DateTime::Format::Natural::Duration - Duration hooks and state handling

 Please see the DateTime::Format::Natural documentation.

package DateTime::Format::Natural::Duration;

use strict;
use warnings;

use DateTime::Format::Natural::Duration::Checks;
use List::MoreUtils qw(all);

our $VERSION = '0.05';

sub _pre_duration
{
    my $self = shift;
    my ($date_strings) = @_;

    my $check_if = sub
    {
        my $sub   = shift;
        my $class = join '::', (__PACKAGE__, 'Checks');
        my $check = $class->can($sub) or die "$sub() not found in $class";

        return $check->($self->{data}->{duration}, $date_strings, @_);
    };

    my ($present, $extract, $adjust);

    if ($check_if->('for', \$present)) {
        @{$self->{insert}}{qw(datetime trace)} = do {
            my $dt = $self->parse_datetime($present);
            ($dt, $self->{traces}[0]);
        };
    }
    elsif ($check_if->('first_to_last', \$extract)) {
        if (my ($complete) = $date_strings->[1] =~ $extract) {
            $date_strings->[0] .= " $complete";
        }
    }
    elsif ($check_if->('from_count_to_count', \$extract, \$adjust)) {
        if (my ($complete) = $date_strings->[0] =~ $extract) {
            $adjust->($date_strings, $complete);
        }
    }
}

sub _post_duration
{
    my $self = shift;
    my ($queue, $traces) = @_;

    my %assign = (
        datetime => $queue,
        trace    => $traces,
    );
    if (all { exists $self->{insert}{$_} } keys %assign) {
        unshift @{$assign{$_}}, $self->{insert}{$_} foreach keys %assign;
    }
}

sub _save_state
{
    my $self = shift;
    my %args = @_;

    return if %{$self->{state}};

    unless ($args{valid_expression}) {
        %{$self->{state}} = %args;
    }
}

sub _restore_state
{
    my $self = shift;

    my %state = %{$self->{state}};

    if (%state) {
        $state{valid_expression}
          ? $self->_set_valid_exp
          : $self->_unset_valid_exp;

        $state{failure}
          ? $self->_set_failure
          : $self->_unset_failure;

        defined $state{error}
          ? $self->_set_error($state{error})
          : $self->_unset_error;
    }
}

1;
__END__