#! /bin/sh
# This is the LHEA perl script: grating2xspec
# The purpose of this special block is to make this script work with
# the user's local perl, regardless of where that perl is installed.
# The variable LHEAPERL is set by the initialization script to
# point to the local perl installation.
#-------------------------------------------------------------------------------
eval '
if [ "x$LHEAPERL" = x ]; then
  echo "Please run standard LHEA initialization before attempting to run acisscr
een."
  exit 3
elif [ "$LHEAPERL" = noperl ]; then
  echo "During LHEA initialization, no acceptable version of Perl was found."
  echo "Cannot execute script acisscreen."
  exit 3
elif [ `$LHEAPERL -v < /dev/null 2> /dev/null | grep -ic "perl"` -eq 0 ]; then
  echo "LHEAPERL variable does not point to a usable perl."
  exit 3
else
  exec $LHEAPERL -x $0 ${1+"$@"}
fi
'
if(0);
# Do not delete anything above this comment from an installed LHEA script!
#-------------------------------------------------------------------------------
#! /usr1/local/bin/perl5 
$version ="1.00";
$date  ="2001-04-28";
$author = "kaa";

# This script takes the standard Chandra grating pipeline PHA2 spectrum and
# creates the background file from the BACKGROUND_DOWN and BACKGROUND_UP files.

# Get and parse the command line option 

    if ($ARGV[0]=~/-(\S+)/){
	$option=$1;
	if($option=~/h/){$help =1;}
	shift(@ARGV);
    }

if($help){
    print "\n grating2xspec version $version $date $author\n\n";
    print "usage: grating2xspec [-h] filename option\n\n";
    print "This script uses the input pipeline PHA2 spectrum to make another\n"; 
    print "type II spectrum file containing the background. The input file\n";
    print "is also copied and the copy modified so that the BACKFILE column\n";
    print "points to the correct background spectrum. The option argument is\n";
    print "either up, down, or both. If up then BACKGROUND_UP is used, if\n";
    print "down then BACKGROUN_DOWN and if both then the _UP and _DOWN spectra\n";
    print "are summed and the BACKSCUP and BACKSCDN keywords are summed.\n";
    print "\n";
    print "e.g.  grating2xspec foo_pha2.fits both\n";
    print "creates a background file foo_bkg2.fits from the sum of the\n";
    print "BACKGROUND_UP and BACKGROUND_DOWN columns in foo_pha2.fits. It\n";
    print "also creates a copy of the input file as foo_npha2.fits which\n";
    print "includes pointers to the background file. To read say the 3rd\n";
    print "spectrum into XSPEC simply give the command\n";
    print "XSPEC> data foo_npha2.fits{3}\n";
    exit(0);
}

# we need HEASOFT...

if($ENV{'LHEASOFT'} !~/\S/) 
{
    print "\n You need to set up HEASOFT to use this script.\n\n";
    exit(0);
}

# Check that the user gave the correct number of arguments.

if(@ARGV != 2)
{
    print "\n usage : grating2xspec [-h] filename option\n";
    print " type grating2xspec -h to get more information\n\n";
    exit(0);
}

$infile = $ARGV[0];
($filename = $infile) =~ s/pha2/npha2/;
($backfile = $infile) =~ s/pha2/bkg2/;

$option = $ARGV[1];
if ( $option != "up" && $option != "down" && $option != "both" ) {
    print "option must be one of up, down or both\n";
    exit(1);
}

# make a copy of the input file

$command = "cp $infile $filename";
print "\n",$command,"\n";
system($command);

# copy the input file into the background file using on-the-fly calculation
# to reset the COUNTS column

if ( $option eq "up" ) {
   $expres = "BACKGROUND_UP"
   } elsif ( $option eq "down" ) {
   $expres = "BACKGROUND_DOWN"
   } elsif ( $option eq "both" ) {
   $expres = "BACKGROUND_UP + BACKGROUND_DOWN"
}

$command = "fcopy '$filename\[SPECTRUM\]\[col COUNTS = $expres\]' $backfile";
print "\n",$command,"\n";
system($command);

# Set the BACKSCAL keyword. 

$command = "fkeypar $filename\[SPECTRUM\] BACKSCUP\n";
system($command);
($backscup = `pget fkeypar value`) =~ s/\n//;
$command = "fkeypar $filename\[SPECTRUM\] BACKSCDN\n";
system($command);
($backscdn = `pget fkeypar value`) =~ s/\n//;

# catch the problem with the BACKSCUP/DN being the inverse of their true
# values

if ( $backscup < 1 ) {
    $backscup = 1/$backscup
}
if ( $backscdn < 1 ) {
    $backscdn = 1/$backscdn
}

if ( $option eq "up" ) {
   $backscal = $backscup
   } elsif ( $option eq "down" ) {
   $backscal = $backscdn
   } else {
   $backscal = $backscup + $backscdn
}

$command = "fparkey value=$backscal fitsfile=$backfile\[SPECTRUM\] keyword=BACKSCAL";
print "\n",$command,"\n";
system($command);

# Delete the superfluous columns

$command = "fdelcol infile=$backfile\[SPECTRUM\] colname=BACKGROUND_UP confirm=no proceed=yes";
print $command,"\n";
system($command);
$command = "fdelcol infile=$backfile\[SPECTRUM\] colname=BACKGROUND_DOWN confirm=no proceed=yes";
print $command,"\n";
system($command);

# Also clobber the STAT_ERR column and set the POISSERR keyword to T

$command = "fdelcol infile=$backfile\[SPECTRUM\] colname=STAT_ERR confirm=no proceed=yes";
print "\n",$command,"\n";
system($command);

$command = "fparkey value=T fitsfile=$backfile\[SPECTRUM\] keyword=POISSERR";
print "\n",$command,"\n";
system($command);

# Finally edit the input filename to set the BACKFILE column appropriately.
# First make an ascii file with the names to place in the column

open(TFILE, "> backlist.tmp");

# get the number of rows

$command = "fkeypar $filename\[SPECTRUM\] NAXIS2\n";
system($command);
($nrows = `pget fkeypar value`) =~ s/\n//;

# and set the BACKFILE values

foreach $i (1 .. $nrows) {

    $backname = $backfile . "{" . $i . "}";
    print TFILE $backname,"\n";

}

close(TFILE);

# Make the file that describes the format for the BACKFILE column

open(TFILE, "> backlist.fmt");
print TFILE "BACKFILE 64A","\n";
close(TFILE);

# Use fcreate to make a FITS file containing this data

$command = "fcreate cdfile=backlist.fmt datafile=backlist.tmp outfile=backlist.fits";
print "\n",$command,"\n";
system($command);

# Finally add this new column back into the input file

$command = "faddcol infile=$filename\[SPECTRUM\] colfile=backlist.fits colname=BACKFILE delkey=yes history=yes casesen=no";
print "\n",$command,"\n";
system($command);

# Tidy up the temporary files

$command = "rm -f backlist.tmp backlist.fmt backlist.fits";
print "\n",$command,"\n";
system($command);

# delete the superfluous BACKFILE keyword if it exists

$command = "fparkey dummy $filename\[SPECTRUM\] BACKFILE add=yes";
print "\n",$command,"\n";
system($command);

$command = "fparkey dummy $filename\[SPECTRUM\] -BACKFILE";
print $command,"\n";
system($command);