#!/bin/sh
#
# OFFSETCOORD, BY ERIC GOTTHELF (NASA/GSFC), 1998.
# Script for offsetting a celestial coordinate value.
# 
if test $# -lt 2 -o $# -gt 4
then
 echo
 echo '         SCRIPT TO OFFSET A CELESTIAL COORDINATE PAIR.'
 echo
 echo '     1: To offset the CRVAL keywords in a FITS image:'
 echo 
 echo '  Usage: offsetcoord fitsfile+ext ra_off dec_off '
 echo
 echo '              or,'
 echo ' '
 echo '     2: To offset a coordinate pair, and write result to the screen:'
 echo
 echo '  Usage: offsetcoord ra_old dec_old ra_off dec_off '
 echo
 echo '    where, "ra_off/dec_off" are RA/DEC offsets in arcmins,'
 echo '      and, "ra_old/dec_old" are RA/DEC in degrees.'
 echo
 echo '    The offsets are simply added (i.e., ra_new = ra_old + offset / 60.0)'
 echo
 echo ' For futher details and a list of ASCA offsets, see ASCAGOF web page:'
 echo
 echo '       http://lheawww.gsfc.nasa.gov/users/evg/updatecoord.html'
 echo
 exit
fi

if test $# -eq 3
then
 file=$1
 del_ra=$2
 del_dec=$3
 dofile=yes
elif test $# -eq 4
then
 ra_old=$1
 dec_old=$2
 del_ra=$3
 del_dec=$4
 dofile=no
else
 echo
 echo 'ERROR: Try program name without arguments to see usage (agr:'$#')'
 echo
 exit
fi

if test $dofile = yes
then
 fkeypar $file CRVAL1
 exist=`pget fkeypar exist`
 if test $exist = yes
 then
  com=`pget fkeypar comm`
  if test `echo $com | grep UPDATED | wc -c` -gt 1
  then
   echo
   echo 'ERROR: The CRVALs in this extention have been updated already?'
   echo '       Exiting without changing file values...'
   echo
   exit
  else
   tmp=`pget fkeypar value`
   ra_old=`printf "%10.5f" $tmp` 
   fkeypar $file CRVAL2
   exist=`pget fkeypar exist`
   if test $exist = yes
   then
    tmp=`pget fkeypar value`
    dec_old=`printf "%10.5f" $tmp` 
   else
    echo
    echo 'ERROR: Could not get CRVAL1 value. Check extention number'
    echo '       Exiting without changing file values...'
    echo
    exit   
   fi
  fi
 else
  echo
  echo 'ERROR: Could not get CRVAL2 value. Check extention number'
  echo '       Exiting without changing file values...'
  echo
  exit
 fi
fi
echo Current RA/DEC: $ra_old $dec_old
ra_new=`echo "scale=5; $ra_old + $del_ra/60.0" | bc -l` 
dec_new=`echo "scale=5; $dec_old + $del_dec/60.0" | bc -l` 
if test $dofile = yes
then
 fparkey $ra_new $file CRVAL1 comm=" UPDATED = $ra_old + $del_ra / 60 (degs)"
 fparkey $dec_new $file CRVAL2 comm="UPDATED = $dec_old + $del_dec / 60 (degs)"
fi
echo Updated RA/DEC: $ra_new $dec_new
exit