package MyObj 0.001;

use 5.012;
use Moose;
use namespace::autoclean;

has 'length' => (
	is       => 'ro',
	isa      => 'Int',
	required => 1,
);

has 'is_circular' => (
	is       => 'ro',
	isa      => 'Bool',
	required => 1,
);

has '_offset_sub' => (
	is       => 'ro',
	isa      => 'CodeRef',
	lazy     => 1,
	builder  => '_build_offset_sub',
	init_arg => undef,
);

sub offset () {
	my ( $self, $current_coord, $offset ) = @_;
	return $self->_offset_sub()->( $self, $current_coord, $offset );
}

sub _build_offset_sub {
	my ($self) = @_;

	if ( $self->is_circular() ) {

		# circular
		return sub {
			my ( $self, $current_coord, $offset ) = @_;
			return ( $current_coord - 1 + $self->length() + $offset ) % $self->length() + 1;
		};
	}

	else {

		# linear
		return sub {
			my ( $self, $current_coord, $offset ) = @_;
			return $current_coord + $offset;
		};
	}
}

__PACKAGE__->meta->make_immutable;

1;