Move FSFile classes to /fsfile

[mediawiki.git] / includes / specials / SpecialSearch.php

<?php
/**
 * Implements Special:Search
 *
 * Copyright © 2004 Brion Vibber <brion@pobox.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup SpecialPage
 */

use MediaWiki\MediaWikiServices;

/**
 * implements Special:Search - Run text & title search and display the output
 * @ingroup SpecialPage
 */
class SpecialSearch extends SpecialPage {
        /**
         * Current search profile. Search profile is just a name that identifies
         * the active search tab on the search page (content, discussions...)
         * For users tt replaces the set of enabled namespaces from the query
         * string when applicable. Extensions can add new profiles with hooks
         * with custom search options just for that profile.
         * @var null|string
         */
        protected $profile;

        /** @var SearchEngine Search engine */
        protected $searchEngine;

        /** @var string Search engine type, if not default */
        protected $searchEngineType;

        /** @var array For links */
        protected $extraParams = [];

        /**
         * @var string The prefix url parameter. Set on the searcher and the
         * is expected to treat it as prefix filter on titles.
         */
        protected $mPrefix;

        /**
         * @var int
         */
        protected $limit, $offset;

        /**
         * @var array
         */
        protected $namespaces;

        /**
         * @var string
         */
        protected $fulltext;

        /**
         * @var bool
         */
        protected $runSuggestion = true;

        /**
         * Names of the wikis, in format: Interwiki prefix -> caption
         * @var array
         */
        protected $customCaptions;

        /**
         * Search engine configurations.
         * @var SearchEngineConfig
         */
        protected $searchConfig;

        const NAMESPACES_CURRENT = 'sense';

        public function __construct() {
                parent::__construct( 'Search' );
                $this->searchConfig = MediaWikiServices::getInstance()->getSearchEngineConfig();
        }

        /**
         * Entry point
         *
         * @param string $par
         */
        public function execute( $par ) {
                $request = $this->getRequest();

                // Fetch the search term
                $search = 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 ( strlen( $par ) && !strlen( $search ) ) {
                        $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 );
                        $this->getOutput()->redirect( $this->getPageTitle()->getFullURL( $query ), 301 );
                        return;
                }

                $this->setHeaders();
                $this->outputHeader();
                $out = $this->getOutput();
                $out->allowClickjacking();
                $out->addModuleStyles( [
                        'mediawiki.special', 'mediawiki.special.search.styles', 'mediawiki.ui', 'mediawiki.ui.button',
                        'mediawiki.ui.input', 'mediawiki.widgets.SearchInputWidget.styles',
                ] );
                $this->addHelpLink( 'Help:Searching' );

                $this->load();
                if ( !is_null( $request->getVal( '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;
                }

                $out->addJsConfigVars( [ 'searchTerm' => $search ] );
                $this->searchEngineType = $request->getVal( 'srbackend' );

                if ( $request->getVal( 'fulltext' )
                        || !is_null( $request->getVal( 'offset' ) )
                ) {
                        $this->showResults( $search );
                } else {
                        $this->goResult( $search );
                }
        }

        /**
         * Set up basic search parameters from the request and user settings.
         *
         * @see tests/phpunit/includes/specials/SpecialSearchTest.php
         */
        public function load() {
                $request = $this->getRequest();
                list( $this->limit, $this->offset ) = $request->getLimitOffset( 20, '' );
                $this->mPrefix = $request->getVal( 'prefix', '' );

                $user = $this->getUser();

                # Extract manually requested namespaces
                $nslist = $this->powerSearch( $request );
                if ( !count( $nslist ) ) {
                        # Fallback to user preference
                        $nslist = $this->searchConfig->userNamespaces( $user );
                }

                $profile = null;
                if ( !count( $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;
                } else {
                        if ( isset( $profiles[$profile]['namespaces'] ) ) {
                                $this->namespaces = $profiles[$profile]['namespaces'];
                        } else {
                                // Unknown profile requested
                                $profile = 'default';
                                $this->namespaces = $profiles['default']['namespaces'];
                        }
                }

                $this->fulltext = $request->getVal( 'fulltext' );
                $this->runSuggestion = (bool)$request->getVal( 'runsuggestion', true );
                $this->profile = $profile;
        }

        /**
         * If an exact title match can be found, jump straight ahead to it.
         *
         * @param string $term
         */
        public function goResult( $term ) {
                $this->setupPage( $term );
                # Try to go to page as entered.
                $title = Title::newFromText( $term );
                # If the string cannot be used to create a title
                if ( is_null( $title ) ) {
                        $this->showResults( $term );

                        return;
                }
                # If there's an exact or very near match, jump right there.
                $title = $this->getSearchEngine()
                        ->getNearMatcher( $this->getConfig() )->getNearMatch( $term );

                if ( !is_null( $title ) &&
                        Hooks::run( 'SpecialSearchGoResult', [ $term, $title, &$url ] )
                ) {
                        if ( $url === null ) {
                                $url = $title->getFullURL();
                        }
                        $this->getOutput()->redirect( $url );

                        return;
                }
                # No match, generate an edit URL
                $title = Title::newFromText( $term );
                if ( !is_null( $title ) ) {
                        Hooks::run( 'SpecialSearchNogomatch', [ &$title ] );
                }
                $this->showResults( $term );
        }

        /**
         * @param string $term
         */
        public function showResults( $term ) {
                global $wgContLang;

                $search = $this->getSearchEngine();
                $search->setFeatureData( 'rewrite', $this->runSuggestion );
                $search->setLimitOffset( $this->limit, $this->offset );
                $search->setNamespaces( $this->namespaces );
                $search->prefix = $this->mPrefix;
                $term = $search->transformSearchTerm( $term );

                Hooks::run( 'SpecialSearchSetupEngine', [ $this, $this->profile, $search ] );

                $this->setupPage( $term );

                $out = $this->getOutput();

                if ( $this->getConfig()->get( 'DisableTextSearch' ) ) {
                        $searchFowardUrl = $this->getConfig()->get( 'SearchForwardUrl' );
                        if ( $searchFowardUrl ) {
                                $url = str_replace( '$1', urlencode( $term ), $searchFowardUrl );
                                $out->redirect( $url );
                        } else {
                                $out->addHTML(
                                        Xml::openElement( 'fieldset' ) .
                                        Xml::element( 'legend', null, $this->msg( 'search-external' )->text() ) .
                                        Xml::element(
                                                'p',
                                                [ 'class' => 'mw-searchdisabled' ],
                                                $this->msg( 'searchdisabled' )->text()
                                        ) .
                                        $this->msg( 'googlesearch' )->rawParams(
                                                htmlspecialchars( $term ),
                                                'UTF-8',
                                                $this->msg( 'searchbutton' )->escaped()
                                        )->text() .
                                        Xml::closeElement( 'fieldset' )
                                );
                        }

                        return;
                }

                $title = Title::newFromText( $term );
                $showSuggestion = $title === null || !$title->isKnown();
                $search->setShowSuggestion( $showSuggestion );

                // fetch search results
                $rewritten = $search->replacePrefixes( $term );

                $titleMatches = $search->searchTitle( $rewritten );
                $textMatches = $search->searchText( $rewritten );

                $textStatus = null;
                if ( $textMatches instanceof Status ) {
                        $textStatus = $textMatches;
                        $textMatches = null;
                }

                // did you mean... suggestions
                $didYouMeanHtml = '';
                if ( $showSuggestion && $textMatches && !$textStatus ) {
                        if ( $textMatches->hasRewrittenQuery() ) {
                                $didYouMeanHtml = $this->getDidYouMeanRewrittenHtml( $term, $textMatches );
                        } elseif ( $textMatches->hasSuggestion() ) {
                                $didYouMeanHtml = $this->getDidYouMeanHtml( $textMatches );
                        }
                }

                if ( !Hooks::run( 'SpecialSearchResultsPrepend', [ $this, $out, $term ] ) ) {
                        # Hook requested termination
                        return;
                }

                // start rendering the page
                $out->addHTML(
                        Xml::openElement(
                                'form',
                                [
                                        'id' => ( $this->isPowerSearch() ? 'powersearch' : 'search' ),
                                        'method' => 'get',
                                        'action' => wfScript(),
                                ]
                        )
                );

                // 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();
                }
                $num = $titleMatchesNum + $textMatchesNum;
                $totalRes = $numTitleMatches + $numTextMatches;

                $out->enableOOUI();
                $out->addHTML(
                        # This is an awful awful ID name. It's not a table, but we
                        # named it poorly from when this was a table so now we're
                        # stuck with it
                        Xml::openElement( 'div', [ 'id' => 'mw-search-top-table' ] ) .
                        $this->shortDialog( $term, $num, $totalRes ) .
                        Xml::closeElement( 'div' ) .
                        $this->searchProfileTabs( $term ) .
                        $this->searchOptions( $term ) .
                        Xml::closeElement( 'form' ) .
                        $didYouMeanHtml
                );

                $filePrefix = $wgContLang->getFormattedNsText( NS_FILE ) . ':';
                if ( trim( $term ) === '' || $filePrefix === trim( $term ) ) {
                        // Empty query -- straight view of search form
                        return;
                }

                $out->addHTML( "<div class='searchresults'>" );

                // prev/next links
                $prevnext = null;
                if ( $num || $this->offset ) {
                        // Show the create link ahead
                        $this->showCreateLink( $title, $num, $titleMatches, $textMatches );
                        if ( $totalRes > $this->limit || $this->offset ) {
                                if ( $this->searchEngineType !== null ) {
                                        $this->setExtraParam( 'srbackend', $this->searchEngineType );
                                }
                                $prevnext = $this->getLanguage()->viewPrevNext(
                                        $this->getPageTitle(),
                                        $this->offset,
                                        $this->limit,
                                        $this->powerSearchOptions() + [ 'search' => $term ],
                                        $this->limit + $this->offset >= $totalRes
                                );
                        }
                }
                Hooks::run( 'SpecialSearchResults', [ $term, &$titleMatches, &$textMatches ] );

                $out->parserOptions()->setEditSection( false );
                if ( $titleMatches ) {
                        if ( $numTitleMatches > 0 ) {
                                $out->wrapWikiMsg( "==$1==\n", 'titlematches' );
                                $out->addHTML( $this->showMatches( $titleMatches ) );
                        }
                        $titleMatches->free();
                }
                if ( $textMatches && !$textStatus ) {
                        // output appropriate heading
                        if ( $numTextMatches > 0 && $numTitleMatches > 0 ) {
                                $out->addHTML( '<div class="mw-search-visualclear"></div>' );
                                // if no title matches the heading is redundant
                                $out->wrapWikiMsg( "==$1==\n", 'textmatches' );
                        }

                        // show results
                        if ( $numTextMatches > 0 ) {
                                $search->augmentSearchResults( $textMatches );
                                $out->addHTML( $this->showMatches( $textMatches ) );
                        }

                        // show secondary interwiki results if any
                        if ( $textMatches->hasInterwikiResults( SearchResultSet::SECONDARY_RESULTS ) ) {
                                $out->addHTML( $this->showInterwiki( $textMatches->getInterwikiResults(
                                                SearchResultSet::SECONDARY_RESULTS ), $term ) );
                        }
                }

                $hasOtherResults = $textMatches &&
                        $textMatches->hasInterwikiResults( SearchResultSet::INLINE_RESULTS );

                if ( $num === 0 ) {
                        if ( $textStatus ) {
                                $out->addHTML( '<div class="error">' .
                                        $textStatus->getMessage( 'search-error' ) . '</div>' );
                        } else {
                                $this->showCreateLink( $title, $num, $titleMatches, $textMatches );
                                $out->wrapWikiMsg( "<p class=\"mw-search-nonefound\">\n$1</p>",
                                        [ $hasOtherResults ? 'search-nonefound-thiswiki' : 'search-nonefound',
                                                        wfEscapeWikiText( $term )
                                        ] );
                        }
                }

                if ( $hasOtherResults ) {
                        foreach ( $textMatches->getInterwikiResults( SearchResultSet::INLINE_RESULTS )
                                                as $interwiki => $interwikiResult ) {
                                if ( $interwikiResult instanceof Status || $interwikiResult->numRows() == 0 ) {
                                        // ignore bad interwikis for now
                                        continue;
                                }
                                // TODO: wiki header
                                $out->addHTML( $this->showMatches( $interwikiResult, $interwiki ) );
                        }
                }

                if ( $textMatches ) {
                        $textMatches->free();
                }

                $out->addHTML( '<div class="mw-search-visualclear"></div>' );

                if ( $prevnext ) {
                        $out->addHTML( "<p class='mw-search-pager-bottom'>{$prevnext}</p>\n" );
                }

                $out->addHTML( "</div>" );

                Hooks::run( 'SpecialSearchResultsAppend', [ $this, $out, $term ] );

        }

        /**
         * Produce wiki header for interwiki results
         * @param string $interwiki Interwiki name
         * @param SearchResultSet $interwikiResult The result set
         * @return string
         */
        protected function interwikiHeader( $interwiki, $interwikiResult ) {
                // TODO: we need to figure out how to name wikis correctly
                $wikiMsg = $this->msg( 'search-interwiki-results-' . $interwiki )->parse();
                return "<p class=\"mw-search-interwiki-header mw-search-visualclear\">\n$wikiMsg</p>";
        }

        /**
         * Decide if the suggested query should be run, and it's results returned
         * instead of the provided $textMatches
         *
         * @param SearchResultSet $textMatches The results of a users query
         * @return bool
         */
        protected function shouldRunSuggestedQuery( SearchResultSet $textMatches ) {
                if ( !$this->runSuggestion ||
                        !$textMatches->hasSuggestion() ||
                        $textMatches->numRows() > 0 ||
                        $textMatches->searchContainedSyntax()
                ) {
                        return false;
                }

                return $this->getConfig()->get( 'SearchRunSuggestedQuery' );
        }

        /**
         * Generates HTML shown to the user when we have a suggestion about a query
         * that might give more results than their current query.
         */
        protected function getDidYouMeanHtml( SearchResultSet $textMatches ) {
                # mirror Go/Search behavior of original request ..
                $params = [ 'search' => $textMatches->getSuggestionQuery() ];
                if ( $this->fulltext === null ) {
                        $params['fulltext'] = 'Search';
                } else {
                        $params['fulltext'] = $this->fulltext;
                }
                $stParams = array_merge( $params, $this->powerSearchOptions() );

                $suggest = Linker::linkKnown(
                        $this->getPageTitle(),
                        $textMatches->getSuggestionSnippet() ?: null,
                        [ 'id' => 'mw-search-DYM-suggestion' ],
                        $stParams
                );

                # HTML of did you mean... search suggestion link
                return Html::rawElement(
                        'div',
                        [ 'class' => 'searchdidyoumean' ],
                        $this->msg( 'search-suggest' )->rawParams( $suggest )->parse()
                );
        }

        /**
         * Generates HTML shown to user when their query has been internally rewritten,
         * and the results of the rewritten query are being returned.
         *
         * @param string $term The users search input
         * @param SearchResultSet $textMatches The response to the users initial search request
         * @return string HTML linking the user to their original $term query, and the one
         *  suggested by $textMatches.
         */
        protected function getDidYouMeanRewrittenHtml( $term, SearchResultSet $textMatches ) {
                // Showing results for '$rewritten'
                // Search instead for '$orig'

                $params = [ 'search' => $textMatches->getQueryAfterRewrite() ];
                if ( $this->fulltext === null ) {
                        $params['fulltext'] = 'Search';
                } else {
                        $params['fulltext'] = $this->fulltext;
                }
                $stParams = array_merge( $params, $this->powerSearchOptions() );

                $rewritten = Linker::linkKnown(
                        $this->getPageTitle(),
                        $textMatches->getQueryAfterRewriteSnippet() ?: null,
                        [ 'id' => 'mw-search-DYM-rewritten' ],
                        $stParams
                );

                $stParams['search'] = $term;
                $stParams['runsuggestion'] = 0;
                $original = Linker::linkKnown(
                        $this->getPageTitle(),
                        htmlspecialchars( $term ),
                        [ 'id' => 'mw-search-DYM-original' ],
                        $stParams
                );

                return Html::rawElement(
                        'div',
                        [ 'class' => 'searchdidyoumean' ],
                        $this->msg( 'search-rewritten' )->rawParams( $rewritten, $original )->escaped()
                );
        }

        /**
         * @param Title $title
         * @param int $num The number of search results found
         * @param null|SearchResultSet $titleMatches Results from title search
         * @param null|SearchResultSet $textMatches Results from text search
         */
        protected function showCreateLink( $title, $num, $titleMatches, $textMatches ) {
                // show direct page/create link if applicable

                // Check DBkey !== '' in case of fragment link only.
                if ( is_null( $title ) || $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 ( $title->quickUserCan( 'create', $this->getUser() ) ) {
                                $messageName = 'searchmenu-new';
                        }
                }

                $params = [
                        $messageName,
                        wfEscapeWikiText( $title->getPrefixedText() ),
                        Message::numParam( $num )
                ];
                Hooks::run( 'SpecialSearchCreateLink', [ $title, &$params ] );

                // Extensions using the hook might still return an empty $messageName
                if ( $messageName ) {
                        $this->getOutput()->wrapWikiMsg( "<p class=\"$linkClass\">\n$1</p>", $params );
                } else {
                        // preserve the paragraph for margins etc...
                        $this->getOutput()->addHTML( '<p></p>' );
                }
        }

        /**
         * @param string $term
         */
        protected function setupPage( $term ) {
                $out = $this->getOutput();
                if ( strval( $term ) !== '' ) {
                        $out->setPageTitle( $this->msg( 'searchresults' ) );
                        $out->setHTMLTitle( $this->msg( 'pagetitle' )
                                ->rawParams( $this->msg( 'searchresults-title' )->rawParams( $term )->text() )
                                ->inContentLanguage()->text()
                        );
                }
                // add javascript specific to special:search
                $out->addModules( 'mediawiki.special.search' );
        }

        /**
         * Return true if current search is a power (advanced) search
         *
         * @return bool
         */
        protected function isPowerSearch() {
                return $this->profile === 'advanced';
        }

        /**
         * Extract "power search" namespace settings from the request object,
         * returning a list of index numbers to search.
         *
         * @param WebRequest $request
         * @return array
         */
        protected function powerSearch( &$request ) {
                $arr = [];
                foreach ( $this->searchConfig->searchableNamespaces() as $ns => $name ) {
                        if ( $request->getCheck( 'ns' . $ns ) ) {
                                $arr[] = $ns;
                        }
                }

                return $arr;
        }

        /**
         * Reconstruct the 'power search' options for links
         *
         * @return array
         */
        protected function powerSearchOptions() {
                $opt = [];
                if ( !$this->isPowerSearch() ) {
                        $opt['profile'] = $this->profile;
                } else {
                        foreach ( $this->namespaces as $n ) {
                                $opt['ns' . $n] = 1;
                        }
                }

                return $opt + $this->extraParams;
        }

        /**
         * Save namespace preferences when we're supposed to
         *
         * @return bool Whether we wrote something
         */
        protected function saveNamespaces() {
                $user = $this->getUser();
                $request = $this->getRequest();

                if ( $user->isLoggedIn() &&
                        $user->matchEditToken(
                                $request->getVal( 'nsRemember' ),
                                'searchnamespace',
                                $request
                        ) && !wfReadOnly()
                ) {
                        // Reset namespace preferences: namespaces are not searched
                        // when they're not mentioned in the URL parameters.
                        foreach ( MWNamespace::getValidNamespaces() as $n ) {
                                $user->setOption( '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 ) {
                                $user->setOption( 'searchNs' . $n, true );
                        }

                        DeferredUpdates::addCallableUpdate( function () use ( $user ) {
                                $user->saveSettings();
                        } );

                        return true;
                }

                return false;
        }

        /**
         * Show whole set of results
         *
         * @param SearchResultSet $matches
         * @param string $interwiki Interwiki name
         *
         * @return string
         */
        protected function showMatches( $matches, $interwiki = null ) {
                global $wgContLang;

                $terms = $wgContLang->convertForSearchResult( $matches->termMatches() );
                $out = '';
                $result = $matches->next();
                $pos = $this->offset;

                if ( $result && $interwiki ) {
                        $out .= $this->interwikiHeader( $interwiki, $matches );
                }

                $out .= "<ul class='mw-search-results'>\n";
                while ( $result ) {
                        $out .= $this->showHit( $result, $terms, $pos++ );
                        $result = $matches->next();
                }
                $out .= "</ul>\n";

                // convert the whole thing to desired language variant
                $out = $wgContLang->convert( $out );

                return $out;
        }

        /**
         * Format a single hit result
         *
         * @param SearchResult $result
         * @param array $terms Terms to highlight
         * @param int $position Position within the search results, including offset.
         *
         * @return string
         */
        protected function showHit( SearchResult $result, $terms, $position ) {

                if ( $result->isBrokenTitle() ) {
                        return '';
                }

                $title = $result->getTitle();

                $titleSnippet = $result->getTitleSnippet();

                if ( $titleSnippet == '' ) {
                        $titleSnippet = null;
                }

                $link_t = clone $title;
                $query = [];

                Hooks::run( 'ShowSearchHitTitle',
                        [ &$link_t, &$titleSnippet, $result, $terms, $this, &$query ] );

                $link = Linker::linkKnown(
                        $link_t,
                        $titleSnippet,
                        [ 'data-serp-pos' => $position ], // HTML attributes
                        $query
                );

                // If page content is not readable, just return the title.
                // This is not quite safe, but better than showing excerpts from non-readable pages
                // Note that hiding the entry entirely would screw up paging.
                if ( !$title->userCan( 'read', $this->getUser() ) ) {
                        return "<li>{$link}</li>\n";
                }

                // If the page doesn't *exist*... our search index is out of date.
                // The least confusing at this point is to drop the result.
                // You may get less results, but... oh well. :P
                if ( $result->isMissingRevision() ) {
                        return '';
                }

                // format redirects / relevant sections
                $redirectTitle = $result->getRedirectTitle();
                $redirectText = $result->getRedirectSnippet();
                $sectionTitle = $result->getSectionTitle();
                $sectionText = $result->getSectionSnippet();
                $categorySnippet = $result->getCategorySnippet();

                $redirect = '';
                if ( !is_null( $redirectTitle ) ) {
                        if ( $redirectText == '' ) {
                                $redirectText = null;
                        }

                        $redirect = "<span class='searchalttitle'>" .
                                $this->msg( 'search-redirect' )->rawParams(
                                        Linker::linkKnown( $redirectTitle, $redirectText ) )->text() .
                                "</span>";
                }

                $section = '';
                if ( !is_null( $sectionTitle ) ) {
                        if ( $sectionText == '' ) {
                                $sectionText = null;
                        }

                        $section = "<span class='searchalttitle'>" .
                                $this->msg( 'search-section' )->rawParams(
                                        Linker::linkKnown( $sectionTitle, $sectionText ) )->text() .
                                "</span>";
                }

                $category = '';
                if ( $categorySnippet ) {
                        $category = "<span class='searchalttitle'>" .
                                $this->msg( 'search-category' )->rawParams( $categorySnippet )->text() .
                                "</span>";
                }

                // format text extract
                $extract = "<div class='searchresult'>" . $result->getTextSnippet( $terms ) . "</div>";

                $lang = $this->getLanguage();

                // format description
                $byteSize = $result->getByteSize();
                $wordCount = $result->getWordCount();
                $timestamp = $result->getTimestamp();
                $size = $this->msg( 'search-result-size', $lang->formatSize( $byteSize ) )
                        ->numParams( $wordCount )->escaped();

                if ( $title->getNamespace() == NS_CATEGORY ) {
                        $cat = Category::newFromTitle( $title );
                        $size = $this->msg( 'search-result-category-size' )
                                ->numParams( $cat->getPageCount(), $cat->getSubcatCount(), $cat->getFileCount() )
                                ->escaped();
                }

                $date = $lang->userTimeAndDate( $timestamp, $this->getUser() );

                $fileMatch = '';
                // Include a thumbnail for media files...
                if ( $title->getNamespace() == NS_FILE ) {
                        $img = $result->getFile();
                        $img = $img ?: wfFindFile( $title );
                        if ( $result->isFileMatch() ) {
                                $fileMatch = "<span class='searchalttitle'>" .
                                        $this->msg( 'search-file-match' )->escaped() . "</span>";
                        }
                        if ( $img ) {
                                $thumb = $img->transform( [ 'width' => 120, 'height' => 120 ] );
                                if ( $thumb ) {
                                        $desc = $this->msg( 'parentheses' )->rawParams( $img->getShortDesc() )->escaped();
                                        // Float doesn't seem to interact well with the bullets.
                                        // Table messes up vertical alignment of the bullets.
                                        // Bullets are therefore disabled (didn't look great anyway).
                                        return "<li>" .
                                                '<table class="searchResultImage">' .
                                                '<tr>' .
                                                '<td style="width: 120px; text-align: center; vertical-align: top;">' .
                                                $thumb->toHtml( [ 'desc-link' => true ] ) .
                                                '</td>' .
                                                '<td style="vertical-align: top;">' .
                                                "{$link} {$redirect} {$category} {$section} {$fileMatch}" .
                                                $extract .
                                                "<div class='mw-search-result-data'>{$desc} - {$date}</div>" .
                                                '</td>' .
                                                '</tr>' .
                                                '</table>' .
                                                "</li>\n";
                                }
                        }
                }

                $html = null;

                $score = '';
                $related = '';
                if ( Hooks::run( 'ShowSearchHit', [
                        $this, $result, $terms,
                        &$link, &$redirect, &$section, &$extract,
                        &$score, &$size, &$date, &$related,
                        &$html
                ] ) ) {
                        $html = "<li><div class='mw-search-result-heading'>" .
                                "{$link} {$redirect} {$category} {$section} {$fileMatch}</div> {$extract}\n" .
                                "<div class='mw-search-result-data'>{$size} - {$date}</div>" .
                                "</li>\n";
                }

                return $html;
        }

        /**
         * Extract custom captions from search-interwiki-custom message
         */
        protected function getCustomCaptions() {
                if ( is_null( $this->customCaptions ) ) {
                        $this->customCaptions = [];
                        // format per line <iwprefix>:<caption>
                        $customLines = explode( "\n", $this->msg( 'search-interwiki-custom' )->text() );
                        foreach ( $customLines as $line ) {
                                $parts = explode( ":", $line, 2 );
                                if ( count( $parts ) == 2 ) { // validate line
                                        $this->customCaptions[$parts[0]] = $parts[1];
                                }
                        }
                }
        }

        /**
         * Show results from other wikis
         *
         * @param SearchResultSet|array $matches
         * @param string $query
         *
         * @return string
         */
        protected function showInterwiki( $matches, $query ) {
                global $wgContLang;

                $out = "<div id='mw-search-interwiki'><div id='mw-search-interwiki-caption'>" .
                        $this->msg( 'search-interwiki-caption' )->text() . "</div>\n";
                $out .= "<ul class='mw-search-iwresults'>\n";

                // work out custom project captions
                $this->getCustomCaptions();

                if ( !is_array( $matches ) ) {
                        $matches = [ $matches ];
                }

                foreach ( $matches as $set ) {
                        $prev = null;
                        $result = $set->next();
                        while ( $result ) {
                                $out .= $this->showInterwikiHit( $result, $prev, $query );
                                $prev = $result->getInterwikiPrefix();
                                $result = $set->next();
                        }
                }

                // @todo Should support paging in a non-confusing way (not sure how though, maybe via ajax)..
                $out .= "</ul></div>\n";

                // convert the whole thing to desired language variant
                $out = $wgContLang->convert( $out );

                return $out;
        }

        /**
         * Show single interwiki link
         *
         * @param SearchResult $result
         * @param string $lastInterwiki
         * @param string $query
         *
         * @return string
         */
        protected function showInterwikiHit( $result, $lastInterwiki, $query ) {

                if ( $result->isBrokenTitle() ) {
                        return '';
                }

                $title = $result->getTitle();

                $titleSnippet = $result->getTitleSnippet();

                if ( $titleSnippet == '' ) {
                        $titleSnippet = null;
                }

                $link = Linker::linkKnown(
                        $title,
                        $titleSnippet
                );

                // format redirect if any
                $redirectTitle = $result->getRedirectTitle();
                $redirectText = $result->getRedirectSnippet();
                $redirect = '';
                if ( !is_null( $redirectTitle ) ) {
                        if ( $redirectText == '' ) {
                                $redirectText = null;
                        }

                        $redirect = "<span class='searchalttitle'>" .
                                $this->msg( 'search-redirect' )->rawParams(
                                        Linker::linkKnown( $redirectTitle, $redirectText ) )->text() .
                                "</span>";
                }

                $out = "";
                // display project name
                if ( is_null( $lastInterwiki ) || $lastInterwiki != $title->getInterwiki() ) {
                        if ( array_key_exists( $title->getInterwiki(), $this->customCaptions ) ) {
                                // captions from 'search-interwiki-custom'
                                $caption = $this->customCaptions[$title->getInterwiki()];
                        } else {
                                // default is to show the hostname of the other wiki which might suck
                                // if there are many wikis on one hostname
                                $parsed = wfParseUrl( $title->getFullURL() );
                                $caption = $this->msg( 'search-interwiki-default', $parsed['host'] )->text();
                        }
                        // "more results" link (special page stuff could be localized, but we might not know target lang)
                        $searchTitle = Title::newFromText( $title->getInterwiki() . ":Special:Search" );
                        $searchLink = Linker::linkKnown(
                                $searchTitle,
                                $this->msg( 'search-interwiki-more' )->text(),
                                [],
                                [
                                        'search' => $query,
                                        'fulltext' => 'Search'
                                ]
                        );
                        $out .= "</ul><div class='mw-search-interwiki-project'><span class='mw-search-interwiki-more'>
                                {$searchLink}</span>{$caption}</div>\n<ul>";
                }

                $out .= "<li>{$link} {$redirect}</li>\n";

                return $out;
        }

        /**
         * Generates the power search box at [[Special:Search]]
         *
         * @param string $term Search term
         * @param array $opts
         * @return string HTML form
         */
        protected function powerSearchBox( $term, $opts ) {
                global $wgContLang;

                // Groups namespaces into rows according to subject
                $rows = [];
                foreach ( $this->searchConfig->searchableNamespaces() as $namespace => $name ) {
                        $subject = MWNamespace::getSubject( $namespace );
                        if ( !array_key_exists( $subject, $rows ) ) {
                                $rows[$subject] = "";
                        }

                        $name = $wgContLang->getConverter()->convertNamespace( $namespace );
                        if ( $name == '' ) {
                                $name = $this->msg( 'blanknamespace' )->text();
                        }

                        $rows[$subject] .=
                                Xml::openElement( 'td' ) .
                                Xml::checkLabel(
                                        $name,
                                        "ns{$namespace}",
                                        "mw-search-ns{$namespace}",
                                        in_array( $namespace, $this->namespaces )
                                ) .
                                Xml::closeElement( 'td' );
                }

                $rows = array_values( $rows );
                $numRows = count( $rows );

                // Lays out namespaces in multiple floating two-column tables so they'll
                // be arranged nicely while still accommodating different screen widths
                $namespaceTables = '';
                for ( $i = 0; $i < $numRows; $i += 4 ) {
                        $namespaceTables .= Xml::openElement( 'table' );

                        for ( $j = $i; $j < $i + 4 && $j < $numRows; $j++ ) {
                                $namespaceTables .= Xml::tags( 'tr', null, $rows[$j] );
                        }

                        $namespaceTables .= Xml::closeElement( 'table' );
                }

                $showSections = [ 'namespaceTables' => $namespaceTables ];

                Hooks::run( 'SpecialSearchPowerBox', [ &$showSections, $term, $opts ] );

                $hidden = '';
                foreach ( $opts as $key => $value ) {
                        $hidden .= Html::hidden( $key, $value );
                }

                # Stuff to feed saveNamespaces()
                $remember = '';
                $user = $this->getUser();
                if ( $user->isLoggedIn() ) {
                        $remember .= Xml::checkLabel(
                                $this->msg( 'powersearch-remember' )->text(),
                                'nsRemember',
                                'mw-search-powersearch-remember',
                                false,
                                // The token goes here rather than in a hidden field so it
                                // is only sent when necessary (not every form submission).
                                [ 'value' => $user->getEditToken(
                                        'searchnamespace',
                                        $this->getRequest()
                                ) ]
                        );
                }

                // Return final output
                return Xml::openElement( 'fieldset', [ 'id' => 'mw-searchoptions' ] ) .
                        Xml::element( 'legend', null, $this->msg( 'powersearch-legend' )->text() ) .
                        Xml::tags( 'h4', null, $this->msg( 'powersearch-ns' )->parse() ) .
                        Xml::element( 'div', [ 'id' => 'mw-search-togglebox' ], '', false ) .
                        Xml::element( 'div', [ 'class' => 'divider' ], '', false ) .
                        implode( Xml::element( 'div', [ 'class' => 'divider' ], '', false ), $showSections ) .
                        $hidden .
                        Xml::element( 'div', [ 'class' => 'divider' ], '', false ) .
                        $remember .
                        Xml::closeElement( 'fieldset' );
        }

        /**
         * @return array
         */
        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,
                        ]
                ];

                Hooks::run( 'SpecialSearchProfiles', [ &$profiles ] );

                foreach ( $profiles as &$data ) {
                        if ( !is_array( $data['namespaces'] ) ) {
                                continue;
                        }
                        sort( $data['namespaces'] );
                }

                return $profiles;
        }

        /**
         * @param string $term
         * @return string
         */
        protected function searchProfileTabs( $term ) {
                $out = Html::element( 'div', [ 'class' => 'mw-search-visualclear' ] ) .
                        Xml::openElement( 'div', [ 'class' => 'mw-search-profile-tabs' ] );

                $bareterm = $term;
                if ( $this->startsWithImage( $term ) ) {
                        // Deletes prefixes
                        $bareterm = substr( $term, strpos( $term, ':' ) + 1 );
                }

                $profiles = $this->getSearchProfiles();
                $lang = $this->getLanguage();

                // Outputs XML for Search Types
                $out .= Xml::openElement( 'div', [ 'class' => 'search-types' ] );
                $out .= Xml::openElement( 'ul' );
                foreach ( $profiles as $id => $profile ) {
                        if ( !isset( $profile['parameters'] ) ) {
                                $profile['parameters'] = [];
                        }
                        $profile['parameters']['profile'] = $id;

                        $tooltipParam = isset( $profile['namespace-messages'] ) ?
                                $lang->commaList( $profile['namespace-messages'] ) : null;
                        $out .= Xml::tags(
                                'li',
                                [
                                        'class' => $this->profile === $id ? 'current' : 'normal'
                                ],
                                $this->makeSearchLink(
                                        $bareterm,
                                        [],
                                        $this->msg( $profile['message'] )->text(),
                                        $this->msg( $profile['tooltip'], $tooltipParam )->text(),
                                        $profile['parameters']
                                )
                        );
                }
                $out .= Xml::closeElement( 'ul' );
                $out .= Xml::closeElement( 'div' );
                $out .= Xml::element( 'div', [ 'style' => 'clear:both' ], '', false );
                $out .= Xml::closeElement( 'div' );

                return $out;
        }

        /**
         * @param string $term Search term
         * @return string
         */
        protected function searchOptions( $term ) {
                $out = '';
                $opts = [];
                $opts['profile'] = $this->profile;

                if ( $this->isPowerSearch() ) {
                        $out .= $this->powerSearchBox( $term, $opts );
                } else {
                        $form = '';
                        Hooks::run( 'SpecialSearchProfileForm', [ $this, &$form, $this->profile, $term, $opts ] );
                        $out .= $form;
                }

                return $out;
        }

        /**
         * @param string $term
         * @param int $resultsShown
         * @param int $totalNum
         * @return string
         */
        protected function shortDialog( $term, $resultsShown, $totalNum ) {
                $searchWidget = new MediaWiki\Widget\SearchInputWidget( [
                        'id' => 'searchText',
                        'name' => 'search',
                        'autofocus' => trim( $term ) === '',
                        'value' => $term,
                        'dataLocation' => 'content',
                        'infusable' => true,
                ] );

                $layout = new OOUI\ActionFieldLayout( $searchWidget, new OOUI\ButtonInputWidget( [
                        'type' => 'submit',
                        'label' => $this->msg( 'searchbutton' )->text(),
                        'flags' => [ 'progressive', 'primary' ],
                ] ), [
                        'align' => 'top',
                ] );

                $out =
                        Html::hidden( 'title', $this->getPageTitle()->getPrefixedText() ) .
                        Html::hidden( 'profile', $this->profile ) .
                        Html::hidden( 'fulltext', 'Search' ) .
                        $layout;

                // Results-info
                if ( $totalNum > 0 && $this->offset < $totalNum ) {
                        $top = $this->msg( 'search-showingresults' )
                                ->numParams( $this->offset + 1, $this->offset + $resultsShown, $totalNum )
                                ->numParams( $resultsShown )
                                ->parse();
                        $out .= Xml::tags( 'div', [ 'class' => 'results-info' ], $top );
                }

                return $out;
        }

        /**
         * Make a search link with some target namespaces
         *
         * @param string $term
         * @param array $namespaces Ignored
         * @param string $label Link's text
         * @param string $tooltip Link's tooltip
         * @param array $params Query string parameters
         * @return string HTML fragment
         */
        protected function makeSearchLink( $term, $namespaces, $label, $tooltip, $params = [] ) {
                $opt = $params;
                foreach ( $namespaces as $n ) {
                        $opt['ns' . $n] = 1;
                }

                $stParams = array_merge(
                        [
                                'search' => $term,
                                'fulltext' => $this->msg( 'search' )->text()
                        ],
                        $opt
                );

                return Xml::element(
                        'a',
                        [
                                'href' => $this->getPageTitle()->getLocalURL( $stParams ),
                                'title' => $tooltip
                        ],
                        $label
                );
        }

        /**
         * Check if query starts with image: prefix
         *
         * @param string $term The string to check
         * @return bool
         */
        protected function startsWithImage( $term ) {
                global $wgContLang;

                $parts = explode( ':', $term );
                if ( count( $parts ) > 1 ) {
                        return $wgContLang->getNsIndex( $parts[0] ) == NS_FILE;
                }

                return false;
        }

        /**
         * Check if query starts with all: prefix
         *
         * @param string $term The string to check
         * @return bool
         */
        protected function startsWithAll( $term ) {

                $allkeyword = $this->msg( 'searchall' )->inContentLanguage()->text();

                $parts = explode( ':', $term );
                if ( count( $parts ) > 1 ) {
                        return $parts[0] == $allkeyword;
                }

                return false;
        }

        /**
         * @since 1.18
         *
         * @return SearchEngine
         */
        public function getSearchEngine() {
                if ( $this->searchEngine === null ) {
                        $this->searchEngine = $this->searchEngineType ?
                                MediaWikiServices::getInstance()->getSearchEngineFactory()->create( $this->searchEngineType ) :
                                MediaWikiServices::getInstance()->newSearchEngine();
                }

                return $this->searchEngine;
        }

        /**
         * Current search profile.
         * @return null|string
         */
        function getProfile() {
                return $this->profile;
        }

        /**
         * Current namespaces.
         * @return array
         */
        function getNamespaces() {
                return $this->namespaces;
        }

        /**
         * Users of hook SpecialSearchSetupEngine can use this to
         * add more params to links to not lose selection when
         * user navigates search results.
         * @since 1.18
         *
         * @param string $key
         * @param mixed $value
         */
        public function setExtraParam( $key, $value ) {
                $this->extraParams[$key] = $value;
        }

        protected function getGroupName() {
                return 'pages';
        }
}