package Class::MOP::Mixin::HasAttributes;
our $VERSION = '2.2015';

use strict;
use warnings;

use Scalar::Util 'blessed';

use parent 'Class::MOP::Mixin';

sub add_attribute {
    my $self = shift;

    my $attribute
        = blessed( $_[0] ) ? $_[0] : $self->attribute_metaclass->new(@_);

    ( $attribute->isa('Class::MOP::Mixin::AttributeCore') )
        || $self->_throw_exception( AttributeMustBeAnClassMOPMixinAttributeCoreOrSubclass => attribute  => $attribute,
                                                                                     class_name => $self->name,
                          );

    $self->_attach_attribute($attribute);

    my $attr_name = $attribute->name;

    $self->remove_attribute($attr_name)
        if $self->has_attribute($attr_name);

    my $order = ( scalar keys %{ $self->_attribute_map } );
    $attribute->_set_insertion_order($order);

    $self->_attribute_map->{$attr_name} = $attribute;

    # This method is called to allow for installing accessors. Ideally, we'd
    # use method overriding, but then the subclass would be responsible for
    # making the attribute, which would end up with lots of code
    # duplication. Even more ideally, we'd use augment/inner, but this is
    # Class::MOP!
    $self->_post_add_attribute($attribute)
        if $self->can('_post_add_attribute');

    return $attribute;
}

sub has_attribute {
    my ( $self, $attribute_name ) = @_;

    ( defined $attribute_name )
        || $self->_throw_exception( MustDefineAnAttributeName => class_name => $self->name );

    exists $self->_attribute_map->{$attribute_name};
}

sub get_attribute {
    my ( $self, $attribute_name ) = @_;

    ( defined $attribute_name )
        || $self->_throw_exception( MustDefineAnAttributeName => class_name => $self->name );

    return $self->_attribute_map->{$attribute_name};
}

sub remove_attribute {
    my ( $self, $attribute_name ) = @_;

    ( defined $attribute_name )
        || $self->_throw_exception( MustDefineAnAttributeName => class_name => $self->name );

    my $removed_attribute = $self->_attribute_map->{$attribute_name};
    return unless defined $removed_attribute;

    delete $self->_attribute_map->{$attribute_name};

    return $removed_attribute;
}

sub get_attribute_list {
    my $self = shift;
    keys %{ $self->_attribute_map };
}

sub _restore_metaattributes_from {
    my $self = shift;
    my ($old_meta) = @_;

    for my $attr (sort { $a->insertion_order <=> $b->insertion_order }
                       map { $old_meta->get_attribute($_) }
                           $old_meta->get_attribute_list) {
        $attr->_make_compatible_with($self->attribute_metaclass);
        $self->add_attribute($attr);
    }
}

1;

# ABSTRACT: Methods for metaclasses which have attributes

__END__

=pod

=encoding UTF-8

=head1 NAME

Class::MOP::Mixin::HasAttributes - Methods for metaclasses which have attributes

=head1 VERSION

version 2.2015

=head1 DESCRIPTION

This class implements methods for metaclasses which have attributes
(L<Class::MOP::Class> and L<Moose::Meta::Role>). See L<Class::MOP::Class> for
API details.

=head1 AUTHORS

=over 4

=item *

Stevan Little <stevan@cpan.org>

=item *

Dave Rolsky <autarch@urth.org>

=item *

Jesse Luehrs <doy@cpan.org>

=item *

Shawn M Moore <sartak@cpan.org>

=item *

יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>

=item *

Karen Etheridge <ether@cpan.org>

=item *

Florian Ragwitz <rafl@debian.org>

=item *

Hans Dieter Pearcey <hdp@cpan.org>

=item *

Chris Prather <chris@prather.org>

=item *

Matt S Trout <mstrout@cpan.org>

=back

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2006 by Infinity Interactive, Inc.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut
