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

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

local $\ = "\n";

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

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

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

chomp($birth_year,$birth_month,$birth_day);

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!";