#!/usr/bin/perl
use strict;
use warnings;

# 
# Filters event files based on the light curves.  If there is more than one 
# time period to excise, it will throw a DssBlockClash warning, but the output 
# will still be correct.
#
# Requirements:
#    0) must be in same directory as input event files. 
#    1) text file which lists the events files to process, one per line
#    2) text file which lists the BAD time intervals, one per line.
#

my $currDir;
chomp ($currDir = `pwd`);

my $m1_flt_evt2 = "m1_flt_evt2.fits";
my $m2_flt_evt2 = "m2_flt_evt2.fits";
my $pn_flt_evt2 = "pn_flt_evt2.fits";
my $unittype = 'N';
my $count = 0;
my $currLine;
my @numbers;
my $num;
my @files;
my $file;
my $m1_evt ;
my $m2_evt ;
my $pn_evt ;
my $inst;

my $process_pn = 0;
my $process_m1 = 0;
my $process_m2 = 0;

# Set the environment variables.

my @res1;
my $baseDir;

if ($currDir =~ m/proc/) {
   @res1 = split(/proc/, $currDir);
   $baseDir = $res1[0];
}

if (-d $baseDir."/ODF") { 
   $ENV{SAS_ODFPATH} = $baseDir."/ODF";
   my $sumsas = glob ($baseDir."/ODF/*SUM.SAS");
   $ENV{SAS_ODF} = $sumsas;
   $ENV{SAS_CCF} = $baseDir."/ODF/ccf.cif";
} 
if (-d $baseDir."/odf") {
   $ENV{SAS_ODFPATH} = $baseDir."/odf";
   my $sumsas = glob ($baseDir."/odf/*SUM.SAS");
   $ENV{SAS_ODF} = $sumsas;
   $ENV{SAS_CCF} = $baseDir."/odf/ccf.cif";
}

# On to the main event.


print "Enter the file listing the event files: ";
chomp (my $event_files = <> );
$event_files = $currDir."/".$event_files;

print "Enter the file with the times to be removed: ";
chomp (my $times_file= <> ) ;
$times_file = $currDir."/".$times_file;

if (-e $event_files) {
   open(EVENTS, "<", $event_files);
   while ($currLine = <EVENTS>) {
      $currLine = $currDir."/".$currLine;
      chomp ($currLine);
      @files = split (/\s/, $currLine);
      foreach $file (@files) {  # Check the headers to find out which instruments we need.
         $inst = $currDir."/"."instru.list";
         `fkeyprint $file instrume outfile=$inst`;
         open (INSTRU, "<", $inst);
         while ($currLine = <INSTRU>) {
            if ($currLine =~ m/INSTRUME= 'EPN     '/ ) {
               $pn_evt = $file;
               $process_pn = 1;
            }
            if ($currLine =~ m/INSTRUME= 'EMOS1   '/ ) {
               $m1_evt = $file;
               $process_m1 = 1;
            }
            if ($currLine =~ m/INSTRUME= 'EMOS2   '/ ) {
               $m2_evt = $file;
               $process_m2 = 1;
            }
         }
         close (INSTRU);
         `rm $inst`;
      }
   }
   close (EVENTS);
}

else {
   print "No events file found!  \n" ;
   exit;
}

my $counttimes = 0;
my $countlines = 0;
my @starttime; 
my @endtime;
my $j=0;
my $filtset;

if (-e $times_file) {
   open(TIMES, "<", $times_file);
   while ($currLine = <TIMES>) { 
   $countlines ++; 
   @numbers = split (/\s/, $currLine);
   # count array elements to confirm the correct format and assign to variables
   if (@numbers != 2) {
      print "The input file does not have the correct format. \n";
      exit;
   }
   push (@starttime, $numbers[0]); 
   push (@endtime, $numbers[1]); 
   }
   close(TIMES);
}
else { 
   print "Can't find the times file! \n";
   exit;
}

#
# Remove the bad times iteratively. 
#

if (! $countlines) { 
   print "Times files is empty.\n"; 
   exit;
}

my $m1_evt_hold = $m1_evt;
my $m2_evt_hold = $m2_evt;
my $pn_evt_hold = $pn_evt;

print "Working... \n";

if ($process_m1) {
   for ($j=0; $j<$countlines; $j++) {
   $filtset = $m1_evt_hold."_".$j;
   `evselect table=$m1_evt_hold withfilteredset=yes expression='!(TIME in [$starttime[$j]:$endtime[$j]])' filteredset=$filtset filtertype=expression keepfilteroutput=yes updateexposure=yes filterexposure=yes`;
   $m1_evt_hold = $filtset;
   }
   `mv $filtset $m1_flt_evt2`;   # Tidy up. 
   $m1_evt_hold = $m1_evt;
   for ($j=0; $j<($countlines-1); $j++) {
      $filtset = $m1_evt_hold."_".$j;
      `rm $filtset`;
      $m1_evt_hold = $filtset;
   } 
}
if ($process_m2) {
   for ($j=0; $j<$countlines; $j++) {
   $filtset = $m2_evt_hold."_".$j;
   `evselect table=$m2_evt_hold withfilteredset=yes expression='!(TIME in [$starttime[$j]:$endtime[$j]])' filteredset=$filtset filtertype=expression keepfilteroutput=yes updateexposure=yes filterexposure=yes`;
   $m2_evt_hold = $filtset;
   }
   `mv $filtset $m2_flt_evt2`;   # Tidy up. 
   $m2_evt_hold = $m2_evt;
   for ($j=0; $j<($countlines-1); $j++) {
      $filtset = $m2_evt_hold."_".$j;
      `rm $filtset`;
      $m2_evt_hold = $filtset;
   }
}
if ($process_pn) {
   for ($j=0; $j<$countlines; $j++) {
   $filtset = $pn_evt_hold."_".$j;
   `evselect table=$pn_evt_hold withfilteredset=yes expression='!(TIME in [$starttime[$j]:$endtime[$j]])' filteredset=$filtset filtertype=expression keepfilteroutput=yes updateexposure=yes filterexposure=yes`;
   $pn_evt_hold = $filtset;
   }
   `mv $filtset $pn_flt_evt2`;   # Tidy up. 
   $pn_evt_hold = $pn_evt;
   for ($j=0; $j<($countlines-1); $j++) {
      $filtset = $pn_evt_hold."_".$j;
      `rm $filtset`;
      $pn_evt_hold = $filtset;
   }
}

print "Done. \n";