#!/usr/local/bin/perl4

# Global config option for hours off of GMT.  i.e. EST is -5.
# NOTE: You may want to use something like 4.5 to average when Daylight
# savings time is in affect.

$GMToffset = -5;

# We Run from the commandline as sample program
$diff = &diffTime($ARGV[0], $ARGV[1]);
print "Diff Seconds: $diff\n";
$diffDays = $diff/(3600*24);
print "Diff Days: $diffDays\n";

if ($diffDays < -16) {    ### NOTE that it's negative for past days.
  print "\n*** Windows up for more than 16 days!\n";
}
exit(0);


# FUNCTION: diffTime (date time)
# Usage &difftime( DD/MM/YYYY [HH:MM:SS] )
# A hyphen may be used as the date separator. only colons valid for time
# Returns seconds from current time.  Negative for past events Posotive for
# future events.
sub diffTime {
   local($rebootDate, $rebootTime, $rDmon, $rDday, $rDyear, $rDhour, $rDmin, $rDsec);
   local(@monthdays);
   local($sec, $leapCount, $i, $time);

   $rebootDate = $_[0];   # First Argument
   $rebootTime = $_[1];   # Second Argument

   unless (($rDmon, $rDday, $rDyear) = $rebootDate =~ /(\d{1,2})[\/-]{1}(\d{1,2})[\/-]{1}(\d{4})/) {
      print STDERR "Invalid Date\n\n";
      exit(1);
   }

   @monthdays=(31,28,31,30,31,30,31,31,30,31,30,31);

   ### NOTE: This will break in the year 2100
   if ($rDyear%4 == 0) { $monthdays[2]=29; }
   $sec = ($rDyear - 1970 ) * 365 * 24 * 60 * 60;
   $leapCount = int(($rDyear - 1972) / 4);
   $sec = $sec + ($leapCount * 24 * 60 * 60);

   for ( $i = $rDmon-2; $i >= 0; $i--) {
      $sec = $sec + ( $monthdays[$i] * 24 * 60 * 60);
   }
   $sec = $sec + ($rDday * 24 * 60 * 60);
   if ($rebootTime) {
      unless (($rDhour, $rDmin, $rDsec) = $rebootTime =~ /(\d{1,2})[:]{1}(\d{1,2})[:]{1}(\d{1,2})/) {
         print STDERR "Invalid Time\n\n";
         exit(2);
      }
      $sec = $sec + ($rDhour * 3600) + ($rDmin * 60) + $rDsec;
   }
   unless ($GMToffset) { $GMToffset = 0; }
   $time = time() + $GMToffset * 60 * 60;
   return $sec - $time;
}