wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\DataModel\Services\Lookup;

use Wikibase\DataModel\Entity\EntityDocument;
use Wikibase\DataModel\Entity\EntityId;
use Wikibase\DataModel\Term\DescriptionsProvider;
use Wikibase\DataModel\Term\LabelsProvider;
use Wikibase\DataModel\Term\TermList;

/**
 * @since 1.1
 *
 * @license GPL-2.0-or-later
 * @author Katie Filbert < aude.wiki@gmail.com >
 * @author Addshore
 */
class EntityRetrievingTermLookup implements TermLookup {

    /**
     * @var EntityLookup
     */
    private $entityLookup;

    /**
     * @var TermList[] Labels in all languages, indexed by entity ID serialization.
     */
    private $labels;

    /**
     * @var TermList[] Descriptions in all languages, indexed by entity ID serialization.
     */
    private $descriptions;

    public function __construct( EntityLookup $entityLookup ) {
        $this->entityLookup = $entityLookup;
    }

    /**
     * @see TermLookup::getLabel()
     *
     * @param EntityId $entityId
     * @param string $languageCode
     *
     * @return string|null
     * @throws TermLookupException
     */
    public function getLabel( EntityId $entityId, $languageCode ) {
        $labels = $this->getAllLabels( $entityId, [ $languageCode ] );

        if ( $labels->hasTermForLanguage( $languageCode ) ) {
            return $labels->getByLanguage( $languageCode )->getText();
        }

        return null;
    }

    /**
     * @see TermLookup::getLabels()
     *
     * @param EntityId $entityId
     * @param string[] $languages
     *
     * @throws TermLookupException
     * @return string[]
     */
    public function getLabels( EntityId $entityId, array $languages ) {
        $labels = $this->getAllLabels( $entityId, $languages )->toTextArray();

        return array_intersect_key( $labels, array_flip( $languages ) );
    }

    /**
     * @see TermLookup::getDescription()
     *
     * @param EntityId $entityId
     * @param string $languageCode
     *
     * @throws TermLookupException
     * @return string|null
     */
    public function getDescription( EntityId $entityId, $languageCode ) {
        $descriptions = $this->getAllDescriptions( $entityId, [ $languageCode ] );

        if ( $descriptions->hasTermForLanguage( $languageCode ) ) {
            return $descriptions->getByLanguage( $languageCode )->getText();
        }

        return null;
    }

    /**
     * @see TermLookup::getDescriptions()
     *
     * @param EntityId $entityId
     * @param string[] $languages
     *
     * @throws TermLookupException
     * @return string[]
     */
    public function getDescriptions( EntityId $entityId, array $languages ) {
        $descriptions = $this->getAllDescriptions( $entityId, $languages )->toTextArray();

        return array_intersect_key( $descriptions, array_flip( $languages ) );
    }

    /**
     * @param EntityId $entityId
     * @param string[] $languageCodes Not used for filtering but in thrown exceptions.
     *
     * @throws TermLookupException
     * @return TermList
     */
    private function getAllLabels( EntityId $entityId, array $languageCodes ) {
        $id = $entityId->getSerialization();

        if ( !isset( $this->labels[$id] ) ) {
            $entity = $this->fetchEntity( $entityId, $languageCodes );
            $this->labels[$id] = $entity instanceof LabelsProvider
                ? $entity->getLabels()
                : new TermList();
        }

        return $this->labels[$id];
    }

    /**
     * @param EntityId $entityId
     * @param string[] $languageCodes Not used for filtering but in thrown exceptions.
     *
     * @throws TermLookupException
     * @return TermList
     */
    private function getAllDescriptions( EntityId $entityId, array $languageCodes ) {
        $id = $entityId->getSerialization();

        if ( !isset( $this->descriptions[$id] ) ) {
            $entity = $this->fetchEntity( $entityId, $languageCodes );
            $this->descriptions[$id] = $entity instanceof DescriptionsProvider
                ? $entity->getDescriptions()
                : new TermList();
        }

        return $this->descriptions[$id];
    }

    /**
     * @param EntityId $entityId
     * @param string[] $languages Not used for filtering but in thrown exceptions.
     *
     * @throws TermLookupException
     * @return EntityDocument
     */
    private function fetchEntity( EntityId $entityId, array $languages ) {
        try {
            $entity = $this->entityLookup->getEntity( $entityId );
        } catch ( EntityLookupException $ex ) {
            throw new TermLookupException( $entityId, $languages, 'The entity could not be loaded', $ex );
        }

        if ( $entity === null ) {
            throw new TermLookupException( $entityId, $languages, 'The entity could not be loaded' );
        }

        return $entity;
    }

}