#include <stdio.h></stdio.h>

#include <stdlib.h></stdlib.h>

#include <string.h></string.h>

int main() {

  int sizeX = 28;

  int sizeY = 28;

  int border = 2;

  int outSizeX = 22;

  int outSizeY = 22;

  const char *filename = "data/symbols-data.bin";

  const char *outFilename = "data/output/symbols22-data.bin";

  printf("read data from '%s'\n", filename);

  FILE *f = fopen(filename, "rb");

  if (!f)

    return printf("cannot open file\n"), 1;

  fseek(f, 0, SEEK_END);

  size_t fs = ftell(f);

  fseek(f, 0, SEEK_SET);

  size_t testSize = sizeX*sizeY + 1;

  int count = fs/testSize;

  if (!count)

    return printf("file is lesser minimal size\n"), fclose(f), 1;

  unsigned char *data = calloc(testSize, count);

  if (!fread(data, testSize*count, 1, f))

    return printf("cannot read"), free(data), fclose(f), 1;

  fclose(f);

  printf("write converted data to '%s'\n", outFilename);

  f = fopen(outFilename, "wb");

  if (!f)

    return printf("cannot open file\n"), 1;

  unsigned char *img = calloc(outSizeX*outSizeY+1, 1);

  int sx = sizeX - 2*border - 1, sy = sizeY - 2*border - 1;

  int osx = outSizeX - 2*border - 1, osy = outSizeY - 2*border - 1;

  for(int i = 0; i < count; ++i) {

    unsigned char *in = data + testSize*i;

    for(int y = 0; y <= osy; ++y) {

      int y0 = y*sy;

      int py = y0%osy;

      y0 /= osy;

      int y1 = y0 < sy ? y0 : sy;

      for(int x = 0; x <= osx; ++x) {

        int x0 = x*sx;

        int px = x0%osx;

        x0 /= osx;

        int x1 = x0 < sx ? x0 : sx-1;

        int p00 = in[(border+y0)*sizeX + x0];

        int p01 = in[(border+y0)*sizeX + x1];

        int p0 = p00*(osx-px) + p01*px;

        int p10 = in[(border+y1)*sizeX + x0];

        int p11 = in[(border+y1)*sizeX + x1];

        int p1 = p10*(osx-px) + p11*px;

        int p = p0*(osy-py) + p1*py;

        p = (p + osx*osy/2)/(osx*osy);

        img[(y+border)*outSizeX + x] = (unsigned int)p1;

      }

    }

    img[outSizeX*outSizeY] = in[sizeX*sizeY];

    if (!fwrite(img, outSizeX*outSizeY+1, 1, f))

      return printf("cannot write\n"), free(data), free(img), fclose(f), 1;

  }

  free(data);

  free(img);

  fclose(f);

  return printf("done\n");

  return 0;

}