#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <math.h>
#include "netcdf.h"

#define START_YEAR (1980)
#define END_YEAR (1994)
#define MAX_STORE_YEARS (END_YEAR - START_YEAR + 1)
#define NROWS (360)
#define NCOLS (720)
#define MISSING_VALUE (-9999.)
#define GRIDSIZE (NROWS * NCOLS)

/*#define SR_UNITS "Tg C mo-1" */
/*#define PATH "/disk10/RAICH/monthly/" */
/*#define SR_FILE_NAME "srtotal" */
/*#define OUT_FILE "/disk10/RAICH/sr_total_0.5degree.nc" */

#define SR_UNITS "g C m-2 d-1" 
#define PATH "/disk10/RAICH/daily/" 
#define SR_FILE_NAME "srdaily" 
#define OUT_FILE "/disk10/RAICH/sr_daily_0.5degree.nc" 

void
check_err(const int stat, const int line, const char *file) {
    if (stat != NC_NOERR) {
           (void) fprintf(stderr, "line %d of %s: %s\n", line, file, nc_strerror(stat));
        exit(1);
    }
}

void main ()
{
   static size_t start[3];
   static size_t count[3];

   time_t current_time;

   int stat, i;
   int sr_ncid;
   int year, month;
   int lat_dim, lon_dim, time_dim, var_dim[3];

   int sr_id, lat_id, lon_id, time_id;

   float fill_val;

   char header [25];
   char description[80];
   char sr_file_name [100];

   int time_data[MAX_STORE_YEARS * 12] ;

   float lat_lon[720];
   float *sr;

   FILE *sr_file;

   void check_err( const int, const int, const char *);

   /* enter define mode */

   stat = nc_create(OUT_FILE, NC_CLOBBER, &sr_ncid);
   check_err(stat,__LINE__,__FILE__);

   /* define dimensions */

   stat = nc_def_dim(sr_ncid, "time", 12 * MAX_STORE_YEARS , &time_dim);
   check_err(stat,__LINE__,__FILE__);

   stat = nc_def_dim(sr_ncid, "lat", NROWS, &lat_dim);
   check_err(stat,__LINE__,__FILE__);

   stat = nc_def_dim(sr_ncid, "lon", NCOLS, &lon_dim);
   check_err(stat,__LINE__,__FILE__);


   /* define variables */

   var_dim[0] = time_dim;
   var_dim[1] = lat_dim;
   var_dim[2] = lon_dim;

   stat = nc_def_var(sr_ncid, "time", NC_FLOAT, 1, &time_dim, &time_id);
   check_err(stat,__LINE__,__FILE__);

   stat = nc_def_var(sr_ncid, "lat", NC_FLOAT, 1, &lat_dim, &lat_id);
   check_err(stat,__LINE__,__FILE__);

   stat = nc_def_var(sr_ncid, "lon", NC_FLOAT, 1, &lon_dim, &lon_id);
   check_err(stat,__LINE__,__FILE__);

   stat = nc_def_var(sr_ncid, "soil_respiration", NC_FLOAT, 3, var_dim, &sr_id);
   check_err(stat,__LINE__,__FILE__);

   /* assign attributes */

   stat = nc_put_att_text(sr_ncid, lat_id, "long_name", 8, "Latitude");
   check_err(stat,__LINE__,__FILE__);
   stat = nc_put_att_text(sr_ncid, lat_id, "units", 13, "degrees_north");
   check_err(stat,__LINE__,__FILE__);

   stat = nc_put_att_text(sr_ncid, lon_id, "long_name", 9, "Longitude");
   check_err(stat,__LINE__,__FILE__);
   stat = nc_put_att_text(sr_ncid, lon_id, "units", 12, "degrees_east");
   check_err(stat,__LINE__,__FILE__);

   sprintf(description, "days since %4d-01-01 00:00:00", START_YEAR);
   stat = nc_put_att_text(sr_ncid, time_id, "units", strlen(description), description);
   check_err(stat,__LINE__,__FILE__);

   fill_val = (float)MISSING_VALUE;

   stat = nc_put_att_float(sr_ncid, sr_id, "missing_value", NC_FLOAT, 1, &fill_val );
   check_err(stat,__LINE__,__FILE__);

   stat = nc_put_att_text(sr_ncid, sr_id, "long_name",16, "Soil Respiration");
   check_err(stat,__LINE__,__FILE__);
   sprintf(description, "%s", SR_UNITS);
   stat = nc_put_att_text(sr_ncid, sr_id, "units", strlen(description), description);
   check_err(stat,__LINE__,__FILE__);

   current_time = time(NULL);
   strcpy(description,ctime(&current_time));
   strlen(description);
   description[strlen(description)-1] = '\0';

   stat = nc_put_att_text(sr_ncid, NC_GLOBAL, "Created", strlen(description)+1, description
);

   stat = nc_put_att_text(sr_ncid, NC_GLOBAL, "Source", 138, "Raich, J.W., C.S. Potter, D. Bhagawati 2002. Interannual variability in global soil respiration, 1980-94. Global Change Biology 8:800-812.");
   check_err(stat,__LINE__,__FILE__);

   stat = nc_put_att_text(sr_ncid, NC_GLOBAL, "Conventions", 11, "COARDS, GDV");
   check_err(stat,__LINE__,__FILE__);

   /* leave define mode */
   stat = nc_enddef (sr_ncid);
   check_err(stat,__LINE__,__FILE__);

   lat_lon[0] = 90.;
   for ( i = 1; i < 360; i++ ) {
      lat_lon[i] = lat_lon[i-1] - 0.5;
      fprintf(stderr,"lat = %d %f\n", i, lat_lon[i]);
   }
   stat = nc_put_var_float(sr_ncid, lat_id, lat_lon);
   check_err(stat,__LINE__,__FILE__);

   lat_lon[0] = -180.;
   for ( i = 1; i < 720; i++ ) { 
      lat_lon[i] = lat_lon[i-1] + 0.5;
      fprintf(stderr,"lon = %d %f\n", i, lat_lon[i]);
   }
   stat = nc_put_var_float(sr_ncid, lon_id, lat_lon);
   check_err(stat,__LINE__,__FILE__);

   for ( i = 0; i < 12 * MAX_STORE_YEARS; i++ ) 
      time_data[i] = (float)i*(365.0/12.0)+15.0;

   stat = nc_put_var_int(sr_ncid, time_id, time_data);
   check_err(stat,__LINE__,__FILE__);

   /* allocate memory for sr values */
   sr = (float *)malloc(NROWS * NCOLS * sizeof(float));

   count[0] = 1; 
   start[1] = 0;
   count[1] = NROWS;
   start[2] = 0;
   count[2] = NCOLS;

   for( year = START_YEAR; year <= END_YEAR; year++) {
      for (month = 1; month <= 12; month++) {
         if(month < 10) sprintf(sr_file_name, "%s%d%s0%db.dat", PATH, year-1900, SR_FILE_NAME, month); 
         else sprintf(sr_file_name, "%s%d%s%db.dat", PATH, year-1900, SR_FILE_NAME, month); 
         fprintf(stderr, "reading file %s\n", sr_file_name);

         if (!(sr_file = fopen(sr_file_name, "r"))) {
            fprintf(stderr, "\nfailure opening soil respiration file\n");
            exit(1);
         }

         /* read 6 header lines */

         for (i = 1; i <= 6; i++) 
            fgets(header, 20, sr_file);

         for (i = 0; i < GRIDSIZE; i++) 
            fscanf(sr_file, "%f", &sr[i]);

         fclose (sr_file);

         /* store soil respiration values */
         start[0] = (year - START_YEAR) * 12 + (month - 1);
         stat = nc_put_vara_float(sr_ncid, sr_id, start, count, (void *)sr);
         check_err(stat,__LINE__,__FILE__);
      }
   
   }  

   /* close nc file before leaving */
   stat = nc_close(sr_ncid);
   check_err(stat,__LINE__,__FILE__);

   free (sr);
}