SpecialSearch.php

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<?php
namespace MediaWiki\Specials;
 
use ISearchResultSet;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\Content\IContentHandlerFactory;
use MediaWiki\Deferred\DeferredUpdates;
use MediaWiki\Html\Html;
use MediaWiki\Interwiki\InterwikiLookup;
use MediaWiki\Languages\LanguageConverterFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\Message\Message;
use MediaWiki\Output\OutputPage;
use MediaWiki\Request\WebRequest;
use MediaWiki\Search\SearchResultThumbnailProvider;
use MediaWiki\Search\SearchWidgets\BasicSearchResultSetWidget;
use MediaWiki\Search\SearchWidgets\DidYouMeanWidget;
use MediaWiki\Search\SearchWidgets\FullSearchResultWidget;
use MediaWiki\Search\SearchWidgets\InterwikiSearchResultSetWidget;
use MediaWiki\Search\SearchWidgets\InterwikiSearchResultWidget;
use MediaWiki\Search\SearchWidgets\SearchFormWidget;
use MediaWiki\Search\TitleMatcher;
use MediaWiki\SpecialPage\SpecialPage;
use MediaWiki\Status\Status;
use MediaWiki\Title\NamespaceInfo;
use MediaWiki\Title\Title;
use MediaWiki\User\Options\UserOptionsManager;
use MediaWiki\Xml\Xml;
use RepoGroup;
use SearchEngine;
use SearchEngineConfig;
use SearchEngineFactory;
use Wikimedia\Rdbms\ReadOnlyMode;
 
class SpecialSearch extends SpecialPage {
    protected $profile;
 
    protected $searchEngine;
 
    protected $searchEngineType = null;
 
    protected $extraParams = [];
 
    protected $mPrefix;
 
    protected int $limit;
    protected int $offset;
 
    protected $namespaces;
 
    protected $fulltext;
 
    protected $sort = SearchEngine::DEFAULT_SORT;
 
    protected $runSuggestion = true;
 
    protected $searchConfig;
 
    private SearchEngineFactory $searchEngineFactory;
    private NamespaceInfo $nsInfo;
    private IContentHandlerFactory $contentHandlerFactory;
    private InterwikiLookup $interwikiLookup;
    private ReadOnlyMode $readOnlyMode;
    private UserOptionsManager $userOptionsManager;
    private LanguageConverterFactory $languageConverterFactory;
    private RepoGroup $repoGroup;
    private SearchResultThumbnailProvider $thumbnailProvider;
    private TitleMatcher $titleMatcher;
 
    private $loadStatus;
 
    private const NAMESPACES_CURRENT = 'sense';
 
    public function __construct(
        SearchEngineConfig $searchConfig,
        SearchEngineFactory $searchEngineFactory,
        NamespaceInfo $nsInfo,
        IContentHandlerFactory $contentHandlerFactory,
        InterwikiLookup $interwikiLookup,
        ReadOnlyMode $readOnlyMode,
        UserOptionsManager $userOptionsManager,
        LanguageConverterFactory $languageConverterFactory,
        RepoGroup $repoGroup,
        SearchResultThumbnailProvider $thumbnailProvider,
        TitleMatcher $titleMatcher
    ) {
        parent::__construct( 'Search' );
        $this->searchConfig = $searchConfig;
        $this->searchEngineFactory = $searchEngineFactory;
        $this->nsInfo = $nsInfo;
        $this->contentHandlerFactory = $contentHandlerFactory;
        $this->interwikiLookup = $interwikiLookup;
        $this->readOnlyMode = $readOnlyMode;
        $this->userOptionsManager = $userOptionsManager;
        $this->languageConverterFactory = $languageConverterFactory;
        $this->repoGroup = $repoGroup;
        $this->thumbnailProvider = $thumbnailProvider;
        $this->titleMatcher = $titleMatcher;
    }
 
    public function execute( $par ) {
        $request = $this->getRequest();
        $out = $this->getOutput();
 
        // Fetch the search term
        $term = str_replace( "\n", " ", $request->getText( 'search' ) );
 
        // Historically search terms have been accepted not only in the search query
        // parameter, but also as part of the primary url. This can have PII implications
        // in releasing page view data. As such issue a 301 redirect to the correct
        // URL.
        if ( $par !== null && $par !== '' && $term === '' ) {
            $query = $request->getValues();
            unset( $query['title'] );
            // Strip underscores from title parameter; most of the time we'll want
            // text form here. But don't strip underscores from actual text params!
            $query['search'] = str_replace( '_', ' ', $par );
            $out->redirect( $this->getPageTitle()->getFullURL( $query ), 301 );
            return;
        }
 
        // Need to load selected namespaces before handling nsRemember
        $this->load();
        // TODO: This performs database actions on GET request, which is going to
        // be a problem for our multi-datacenter work.
        if ( $request->getCheck( 'nsRemember' ) ) {
            $this->saveNamespaces();
            // Remove the token from the URL to prevent the user from inadvertently
            // exposing it (e.g. by pasting it into a public wiki page) or undoing
            // later settings changes (e.g. by reloading the page).
            $query = $request->getValues();
            unset( $query['title'], $query['nsRemember'] );
            $out->redirect( $this->getPageTitle()->getFullURL( $query ) );
            return;
        }
 
        if ( !$request->getVal( 'fulltext' ) && !$request->getCheck( 'offset' ) ) {
            $url = $this->goResult( $term );
            if ( $url !== null ) {
                // successful 'go'
                $out->redirect( $url );
                return;
            }
            // No match. If it could plausibly be a title
            // run the No go match hook.
            $title = Title::newFromText( $term );
            if ( $title !== null ) {
                $this->getHookRunner()->onSpecialSearchNogomatch( $title );
            }
        }
 
        $this->setupPage( $term );
 
        if ( $this->getConfig()->get( MainConfigNames::DisableTextSearch ) ) {
            $searchForwardUrl = $this->getConfig()->get( MainConfigNames::SearchForwardUrl );
            if ( $searchForwardUrl ) {
                $url = str_replace( '$1', urlencode( $term ), $searchForwardUrl );
                $out->redirect( $url );
            } else {
                $out->addHTML( $this->showGoogleSearch( $term ) );
            }
 
            return;
        }
 
        $this->showResults( $term );
    }
 
    private function showGoogleSearch( $term ) {
        return "<fieldset>" .
                "<legend>" .
                    $this->msg( 'search-external' )->escaped() .
                "</legend>" .
                "<p class='mw-searchdisabled'>" .
                    $this->msg( 'searchdisabled' )->escaped() .
                "</p>" .
                // googlesearch is part of $wgRawHtmlMessages and safe to use as is here
                $this->msg( 'googlesearch' )->rawParams(
                    htmlspecialchars( $term ),
                    'UTF-8',
                    $this->msg( 'searchbutton' )->escaped()
                )->text() .
            "</fieldset>";
    }
 
    public function load() {
        $this->loadStatus = new Status();
 
        $request = $this->getRequest();
        $this->searchEngineType = $request->getVal( 'srbackend' );
 
        [ $this->limit, $this->offset ] = $request->getLimitOffsetForUser(
            $this->getUser(),
            20,
            'searchlimit'
        );
        $this->mPrefix = $request->getVal( 'prefix', '' );
        if ( $this->mPrefix !== '' ) {
            $this->setExtraParam( 'prefix', $this->mPrefix );
        }
 
        $sort = $request->getVal( 'sort', SearchEngine::DEFAULT_SORT );
        $validSorts = $this->getSearchEngine()->getValidSorts();
        if ( !in_array( $sort, $validSorts ) ) {
            $this->loadStatus->warning( 'search-invalid-sort-order', $sort,
                implode( ', ', $validSorts ) );
        } elseif ( $sort !== $this->sort ) {
            $this->sort = $sort;
            $this->setExtraParam( 'sort', $this->sort );
        }
 
        $user = $this->getUser();
 
        # Extract manually requested namespaces
        $nslist = $this->powerSearch( $request );
        if ( $nslist === [] ) {
            # Fallback to user preference
            $nslist = $this->searchConfig->userNamespaces( $user );
        }
 
        $profile = null;
        if ( $nslist === [] ) {
            $profile = 'default';
        }
 
        $profile = $request->getVal( 'profile', $profile );
        $profiles = $this->getSearchProfiles();
        if ( $profile === null ) {
            // BC with old request format
            $profile = 'advanced';
            foreach ( $profiles as $key => $data ) {
                if ( $nslist === $data['namespaces'] && $key !== 'advanced' ) {
                    $profile = $key;
                }
            }
            $this->namespaces = $nslist;
        } elseif ( $profile === 'advanced' ) {
            $this->namespaces = $nslist;
        } elseif ( isset( $profiles[$profile]['namespaces'] ) ) {
            $this->namespaces = $profiles[$profile]['namespaces'];
        } else {
            // Unknown profile requested
            $this->loadStatus->warning( 'search-unknown-profile', $profile );
            $profile = 'default';
            $this->namespaces = $profiles['default']['namespaces'];
        }
 
        $this->fulltext = $request->getVal( 'fulltext' );
        $this->runSuggestion = (bool)$request->getVal( 'runsuggestion', '1' );
        $this->profile = $profile;
    }
 
    public function goResult( $term ) {
        # If the string cannot be used to create a title
        if ( Title::newFromText( $term ) === null ) {
            return null;
        }
        # If there's an exact or very near match, jump right there.
        $title = $this->titleMatcher->getNearMatch( $term );
        if ( $title === null ) {
            return null;
        }
        $url = null;
        if ( !$this->getHookRunner()->onSpecialSearchGoResult( $term, $title, $url ) ) {
            return null;
        }
 
        if (
            // If there is a preference set to NOT redirect on exact page match
            // then return null (which prevents direction)
            !$this->redirectOnExactMatch()
            // BUT ...
            // ... ignore no-redirect preference if the exact page match is an interwiki link
            && !$title->isExternal()
            // ... ignore no-redirect preference if the exact page match is NOT in the main
            // namespace AND there's a namespace in the search string
            && !( $title->getNamespace() !== NS_MAIN && strpos( $term, ':' ) > 0 )
        ) {
            return null;
        }
 
        return $url ?? $title->getFullUrlForRedirect();
    }
 
    private function redirectOnExactMatch() {
        if ( !$this->getConfig()->get( MainConfigNames::SearchMatchRedirectPreference ) ) {
            // If the preference for whether to redirect is disabled, use the default setting
            return $this->userOptionsManager->getDefaultOption(
                'search-match-redirect',
                $this->getUser()
            );
        } else {
            // Otherwise use the user's preference
            return $this->userOptionsManager->getOption( $this->getUser(), 'search-match-redirect' );
        }
    }
 
    public function showResults( $term ) {
        if ( $this->searchEngineType !== null ) {
            $this->setExtraParam( 'srbackend', $this->searchEngineType );
        }
 
        $out = $this->getOutput();
        $widgetOptions = $this->getConfig()->get( MainConfigNames::SpecialSearchFormOptions );
        $formWidget = new SearchFormWidget(
            new ServiceOptions(
                SearchFormWidget::CONSTRUCTOR_OPTIONS,
                $this->getConfig()
            ),
            $this,
            $this->searchConfig,
            $this->getHookContainer(),
            $this->languageConverterFactory->getLanguageConverter( $this->getLanguage() ),
            $this->nsInfo,
            $this->getSearchProfiles()
        );
        $filePrefix = $this->getContentLanguage()->getFormattedNsText( NS_FILE ) . ':';
        if ( trim( $term ) === '' || $filePrefix === trim( $term ) ) {
            // Empty query -- straight view of search form
            if ( !$this->getHookRunner()->onSpecialSearchResultsPrepend( $this, $out, $term ) ) {
                # Hook requested termination
                return;
            }
            $out->enableOOUI();
            // The form also contains the 'Showing results 0 - 20 of 1234' so we can
            // only do the form render here for the empty $term case. Rendering
            // the form when a search is provided is repeated below.
            $out->addHTML( $formWidget->render(
                $this->profile, $term, 0, 0, $this->offset, $this->isPowerSearch(), $widgetOptions
            ) );
            return;
        }
 
        $engine = $this->getSearchEngine();
        $engine->setFeatureData( 'rewrite', $this->runSuggestion );
        $engine->setLimitOffset( $this->limit, $this->offset );
        $engine->setNamespaces( $this->namespaces );
        $engine->setSort( $this->sort );
        $engine->prefix = $this->mPrefix;
 
        $this->getHookRunner()->onSpecialSearchSetupEngine( $this, $this->profile, $engine );
        if ( !$this->getHookRunner()->onSpecialSearchResultsPrepend( $this, $out, $term ) ) {
            # Hook requested termination
            return;
        }
 
        $title = Title::newFromText( $term );
        $languageConverter = $this->languageConverterFactory->getLanguageConverter( $this->getContentLanguage() );
        if ( $languageConverter->hasVariants() ) {
            // findVariantLink will replace the link arg as well but we want to keep our original
            // search string, use a copy in the $variantTerm var so that $term remains intact.
            $variantTerm = $term;
            $languageConverter->findVariantLink( $variantTerm, $title );
        }
 
        $showSuggestion = $title === null || !$title->isKnown();
        $engine->setShowSuggestion( $showSuggestion );
 
        $rewritten = $engine->replacePrefixes( $term );
        if ( $rewritten !== $term ) {
            wfDeprecatedMsg( 'SearchEngine::replacePrefixes()  was overridden by ' .
                get_class( $engine ) . ', this is deprecated since MediaWiki 1.32',
                '1.32', false, false );
        }
 
        // fetch search results
        $titleMatches = $engine->searchTitle( $rewritten );
        $textMatches = $engine->searchText( $rewritten );
 
        $textStatus = null;
        if ( $textMatches instanceof Status ) {
            $textStatus = $textMatches;
            $textMatches = $textStatus->getValue();
        }
 
        // Get number of results
        $titleMatchesNum = $textMatchesNum = $numTitleMatches = $numTextMatches = 0;
        if ( $titleMatches ) {
            $titleMatchesNum = $titleMatches->numRows();
            $numTitleMatches = $titleMatches->getTotalHits();
        }
        if ( $textMatches ) {
            $textMatchesNum = $textMatches->numRows();
            $numTextMatches = $textMatches->getTotalHits();
            if ( $textMatchesNum > 0 ) {
                $engine->augmentSearchResults( $textMatches );
            }
        }
        $num = $titleMatchesNum + $textMatchesNum;
        $totalRes = $numTitleMatches + $numTextMatches;
 
        // start rendering the page
        $out->enableOOUI();
        $out->addHTML( $formWidget->render(
            $this->profile, $term, $num, $totalRes, $this->offset, $this->isPowerSearch(), $widgetOptions
        ) );
 
        // did you mean... suggestions
        if ( $textMatches ) {
            $dymWidget = new DidYouMeanWidget( $this );
            $out->addHTML( $dymWidget->render( $term, $textMatches ) );
        }
 
        $hasSearchErrors = $textStatus && $textStatus->getMessages() !== [];
        $hasInlineIwResults = $textMatches &&
            $textMatches->hasInterwikiResults( ISearchResultSet::INLINE_RESULTS );
        $hasSecondaryIwResults = $textMatches &&
            $textMatches->hasInterwikiResults( ISearchResultSet::SECONDARY_RESULTS );
 
        $classNames = [ 'searchresults' ];
        if ( $hasSecondaryIwResults ) {
            $classNames[] = 'mw-searchresults-has-iw';
        }
        if ( $this->offset > 0 ) {
            $classNames[] = 'mw-searchresults-has-offset';
        }
        $out->addHTML( '<div class="' . implode( ' ', $classNames ) . '">' );
 
        $out->addHTML( '<div class="mw-search-results-info">' );
 
        if ( $hasSearchErrors || $this->loadStatus->getMessages() ) {
            if ( $textStatus === null ) {
                $textStatus = $this->loadStatus;
            } else {
                $textStatus->merge( $this->loadStatus );
            }
            [ $error, $warning ] = $textStatus->splitByErrorType();
            if ( $error->getMessages() ) {
                $out->addHTML( Html::errorBox(
                    $error->getHTML( 'search-error' )
                ) );
            }
            if ( $warning->getMessages() ) {
                $out->addHTML( Html::warningBox(
                    $warning->getHTML( 'search-warning' )
                ) );
            }
        }
 
        // If we have no results and have not already displayed an error message
        if ( $num === 0 && !$hasSearchErrors ) {
            $out->wrapWikiMsg( "<p class=\"mw-search-nonefound\">\n$1</p>", [
                $hasInlineIwResults ? 'search-nonefound-thiswiki' : 'search-nonefound',
                wfEscapeWikiText( $term ),
                $term
            ] );
        }
 
        // Show the create link ahead
        $this->showCreateLink( $title, $num, $titleMatches, $textMatches );
 
        $this->getHookRunner()->onSpecialSearchResults( $term, $titleMatches, $textMatches );
 
        // Close <div class='mw-search-results-info'>
        $out->addHTML( '</div>' );
 
        // Although $num might be 0 there can still be secondary or inline
        // results to display.
        $linkRenderer = $this->getLinkRenderer();
        $mainResultWidget = new FullSearchResultWidget(
            $this,
            $linkRenderer,
            $this->getHookContainer(),
            $this->repoGroup,
            $this->thumbnailProvider,
            $this->userOptionsManager
        );
 
        $sidebarResultWidget = new InterwikiSearchResultWidget( $this, $linkRenderer );
        $sidebarResultsWidget = new InterwikiSearchResultSetWidget(
            $this,
            $sidebarResultWidget,
            $linkRenderer,
            $this->interwikiLookup,
            $engine->getFeatureData( 'show-multimedia-search-results' )
        );
 
        $widget = new BasicSearchResultSetWidget( $this, $mainResultWidget, $sidebarResultsWidget );
 
        $out->addHTML( '<div class="mw-search-visualclear"></div>' );
        $this->prevNextLinks( $totalRes, $textMatches, $term, 'mw-search-pager-top', $out );
 
        $out->addHTML( $widget->render(
            $term, $this->offset, $titleMatches, $textMatches
        ) );
 
        $out->addHTML( '<div class="mw-search-visualclear"></div>' );
        $this->prevNextLinks( $totalRes, $textMatches, $term, 'mw-search-pager-bottom', $out );
 
        // Close <div class='searchresults'>
        $out->addHTML( "</div>" );
 
        $this->getHookRunner()->onSpecialSearchResultsAppend( $this, $out, $term );
    }
 
    protected function showCreateLink( $title, $num, $titleMatches, $textMatches ) {
        // show direct page/create link if applicable
 
        // Check DBkey !== '' in case of fragment link only.
        if ( $title === null || $title->getDBkey() === ''
            || ( $titleMatches !== null && $titleMatches->searchContainedSyntax() )
            || ( $textMatches !== null && $textMatches->searchContainedSyntax() )
        ) {
            // invalid title
            // preserve the paragraph for margins etc...
            $this->getOutput()->addHTML( '<p></p>' );
 
            return;
        }
 
        $messageName = 'searchmenu-new-nocreate';
        $linkClass = 'mw-search-createlink';
 
        if ( !$title->isExternal() ) {
            if ( $title->isKnown() ) {
                $messageName = 'searchmenu-exists';
                $linkClass = 'mw-search-exists';
            } elseif (
                $this->contentHandlerFactory->getContentHandler( $title->getContentModel() )
                    ->supportsDirectEditing()
                && $this->getAuthority()->probablyCan( 'edit', $title )
            ) {
                $messageName = 'searchmenu-new';
            }
        }
 
        $params = [
            $messageName,
            wfEscapeWikiText( $title->getPrefixedText() ),
            Message::numParam( $num )
        ];
        $this->getHookRunner()->onSpecialSearchCreateLink( $title, $params );
 
        // Extensions using the hook might still return an empty $messageName
        // @phan-suppress-next-line PhanRedundantCondition Set by hook
        if ( $messageName ) {
            $this->getOutput()->wrapWikiMsg( "<p class=\"$linkClass\">\n$1</p>", $params );
        } else {
            // preserve the paragraph for margins etc...
            $this->getOutput()->addHTML( '<p></p>' );
        }
    }
 
    protected function setupPage( $term ) {
        $out = $this->getOutput();
 
        $this->setHeaders();
        $this->outputHeader();
        // TODO: Is this true? The namespace remember uses a user token
        // on save.
        $out->setPreventClickjacking( false );
        $this->addHelpLink( 'Help:Searching' );
 
        if ( strval( $term ) !== '' ) {
            $out->setPageTitleMsg( $this->msg( 'searchresults' ) );
            $out->setHTMLTitle( $this->msg( 'pagetitle' )
                ->plaintextParams( $this->msg( 'searchresults-title' )->plaintextParams( $term )->text() )
                ->inContentLanguage()->text()
            );
        }
 
        if ( $this->mPrefix !== '' ) {
            $subtitle = $this->msg( 'search-filter-title-prefix' )->plaintextParams( $this->mPrefix );
            $params = $this->powerSearchOptions();
            unset( $params['prefix'] );
            $params += [
                'search' => $term,
                'fulltext' => 1,
            ];
 
            $subtitle .= ' (';
            $subtitle .= Xml::element(
                'a',
                [
                    'href' => $this->getPageTitle()->getLocalURL( $params ),
                    'title' => $this->msg( 'search-filter-title-prefix-reset' )->text(),
                ],
                $this->msg( 'search-filter-title-prefix-reset' )->text()
            );
            $subtitle .= ')';
            $out->setSubtitle( $subtitle );
        }
 
        $out->addJsConfigVars( [ 'searchTerm' => $term ] );
        $out->addModules( 'mediawiki.special.search' );
        $out->addModuleStyles( [
            'mediawiki.special', 'mediawiki.special.search.styles',
            'mediawiki.widgets.SearchInputWidget.styles',
        ] );
    }
 
    protected function isPowerSearch() {
        return $this->profile === 'advanced';
    }
 
    protected function powerSearch( &$request ) {
        $arr = [];
        foreach ( $this->searchConfig->searchableNamespaces() as $ns => $name ) {
            if ( $request->getCheck( 'ns' . $ns ) ) {
                $arr[] = $ns;
            }
        }
 
        return $arr;
    }
 
    public function powerSearchOptions() {
        $opt = [];
        if ( $this->isPowerSearch() ) {
            foreach ( $this->namespaces as $n ) {
                $opt['ns' . $n] = 1;
            }
        } else {
            $opt['profile'] = $this->profile;
        }
 
        return $opt + $this->extraParams;
    }
 
    protected function saveNamespaces() {
        $user = $this->getUser();
        $request = $this->getRequest();
 
        if ( $user->isRegistered() &&
            $user->matchEditToken(
                $request->getVal( 'nsRemember' ),
                'searchnamespace',
                $request
            ) && !$this->readOnlyMode->isReadOnly()
        ) {
            // Reset namespace preferences: namespaces are not searched
            // when they're not mentioned in the URL parameters.
            foreach ( $this->nsInfo->getValidNamespaces() as $n ) {
                $this->userOptionsManager->setOption( $user, 'searchNs' . $n, false );
            }
            // The request parameters include all the namespaces to be searched.
            // Even if they're the same as an existing profile, they're not eaten.
            foreach ( $this->namespaces as $n ) {
                $this->userOptionsManager->setOption( $user, 'searchNs' . $n, true );
            }
 
            DeferredUpdates::addCallableUpdate( static function () use ( $user ) {
                $user->saveSettings();
            } );
 
            return true;
        }
 
        return false;
    }
 
    protected function getSearchProfiles() {
        // Builds list of Search Types (profiles)
        $nsAllSet = array_keys( $this->searchConfig->searchableNamespaces() );
        $defaultNs = $this->searchConfig->defaultNamespaces();
        $profiles = [
            'default' => [
                'message' => 'searchprofile-articles',
                'tooltip' => 'searchprofile-articles-tooltip',
                'namespaces' => $defaultNs,
                'namespace-messages' => $this->searchConfig->namespacesAsText(
                    $defaultNs
                ),
            ],
            'images' => [
                'message' => 'searchprofile-images',
                'tooltip' => 'searchprofile-images-tooltip',
                'namespaces' => [ NS_FILE ],
            ],
            'all' => [
                'message' => 'searchprofile-everything',
                'tooltip' => 'searchprofile-everything-tooltip',
                'namespaces' => $nsAllSet,
            ],
            'advanced' => [
                'message' => 'searchprofile-advanced',
                'tooltip' => 'searchprofile-advanced-tooltip',
                'namespaces' => self::NAMESPACES_CURRENT,
            ]
        ];
 
        $this->getHookRunner()->onSpecialSearchProfiles( $profiles );
 
        foreach ( $profiles as &$data ) {
            if ( !is_array( $data['namespaces'] ) ) {
                continue;
            }
            sort( $data['namespaces'] );
        }
 
        return $profiles;
    }
 
    public function getSearchEngine() {
        if ( $this->searchEngine === null ) {
            $this->searchEngine = $this->searchEngineFactory->create( $this->searchEngineType );
        }
 
        return $this->searchEngine;
    }
 
    public function getProfile() {
        return $this->profile;
    }
 
    public function getNamespaces() {
        return $this->namespaces;
    }
 
    public function setExtraParam( $key, $value ) {
        $this->extraParams[$key] = $value;
    }
 
    public function getPrefix() {
        return $this->mPrefix;
    }
 
    private function prevNextLinks(
        ?int $totalRes,
        ?ISearchResultSet $textMatches,
        string $term,
        string $class,
        OutputPage $out
    ) {
        if ( $totalRes > $this->limit || $this->offset ) {
            // Allow matches to define the correct offset, as interleaved
            // AB testing may require a different next page offset.
            if ( $textMatches && $textMatches->getOffset() !== null ) {
                $offset = $textMatches->getOffset();
            } else {
                $offset = $this->offset;
            }
 
            // use the rewritten search term for subsequent page searches
            $newSearchTerm = $term;
            if ( $textMatches && $textMatches->hasRewrittenQuery() ) {
                $newSearchTerm = $textMatches->getQueryAfterRewrite();
            }
 
            $prevNext =
                // @phan-suppress-next-line PhanTypeMismatchArgumentNullable offset is not null
                $this->buildPrevNextNavigation( $offset, $this->limit,
                    $this->powerSearchOptions() + [ 'search' => $newSearchTerm ],
                    $this->limit + $this->offset >= $totalRes );
            $out->addHTML( "<div class='{$class}'>{$prevNext}</div>\n" );
        }
    }
 
    protected function getGroupName() {
        return 'pages';
    }
}
 
class_alias( SpecialSearch::class, 'SpecialSearch' );