wikimedia/mediawiki-extensions-Wikibase

<?php

declare( strict_types = 1 );

namespace Wikibase\Repo\Merge\Validator;

use Wikibase\DataModel\Entity\EntityId;
use Wikibase\DataModel\Entity\EntityIdValue;
use Wikibase\DataModel\Entity\PropertyId;
use Wikibase\DataModel\Entity\StatementListProvidingEntity;
use Wikibase\DataModel\Snak\PropertyValueSnak;
use Wikibase\DataModel\Snak\Snak;
use Wikibase\DataModel\Statement\Statement;

/**
 * @license GPL-2.0-or-later
 */
class NoCrossReferencingStatements {

    /** @var PropertyId[] */
    private $violations = [];

    public function validate( StatementListProvidingEntity $source, StatementListProvidingEntity $target ): bool {
        $this->violations = [];

        foreach ( $target->getStatements()->toArray() as $toStatement ) {
            $this->checkStatementHasLink( $toStatement, $source->getId() );
        }

        foreach ( $source->getStatements()->toArray() as $fromStatement ) {
            $this->checkStatementHasLink( $fromStatement, $target->getId() );
        }

        return !$this->violations;
    }

    /**
     * @return PropertyId[] Properties used to link across
     */
    public function getViolations(): array {
        return $this->violations;
    }

    private function checkStatementHasLink( Statement $statement, EntityId $id ) {
        $snaks = $statement->getAllSnaks();

        foreach ( $snaks as $snak ) {
            $this->checkSnakIsLink( $snak, $id );
        }
    }

    private function checkSnakIsLink( Snak $snak, EntityId $id ) {
        if ( !( $snak instanceof PropertyValueSnak ) ) {
            return;
        }

        $dataValue = $snak->getDataValue();

        if ( !( $dataValue instanceof EntityIdValue ) ) {
            return;
        }

        if ( $dataValue->getEntityId()->equals( $id ) ) {
            $this->violations[] = $snak->getPropertyId();
        }
    }

}