package HTML::Widget::Constraint::ISODate;

use warnings;
use strict;
use base 'HTML::Widget::Constraint';
use DateTime::Format::Strptime;

my $format=DateTime::Format::Strptime->new(pattern=>'%F');

sub validate {
    my ($self,$value)=@_;

    my $ret=eval {
        my $val=$format->parse_datetime($value);
        return unless defined($val);

        my $round_tripped=$val->strftime('%F');

        return ($value eq $round_tripped);
    };
    return if $@;
    return $ret;
}

1;