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

int  *big_map=NULL,
     *temp_map=NULL;

int map_edge;

/*{{{  friggy stuff*/
static int clut[16] = {  4,  5,  6,  7,
                         8, 10, 12, 14,
                        16, 20, 24, 28,
                        32, 40, 48, 56 };
/*}}}  */

/*{{{  static int funny_fourbits ( int eight )*/
static int funny_fourbits ( int eight )
{
  int ix=0, c0, c1;

  if ((eight & 15) > 7) {
    eight+=15;
    if (eight > 255) return 15;
  }
  return eight>>4;

  eight>>=2;

  if (eight > clut[15])
    eight=clut[15];

  while (clut[ix+1] < eight)
    ix++;

  c0=clut[ix];
  c1=clut[ix+1];

  c0-=eight;
  c1-=eight;

  if ((c0*c0) < (c1*c1))
    return ix;
  else
    return ix+1;
}
/*}}}  */


/*{{{  static void fourbit_mono ( int field, int *temp_map, int *big_map )*/
static void fourbit_mono ( int field, int *temp_map, int *big_map )
{
  int i, mask, shift;

  mask=~(0xf<<field);

  shift=field;

  printf ("fourbitmono, field 0x%x mask 0x%x shift 0x%x\n", field, mask, shift );
  printf ("Munging %d texels\n", map_edge );

  for (i=0; i<map_edge; i++ ) {
    int v, w, r, g, b;

    v=*temp_map;

    b=0xff & (v>>8);
    r=0xff & (v>>16);
    g=0xff & (v>>24);

    v=0xff & (((180*g)+(51*r)+(25*b)) >> 8);
    v=funny_fourbits(v);
    w=*big_map;

    *big_map=(w&mask)|(v<<shift);
    temp_map++;
    big_map++;

  }
}
/*}}}  */
/*{{{  static void eightbit_mono ( int field, int *temp_map, int *big_map )*/
static void eightbit_mono ( int field, int *temp_map, int *big_map )
{
  int i, mask, shift;

  mask=~(0xff<<field);

  shift=field;

  printf ("eightbitmono, field 0x%x mask 0x%x shift 0x%x\n", field, mask, shift );

  for (i=0; i<map_edge; i++ ) {
    int v, w, r, g, b;

    printf ("Munging %d texels\n", map_edge );
    v=*temp_map;

    b=0xff & (v>>8);
    r=0xff & (v>>16);
    g=0xff & (v>>24);

    v=0xff & (((180*g)+(51*r)+(25*b)) >> 8);
    w=*big_map;

    *big_map=(w&mask)|(v<<shift);

    temp_map++;
    big_map++;

  }
}
/*}}}  */
/*{{{  static void bilinear ( int *temp_map, int *big_map )*/
static void bilinear ( int *temp_map, int *big_map )
{
  printf ("Dont bother - just make the loader do it\n");
  memcpy ( big_map, temp_map, 4*map_edge );
}
/*}}}  */
/*{{{  static void eightbit_color ( int field, int *temp_map, int *big_map )*/
static void eightbit_color ( int field, int *temp_map, int *big_map )
{
  int i, mask, shift;

  mask=~(0xff<<field);

  shift=field;

  printf ("eightbitcolor, field 0x%x mask 0x%x shift 0x%x\n", field, mask, shift );
  printf ("Munging %d texels\n", map_edge );

  for (i=0; i<map_edge; i++ ) {
    int v, w, r, g, b;

    v=*temp_map;

    b=0xff & (v>>8);
    g=0xff & (v>>16);
    r=0xff & (v>>24);

    r = (r>>5) & 0x7;
    g = (g>>5) & 0x7;
    b = (b>>6) & 0x3;

    v=r|(g<<3)|(b<<6);

    w=*big_map;

    *big_map=(w&mask)|(v<<shift);
    temp_map++;
    big_map++;

  }
}
/*}}}  */
/*{{{  static void twelvebit_color ( int field, int *temp_map, int *big_map )*/
static void twelvebit_color ( int field, int *temp_map, int *big_map )
{

  int i, mask, shift;

  mask=~(0xfff<<field);

  shift=field;

  printf ("twelvebitcolor, field 0x%x mask 0x%x shift 0x%x\n", field, mask, shift );
  printf ("Munging %d texels\n", map_edge );

  for (i=0; i<map_edge; i++ ) {
    int v, w, r, g, b;

    v=*temp_map;

    b=0xff & (v>>8);
    g=0xff & (v>>16);
    r=0xff & (v>>24);

    r=funny_fourbits ( r );
    g=funny_fourbits ( g );
    b=funny_fourbits ( b );

    v=r|(g<<4)|(b<<8);

    w=*big_map;

    *big_map=(w&mask)|(v<<shift);
    temp_map++;
    big_map++;

  }
}
/*}}}  */


/*{{{  load_svt ( char *full_name )*/
int
load_svt ( char *full_name, int mode )
{
  FILE *fp=fopen(full_name, "rb" );
  long l_edge, texels;
  int i, edge;
  char *texelp;

  if (fp==NULL) {
    printf ("failed to open file %s\n", full_name );
    return 0;
  }
  else {
    fseek ( fp, 0L, SEEK_END );
    l_edge=ftell(fp);
    fseek ( fp, 0L, SEEK_SET );

    edge=128;

    if      (l_edge == 16384L)  edge=64;
    else if (l_edge == 65536L)  edge=128;
    else if (l_edge == 262144L) edge=256;
    else  {
      printf("Bad texture file size 0x%lx\n",l_edge);
      fclose(fp);
      return 0;
    }
  }

  texels=edge*edge;

  if (temp_map == NULL) {
    map_edge=texels;
    temp_map=malloc(texels*4);
    big_map =malloc(texels*4);
    for (i=0; i<texels; i++ ) {
      temp_map[i]=0x0;
      big_map[i]=0x0;
    }
  }
  else {
    if (map_edge != texels) {
      printf ("File size mismatch\n" );
      exit (666);
    }
  }

  texelp=(char *) temp_map;

  while (texels) {
    int i;
    fread ( texelp, 1, 8192, fp );

    texels-=2048;
    texelp+=8192;
  }
  fclose(fp);

  switch ( mode) {
    case 0x3 :
      fourbit_mono ( 8, temp_map, big_map );
      break;
    case 0x2 :
      fourbit_mono ( 12, temp_map, big_map );
      break;
    case 0x1 :
      fourbit_mono ( 16, temp_map, big_map );
      break;
    case 0x0 :
      fourbit_mono ( 20, temp_map, big_map );
      break;

    case 0x4 :
      eightbit_mono ( 8, temp_map, big_map );
      break;

    case 0x5 :
      bilinear ( temp_map, big_map );
      break;

    case 0x6 :
      eightbit_color ( 0, temp_map, big_map );
      break;

    case 0x7 :
      twelvebit_color ( 0, temp_map, big_map );
      break;

  }
  return 1;
}
/*}}}  */
/*{{{  save_svt ( char *full_name )*/
int
save_svt ( char *full_name )
{
  FILE *fp=fopen(full_name, "wb" );
  long texels;
  char *texelp;

  if (fp==NULL) {
    printf ("failed to open write file %s\n", full_name );
    return 0;
  }
  if (big_map==NULL) {
    printf ("No operations performed to generate file %s\n", full_name );
    fclose(fp);
    return 0;
  }
  else {
    texelp=(char *) big_map;
    texels=map_edge;
    printf ("Saving %d texels\n", texels );

    while (texels) {
      int i;

      for (i=0; i<2048; i++ ) {
        char a, b, c, d;
        int ix=i<<2;

        a=texelp[ix+0];
        b=texelp[ix+1];
        c=texelp[ix+2];
        d=texelp[ix+3];

        texelp[ix+0]=d;
        texelp[ix+1]=c;
        texelp[ix+2]=b;
        texelp[ix+3]=a;
      }
      fwrite ( texelp, 1, 8192, fp );

      texels-=2048;
      texelp+=8192;
    }
    fclose(fp);
  }
  return 1;
}
/*}}}  */



/*

usage - glomm /mode 0x0 name /mode 0x1 name destname

*/

int main ( int argc, char **argv )
{
  int n_files, i=0;
  char *write_name=NULL;

  for (i=1; i<argc; i++) {
    char *s=argv[i];
    int l=strlen(s);

    if (strcmp(s,"/mode") == 0) {
      int mode;
      char *fname;
      /* got a file thing, do it */
      i++;
      if (i == argc) {
        printf ("malformed arguments\n" );
        exit(666);
      }
      s=argv[i];
      sscanf ( s, "%x", &mode );
      i++;
      if (i == argc) {
        printf ("malformed arguments\n" );
        exit(666);
      }
      fname=argv[i];
      load_svt ( fname, mode );
    }
    else {
      if (write_name) {
        printf ("destination file name specified twice : %s : %s\n",
           write_name, s );
        exit(666);
      }
      else write_name=s;
    }
  }
  if (write_name)
    save_svt(write_name);
  else
    printf ("No destination name specified\n");
}