/*
 * Copyright 2005-2016 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

/*
 * C Implementation: set
 *
 * Description: how to set key values.
 *
 */
#include <stdio.h>
#include <stdlib.h>

#include "grib_api.h"

int main(int argc, char** argv)
{
  int err = 0;
  long centre=80;
  long long_value=0;
  char string_value[100];
  size_t len = sizeof(string_value)/sizeof(char);
  size_t size=0;

  FILE* in = NULL;
  char* infile = "../../data/regular_latlon_surface.grib1";
  FILE* out = NULL;
  char* outfile = "out.set.grib1";
  grib_handle *h = NULL;
  const void* buffer = NULL;
  size_t str_len = 0; /* See the call to grib_set_string later */

  in = fopen(infile,"r");
  if(!in) {
    printf("ERROR: unable to open file %s\n",infile);
    return 1;
  }

  out = fopen(outfile,"w");
  if(!out) {
    printf("ERROR: unable to open file %s\n",outfile);
        fclose(in);
    return 1;
  }

  /* create a new handle from a message in a file */
  h = grib_handle_new_from_file(0,in,&err);
  if (h == NULL) {
    printf("Error: unable to create handle from file %s\n",infile);
  }

  /* set centre as a long */
  GRIB_CHECK(grib_set_long(h,"centre",centre),0);
  
  /* set paramId and shortName - normally you would do one or the other */
  GRIB_CHECK(grib_set_long(h,"paramId", 500004),0);
  /* the value of str_len is not used, it can be anything! */
  GRIB_CHECK(grib_set_string(h,"shortName", "fis", &str_len),0);

  /* get centre as a long */
  GRIB_CHECK(grib_get_long(h,"centre",&long_value),0);
  printf("centre long value=%ld\n",long_value);

  /* get centre as a string */
  GRIB_CHECK(grib_get_string(h,"centre",string_value,&len),0);
  printf("centre string value=%s\n",string_value);

  /* get the coded message in a buffer */
  GRIB_CHECK(grib_get_message(h,&buffer,&size),0);

  /* write the buffer in a file*/
  if(fwrite(buffer,1,size,out) != size) 
  {
     perror(argv[1]);
     exit(1);
  }

  grib_handle_delete(h);
  fclose(in);
  fclose(out);

  return 0;
}
