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


struct spe_header{
  int reclA;            /* 24 */
  char title[8];
  int dim;
  int a1;               /*  1 */
  int a2;               /*  1 */
  int a3;               /*  1 */
  int reclB;            /* 24 */
};

/*write_spectrum
 *
 * saves the spectrum pointed to by "spec". Returns 0 if unsuccessful,
 * 1 if successful.
 * The name is truncated by removing any trailing .spe (and any
 * subsequent characters...), as well as any leading directory names.
 * If the resulting string is longer than the maximum allowed 8
 * characters, only the first 8 are retained
 */
static int write_spectrum(float *spec, int nchs, char *name) {  
  FILE *fp;
  int record_length;
  struct spe_header header;

  header.reclA = header.reclB = 24; 
  header.title[0] = header.title[1] = 0;
  header.a1 = header.a2 = header.a3 = 1;

  fp = fopen(name,"w");
  if (fp == NULL){
    fprintf(stderr,"Error! Unable to open spectrum file %s \n",name);
    return 0;
  }
  header.dim = nchs;
  memcpy(header.title, name, 8);
  record_length = sizeof(float)*header.dim;

  fwrite(&header, sizeof(header), 1, fp);
  fwrite(&record_length, sizeof(record_length), 1, fp);
  fwrite(spec, sizeof(float), nchs, fp); 
  fwrite(&record_length, sizeof(record_length), 1,fp);
  fclose(fp);

  return 1;
}

int main(int argc, char **argv) {

  int    i, nchs=0;
  char   fin[256], fout[256],line[120], *c;
  float  spec[16384];
  int    isp[16384] = {0};
  float  e, e0=0, ef=0;
  double a[2] = {0};
  FILE  *fp;

  if (argc < 2) {
    printf("No file name provided...\n");
    return 1;
  }
  
  strncpy(fin, argv[1], sizeof(fin));
  if ((fp = fopen(fin, "r")) == NULL) {
    printf("Cannot open input file %s\n", fin);
    return 1;
  }
  // skip first line of file (one-line header)
  fgets(line, 120, fp);

  /* read data */
  while (fgets(line, 120, fp) &&
         (sscanf(line, "%f, %d", &e, &isp[nchs]) == 2 ||    // spacer is comma
          sscanf(line, "%f %d",  &e, &isp[nchs]) == 2)) {   // spacer is space
    if (nchs++ == 0) e0 = e;
    ef = e;
  }
  fclose(fp);

  printf("%i channels... energies %.4f to %.4f\n", nchs, e0, ef);
  if (nchs < 4) {
    printf("Cannot read input file %s\n", fin);
    return 1;
  }

  /* write .spe file */
  for (i=0; i<nchs; i++) spec[i] = isp[i];
  strncpy(fout, fin, sizeof(fout));
  if ((c = strstr(fout, ".TXT")) == NULL &&
      (c = strstr(fout, ".txt")) == NULL) c = fout + strlen(fout);
  strncpy(c, ".spe", 4);
  write_spectrum(spec, nchs, fout);
  printf("  %s ==> %s\n", fin, fout);

  /* write .aca file */
  strncpy(c, ".aca", 4);
  if ((fp = fopen(fout, "w")) == NULL) return 1;
  a[1] = (ef - e0)/(double) (nchs-1);
  a[0] = e0;
  fprintf(fp, "  ENCAL OUTPUT FILE\n From %s\n", fin);
  fprintf(fp, "%5d %18.11E %18.11E %18.11E\n"
          "      %18.11E %18.11E %18.11E\n", 1,
          a[0], a[1], 0.0, 0.0, 0.0, 0.0);
  fclose(fp);
  printf("   ...Calibration file %s created.\n", fout);
  fclose(fp);

  return 0;
}