#include "stdio.h"
#include "stdlib.h"
#include "math.h"
#include "time.h"
#include "sethead.h"
  
/*
   Minimal conversion program for continuous EEG files
   The output file is as follows
   First line:      nchannels adcrate nevents nsamples
   Second line:     "sample event elec_1 elec_2 .... elec_nchannels"
   Rest of file:    sample event# sample_1 sample_2 .... sample_nchannels

   Be warned: check whether the machine being used is big or small endian
   Also check the size of short and int, shoult be 2 and 4 bytes respectively
*/

#define TRUE  1
#define FALSE 0
#define SWAPENDIAN FALSE

#define MAXEVENT 1000
int event[MAXEVENT];
int nevent = 0;

int main(argc,argv)
int argc;
char **argv;
{
   int i,j,readok,foundevent,showheader = TRUE;
   short sample;
   short unsigned nchannels;
   short unsigned adc;
   int c,filesize=0;
   int nsamples;
   int eventoffset,offset,eventsize;
   char ename[16];
   int eventtype;
   FILE *fptr;

   /* Do we have enough arguments */
   if (argc < 2) {
      fprintf(stderr,"Usage: %s cntfile [-h]\n",argv[0]);
      exit(0);
   }

   /* Do we want to show the header ? */
   if (argc >= 3) {
      if (strcmp(argv[2],"-h") == 0)
         showheader = FALSE;   
   }

   /* Attempt to open the continuous EEG file */
   if ((fptr = fopen(argv[1],"r")) == NULL) {
      fprintf(stderr,"Unable to open file <%s>\n",argv[1]);
      exit(0);
   }
 
   /* Calculate the file size */
   while ((c = fgetc(fptr)) != EOF)
      filesize++;
   fseek(fptr,0L,SEEK_SET);

   /* Read the number of channels */
   fseek(fptr,370L,SEEK_SET);
   readok = ReadUShort(fptr,&nchannels,SWAPENDIAN);  
   if (!readok || nchannels < 1 || nchannels > 64) {
      fprintf(stderr,"Unexpected number of channels <%d>\n",nchannels);
      exit(0);
   }
   if (showheader)
      printf("%d ",nchannels);

   /* Read the ADC rate */
   fseek(fptr,376L,SEEK_SET);
   readok = ReadUShort(fptr,&adc,SWAPENDIAN);
   if (!readok || adc < 1) {
      fprintf(stderr,"Unexpected error reading adc rate\n",adc);
      exit(0);
   }
   if (showheader)
      printf("%d ",adc);

   /* Read the event table offset */
   fseek(fptr,886L,SEEK_SET);
   readok = ReadInt(fptr,&eventoffset,SWAPENDIAN);
   if (!readok || eventoffset > filesize) {
      fprintf(stderr,"Event offset %ld is greater than the file size\n",
         eventoffset);
      exit(0);
   }

   /* Read the events */
   fseek(fptr,eventoffset,SEEK_SET);
   eventtype = fgetc(fptr);
   if (eventtype < 1 || eventtype > 2) {
      fprintf(stderr,"Unexpected eventtype <%d>\n",eventtype);
      exit(0);
   }
   readok = ReadInt(fptr,&eventsize,SWAPENDIAN);
   if (!readok || eventsize < 0) {
      fprintf(stderr,"Unexpected event size <%ld>\n",eventsize);
      exit(0);
   }
   if (eventtype == 1)
      nevent = eventsize / 8;
   else
      nevent = eventsize / 19;
   for (i=0;i<nevent;i++) {
      if (eventtype == 1)
         fseek(fptr,eventoffset + 9 + i * 8 + 4,SEEK_SET);
      else
         fseek(fptr,eventoffset + 9 + i * 19 + 4,SEEK_SET);
      readok = ReadInt(fptr,&offset,SWAPENDIAN);
      if (!readok || offset < 0) {
         fprintf(stderr,"Unexpected event offset <%ld>\n",offset);
         exit(0);
      }
      event[i] = (offset - 900 - 75 * nchannels) / (nchannels * 2);
      if (event[i] < 0) {
         fprintf(stderr,"Unexpected event sample <%ld>\n",event[i]);
         exit(0);
      }
   }
   if (showheader)
      printf("%d ",nevent);

   /* Calculate the number of expected samples */
   nsamples = (eventoffset - (900L + 75 * nchannels)) / (2 * nchannels);
   if (showheader)
      printf("%ld\n",nsamples);
   if (nsamples < 1) {
      fprintf(stderr,"Unexpected number of samples <%ld>\n",nsamples);
      exit(0);
   }

   /* Read the electrode names */
   if (showheader)
      printf("sample event ");
   for (i=0;i<nchannels;i++) {
      fseek(fptr,900L + i * 75,SEEK_SET);
      readok = ReadString(fptr,ename,10);
      if (showheader)
         printf("%s ",ename);
   }
   if (showheader)
      printf("\n");

   /* Read the samples and write results */
   fseek(fptr,900 + 75 * nchannels,SEEK_SET);
   for (i=0;i<nsamples;i++) {

      /* The first column is the sample counter */
      printf("%ld ",i); 

      /* The second column is the event flag */
      foundevent = 0;
      for (j=0;j<nevent;j++) {
         if (event[j] == i) {
            foundevent = j + 1;
            break;
         }
      }
      printf("%d ",foundevent); 

      /* The remaining channels are the samples */
      for (j=0;j<nchannels;j++) {
         if (!ReadShort(fptr,&sample,SWAPENDIAN)) {
            fprintf(stderr,"Unexpected end of samples\n");
            exit(0);
         }
         printf("%d ",sample);
      }

      printf("\n");
   }

   fclose(fptr);
}