package DBIx::Class::KiokuDB;
BEGIN {
  $DBIx::Class::KiokuDB::AUTHORITY = 'cpan:NUFFIN';
}
# ABSTRACT: Refer to KiokuDB objects from DBIx::Class tables.
$DBIx::Class::KiokuDB::VERSION = '1.23';
use strict;
use warnings;

use Carp;
use Scalar::Util qw(weaken);

use namespace::clean;

use base qw(DBIx::Class::Core);

sub new {
    my $self = shift->next::method(@_);

    foreach my $key ( $self->result_source->columns ) {
        my $col_info = $self->column_info($key);

        if ( $col_info->{_kiokudb_info} and ref( my $obj = $self->get_column($key) ) ) {
            $self->store_kiokudb_column( $key => $obj );
        }
    }

    return $self;
}

sub insert {
    my ( $self, @args ) = @_;

    my $schema = $self->result_source->schema;

    my $g = $schema->txn_scope_guard;

    my $dir = $schema->kiokudb_handle;
    my $lo = $dir->live_objects;

    if ( my @insert = grep { ref and not $lo->object_to_entry($_) } values %{ $self->{_kiokudb_column} } ) {
        $dir->insert(@insert);
    }

    my $ret = $self->next::method(@args);

    $g->commit;

    return $ret;
}

sub update {
    my ( $self, @args ) = @_;

    my $dir = $self->result_source->schema->kiokudb_handle;
    my $lo = $dir->live_objects;

    if ( my @insert = grep { ref and not $lo->object_to_entry($_) } values %{ $self->{_kiokudb_column} } ) {
        croak("Can't update object, related KiokuDB objects are not in storage");
    }

    $self->next::method(@args);
}

sub store {
    my ( $self, @args ) = @_;

    my $schema = $self->result_source->schema;

    my $g = $schema->txn_scope_guard;

    if ( my @objects = grep { ref } values %{ $self->{_kiokudb_column} } ) {
        $schema->kiokudb_handle->store(@objects);
    }

    my $ret = $self->insert_or_update;

    $g->commit;

    return $ret;
}

sub kiokudb_column {
    my ($self, $rel, $cond, $attrs) = @_;

    # assume a foreign key contraint unless defined otherwise
    $attrs->{is_foreign_key_constraint} = 1
        if not exists $attrs->{is_foreign_key_constraint};

    my $fk = defined $cond ? $cond : $rel;

    $self->add_relationship( $rel, 'entries', { 'foreign.id' => "self.$fk" }, $attrs ); # FIXME hardcoded 'entries'

    my $col_info = $self->column_info($fk);

    $col_info->{_kiokudb_info} = {};

    my $accessor = $col_info->{accessor};
    $accessor = $rel unless defined $accessor;

    $self->mk_group_accessors('kiokudb_column' => [ $accessor, $fk]);
}

sub _kiokudb_id_to_object {
    my ( $self, $id ) = @_;

    if ( ref( my $obj = $self->result_source->schema->kiokudb_handle->lookup($id) ) ) {
        return $obj;
    } else {
        croak("No object with ID '$id' found") unless ref $obj;
    }
}

sub _kiokudb_object_to_id {
    my ( $self, $object ) = @_;

    confess unless ref $object;

    my $dir = $self->result_source->schema->kiokudb_handle;

    if ( my $id = $dir->object_to_id($object) ) {
        return $id;
    } else {
        # generate an ID
        my $collapser = $dir->collapser;
        my $id_method = $collapser->id_method(ref $object);
        my $id = $id = $collapser->$id_method($object);

        # register the ID
        $dir->live_objects->insert( $id => $object );

        return $id;
    }
}

sub get_kiokudb_column {
    my ( $self, $col ) = @_;

    $self->throw_exception("$col is not a KiokuDB column")
        unless exists $self->column_info($col)->{_kiokudb_info};

    return $self->{_kiokudb_column}{$col}
        if defined $self->{_kiokudb_column}{$col};

    if ( defined( my $val = $self->get_column($col) ) ) {
        my $obj = ref $val ? $val : $self->_kiokudb_id_to_object($val);

        # weaken by default, in case there are cycles, the live object scope will
        # take care of this
        weaken( $self->{_kiokudb_column}{$col} = $obj );

        return $obj;
    } else {
        return;
    }
}

sub _set_kiokudb_column {
    my ( $self, $method, $col, $obj ) = @_;

    if ( ref $obj ) {
        $self->$method( $col, $self->_kiokudb_object_to_id($obj) );
        $self->{_kiokudb_column}{$col} = $obj;
    } else {
        $self->$method( $col, undef );
        delete $self->{_kiokudb_column}{$col};
    }

    return $obj;
}

sub set_kiokudb_column {
    my ( $self, @args ) = @_;
    $self->_set_kiokudb_column( set_column => @args );
}

sub store_kiokudb_column {
    my ( $self, @args ) = @_;
    $self->_set_kiokudb_column( store_column => @args );
}

# ex: set sw=4 et:

__PACKAGE__

__END__

=pod

=encoding UTF-8

=head1 NAME

DBIx::Class::KiokuDB - Refer to KiokuDB objects from DBIx::Class tables.

=head1 VERSION

version 1.23

=head1 SYNOPSIS

See L<DBIx::Class::Schema::KiokuDB>.

    package MyApp::DB::Result::Album;
    use base qw(DBIx::Class);

    __PACKAGE__>load_components(qw(Core KiokuDB));

    __PACKAGE__->table('album');

    __PACKAGE__->add_columns(
        id => { data_type => "integer" },
        title => { data_type => "varchar" },

        # the foreign key for the KiokuDB object:
        metadata => { data_type => "varchar" },
    );

    __PACKAGE__->set_primary_key('id');

    # enable a KiokuDB rel on the column:
    __PACKAGE__->kiokudb_column('metadata');

=head1 DESCRIPTION

This L<DBIx::Class> component provides the code necessary for
L<DBIx::Class::Row> objects to refer to L<KiokuDB> objects stored in
L<KiokuDB::Backend::DBI>.

=head1 CLASS METHODS

=over 4

=item kiokudb_column $rel

Declares a relationship to any L<KiokuDB> object.

In future versions adding relationships to different sub-collections will be
possible as well.

=back

=head1 METHODS

=over 4

=item store

A convenience method that calls L<KiokuDB/store> on all referenced L<KiokuDB>
objects, and then invokes C<insert_or_update> on C<$self>.

=item get_kiokudb_column $col

=item set_kiokudb_column $col, $obj

=item store_kiokudb_column $col, $obj

See L<DBIx::Class::Row>.

=back

=head1 OVERRIDDEN METHODS

=over 4

=item new

Recognizes objects passed in as column values, much like standard relationships
do.

=item insert

Also calls L<KiokuDB/insert> on all referenced objects that are not in the
L<KiokuDB> storage.

=item update

Adds a check to ensure that all referenced L<KiokuDB> objects are in storage.

=back

=head1 AUTHOR

Yuval Kogman <nothingmuch@woobling.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2014 by Yuval Kogman, Infinity Interactive.

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