#!/usr/bin/perl
use strict;
use warnings;
use 5.012;
# Lady Aleena's # 927621
use Data::Dumper;

use Date::Calc qw(:all);
use Lingua::EN::Inflect qw(ORD);

#local $\ = "\n";      #commenting this out puts data entry on same line as the relevant prompt; personal pref

sub commify {
  local $_  = shift;
  1 while s/^([-+]?\d+)(\d{3})/$1,$2/;
  return $_;
}

say "\n\tUsage: 4 digit year, Month as name -* OR *- as month_number, 1-12, day_of_month as number.\n";

print "What year were you born? ";
chomp (my $birth_year = <>);
print "What month were you born? ";
chomp (my $birth_month = <>);
print "What day were you born? ";
chomp (my $birth_day = <>);

if ( $birth_month =~ /[A-Z]+/i ) { 
	$birth_month = convert($birth_month);  # NOTE 1 in head, below
}

my $year = (localtime)[5] + 1900;
my $month = (localtime)[4] + 1;
my $day = (localtime)[3];


my @birth = ($birth_year,$birth_month,$birth_day);
my @today = ($year,$month,$day);

# Just figuring how many birthdays you have had.

my $birthdays;
if ($birth_month > $month) {
  $birthdays = $year - $birth_year - 1;
}
else {
  if ($birth_day > $day) {
    $birthdays = $year - $birth_year - 1;
  }
  else {
    $birthdays = $year - $birth_year;
  }
}

my $days_alive = Delta_Days(@birth,@today);

my $unbirthdays = ORD(commify($days_alive - $birthdays));
print "Happy $unbirthdays unbirthday!";


sub convert       # named months to Date::Calc numeric months
{
	my $word_month=$_[0];

	my %months = ('jan' => 1,      # NOT zero-based - Date::Calc format
				  'feb' => 2,
				  'mar' => 3,
				  'apr' => 4,
				  'may' => 5,
				  'jun' => 6,
				  'jul' => 7,
				  'aug' => 8,
				  'sep' => 9,
				  'oct' => 10,
				  'nov' => 11,
				  'dec' => 12);

	my ($key, $value);
	while (($key, $value) = each(%months)) {
		if ( $key =~ /$word_month/i ) {
			return($value)
		} else {
			next;
		}
	} 
}

=head NOTE 1

# Conversion with the sub here is for illustration only; in practice, it's better done 
with '$birth_month=Decode_Month($Birth Month);'
cf
perl -e "use Date::Calc qw/Decode_Month/; $mon='Dec'; $mon_name = Decode_Month($mon); print '\$mon_name: ' . $mon_name;" 
\$mon_name: 12

=cut