/*****************************************************************************
*
* write_grhdr 
*
* LAST UPDATE: 31 December 1997 
*
* DESCRIPTION:
*   Writes output header file in CLIMSAT (GrADS-like) format.
*
* MODIFICATIONS:
*   Catherine Cormack 11/16/01 localtime returns years as number of
*                              years since 1900.  Modified sprintf to
*                              add 1900 to years. 
*   Don Anderson  12/08/97  Corrected error in TDEF month handling: 
*                            strcat ( tdefdate, mon[month] ) ; changed to 
*                            strcat ( tdefdate, mon[month-1] ) ;
*
*   Wesley Berg   12/31/97  Modified inputs for grid_data routine
*
*****************************************************************************/
#include <stdio.h>
#include <time.h>
#include "common_structures"

extern FILE *inf, *opf, *opf2, *stf, *hdf;

int write_grhdr ( char *header_file, char *data_file, long stime, long etime,
                  double xstart, double xend, int xdim, double ystart,
                  double yend, int ydim, struct std_hdr hdr )
 {

 char   title[80] ;
 char   subtitle[80] ;
 char   cdate[20] ;
 char   datatype_str[8] ;
 char   error_flag ;
 char   sdate[20] ;
 time_t st;
 char   tdeftime[6] ;
 char   tdefdate[10] ;
 char   tinc[5] ;
 int    tval ;
 int    tdif ;
 char   varstr[80] ;
 char   xdefstr[60] ;
 double xstartcen ;
 double xinc ;
 char   xunit[10] ;
 char   ydefstr[60] ;
 char   yearstr[3] ;
 double ystartcen ;
 double yinc ;
 char   yunit[10] ;
 int    i ;

 static char *mon[]={"JAN","FEB","MAR","APR","MAY","JUN","JUL","AUG",
                     "SEP","OCT","NOV","DEC"} ;
 struct tm *lt;

/** Massage all the date data **/

 strcpy ( title, hdr.sensor ) ;
 strcpy ( subtitle, hdr.filename ) ;
 error_flag = 0 ;
 date(tdefdate, tdeftime, stime) ;
 /*  printf("tdefdate = %s, tdeftime = %s\n", tdefdate,tdeftime);  */
 tdif = etime - stime;
 if (tdif < 0) tdif = stime - etime;
 if (tdif >= 31536000 ) {
   strcpy(tinc,"YR");
   tval=(int)(tdif/31536000);
 }
 else if (tdif >= 2592000 ) {
   strcpy(tinc,"MO");
   tval=(int)(tdif/2592000) ;
 }
 else if (tdif >= 86400 ) {
   strcpy(tinc,"DY");
   tval=(int)(tdif/86400) ;
 }
 else if (tdif >= 3600 ) {
   strcpy(tinc,"HR");
   tval=(int)(tdif/3600) ;
 }
 else {
   strcpy(tinc,"MN");
   tval=(int)(tdif/60) ;
 }

/** Determine lower left pixel center x,y **/

 xinc = ( xend - xstart ) / xdim ;
 yinc = ( yend - ystart ) / ydim ;

 xstartcen = xstart + ( xinc / 2.0 ) ; 
 ystartcen = yend - ( yinc / 2.0 ) ; 

/** Specify x, y units **/

 strcpy ( xunit, "DD" ) ;
 strcpy ( yunit, "DD" ) ;

/** Get current time **/

 st = time ( NULL ) ;
 lt = localtime ( &st ) ;

/** Specify data type **/

 strcpy ( datatype_str, "INTEGER" ) ; 

/** Write out the dang file **/

 sprintf ( cdate, "%2.2d%3s%4d",lt->tm_mday,mon[lt->tm_mon], lt->tm_year+1900 ) ;
 sprintf ( xdefstr, "%d LINEAR %10.4f %7.4f %s", 
                    xdim, xstartcen, xinc, xunit ) ;
 sprintf ( ydefstr, "%d LINEAR %10.4f %7.4f %s", 
                    ydim, ystartcen, -yinc, yunit ) ;
 fprintf ( hdf, "DSET      %s\n", data_file ) ;
 fprintf ( hdf, "TITLE     %s\n", title ) ;
 fprintf ( hdf, "SUBTITLE  %s\n", subtitle ) ;
 fprintf ( hdf, "CREATED   %s NOAA-CIRES/CDC\n", cdate ) ;
 fprintf ( hdf, "UNDEF     -1\n" ) ;
 fprintf ( hdf, "DTYPE     %s\n", datatype_str ) ;
 fprintf ( hdf, "XDEF      %s\n", xdefstr ) ;
 fprintf ( hdf, "YDEF      %s\n", ydefstr ) ;
 fprintf ( hdf, "ZDEF       1 LINEAR      0    1\n" ) ;
 fprintf ( hdf, "TDEF       1 LINEAR %sZ%s %3d%2s\n", tdeftime, tdefdate,
           tval, tinc ) ;
 fprintf ( hdf, "VARS %2d\n",hdr.fields+hdr.hifields ) ;
 for (i=0; i<hdr.fields+hdr.hifields; i++) {
   fprintf ( hdf, "var%1d %9.2f %9.2f %10s %40s\n", i+1,hdr.scale[i],
             hdr.offset[i], &hdr.units[i], &hdr.description[i] ) ;
 }
 fprintf ( hdf, "ENDVARS\n" ) ;

/** Go home **/

 fclose ( hdf ) ; 

 return ( error_flag ) ;

 }