wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Lib\Store;

use MediaWiki\Linker\LinkTarget;
use Wikibase\DataAccess\DatabaseEntitySource;
use Wikibase\DataAccess\EntitySourceDefinitions;
use Wikibase\DataModel\Entity\EntityId;
use Wikibase\DataModel\Entity\EntityIdParser;
use Wikibase\DataModel\Entity\EntityIdParsingException;

/**
 * @license GPL-2.0-or-later
 */
class EntityLinkTargetEntityIdLookup implements LinkTargetEntityIdLookup {
    /**
     * used e.g. for links from Commons to Wikidata in the form of d:Special:EntityPage/Q42
     */
    private const SPECIAL_ENTITY_PAGE = 'Special:EntityPage';

    /**
     * @var EntityNamespaceLookup
     */
    private $namespaceLookup;

    /**
     * @var EntityIdParser
     */
    private $entityIdParser;

    /**
     * @var EntitySourceDefinitions
     */
    private $entitySourceDefinitions;
    /**
     * @var DatabaseEntitySource
     */
    private $localSource;

    public function __construct(
        EntityNamespaceLookup $namespaceLookup,
        EntityIdParser $entityIdParser,
        EntitySourceDefinitions $entitySourceDefinitions,
        DatabaseEntitySource $localSource
    ) {
        $this->namespaceLookup = $namespaceLookup;
        $this->entityIdParser = $entityIdParser;
        $this->entitySourceDefinitions = $entitySourceDefinitions;
        $this->localSource = $localSource;
    }

    public function getEntityId( LinkTarget $linkTarget ): ?EntityId {
        return $linkTarget->isExternal()
            ? $this->getEntityIdFromExternalLink( $linkTarget )
            : $this->getEntityIdFromLocalLink( $linkTarget );
    }

    private function getEntityIdFromExternalLink( LinkTarget $linkTarget ): ?EntityId {
        $potentialSpecialEntityPageParts = explode( '/', $linkTarget->getText(), 2 );
        if (
            $potentialSpecialEntityPageParts[0] !== self::SPECIAL_ENTITY_PAGE ||
            count( $potentialSpecialEntityPageParts ) < 2
        ) {
            return null;
        }

        $id = $this->parseEntityId( $potentialSpecialEntityPageParts[1] );
        if ( !$id ) {
            return null;
        }

        $source = $this->entitySourceDefinitions->getDatabaseSourceForEntityType( $id->getEntityType() );
        return $source && $source->getInterwikiPrefix() === $linkTarget->getInterwiki() ? $id : null;
    }

    private function getEntityIdFromLocalLink( LinkTarget $linkTarget ): ?EntityId {
        $entityTypeForNamespace = $this->namespaceLookup->getEntityType( $linkTarget->getNamespace() );
        if ( !$entityTypeForNamespace ) {
            return null;
        }

        $entityId = $this->parseEntityId( $linkTarget->getText() );
        return (
            $entityId &&
            $entityId->getEntityType() === $entityTypeForNamespace &&
            in_array( $entityId->getEntityType(), $this->localSource->getEntityTypes() )
        ) ? $entityId : null;
    }

    private function parseEntityId( string $id ): ?EntityId {
        try {
            return $this->entityIdParser->parse( $id );
        } catch ( EntityIdParsingException $e ) {
            return null;
        }
    }

}