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

/* This program takes a 2mass-format strip and spits out fits files */
/* Usage  mkfits 2massfile 10 20 x  */
/* Which would make fits files x010...x039.fit (i.e. 20 files starting at #10 */

void main(argc,argv)
     char **argv;
     int argc;

{ int i=0,j=0,k=0;
  int iskip,bskip,inum,size = 65536;
  short buffer[65536],frame[65536];
  char outfil[80],ext[4],fitshead[2880];
  FILE *infile,*fits,*outfile;

  if (argc<4) 
      {printf("\7\n Usage: mkfits 2massraw frames_to_skip frames_to_make output_file_name\n\n");
               exit(1);
	     }

/* load fits header */
  /*  fits = fopen("/home/skrutski/tools/fits.200","r");
      fread(fitshead,sizeof(short),1440,fits); */
  for(i=0;i<1440;i++){fitshead[i]=0.;}
  
  strncpy(&fitshead[0],"SIMPLE  =                    T / STANDARD FITS                                   ",80);
  strncpy(&fitshead[80],"BITPIX  =                   16 / BITS/PIXEL                                      ",80);
  strncpy(&fitshead[160],"NAXIS   =                    2 / NUMBER OF AXES                                  ",80);
  strncpy(&fitshead[240],"NAXIS1  =                  256 / NUMBER OF COLUMNS                               ",80);
  strncpy(&fitshead[320],"NAXIS2  =                  256 / NUMBER OF ROWS                                  ",80);
  strncpy(&fitshead[400],"BSCALE  =        1.0000000E+00 / PHYSICAL = BSCALE * DATA + BZERO                ",80);
  strncpy(&fitshead[480],"BZERO   =        0.0000000E+00 /                                                 ",80);
  strncpy(&fitshead[560],"ORIGIN  = 'mk utilities'       /                                                 ",80);
  strncpy(&fitshead[640],"INSTRUME= '2MASS Survcam'      /                                                 ",80);
  strncpy(&fitshead[720],"FRAME   =   1                  /                                                 ",80);
  strncpy(&fitshead[800],"OBJECT  = 'Unknown'            /                                                 ",80);
  strncpy(&fitshead[880],"GAIN    =                10.5  / Nominal gain (e-/ADU)                           ",80);
  strncpy(&fitshead[960],"END                                                                              ",80);

  infile=fopen(argv[1],"r");
  iskip = atoi(argv[2]);
  inum  = atoi(argv[3]);

  bskip = iskip * size * 2 * 2;  /* skipping pairs of reads */
  fseek(infile,bskip,0);
  printf("Writing fits files:\n");

  for (j=0;j<inum;j++){

      fread(frame, sizeof(short), size, infile);

      fread(buffer, sizeof(short), size, infile);

      for (i=0;i<65536;i++){frame[i]= buffer[i]-frame[i];}

      swab(frame, frame, 2*size);

      strcpy(outfil,argv[4]);
      sprintf(ext,"%d",j);
      if (strlen(ext)==3){strcat(outfil,ext);}
      if (strlen(ext)==2){strcat(outfil,"0"); strcat(outfil,ext);}
      if (strlen(ext)==1){strcat(outfil,"00"); strcat(outfil,ext);}
      printf("%s\n",outfil);
      outfile = fopen(outfil,"w");
      fwrite(fitshead,2,1440,outfile);
      fwrite(frame,2,65536,outfile);
      fwrite(frame,2,704,outfile); 
      fclose(outfile); 
   

  } 
}