use warnings;
use strict;

package MyDate {
	use Moo;
	use Types::Standard qw/ Int /;
	use Carp;
	use Date::Calc qw/Today/;
	use namespace::clean;
	has year  => ( is=>'ro', required=>1, isa=>Int );
	has month => ( is=>'ro', required=>1, isa=>Int );
	has day   => ( is=>'ro', required=>1, isa=>Int );
	around BUILDARGS => sub {
		my ( $orig, $class, %args ) = @_;
		my %newargs;
		# NOTE: This does not handle incorrect arguments!
		if ( keys %args ) {
			if ( keys %args == 3 ) {
				%newargs = %args;
			}
			elsif ( $args{date} ) {
				@newargs{qw/year month day/}
					= $args{date}=~/^(\d{4})(\d\d)(\d\d)$/
						or croak "bad date $args{date}";
			}
		}
		else {
			my ($year,$month,$day) = Today();
			%newargs = (year=>$year, month=>$month, day=>$day);
		}
		return $class->$orig(%newargs);
	};
	sub ymd {
		my $self = shift;
		return $self->year.'-'.$self->month.'-'.$self->day;
	}
}

print "1. ", MyDate->new()->ymd, "\n";
print "2. ", MyDate->new(year=>2019, month=>5, day=>14)->ymd, "\n";
print "3. ", MyDate->new(date=>20190512)->ymd, "\n";

__END__

1. 2019-5-16
2. 2019-5-14
3. 2019-05-12