HTML::FormFu::Deflator::CompoundDateTime - CompoundDateTime deflator

    ---
    element:
      - type: Multi
        name: date

        elements:
          - name: day
          - name: month
          - name: year

        deflator:
          - type: CompoundDateTime

    # set the default

    $form->get_field('date')->default( $datetime );

    ---
    element:
      - type: Multi
        name: date

        elements:
          - name: m
          - name: d
          - name: y

        deflator:
          - type: CompoundDateTime
            field_order:
              - month
              - day
              - year

package HTML::FormFu::Deflator::CompoundDateTime;

use Moose;
extends 'HTML::FormFu::Deflator';

use HTML::FormFu::Constants qw( $EMPTY_STR );
use DateTime;
use List::MoreUtils qw( none );
use Carp qw( croak );

has field_order => ( is => 'rw', traits  => ['Chained'] );

my @known_fields = qw( year month day hour minute second nanosecond time_zone );

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

    return if !defined $value || $value eq $EMPTY_STR;

    # do we have a DateTime object?

    eval { $value->$_ for @known_fields };

    return $value if $@;

    my ( $multi, @fields ) = @{ $self->parent->get_fields };

    if ( defined( my $order = $self->field_order ) ) {
        for my $order (@$order) {
            croak "unknown DateTime field_order name"
                if none { $order eq $_ } @known_fields;

            my $field = shift @fields;

            $field->default( $value->$order );
        }
    }
    else {
        for my $field (@fields) {
            my $name = $field->name;

            croak "unknown DateTime field name"
                if none { $name eq $_ } @known_fields;

            $field->default( $value->$name );
        }
    }

    return;
}

__PACKAGE__->meta->make_immutable;

1;

__END__