#!/usr/bin/perl 

use Date::Calc qw(Day_of_Year check_date Days_in_Year);

#################################################################
#
# program: dates.pl 		date: 05/22/2003
# Author Mike Raley
# Purpose:  currently, to take a date : yyyy mm dd
# and convert it to the number day of the year.
#
#################################################################

if ( scalar(@ARGV) == 0 )  {
  usage();
  exit;
}
elsif ( scalar(@ARGV) == 3 )  {
 ( $year, $month, $day ) = @ARGV;
}
elsif ( scalar(@ARGV) == 2 )  {
 ( $year, $month ) = @ARGV;
 $day = 1;
}
else {
  usage();
  exit;
}

$year = sprintf "%04d", $year;
$month = sprintf "%02d", $month;
$day = sprintf "%02d", $day;

if ( !check_date($year, $month, $day) )  { # Now check the date is correct
  warning();
  exit;
}

$doy = Day_of_Year($year,$month,$day);
$percentage =  $doy/Days_in_Year($year,12);

print "\nEntered date is: $month/$day/$year\n";
print "Day of year $year is: $doy\n";
$doy = sprintf "%03d", $doy;
print "Check observation list for: $year:$doy\n";
 
exit;

#################################################################
#
# subroutines follow
#
#################################################################

sub warning {
  print "\nDate is incorrect, check entered values\n";
}

sub usage {
  print "\nInput date in following form: dates.pl yyyy mm dd\n";
  print "If no day is entered, assumes dd = 1\n";
}