wikimedia/mediawiki-extensions-CirrusSearch

<?php

namespace CirrusSearch\Search\Rescore;

use CirrusSearch\SearchConfig;
use Elastica\Query\FunctionScore;
use MediaWiki\Context\RequestContext;

/**
 * Boosts documents in user language and in wiki language if different
 * Uses getUserLanguage in SearchConfig and LanguageCode for language values
 * and CirrusSearchLanguageWeight['user'|'wiki'] for respective weights.
 */
class LangWeightFunctionScoreBuilder extends FunctionScoreBuilder {
    /**
     * @var string user language
     */
    private $userLang;

    /**
     * @var float user language weight
     */
    private $userWeight;

    /**
     * @var string wiki language
     */
    private $wikiLang;

    /**
     * @var float wiki language weight
     */
    private $wikiWeight;

    /**
     * @param SearchConfig $config
     * @param float $weight
     * @param string|null $userLang
     */
    public function __construct( SearchConfig $config, $weight, $userLang = null ) {
        parent::__construct( $config, $weight );
        $this->userLang = $userLang;
        $this->userWeight =
            $config->getElement( 'CirrusSearchLanguageWeight', 'user' );
        $this->wikiLang = $config->get( 'LanguageCode' );
        $this->wikiWeight =
            $config->getElement( 'CirrusSearchLanguageWeight', 'wiki' );
    }

    public function append( FunctionScore $functionScore ) {
        // Boost pages in a user's language
        $userLang = $this->getUserLang();
        if ( $this->userWeight ) {
            $functionScore->addWeightFunction( $this->userWeight * $this->weight,
                new \Elastica\Query\Term( [ 'language' => $userLang ] ) );
        }

        // And a wiki's language, if it's different
        if ( $this->wikiWeight && $this->userLang != $this->wikiLang ) {
            $functionScore->addWeightFunction( $this->wikiWeight * $this->weight,
                new \Elastica\Query\Term( [ 'language' => $this->wikiLang ] ) );
        }
    }

    private function getUserLang() {
        if ( $this->userLang === null ) {
            $this->userLang = RequestContext::getMain()->getLanguage()->getCode();
        }
        return $this->userLang;
    }
}