1;
  }
  const unsigned char* a = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, 0, 0);
  if(a == MAP_FAILED){
    perror("mmap");
    return 1;
  }
  if(!qoi_to_bmp(a)){
    fprintf(stderr, "Failed to parse qoi\n");
    return 1;
  }
  munmap((void*)a, sb.st_size);
}