wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Repo\EntityReferenceExtractors;

use DataValues\DataValue;
use DataValues\UnboundedQuantityValue;
use Wikibase\DataModel\Entity\EntityDocument;
use Wikibase\DataModel\Entity\EntityId;
use Wikibase\DataModel\Entity\EntityIdParsingException;
use Wikibase\DataModel\Entity\EntityIdValue;
use Wikibase\DataModel\Services\EntityId\SuffixEntityIdParser;
use Wikibase\DataModel\Snak\PropertyValueSnak;
use Wikibase\DataModel\Snak\Snak;
use Wikibase\DataModel\Statement\Statement;
use Wikibase\DataModel\Statement\StatementListProvider;

/**
 * Extracts ids of entities that are referenced on a given entity within its statements.
 *
 * @license GPL-2.0-or-later
 */
class StatementEntityReferenceExtractor implements EntityReferenceExtractor {

    /**
     * @var EntityId[]
     */
    private $entityIds = [];

    /**
     * @var SuffixEntityIdParser
     */
    private $quantityUnitEntityIdUriParser;

    public function __construct( SuffixEntityIdParser $quantityUnitEntityIdUriParser ) {
        $this->quantityUnitEntityIdUriParser = $quantityUnitEntityIdUriParser;
    }

    /**
     * @param EntityDocument|StatementListProvider $entity
     *
     * @return EntityId[]
     * @suppress PhanTypeMismatchDeclaredParam,PhanUndeclaredMethod Intersection type
     */
    public function extractEntityIds( EntityDocument $entity ) {
        foreach ( $entity->getStatements() as $statement ) {
            $this->processStatement( $statement );
        }

        $entityIds = array_values( $this->entityIds );
        $this->entityIds = [];
        return $entityIds;
    }

    private function processStatement( Statement $statement ) {
        foreach ( $statement->getAllSnaks() as $snak ) {
            $this->processSnak( $snak );
        }
    }

    private function processSnak( Snak $snak ) {
        $propertyId = $snak->getPropertyId();
        $this->entityIds[$propertyId->getSerialization()] = $propertyId;

        if ( $snak instanceof PropertyValueSnak ) {
            $this->processDataValue( $snak->getDataValue() );
        }
    }

    private function processDataValue( DataValue $dataValue ) {
        if ( $dataValue instanceof EntityIdValue ) {
            $entityId = $dataValue->getEntityId();
            $this->entityIds[$entityId->getSerialization()] = $entityId;
        } elseif ( $dataValue instanceof UnboundedQuantityValue ) {
            $unitUri = $dataValue->getUnit();
            $this->processQuantityUnitUri( $unitUri );
        }

        // TODO: EntityIds from GlobeCoordinateValue's globe URI (Wikidata, not local item URI!)
        // TODO: EntityIds from TimeValue's calendar URI (Wikidata, not local item URI!)
    }

    private function processQuantityUnitUri( $uri ) {
        try {
            $entityId = $this->quantityUnitEntityIdUriParser->parse( $uri );
            $this->entityIds[$entityId->getSerialization()] = $entityId;
        } catch ( EntityIdParsingException $ex ) {
            // noop
        }
    }

}