#! /usr/bin/perl 
$version ="1.00";
$date  ="2002-11-11";
$author = "kaa";

# This script filters the XMM event file on PATTERN, PI, and FLAG

# Get and parse the command line option 

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

if($help){
    print "\n xmmclean version $version $date $author\n\n";
    print "usage: xmmclean [-h] infile outfile pattern flag\n\n";
    print "This script filters the input XMM event file using the\n";
    print "standard criteria ie PATTERN <= 12 (for MOS) or <= 4 (for PN),\n";
    print "PI between 200 and 15000, and FLAG = 0. If a third argument is\n";
    print "given then it is used for the upper limit on PATTERN. If a\n";
    print "fourth argument is given it used for the upper limit on FLAG.\n";
    print "This script should not be run on an event file that has been\n";
    print "filtered using the SAS tool xmmselect.\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 || @ARGV > 4)
{
    print "\n usage : xmmclean [-h] infile outfile pattern flag\n";
    print " type xmmclean -h to get more information\n\n";
    exit(0);
}

$infile  = $ARGV[0];
$outfile = $ARGV[1];

# check that DSTYP3 doesn't already exist in the input file. If it does
# the user has already run xmmselect or the XMM folks have changed the
# event file format.

$command = "fkeypar $infile\[EVENTS\] DSTYP3";
system($command);
if ( `pget fkeypar exist` eq "yes" ) {
    print "\n The DSTYP3 keyword already exists in the input file. Either you\n";
    print " have already run xmmselect or the event file format has changed.\n\n";
    exit(0);
}

# get the instrument name to set the default upper limit on the pattern

$command = "fkeypar $infile+0 INSTRUME";
system($command);
$instrument = `pget fkeypar value`;
$instrument =~ tr/'\n//d;

print "Instrument is ", $instrument, "\n";
if ( substr($instrument,0,5) eq "EMOS1" ||
     substr($instrument,0,5) eq "EMOS2" ) {
   $pattern_max = 12;
} elsif ( substr($instrument,0,3) eq "EPN" ) {
   $pattern_max = 4;
} else {
   print "Instrument must be one of EMOS1, EMOS2, or EPN\n";
   exit(0);
}

# If a third argument has been given then override the default pattern

if ( @ARGV >= 3 ) {
   $pattern_max = $ARGV[2];
}

# and if a fourth argument has been given then override the default flag

if ( @ARGV == 4 ) {
   $flag_max = $ARGV[3];
} else {
   $flag_max = 0;
}

# run fselect to do filtering

$command = "fselect infile=$infile\[EVENTS\] outfile=$outfile expr='PATTERN <= $pattern_max && PI <= 15000 && PI >= 200 && FLAG <= $flag_max' histkw=yes copyall=yes keycopy=yes clobber=no";
print "\n",$command,"\n\n";
system($command);

# write the DS keywords

$command = "fparkey FLAG $outfile\[EVENTS\] DSTYP3 add=yes comm='data subspace descriptor: name'";
system($command);
$command = "fparkey PATTERN $outfile\[EVENTS\] DSTYP4 add=yes comm='data subspace descriptor: name'";
system($command);
$command = "fparkey PI $outfile\[EVENTS\] DSTYP5 add=yes comm='data subspace descriptor: name'";
system($command);
$command = "fparkey CHAN $outfile\[EVENTS\] DSUNI5 add=yes comm='data subspace descriptor: units'";
system($command);
$command = "fparkey '0:$flag_max' $outfile\[EVENTS\] DSVAL3 add=yes  comm='data subspace descriptor: value'";
system($command);
$command = "fparkey '0:$pattern_max' $outfile\[EVENTS\] DSVAL4 add=yes  comm='data subspace descriptor: value'";
system($command);
$command = "fparkey '200:15000' $outfile\[EVENTS\] DSVAL5 add=yes comm='data subspace descriptor: value'";
system($command);