#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "LatLong-UTMconversion.h"

#define READGPS_MINI 10

FILE *readgps_serialsetup(char *path);
struct eivadata readgps_read(FILE *term);
int readgps_close(FILE *term);

int latitude_int, longitude_int;

struct eivadata
{
  struct tm time;
  double northing, easting;
  double latitude, longitude;
	char raw_latitude[50];
	char raw_longitude[50];
  char zone[4];
  char tsource;
};

FILE *readgps_serialsetup(char *path)
{
  FILE *term;
  int tset;
  termios options;

  tset = open(path, O_RDWR | O_NOCTTY);

  if (tset < 0)
    return NULL;

  tcgetattr(tset, &options);
  options.c_iflag |= IGNBRK;
  options.c_iflag |= IGNPAR;

  options.c_iflag &= ~INLCR;
  options.c_iflag &= ~INPCK;
  options.c_iflag &= ~PARMRK;
  options.c_iflag &= ~ISTRIP;
  options.c_iflag &= ~IXOFF;
  options.c_iflag &= ~IXON;

  options.c_iflag &= ~ONLCR;
  options.c_iflag &= ~OCRNL;

  options.c_iflag &= ~ICRNL;

  options.c_iflag &= ~BRKINT;
  options.c_cflag &= ~PARENB;
  options.c_cflag &= ~CSTOPB;
  options.c_cflag &= ~CSIZE;
  options.c_cc[VTIME]=0;
  options.c_cc[VMIN]=1;
  options.c_cflag |= CS8;
  options.c_lflag &= ~ICANON;
  options.c_lflag &= ~ECHO;
  options.c_lflag &= ~ECHOE;
  options.c_lflag &= ~ECHONL;
  options.c_lflag &= ~ISIG;
  tcsetattr(tset, TCSANOW, &options);
  close(tset);

  term = fopen(path, "a+");

  return term;
}

struct eivadata readgps_read(FILE *term)
{
  struct eivadata eiva;
  int state = 0;
  int cnum;
  char minibuff[READGPS_MINI];
  int chr;
  char lath, longh;
  time_t ct;

  /* Read PGRMF sentences, and put them in global eivadata structure eiva */
  while (state < 10)
    {
      chr = fgetc(term);

      switch (state)
	{
	case 1:
	  /* Skip GPS week number */
	case 2:
	  /* Skip GPS seconds */
	case 5:
	  /* Skip GPS leap seconds */
	  if (chr == ',')
	    {
	      cnum = 0;
	      state++;
	    }
	  break;

	case 3:
	  /* UTC date */

	  /* Day of month */
	  if (cnum < 2)
	    {
	      minibuff[cnum] = chr;
	      if (cnum == 1)
		{
		  minibuff[2] = '\0';
		  eiva.time.tm_mday = atoi(minibuff);
		}
	    }

	  /* Month */
	  else if (cnum < 4)
	    {
	      minibuff[cnum - 2] = chr;
	      if (cnum == 3)
		{
		  minibuff[2] = '\0';
		  eiva.time.tm_mon = atoi(minibuff);
		}
	    }

	  /* Year */
	  else if (cnum < 6)
	    {
	      minibuff[cnum - 4] = chr;
	      if (cnum == 5)
		{
		  minibuff[2] = '\0';
		  eiva.time.tm_year = atoi(minibuff) + 100;
		}
	    }

	  /* Date finished? */
	  if (chr == ',')
	    {
	      if (cnum > 4)
		eiva.tsource = 'G';
	      else
		eiva.tsource = 'S';

	      cnum = 0;
	      state++;
	    }
	  else
	    cnum++;

	  break;

	case 4:
	  /* UTC time */

	  /* Hours */
	  if (cnum < 2)
	    {
	      minibuff[cnum] = chr;
	      if (cnum == 1)
		{
		  minibuff[2] = '\0';
		  eiva.time.tm_hour = atoi(minibuff);
		}
	    }

	  /* Minutes */
	  else if (cnum < 4)
	    {
	      minibuff[cnum - 2] = chr;
	      if (cnum == 3)
		{
		  minibuff[2] = '\0';
		  eiva.time.tm_min = atoi(minibuff);
		}
	    }

	  /* Seconds */
	  else if (cnum < 6)
	    {
	      minibuff[cnum - 4] = chr;
	      if (cnum == 5)
		{
		  minibuff[2] = '\0';
		  eiva.time.tm_sec = atoi(minibuff);
		}
	    }

	  /* Time finished? */
	  if (chr == ',')
	    {
	      /* Valid GPS data? If not, use system time */
	      if (eiva.tsource == 'S')
		gmtime_r(&ct, &eiva.time);

	      /* Next token */
	      cnum = 0;
	      state++;
	    }
	  else
	    cnum++;

	  break;

	case 6:
	  /* Latitude */
	  if (chr == ',')
	    {
	      minibuff[cnum] = '\0';
				strcpy(eiva.raw_latitude, minibuff);				// Get original GPS data string

	      eiva.latitude = atof(minibuff);
				latitude_int  = (int) (eiva.latitude / 100);
				eiva.latitude = (( eiva.latitude - (latitude_int * 100)) / 60) + latitude_int;
	      // Jan Inges påfunn:
				//eiva.latitude = ((eiva.latitude - ((double)(int)eiva.latitude)) / 60) + ((double)(int)eiva.latitude / 100);

	      cnum = 0;
	      state++;
	    }

	  else
	    {
	      minibuff[cnum] = chr;
	      cnum++;
	    }

	  break;

	case 7:
	  /* Latitude hemisphere */
	  if (chr == ',')
	    state++;
	  else
	    lath = chr;
	  break;

	case 8:
	  /* Longitude */
	  if (chr == ',')
	    {
	      minibuff[cnum] = '\0';
				strcpy(eiva.raw_longitude, minibuff);				// Get original GPS data string

	      eiva.longitude = atof(minibuff);
				longitude_int  = (int) (eiva.longitude / 100);
				eiva.longitude = (( eiva.longitude - (longitude_int * 100)) / 60) + longitude_int;

				// Jan Inges påfunn - feil!!!    :
				// eiva.longitude = ((eiva.longitude - ((double)(int)eiva.longitude)) / 60) + ((double)(int)eiva.longitude / 100);

	      cnum = 0;
	      state++;
	    }

	  else
	    {
	      minibuff[cnum] = chr;
	      cnum++;
	    }

	  break;

	case 9:
	  /* Longitude hemisphere */
	  if (chr == ',')
	    {
	      state++;
	      
	      /* All done */
	      if (lath == 'S')
		eiva.latitude -= eiva.latitude + eiva.latitude;
	      if (longh == 'W')
		eiva.longitude -= eiva.longitude + eiva.longitude;

	      LLtoUTM(23, eiva.latitude, eiva.longitude, eiva.northing, eiva.easting, eiva.zone); /* Convert to UTM */
	    }
	  else
	    longh = chr;

	  break;

	default:
	  /* PGRMF sentence? */
	  if (chr == '$')
	    if (fgetc(term) == 'P')
	      if (fgetc(term) == 'G')
		if (fgetc(term) == 'R')
		  if (fgetc(term) == 'M')
		    if (fgetc(term) == 'F')
		      {
			time(&ct);
			gmtime_r(&ct, &eiva.time);
			fgetc(term);

			state = 1;
		      }
	  break;
	}

    }

  return eiva;
}

int readgps_close(FILE *term)
{

  return fclose(term);
}