=head3 get_usage_count

    $count = Koha::Authorities->get_usage_count({ authid => $i });

    Returns the number of linked biblio records.

    Note: Code originates from C4::AuthoritiesMarc::CountUsage.

    This is a class method, since the authid may refer to a deleted record.

sub get_usage_count {

    my ( $class, $params ) = @_;

    my $authid = $params->{authid} || return;

    my $searcher = Koha::SearchEngine::Search->new({ index => $Koha::SearchEngine::BIBLIOS_INDEX });

    my ( $err, $result, $count ) = $searcher->simple_search_compat( 'an:' . $authid, 0, 0 );

    if( $err ) {

        warn "Error: $err from search for " . $authid;

        return;

    }

    return $count;

}

=head3 linked_biblionumbers

    my @biblios = Koha::Authorities->linked_biblionumbers({

        authid => $id, [ max_results => $max ], [ offset => $offset ],

    });

    Returns array of biblionumbers, as extracted from the result records of

    the search engine.

    This is a class method, since the authid may refer to a deleted record.

=cut

sub linked_biblionumbers {

    my ( $self, $params ) = @_;

    my $authid = $params->{authid} || return;

    my $searcher = Koha::SearchEngine::Search->new({ index => $Koha::SearchEngine::BIBLIOS_INDEX });

    # if max_results is undefined, we will get all results

    my ( $err, $result, $count ) = $searcher->simple_search_compat( 'an:' . $authid, $params->{offset} // 0, $params->{max_results} );

    if( $err ) {

        warn "Error: $err from search for " . $authid;

        return;

    }

    my @biblionumbers;

    foreach my $res ( @$result ) {

        my $bibno = $searcher->extract_biblionumber( $res );

        push @biblionumbers, $bibno if $bibno;

    }

    return @biblionumbers;

}

use Koha::SearchEngine::Search;

sub get_usage_count {

    my ( $self ) = @_;

    return Koha::Authorities->get_usage_count({ authid => $self->authid });

}

=head3 linked_biblionumbers

    my @biblios = $self->linked_biblionumbers({

        [ max_results => $max ], [ offset => $offset ],

    });

    Returns an array of biblionumbers.

=cut

sub linked_biblionumbers {

    my ( $self, $params ) = @_;

    $params->{authid} = $self->authid;

    return Koha::Authorities->linked_biblionumbers( $params );

}

=head2 Class Methods

use Test::MockModule;

use Test::MockObject;

use Test::Warn;

use C4::Context;

use t::lib::Mocks;

BEGIN {

    #TODO Helpful as long as we have issues here

    my $mock = Test::MockObject->new();

    $mock->fake_module( 'Catmandu::Store::ElasticSearch' );

}

subtest 'Trivial tests for get_count_usage and linked_biblionumbers' => sub {

    plan tests => 5;

    # NOTE: We are not testing $searcher->simple_search_compat here. Suppose

    # that should be done in t/db../Koha/SearchEngine?

    # So we're just testing the 'wrapper' here.

    my ( $mods, $koha_fields );

    t::lib::Mocks::mock_preference('SearchEngine', 'Zebra');

    $mods->{zebra} = Test::MockModule->new( 'Koha::SearchEngine::Zebra::Search' );

    $mods->{elastic} = Test::MockModule->new( 'Koha::SearchEngine::Elasticsearch::Search' );

    $mods->{biblio} = Test::MockModule->new( 'C4::Biblio' );

    $mods->{zebra}->mock( 'simple_search_compat', \&simple_search_compat );

    $mods->{elastic}->mock( 'simple_search_compat', \&simple_search_compat );

    $mods->{biblio}->mock( 'GetMarcFromKohaField', sub { return @$koha_fields; });

    my $auth1 = $builder->build({ source => 'AuthHeader' });

    $auth1 = Koha::Authorities->find( $auth1->{authid} );

    # Test error condition

    my $count;

    $search_compat_pars = [ 0, 'some_error' ];

    warning_like { $count = $auth1->get_usage_count }

        qr/some_error/, 'Catch warn of simple_search_compat';

    is( $count, undef, 'Undef returned when error encountered' );

    # Simple test with some results; one result discarded in the 2nd test

    $search_compat_pars = [ 1 ];

    $koha_fields = [ '001', '' ];

    is(  $auth1->get_usage_count, 3, 'Three results expected (Zebra)' );

    cmp_deeply( [ $auth1->linked_biblionumbers ], [ 1001, 3003 ],

        'linked_biblionumbers should ignore record without biblionumber' );

    # And a simple test with Elastic

    t::lib::Mocks::mock_preference('SearchEngine', 'Elasticsearch');

    cmp_deeply( [ $auth1->linked_biblionumbers ], [ 2001 ],

        'linked_biblionumbers with Elasticsearch' );

};

sub simple_search_compat {

    if( $search_compat_pars->[0] == 0 ) {

        return ( $search_compat_pars->[1], [], 0 );

    } elsif( $search_compat_pars->[0] == 1 ) {

        my $records = C4::Context->preference('SearchEngine') eq 'Zebra'

            ? few_marcxml_records()

            : few_marc_records();

        return ( undef, $records, scalar @$records );

    }

}

sub few_marcxml_records {

    return [

q|<?xml version="1.0" encoding="UTF-8"?>

<record xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.loc.gov/MARC21/slim" xsi:schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">

    <controlfield tag="001">1001</controlfield>

    <datafield tag="110" ind1=" " ind2=" ">

        <subfield code="9">102</subfield>

        <subfield code="a">My Corporation</subfield>

    </datafield>

</record>|,

q|<?xml version="1.0" encoding="UTF-8"?>

<record xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.loc.gov/MARC21/slim" xsi:schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">

    <!-- No biblionumber here -->

    <datafield tag="610" ind1=" " ind2=" ">

        <subfield code="9">112</subfield>

        <subfield code="a">Another Corporation</subfield>

    </datafield>

</record>|,

q|<?xml version="1.0" encoding="UTF-8"?>

<record xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.loc.gov/MARC21/slim" xsi:schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">

    <controlfield tag="001">3003</controlfield>

    <datafield tag="110" ind1=" " ind2=" ">

        <subfield code="9">102</subfield>

        <subfield code="a">My Corporation</subfield>

    </datafield>

</record>|

    ];

}

sub few_marc_records {

    my $marc = MARC::Record->new;

    $marc->append_fields(

        MARC::Field->new( '001', '2001' ),

        MARC::Field->new( '245', '', '', a => 'Title' ),

    );

    return [ $marc ];

}