MDNodaHelpers/src/NodaWikidataFetcher.php

<?PHP
/**
 * This file contains tools for fetching data from Wikidata.
 *
 * @file
 * @author Joshua Ramon Enslin <joshua@museum-digital.de>
 */
declare(strict_types = 1);

/**
 * Helps fetching information from Wikidata.
 */
final class NodaWikidataFetcher {

    const LANGUAGES_MAIN_DESC = ['de', 'da', 'en', 'es', 'fr', 'hu', 'it', 'jp', 'nl', 'pt', 'ru', 'sv', 'zh'];
    const LANGUAGES_TO_CHECK = ['ar', 'bn', 'cs', 'da', 'de', 'el', 'en', 'es', 'fa', 'fi', 'fr', 'ha', 'he', 'hi', 'hu', 'id', 'it', 'ja', 'ka', 'ko', 'nl', 'pl', 'pt', 'ro', 'ru', 'sv', 'sw', 'ta', 'th', 'tl', 'tr', 'ur', 'vi', 'zh'];

    const LANGUAGES_TO_CAPITALIZE = ["cs", "da", "de", "en", "es", "fr", "fi", "id", "it", "nl", "pl", "pt", "ru", "sv", "tl", "tr"];

    const URL_PREFIXES_PLACES_NODA_SOURCE = [
        "gnd" => "https://d-nb.info/gnd/",
        "nomisma" => "http://nomisma.org/id/",
        "osm" => "https://www.openstreetmap.org/relation/",
        "loc" => "http://id.loc.gov/authorities/names/",
        "cona" => "http://vocab.getty.edu/page/cona/",
        "aat" => "http://vocab.getty.edu/page/aat/",
        "iconclass" => "http://iconclass.org/rkd/",
        "lcsh"      => "http://id.loc.gov/authorities/subjects/",
        "wikidata"  => "https://www.wikidata.org/wiki/",
        "bne" => "http://datos.bne.es/persona/",
        "viaf" => "https://viaf.org/viaf/",
        "bnf" => "https://catalogue.bnf.fr/ark:/12148/cb",
        "ulan" => "http://vocab.getty.edu/page/ulan/",
        "rkd" => "https://rkd.nl/explore/artists/",
        "pim"  => "https://opac-nevter.pim.hu/en/record/-/record/",
        "ndl" => "https://id.ndl.go.jp/auth/ndlna/",
        "npg" => "https://www.npg.org.uk/collections/search/person/",
        "orcid" => "https://orcid.org/",
    ];

    const P_IDS_NODA_TAGS = [
        'gnd' => 'P227',
        'lcsh' => 'P244',
        'aat' => 'P1014',
        'iconclass' => 'P1256',
        'osm' => 'P402',
        'loc' => 'P244',
        'nomisma' => 'P2950',
        'cona' => 'P1669',

        "rkd"  => "P650",
        "ulan" => "P245",
        "viaf" => "P214",
        "bnf"  => "P268",
        "pim"  => "P3973",
        "ndl"  => "P349",    // National Diet Library (Japan)
        "npg"  => "P1816",   // "National" portrait gallery
        //"bmpi" => "P6077",   // British Museum Person-Institution
        "bne"  => "P950",  // Espana National Library
        "orcid" => "P496",
    ];

    const WIKIPEDIA_REMOVE_LITERALS = [
        "<p>Si vous disposez d'ouvrages ou d'articles de référence ou si vous ",
        '<p><b>En pratique&#160;:</b> <a href="/wiki/Wikip%C3%A9dia:Citez_vos_sources#Qualité_des_sources" title="Wikipédia:Citez vos sources">Quelles sources sont attendu',
        '<pVous pouvez partager vos connaissances en l’améliorant (',
        '<p class="mw-empty-elt">',
        '<p><small>Géolocalisation sur la carte',
        '<p><b>Koordinaatit:</b>',
        '<p><span class="executeJS" data-gadgetname="ImgToggle"></span',
        '<p><span class="imgtoggleboxTitle">',
        //'<div class="mw-parser-output"><p>',
        '<p><span style="font-size: small;"><span id="coordinates">',
        '<p><span></span></p>',
        '<p><a rel="nofollow" class="external text" href="https://maps.gs',
        '<p><span class="plainlinks nourlexpansion"><a class="external text" href="//tools.wmflabs.org/geohack/geohack.php?langu',
        '<p><span style="display:none">',
        '<p>&#32;</p>',
        '<p><span class="geo noexcerpt"',
    ];

    /** @var MDMysqli */
    private MDMysqli $_mysqli_noda;

    /**
     * Attempts to fetch a Wikidata ID from a provided URL.
     *
     * @param string $linkUrl Link to a Wikipedia page.
     *
     * @return string
     */
    public static function getWikidataIdFromWikipedia(string $linkUrl):string {

        if (!filter_var($linkUrl, FILTER_VALIDATE_URL)) {
            throw new MDExpectedException("Invalid URL");
        }

        $wikipedia_cont = MD_STD::runCurl($linkUrl);

        $doc = new DOMDocument();
        if (!($doc->loadHTML($wikipedia_cont))) {
            return '';
        }

        if (!($wikidataLinkLi = $doc->getElementById("t-wikibase"))) {
            return '';
        }
        if (!($wikidataLink = $wikidataLinkLi->firstChild)) {
            return '';
        }

        if (!($t_wikibase_href = $wikidataLink->getAttribute('href'))) {
            return '';
        }
        $t_wikibase = (string)$t_wikibase_href;

        if (!empty($t_wikibase)) {
            if (($wikidata_id_end = strrpos($t_wikibase, '/')) !== false) {
                $wikidata_id = trim(substr($t_wikibase, $wikidata_id_end + 1), '/');

                if (substr($wikidata_id, 0, 1) === 'Q') {
                    return $wikidata_id;
                }
            }
        }

        return '';

    }

    /**
     * Gets translation source Wikipedia pages from Wikidata.
     *
     * @param array<string> $checkagainstLanguage The language to check against.
     * @param array<mixed>  $data                 Data fetched from Wikidata.
     *
     * @return array<array<string>>
     */
    public static function getWikidataWikipediaTranslationSources(array $checkagainstLanguage, array $data) {

        $languagesToFetch = $wikilinks = [];
        foreach ($checkagainstLanguage as $lang) {

            if (empty($data['labels'][$lang])) {
                continue;
            }

            if (!empty($data['sitelinks'][$lang . 'wiki'])) {

                $wikilink = $data['sitelinks'][$lang . 'wiki']['url'];
                $wikilinkterm = str_replace(' ', '_', $data['sitelinks'][$lang . 'wiki']['title']);

                if (isset($wikilink)) {

                    $languagesToFetch[$lang] = "https://" . $lang . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode($wikilinkterm) . "&prop=text&section=0&format=json";
                    $wikilinks[$lang] = $wikilink;

                }
            }
        }

        return [$languagesToFetch, $wikilinks];

    }

    /**
     * Cleans contents parsed from Wikipedia.
     *
     * @param string $input Input string.
     *
     * @return string
     */
    private static function _cleanWikidataInput(string $input):string {

        if (substr($input, 0, strlen('<')) === '<') {
            $doc = new DOMDocument();
            $doc->loadXML($input);

            $list = $doc->getElementsByTagName("style");
            while ($list->length > 0) {
                $p = $list->item(0);
                $p->parentNode->removeChild($p);
            }

            $list = $doc->getElementsByTagName("table");
            while ($list->length > 0) {
                $p = $list->item(0);
                $p->parentNode->removeChild($p);
            }

            $list = $doc->getElementsByTagName("div");
            while ($list->length > 1) {
                $p = $list->item(1);
                $p->parentNode->removeChild($p);
            }

            $list = $doc->getElementsByTagName("ol");
            while ($list->length > 0) {
                $p = $list->item(0);
                $p->parentNode->removeChild($p);
            }

            $firstP = $doc->getElementsByTagName("p")->item(0);
            if (strpos($doc->saveHTML($firstP), 'geohack') !== false) {
                $firstP->parentNode->removeChild($firstP);
            }

            /*
            if (strpos($doc->saveHTML(), 'Coordinates:') !== false) {
                echo $doc->saveHTML();
                exit;
            }
             */

            $input = str_replace(PHP_EOL, PHP_EOL . PHP_EOL, trim($doc->textContent));

            if (mb_strlen($input) > 600) {
                if (strpos($input, PHP_EOL . PHP_EOL, 600) !== false) {
                    $input = substr($input, 0, strpos($input, PHP_EOL . PHP_EOL, 600));
                }
            }

            $bracketsToRemove = [];
            for ($i = 0; $i < 100; $i++) {
                $bracketsToRemove["[$i]"] = "";
            }
            $input = strtr($input, $bracketsToRemove);

            $input = str_replace("\t", " ", $input);

            // Remove newlines with ensuing spaces
            while (strpos($input, PHP_EOL . " ") !== false) {
                $input = str_replace(PHP_EOL . " ", PHP_EOL, $input);
            }

            // Remove double newlines
            while (strpos($input, PHP_EOL . PHP_EOL . PHP_EOL) !== false) {
                $input = str_replace(PHP_EOL . PHP_EOL . PHP_EOL, PHP_EOL . PHP_EOL, $input);
            }
            return $input;

        }

        $input = str_replace(PHP_EOL, '', $input);

        foreach (self::WIKIPEDIA_REMOVE_LITERALS as $tToRemove) $input = str_replace($tToRemove, "", $input);

        $first_mention_of_paragraph = strpos($input, '<p>');
        if ($first_mention_of_paragraph !== false) $input = substr($input, $first_mention_of_paragraph, (strrpos($input, '</p>') ?: strlen($input)) - $first_mention_of_paragraph);

        // Remove infobox tables specifically
        $removeFirstParagraph = false;
        $firstParagraphPosition = strpos($input, '<p', 1);
        $currentSearchPos = strpos($input, "<table>");
        if ($currentSearchPos !== false && $currentSearchPos < $firstParagraphPosition) {
            if (($tableEndPos = strpos($input, "</table>")) !== false) {
                if (($pStartPos = strpos($input, '<p', $tableEndPos + 6)) !== false) {
                    $input = substr($input, $pStartPos);
                }
            }
        }

        // Remove leftover unnecessary paragraphs before actual content

        $removeFirstParagraph = false;
        $firstParagraphPosition = strpos($input, '<p', 1);

        foreach (["</table>", "<img"] as $tagPart) {
            $currentSearchPos = strpos($input, $tagPart);
            if ($currentSearchPos !== false && $currentSearchPos < $firstParagraphPosition) {
                $removeFirstParagraph = true;
                break;
            }
        }

        if ($removeFirstParagraph === true) {
            $input = substr($input, $firstParagraphPosition ?: 0);
        }

        $input = str_replace('</p>', '</p>' . PHP_EOL . PHP_EOL . PHP_EOL, $input);
        # $input = str_replace('?/i', '', $input);
        $input = strip_tags($input);

        # for ($i = 150; $i < 1000; $i++) $input = str_replace("&#$i;", " ", $input);
        $i = 0;
        while (strpos($input, ".mw-parser-output") !== false and strpos($input, "}", strpos($input, ".mw-parser-output")) !== false) {
            $part1 = substr($input, 0, strpos($input, ".mw-parser-output"));
            $part2 = substr($input, strpos($input, "}", strpos($input, ".mw-parser-output")) + 1);
            $input = $part1 . $part2;
            ++$i;
            if ($i === 30) break;
        }

        $bracketsToRemove = [];
        for ($i = 0; $i < 100; $i++) {
            $bracketsToRemove["[$i]"] = "";
        }
        $input = strtr($input, $bracketsToRemove);

        $input = str_replace("\t", " ", $input);

        // Remove double whitespaces
        while (strpos($input, "  ") !== false) {
            $input = str_replace("  ", " ", $input);
        }

        // Remove newlines with ensuing spaces
        while (strpos($input, PHP_EOL . " ") !== false) {
            $input = str_replace(PHP_EOL . " ", PHP_EOL, $input);
        }

        // Remove double newlines
        while (strpos($input, PHP_EOL . PHP_EOL . PHP_EOL) !== false) {
            $input = str_replace(PHP_EOL . PHP_EOL . PHP_EOL, PHP_EOL . PHP_EOL, $input);
        }

        $stableToRemove = [
            "Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants.",
        ];
        foreach ($stableToRemove as $tToRemove) $input = str_replace($tToRemove, "", $input);

        $endings = [
            "StubDenne artikel om et vandløb ",
        ];
        foreach ($endings as $ending) {
            if (strpos($input, $ending) !== false) $input = substr($input, 0, strpos($input, $ending));
        }

        $input = trim($input);

        // Cut off overly long articles
        if (mb_strlen($input) > 600) {
            if (strpos($input, PHP_EOL . PHP_EOL, 600) !== false) {
                $input = substr($input, 0, strpos($input, PHP_EOL . PHP_EOL, 600));
            }
        }

        // Trim again to make really, really no superfluous whitespaces remain
        $input = trim($input);

        $input = str_replace("'", "´", MD_STD::preg_replace_str("/\&\#91\;[0-9]\&\#93\;/", '', $input));

        $input = html_entity_decode($input);

        return $input;

    }

    /**
     * Function for fetching description from Wikipedia
     *
     * @param integer $persinst_id  Person ID.
     * @param string  $wikidata_id  Wikidata ID.
     * @param string  $datafromwiki Data fetched from Wikipedia.
     * @param string  $wikilink     Link to wikipedia entry.
     * @param string  $preflang     The user's currently used language.
     * @param string  $lang         Currently queried language.
     * @param string  $erfasst_von  User who adds the info.
     *
     * @return boolean
     */
    public function retrievePersinstDescFromWikipedia(int $persinst_id, string $wikidata_id, string $datafromwiki, string $wikilink, string $preflang, string $lang, string $erfasst_von):bool {

        $output = false;

        $datafromwiki = '"' . $datafromwiki . '" - (Wikipedia (' . $lang . ') ' . date('d.m.Y') . ')';

        $cergebnis = $this->_mysqli_noda->query_by_stmt("SELECT `persinst_kurzinfo`, `persinst_anzeigename` AS `display_name`
            FROM `persinst`
            WHERE `persinst_id` = ?", "i", $persinst_id);

        // Update persinst table
        $updatePersinstStmt = $this->_mysqli_noda->do_prepare("UPDATE `persinst`
            SET `persinst_kurzinfo` = ?
            WHERE `persinst_id` = ?");

        if ($cergebnis->num_rows === 0) exit;

        $cinfo = $cergebnis->fetch_assoc();
        if (!empty($cinfo['persinst_kurzinfo']) and substr($cinfo['persinst_kurzinfo'], 0, 3) != 'GND') {

            if (isset($_GET['keep'])) {
                if (!($_GET['keep']) || $_GET['keep'] === 'replace') {

                    $updatePersinstStmt->bind_param("si", $datafromwiki, $persinst_id);
                    $updatePersinstStmt->execute();

                }
                else if ($_GET['keep'] === 'add') {

                    $newDesc = $cinfo['persinst_kurzinfo'] . PHP_EOL . PHP_EOL . $datafromwiki;

                    $updatePersinstStmt->bind_param("si", $newDesc, $persinst_id);
                    $updatePersinstStmt->execute();

                }

                $output = true;
            }
            else {

                $tlLoader = new MDTlLoader("wiki_getter_persinst", $preflang);
                echo self::generateHTMLHeadForWikidataFetcher($lang);
                echo self::generateWikidataFetcherHeader($tlLoader, "", $cinfo['display_name']);
                echo '
        <p class="alert icons iconsAlert">Es gibt schon einen Eintrag im Beschreibungsfeld</p>
        <div class="wikiReplaceTTile">
            <h3>Bisher vorhanden</h3>
            <p>' . nl2br($cinfo['persinst_kurzinfo']) . '</p>
        </div>
        <div class="wikiReplaceTTile">
            <h3>Jetzt gefunden</h3><p>' . $datafromwiki . '</p>
        </div>
            <a href="get_wikidata_for_persinst.php?wikidata_id=' . $wikidata_id . write_get_vars(['suchbegriff', 'lang', 'persinst_id']) . '&keep=keep" class="buttonLike icons iconsPin">Keep old entry</a>';
                echo '<br><a href="get_wikidata_for_persinst.php?wikidata_id=' . $wikidata_id . write_get_vars(['suchbegriff', 'lang', 'persinst_id']) . '&keep=replace" class="buttonLike icons iconsPinOff">Replace with new entry</a>';
                echo '<br><a href="get_wikidata_for_persinst.php?wikidata_id=' . $wikidata_id . write_get_vars(['suchbegriff', 'lang', 'persinst_id']) . '&keep=add" class="buttonLike icons iconsPlusOne">Keep old and add new entry</a><br><br><br>';

                 exit;

            }

        }
        else {

            $updatePersinstStmt->bind_param("si", $datafromwiki, $persinst_id);
            $updatePersinstStmt->execute();

            $output = true;

        }

        $cergebnis->close();
        $updatePersinstStmt->close();

        // Set link to Wikipedia in noda table

        $insertNodaStmt = $this->_mysqli_noda->do_prepare("INSERT INTO `noda`
            (`persinst_id`, `noda_source`, `noda_nrinsource`, `noda_link`, `noda_erfasst_von`)
            VALUES
            (?, 'Wikipedia', '', ?, ?)
            ON DUPLICATE KEY UPDATE `noda_link` = ?");
        $insertNodaStmt->bind_param("isss", $persinst_id, $wikilink, $erfasst_von, $wikilink);
        $insertNodaStmt->execute();
        $insertNodaStmt->close();

        // Update edit metadata
        $updatePersinstEditInfoStmt = $this->_mysqli_noda->do_prepare("UPDATE `persinst`
            SET `persinst_erfasst_am` = NOW(),
                `persinst_erfasst_von` = ?
            WHERE `persinst_id` = ?");
        $updatePersinstEditInfoStmt->bind_param("si", $erfasst_von, $persinst_id);
        $updatePersinstEditInfoStmt->execute();
        $updatePersinstEditInfoStmt->close();
        $updatePersinstEditInfoStmt = null;

        return $output;

    }

    /**
     * Function for updating birth and death times based on Wikidata information.
     *
     * @param array<mixed> $data        Data loaded from Wikidata.
     * @param integer      $persinst_id Actor ID.
     *
     * @return void
     */
    public function enterPersinstBirthDeathDatesFromWikidata(array $data, int $persinst_id):void {

        $result = $this->_mysqli_noda->query_by_stmt("SELECT `persinst_geburtsjahr`,
                `persinst_sterbejahr`, `persinst_gender`
            FROM `persinst`
            WHERE `persinst_id` = ?", "i", $persinst_id);
        if (!($actor_dates = $result->fetch_assoc())) {
            throw new MDmainEntityNotExistentException("Failed to fetch actor information");
        }
        $result->close();
        $result = null;

        if ($actor_dates['persinst_geburtsjahr'] === '') {

            // Try to get birth date
            if (!empty($data['claims']['P569']) and !empty($data['claims']['P569']['0']['mainsnak']['datavalue']['value']['time'])) {
                $birth_date_int = strtotime(substr($data['claims']['P569']['0']['mainsnak']['datavalue']['value']['time'], 1, 4));
                if ($birth_date_int) {
                    $birth_date = date("Y", $birth_date_int);
                    if ($birth_date === date("Y")) {
                        $birth_date = date("Y", strtotime($data['claims']['P569']['0']['mainsnak']['datavalue']['value']['time']));
                    }
                }
            }

            if (!empty($birth_date)) {
                $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `persinst`
                    SET `persinst_geburtsjahr` = ?
                    WHERE `persinst_id` = ?
                    LIMIT 1");
                $updateStmt->bind_param("ii", $birth_date, $persinst_id);
                $updateStmt->execute();
                $updateStmt->close();
                $updateStmt = null;
            }

        }

        if ($actor_dates['persinst_sterbejahr'] === '') {

            // Try to get birth date
            if (!empty($data['claims']['P570']) and !empty($data['claims']['P570']['0']['mainsnak']['datavalue']['value']['time'])) {
                $death_date_int = strtotime(substr($data['claims']['P570']['0']['mainsnak']['datavalue']['value']['time'], 1, 4));
                if ($death_date_int) {
                    $death_date = date("Y", $death_date_int);
                    if ($death_date === date("Y")) {
                        $death_date = date("Y", strtotime($data['claims']['P570']['0']['mainsnak']['datavalue']['value']['time']));
                    }
                }
            }

            if (!empty($death_date)) {
                $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `persinst`
                    SET `persinst_sterbejahr` = ?
                    WHERE `persinst_id` = ?
                    LIMIT 1");
                $updateStmt->bind_param("ii", $death_date, $persinst_id);
                $updateStmt->execute();
                $updateStmt->close();
                $updateStmt = null;
            }

        }

        if ($actor_dates['persinst_gender'] === '') {

            // Try to get birth date
            if (!empty($data['claims']['P21']) and !empty($data['claims']['P21']['0']['mainsnak']['datavalue']['value']['id'])) {
                $wikidata_gender_id = $data['claims']['P21']['0']['mainsnak']['datavalue']['value']['id'];

                switch ($wikidata_gender_id) {
                case "Q6581097":
                    $wikidata_gender = "male";
                    break;
                case "Q6581072":
                case "Q1052281":
                    $wikidata_gender = "female";
                    break;
                case "Q48270":
                    $wikidata_gender = "other";
                    break;
                default:
                    throw new Exception("Unknown gender: Q-ID is " . $wikidata_gender_id);
                }
            }

            if (!empty($wikidata_gender)) {
                $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `persinst`
                    SET `persinst_gender` = ?
                    WHERE `persinst_id` = ?
                    LIMIT 1");
                $updateStmt->bind_param("si", $wikidata_gender, $persinst_id);
                $updateStmt->execute();
                $updateStmt->close();
                $updateStmt = null;
            }

        }

    }

    /**
     * Function for retrieving information.
     *
     * @param string  $lang        The user's selected used language.
     * @param string  $wikidata_id Wikidata ID.
     * @param integer $persinst_id Actor ID.
     * @param string  $erfasst_von User name who's currently editing.
     *
     * @return void
     */
    public function retrievePersinstInfoFromWikidataID(string $lang, string $wikidata_id, int $persinst_id, string $erfasst_von) {

        $data = json_decode(MD_STD::runCurl("https://www.wikidata.org/wiki/Special:EntityData/" . $wikidata_id . ".json", 10000), true);
        if ($data === null) {
            throw new MDhttpFailedException("Failed fetching from Wikidata. Try again later.");
        }
        $data = $data['entities'][$wikidata_id];

        // Get links to wikipedia
        $wikilink = $wikilinkterm = [];

        foreach (self::LANGUAGES_MAIN_DESC as $tLang) {
            if (isset($data['sitelinks'][$tLang . 'wiki']['url']))   $wikilink[$tLang] = $data['sitelinks'][$tLang . 'wiki']['url'];
            if (isset($data['sitelinks'][$tLang . 'wiki']['title'])) $wikilinkterm[$tLang] = str_replace(' ', '_', $data['sitelinks'][$tLang . 'wiki']['title']);
        }

        $alreadyEntered = false;

        if (isset($wikilink[$lang]) and isset($wikilinkterm[$lang]) and is_string($wikilinkterm[$lang])) {

            $datafromwiki = MD_STD::runCurl("https://" . $lang . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode($wikilinkterm[$lang]) . "&prop=text&section=0&format=json", 10000);
            $datafromwiki = json_decode($datafromwiki, true)['parse']['text']['*'];

            # Process data retrieved from wikipedia
            if (!empty($datafromwiki = self::_cleanWikidataInput((string)$datafromwiki))) {
                $alreadyEntered = $this->retrievePersinstDescFromWikipedia($persinst_id, $wikidata_id, $datafromwiki, $wikilink[$lang], $lang, $lang, $erfasst_von);
            }

        }

        foreach (self::LANGUAGES_MAIN_DESC as $sprache) {

            if ($alreadyEntered === true) break;
            if (!isset($wikilink[$sprache]) || !isset($wikilinkterm[$sprache]) || !is_string($wikilinkterm[$sprache])) continue;

            $datafromwiki = MD_STD::runCurl("https://" . $sprache . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode((string)$wikilinkterm[$sprache]) . "&prop=text&section=0&format=json", 10000);
            $datafromwiki = json_decode($datafromwiki, true)['parse']['text']['*'];

            # Process data retrieved from wikipedia
            if ($datafromwiki = self::_cleanWikidataInput((string)$datafromwiki)) {
                $alreadyEntered = $this->retrievePersinstDescFromWikipedia($persinst_id, $wikidata_id, $datafromwiki, $wikilink[$sprache], $lang, "$sprache", $erfasst_von);
            }

        }

        $this->enterPersinstBirthDeathDatesFromWikidata($data, $persinst_id);

        // Get links to other norm data sources

        $nodaLinks = [
            "wikidata" => $wikidata_id,
        ];
        foreach (self::P_IDS_NODA_TAGS as $vocabName => $pId) {
            if ($vocabName === 'lcsh') continue;
            if (isset($data['claims'][$pId])) $nodaLinks[$vocabName] = $data['claims'][$pId][0]['mainsnak']['datavalue']['value'];
        }

        // GET links to other noda entries.

        $insertNodaLinkStmt = $this->_mysqli_noda->do_prepare("INSERT INTO `noda`
            (`persinst_id`, `noda_source`, `noda_nrinsource`, `noda_link`, `noda_erfasst_von`)
            VALUES
            (?, ?, ?, ?, ?)
            ON DUPLICATE KEY UPDATE `noda_nrinsource` = ?,
                    `noda_link` = ?,
                    `noda_erfasst_von` = ?");

        $this->_mysqli_noda->autocommit(false);

        foreach ($nodaLinks as $noda_source => $nodaId) {

            if (!isset(self::URL_PREFIXES_PLACES_NODA_SOURCE[$noda_source])) {
                throw new Exception("Unknown noda link: " . $noda_source);
            }
            $noda_link_url = self::URL_PREFIXES_PLACES_NODA_SOURCE[$noda_source] . $nodaId;

            $insertNodaLinkStmt->bind_param("isssssss", $persinst_id, $noda_source, $nodaId, $noda_link_url, $erfasst_von, $nodaId, $noda_link_url, $noda_link_url);
            $insertNodaLinkStmt->execute();
        }

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

        $insertNodaLinkStmt->close();

        $this->getWikidataTranslationsForPersinst($data, $persinst_id);

    }

    /**
     * Function for fetching translations from Wikipedia, based on Wikidata information.
     *
     * @param array<mixed> $data        Entity fetched from wikidata.
     * @param integer      $persinst_id Actor ID.
     *
     * @return void
     */
    public function getWikidataTranslationsForPersinst(array $data, int $persinst_id) {

        $checkagainstLanguage = self::LANGUAGES_TO_CHECK;

        $insertStmt = $this->_mysqli_noda->do_prepare("CALL nodaInsertPersinstTranslation(?, ?, ?, ?, ?)");

        list($languagesToFetch, $wikilinks) = self::getWikidataWikipediaTranslationSources($checkagainstLanguage, $data);

        try {
            $contents = MD_STD::runCurlMulti($languagesToFetch, 10000);
        }
        catch (TypeError $e) {
            throw new MDExpectedException("Failed to initialize a request. Try pressing F5 to run the requests again.");
        }

        $this->_mysqli_noda->autocommit(false);

        foreach ($checkagainstLanguage as $lang) {

            if (!empty($languagesToFetch[$lang]) && !empty($data['sitelinks'][$lang . 'wiki'])) {

                $url = $languagesToFetch[$lang];

                $wikilink = $wikilinks[$lang];
                if (!empty($contents[$lang])) {

                    $descFromWiki = $contents[$lang];
                    $descFromWiki = json_decode($descFromWiki, true)['parse']['text']['*'];

                    # Process data retrieved from wikipedia

                    if ($descFromWiki !== null) $tDescription = self::_cleanWikidataInput((string)$descFromWiki);
                    else $tDescription = "";

                    if (substr($tDescription, -1) == chr(10)) $tDescription = substr($tDescription, 0, strlen($tDescription) - 1);

                    $tDescription = '"' . $tDescription . '" - (' . $data['labels'][$lang]['language'] . '.wikipedia.org ' . date('d.m.Y') . ')';
                    // Inhalt erster Absatz jeweilige Wikipedia: ' . $tDescription
                    // dies enthält den ersten Absatz der jeweiligen Wikipedia

                }
                else {
                    $tDescription = "";
                }

                $tLang = self::_cleanWikidataInput((string)$data['labels'][$lang]['language']);
                $tLabel = self::_cleanWikidataInput((string)$data['labels'][$lang]['value']);

                try {
                    $insertStmt->bind_param("issss", $persinst_id, $tLang, $tLabel, $tDescription, $wikilink);
                    $insertStmt->execute();
                }
                catch (MDMysqliInvalidEncodingError $e) {
                }

            }
                // echo '<br><b style="color: cc0000;">Wikipedia Links fehlen</b>';
            else if (!empty($data['labels'][$lang]['value']) and !empty($data['descriptions'][$lang])) {

                $wikilink = "";
                $insertStmt->bind_param("issss", $persinst_id, $data['labels'][$lang]['language'], $data['labels'][$lang]['value'], $data['descriptions'][$lang]['value'], $wikilink);
                $insertStmt->execute();
            }

        }

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

        $insertStmt->close();
        unset($insertStmt);

    }

    /**
     * Function for entering base information about a place from wikidata.
     *
     * @param mysqli_result $currentPlaceResult Mysqli result pointing to the current place.
     * @param string        $datafromwiki       Data parsed from wikidata.
     * @param array<mixed>  $wikilink           Wikilink.
     * @param string        $preflang           Language of the user interface in general.
     * @param string        $lang               Language of the main entry.
     * @param integer       $placeID            ID of the place.
     * @param string        $erfasst_von        User name.
     *
     * @return boolean
     */
    public function enterPlaceDescFromWikidata(mysqli_result $currentPlaceResult, string $datafromwiki, array $wikilink, string $preflang, string $lang, int $placeID, string $erfasst_von) {

        $datafromwiki = '"' . $datafromwiki . '" - (Wikipedia (' . $lang . ') ' . date("d.m.Y") . ')';

        if (!($curPlaceInfo = $currentPlaceResult->fetch_assoc())) return false;

        if (!empty(trim($curPlaceInfo['ort_anmerkung'])) and substr($curPlaceInfo['ort_anmerkung'], 0, 3) !== 'GND') {

            if (isset($_GET['keep'])) {

                if ($_GET['keep'] === 'add') {

                    $datafromwiki = $curPlaceInfo['ort_anmerkung'] . PHP_EOL . PHP_EOL . $datafromwiki;

                }
                else if ($_GET['keep'] === 'keep') {
                    $datafromwiki = $curPlaceInfo['ort_anmerkung'];
                }

            }
            else {

                $tlLoader = new MDTlLoader("wiki_getter_place", $preflang);
                echo self::generateHTMLHeadForWikidataFetcher($lang);
                echo self::generateWikidataFetcherHeader($tlLoader);
                echo '
                <p class="alert icons iconsAlert">There is already an entry for description ...</p>
                <div class="wikiReplaceTTile">
                    <h3>Actual entry</h3><p>' . nl2br($curPlaceInfo['ort_anmerkung']) . '</p>
                </div>
                <div class="wikiReplaceTTile">
                    <h3>Now found</h3>
                    <p>' . $datafromwiki . '</p>
                </div>
                <a href="get_wikidata_for_ort.php?keep=keep' . write_get_vars(['suchbegriff', 'lang', 'wikidata_id', 'ort_id']) . '" class="buttonLike icons iconsPin">Keep old entry</a>
                <br><a href="get_wikidata_for_ort.php?keep=replace' . write_get_vars(['suchbegriff', 'lang', 'wikidata_id', 'ort_id']) . '" class="buttonLike icons iconsPinOff">Replace with new entry</a>
                <br><a href="get_wikidata_for_ort.php?keep=add' . write_get_vars(['suchbegriff', 'lang', 'wikidata_id', 'ort_id']) . '" class="buttonLike icons iconsPlusOne">Keep old and add new entry</a><br><br><br>
                ';

                exit;

            }

        }

        // Write description to DB
        $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `orte`
            SET `ort_anmerkung` = ?,
                `ort_erfasst_am` = NOW(),
                `ort_erfasst_von` = ?
            WHERE ort_id = ?");
        try {
            $updateStmt->bind_param("ssi", $datafromwiki, $erfasst_von, $placeID);
            $updateStmt->execute();
        }
        catch (MDMysqliInvalidEncodingError $e) {
            $_SESSION["editHistory"] = ["changesStored", "Error adding base description"];
        }
        $updateStmt->close();
        unset($updateStmt);

        // Write link to wikipedia to relevant noda DB table

        $wikiAlreadyResult = $this->_mysqli_noda->query_by_stmt("SELECT `noda_orte`.`noda_id`
            FROM `noda_orte`
            WHERE `noda_orte`.`ort_id` = ?
                AND `noda_orte`.`noda_source` = 'Wikipedia'", "i", $placeID);

        switch ($wikiAlreadyResult->num_rows) {
        case 0:

            $insertWikiStmt = $this->_mysqli_noda->do_prepare("INSERT INTO `noda_orte`
                (`ort_id`, `noda_source`, `noda_nrinsource`, `noda_link`, `noda_erfasst_am`, `noda_erfasst_von`)
                VALUES
                (?, 'Wikipedia', '', ?, NOW(), ?)");
            $insertWikiStmt->bind_param("iss", $placeID, $wikilink[$lang], $erfasst_von);
            $insertWikiStmt->execute();
            $insertWikiStmt->close();
            unset($insertWikiStmt);

            break;
        case 1:

            if ($wikiAlreadyData = $wikiAlreadyResult->fetch_assoc()) {
                $wikischon_id = $wikiAlreadyData['noda_id'];

                $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `noda_orte` SET `noda_link` = ? WHERE `noda_id` = ?");
                $updateStmt->bind_param("si", $wikilink[$lang], $wikischon_id);
                $updateStmt->execute();
                $updateStmt->close();
                unset($updateStmt);
            }
            break;
        }

        $wikiAlreadyResult->close();
        unset($wikiAlreadyResult);

        return true;

    }

    /**
     * Function for retrieving place information based on a Wikidata ID.
     *
     * @param string  $lang        Language.
     * @param string  $wikidata_id Wikidata Q-ID.
     * @param integer $onum        Place ID.
     * @param string  $erfasst_von User name of the current user.
     *
     * @return void
     */
    public function retrievePlaceInfoFromWikidataID(string $lang, string $wikidata_id, int $onum, string $erfasst_von) {

        $data = MD_STD::runCurl("https://www.wikidata.org/wiki/Special:EntityData/" . urlencode($wikidata_id) . ".json", 10000);
        if (!$data = json_decode($data, true)) {
            throw new MDhttpFailedException("Failed fetching from Wikidata. Try again later.");
        }
        $data = $data['entities'][$wikidata_id];

        $wikilink = $wikilinkterm = [];

        foreach (self::LANGUAGES_MAIN_DESC as $tLang) {
            if (isset($data['sitelinks'][$tLang . 'wiki']['url']))   $wikilink[$tLang] = $data['sitelinks'][$tLang . 'wiki']['url'];
            if (isset($data['sitelinks'][$tLang . 'wiki']['title'])) $wikilinkterm[$tLang] = str_replace(' ', '_', $data['sitelinks'][$tLang . 'wiki']['title']);
        }

        $currentPlaceResult = $this->_mysqli_noda->query_by_stmt("SELECT `ort_anmerkung`
            FROM `orte`
            WHERE `ort_id` = ?", "i", $onum);

        $alreadyEntered = false;

        if (!empty($wikilink[$lang])) {

            $datafromwiki = MD_STD::runCurl("https://" . urlencode($lang) . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode($wikilinkterm[$lang]) . "&prop=text&section=0&format=json", 10000);
            $datafromwiki = json_decode($datafromwiki, true)['parse']['text']['*'];

            if (!empty($datafromwiki) and $datafromwiki = self::_cleanWikidataInput((string)$datafromwiki)) {
                $alreadyEntered = $this->enterPlaceDescFromWikidata($currentPlaceResult, $datafromwiki, $wikilink, $lang, $lang, $onum, $erfasst_von);
            }
        }

        foreach (self::LANGUAGES_MAIN_DESC as $sprache) {

            //if ($alreadyEntered === true) break;
            if ($alreadyEntered === true) break;
            if (!isset($wikilink[$sprache])) continue;

            $datafromwiki = MD_STD::runCurl("https://" . urlencode($sprache) . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode($wikilinkterm[$sprache]) . "&prop=text&section=0&format=json", 10000);
            $datafromwiki = json_decode($datafromwiki, true)['parse']['text']['*'];
            if (!empty($datafromwiki) and $datafromwiki = self::_cleanWikidataInput((string)$datafromwiki)) {
                $alreadyEntered = $this->enterPlaceDescFromWikidata($currentPlaceResult, $datafromwiki, $wikilink, $lang, $sprache, $onum, $erfasst_von);
            }

        }
        $currentPlaceResult->close();
        unset($currentPlaceResult);

        if (isset($data['claims']['P1566'])) $geonames_id = $data['claims']['P1566'][0]['mainsnak']['datavalue']['value'];
        if (isset($data['claims']['P1667'])) $tgn_id = $data['claims']['P1667'][0]['mainsnak']['datavalue']['value'];

        $nodaLinks = [
            "wikidata" => $wikidata_id,
        ];
        foreach (self::P_IDS_NODA_TAGS as $vocabName => $pId) {
            if ($vocabName === 'lcsh') continue;
            if (isset($data['claims'][$pId])) $nodaLinks[$vocabName] = $data['claims'][$pId][0]['mainsnak']['datavalue']['value'];
        }

        if (isset($data['claims']['P625'])) {
            $latitude_wd = $data['claims']['P625'][0]['mainsnak']['datavalue']['value']['latitude'];
            $longitude_wd = $data['claims']['P625'][0]['mainsnak']['datavalue']['value']['longitude'];
        }

        $this->_mysqli_noda->autocommit(false);

        $insertNodaLinkStmt = $this->_mysqli_noda->do_prepare("INSERT INTO `noda_orte`
            (`ort_id`, `noda_source`, `noda_nrinsource`, `noda_link`, `noda_erfasst_von`)
            VALUES
            (?, ?, ?, ?, ?)
            ON DUPLICATE KEY UPDATE `noda_nrinsource` = ?,
                `noda_link` = ?");

        foreach ($nodaLinks as $noda_source => $nodaId) {

            if (!isset(self::URL_PREFIXES_PLACES_NODA_SOURCE[$noda_source])) {
                throw new Exception("Unknown noda link: " . $noda_source);
            }
            $noda_link_url = self::URL_PREFIXES_PLACES_NODA_SOURCE[$noda_source] . $nodaId;

            $insertNodaLinkStmt->bind_param("issssss", $onum, $noda_source, $nodaId, $noda_link_url, $erfasst_von, $nodaId, $noda_link_url);
            $insertNodaLinkStmt->execute();
        }

        $insertNodaLinkStmt->close();
        unset($insertNodaLinkStmt);

        if (!empty($tgn_id)) {

            $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `orte`
                SET `ort_land` = ?
                WHERE `ort_id` = ?");
            $updateStmt->bind_param("si", $tgn_id, $onum);
            $updateStmt->execute();
            $updateStmt->close();
            unset($updateStmt);

        }
        if (!empty($geonames_id)) {

            $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `orte`
                SET `ort_geonames` = ?
                WHERE `ort_id` = ?");
            $updateStmt->bind_param("si", $geonames_id, $onum);
            $updateStmt->execute();
            $updateStmt->close();
            unset($updateStmt);

        }
        if (!empty($latitude_wd) and !empty($longitude_wd)) {

            $updateStmt = $this->_mysqli_noda->do_prepare("UPDATE `orte`
                SET `ort_nord_sued` = ?, `ort_west_ost` = ?, ort_zoom = '9'
                WHERE `ort_id` = ?");
            $updateStmt->bind_param("ssi", $latitude_wd, $longitude_wd, $onum);
            $updateStmt->execute();
            $updateStmt->close();
            unset($updateStmt);

        }

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

        $this->getWikidataTranslationsForPlace($data, $onum);

    }

    /**
     * Function for fetching translations from wikidata.
     *
     * @param array<mixed> $data   Entity data fetched from wikidata.
     * @param integer      $ort_id Place ID.
     *
     * @return void
     */
    public function getWikidataTranslationsForPlace(array $data, int $ort_id) {

        $checkagainstLanguage = self::LANGUAGES_TO_CHECK;

        list($languagesToFetch, $wikilinks) = self::getWikidataWikipediaTranslationSources($checkagainstLanguage, $data);

        try {
            $contents = MD_STD::runCurlMulti($languagesToFetch, 10000);
        }
        catch (TypeError $e) {
            throw new MDExpectedException("Failed to initialize a request. Try pressing F5 to run the requests again.");
        }

        $insertStmt = $this->_mysqli_noda->do_prepare("CALL `nodaInsertOrtTranslation`(?, ?, ?, ?, ?)");

        $this->_mysqli_noda->autocommit(false);

        foreach ($checkagainstLanguage as $lang) {

            if (!empty($languagesToFetch[$lang]) && !empty($data['sitelinks'][$lang . 'wiki'])) {

                $url = $languagesToFetch[$lang];

                $wikilink = $wikilinks[$lang];
                if (!empty($contents[$lang])) {

                    $descFromWiki = $contents[$lang];

                    if (!($wikiDataDecoded = json_decode($descFromWiki, true))) {
                        continue;
                    }
                    $tLabel = $wikiDataDecoded['parse']['title'];
                    $descFromWiki = $wikiDataDecoded['parse']['text']['*'];

                    # Process data retrieved from wikipedia
                    if (empty($descFromWiki)) $tDescription = "";
                    else {

                        $tDescription = self::_cleanWikidataInput((string)$descFromWiki);

                        if (substr($tDescription, -1) == chr(10)) $tDescription = substr($tDescription, 0, strlen($tDescription) - 1);
                        $tDescription = '"' . $tDescription . '" - (' . $data['labels'][$lang]['language'] . '.wikipedia.org ' . date('d.m.Y') . ')';
                        $tDescription = str_replace("'", "´", MD_STD::preg_replace_str("/\&\#91\;[0-9]\&\#93\;/", '', $tDescription));
                        // echo '<br>Inhalt erster Absatz jeweilige Wikipedia: ' . $tDescription; // dies enthält den ersten Absatz der jeweiligen Wikipedia

                    }

                }
                else {
                    $tDescription = "";
                }

                $tLang = self::_cleanWikidataInput((string)$data['labels'][$lang]['language']);
                if (empty($tLabel)) $tLabel = self::_cleanWikidataInput((string)$data['labels'][$lang]['value']);

                try {
                    $insertStmt->bind_param("issss", $ort_id, $tLang, $tLabel, $tDescription, $wikilink);
                    $insertStmt->execute();
                }
                catch (MDMysqliInvalidEncodingError $e) {
                    $_SESSION["editHistory"] = ["changesStored", "Error adding translation for language $tLang"];
                }

            }
            else if (!empty($data['labels'][$lang]['value']) and !empty($data['descriptions'][$lang])) {

                $wikilink = "";
                $insertStmt->bind_param("issss", $ort_id, $data['labels'][$lang]['language'], $data['labels'][$lang]['value'], $data['descriptions'][$lang]['value'], $wikilink);
                $insertStmt->execute();
            }

        }

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

        $insertStmt->close();
        unset($insertStmt);

    }

    /**
     * Function for fetching description from Wikipedia
     *
     * @param integer $tag_id       Tag ID.
     * @param string  $datafromwiki Data fetched from Wikipedia.
     * @param string  $wikilink     Link to wikipedia entry.
     * @param string  $preflang     The user's currently used language.
     * @param string  $lang         Currently queried language.
     * @param string  $erfasst_von  User who adds the info.
     *
     * @return boolean
     */
    public function retrieveTagDescFromWikipedia(int $tag_id, string $datafromwiki, string $wikilink, string $preflang, string $lang, string $erfasst_von):bool {

        $output = false;

        $datafromwiki = '"' . $datafromwiki . '" - (Wikipedia (' . $lang . ') ' . date("d.m.Y") . ')';
        $datafromwiki = str_replace("'", "´", MD_STD::preg_replace_str("/\&\#91\;[0-9]\&\#93\;/", '', $datafromwiki));

        $cergebnis = $this->_mysqli_noda->query_by_stmt("SELECT `tag_anmerkung`
            FROM `tag`
            WHERE `tag_id` = ?", "i", $tag_id);

        if (!($cinfo = $cergebnis->fetch_assoc())) {
            $cergebnis->close();
            $cergebnis = null;
            return $output;
        }

        $cergebnis->close();
        $cergebnis = null;

        $this->_mysqli_noda->autocommit(false);

        $updateTagDescStmt = $this->_mysqli_noda->do_prepare("UPDATE `tag`
            SET `tag_anmerkung` = ?
            WHERE `tag_id` = ?");

        if (!empty($cinfo['tag_anmerkung']) and substr($cinfo['tag_anmerkung'], 0, 3) != 'GND') {

            if (isset($_GET['keep'])) {
                if (!($_GET['keep']) || $_GET['keep'] === 'replace') {

                    $updateTagDescStmt->bind_param("si", $datafromwiki, $tag_id);
                    $updateTagDescStmt->execute();

                }
                else if ($_GET['keep'] === 'add') {

                    $newDesc = $cinfo['tag_anmerkung'] . PHP_EOL . PHP_EOL . $datafromwiki;

                    $updateTagDescStmt->bind_param("si", $newDesc, $tag_id);
                    $updateTagDescStmt->execute();

                }

                $output = true;
            }
            else {

                $tlLoader = new MDTlLoader("wiki_getter_tag", $preflang);
                echo self::generateHTMLHeadForWikidataFetcher($lang);
                echo self::generateWikidataFetcherHeader($tlLoader);
                echo '
                <p class="alert icons iconsAlert">Es gibt schon einen Eintrag im Beschreibungsfeld</b>
                <div class="wikiReplaceTTile">
                    <h3>Bisher vorhanden</h3><p>' . nl2br($cinfo['tag_anmerkung']) . '</p>
                </div>
                <div class="wikiReplaceTTile">
                    <h3>Jetzt gefunden</h3><p>' . $datafromwiki . '<p>
                </div>

                <a href="get_wikidata_for_tag.php?keep=keep' . write_get_vars(['suchbegriff', 'lang', 'wikidata_id', 'tag_id']) . '" class="buttonLike icons iconsPin">Keep old entry</a>';
                echo '<br><a href="get_wikidata_for_tag.php?keep=replace' . write_get_vars(['suchbegriff', 'lang', 'wikidata_id', 'tag_id']) . '" class="buttonLike icons iconsPinOff">Replace with new entry</a>';
                echo '<br><a href="get_wikidata_for_tag.php?keep=add' . write_get_vars(['suchbegriff', 'lang', 'wikidata_id', 'tag_id']) . '" class="buttonLike icons iconsPlusOne">Keep old and add new entry</a><br><br><br>';

                exit;

            }

        }
        else {

            $updateTagDescStmt->bind_param("si", $datafromwiki, $tag_id);
            $updateTagDescStmt->execute();
        }

        $updateTagDescStmt->close();
        $updateTagDescStmt = null;

        $insertNodaTagStmt = $this->_mysqli_noda->do_prepare("INSERT INTO `noda_tag`
            (`tag_id`, `noda_source`, `noda_nrinsource`, `noda_link`, `noda_erfasst_von`)
            VALUES
            (?, 'Wikipedia', '', ?, ?)
            ON DUPLICATE KEY UPDATE `noda_link` = ?");
        $insertNodaTagStmt->bind_param("isss", $tag_id, $wikilink, $erfasst_von, $wikilink);
        $insertNodaTagStmt->execute();
        $insertNodaTagStmt->close();

        $output = true;

        // Update tag editing metadata
        $updateTagEditInfoStmt = $this->_mysqli_noda->do_prepare("UPDATE `tag`
            SET `tag_erfasst_am` = NOW(),
                `tag_erfasst_von` = ?
            WHERE `tag_id` = ?");
        $updateTagEditInfoStmt->bind_param("si", $erfasst_von, $tag_id);
        $updateTagEditInfoStmt->execute();
        $updateTagEditInfoStmt->close();
        $updateTagEditInfoStmt = null;

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

        return $output;

    }

    /**
     * Writes relations to norm data sources to DB.
     *
     * @param array<string> $nodaLinks   Links to other noda sources.
     * @param integer       $tag_id      Tag ID.
     * @param string        $erfasst_von Name of the user to edit this.
     *
     * @return void
     */
    public function writeNodaLinksTag(array $nodaLinks, int $tag_id, string $erfasst_von):void {

        $this->_mysqli_noda->autocommit(false);

        $insertNodaTagStmt = $this->_mysqli_noda->do_prepare("INSERT INTO `noda_tag`
            (`tag_id`, `noda_source`, `noda_nrinsource`, `noda_link`, `noda_erfasst_von`)
            VALUES
            (?, ?, ?, ?, ?)
            ON DUPLICATE KEY UPDATE
                `noda_nrinsource` = ?,
                `noda_link` = ?,
                `noda_erfasst_von` = ?");

        foreach ($nodaLinks as $vocabName => $nodaId) {

            if (empty(self::URL_PREFIXES_PLACES_NODA_SOURCE[$vocabName])) {
                throw new Exception("Unknown URL prefix for: " . $vocabName);
            }

            $noda_link = self::URL_PREFIXES_PLACES_NODA_SOURCE[$vocabName] . $nodaId;

            $insertNodaTagStmt->bind_param("isssssss", $tag_id, $vocabName, $nodaId, $noda_link, $erfasst_von, $nodaId, $noda_link, $erfasst_von);
            $insertNodaTagStmt->execute();
        }

        $insertNodaTagStmt->close();
        $insertNodaTagStmt = null;

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

    }

    /**
     * Function for retrieving information.
     *
     * @param string  $lang        The user's selected used language.
     * @param string  $wikidata_id Wikidata ID.
     * @param integer $tag_id      Tag ID.
     * @param string  $erfasst_von User name who's currently editing.
     *
     * @return void
     */
    public function retrieveTagInfoFromWikidataID(string $lang, string $wikidata_id, int $tag_id, string $erfasst_von) {

        $data = MD_STD::runCurl("https://www.wikidata.org/wiki/Special:EntityData/" . $wikidata_id . ".json", 10000);
        $data = json_decode($data, true);
        if ($data === null) {
            throw new MDhttpFailedException("Failed fetching from Wikidata. Try again later.");
        }
        $data = $data['entities'][$wikidata_id];

        $wikilink = $wikilinkterm = [];

        foreach (self::LANGUAGES_MAIN_DESC as $tLang) {
            if (isset($data['sitelinks'][$tLang . 'wiki']['url']))   $wikilink[$tLang] = $data['sitelinks'][$tLang . 'wiki']['url'];
            if (isset($data['sitelinks'][$tLang . 'wiki']['title'])) $wikilinkterm[$tLang] = str_replace(' ', '_', $data['sitelinks'][$tLang . 'wiki']['title']);
        }

        $alreadyEntered = false;

        if (isset($wikilink[$lang]) and isset($wikilinkterm[$lang]) and is_string($wikilinkterm[$lang])) {

            $datafromwiki = MD_STD::runCurl("https://" . $lang . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode($wikilinkterm[$lang]) . "&prop=text&section=0&format=json", 10000);
            $datafromwiki = json_decode($datafromwiki, true)['parse']['text']['*'];

            # Process data retrieved from wikipedia
            if (!empty($datafromwiki = self::_cleanWikidataInput((string)$datafromwiki))) {
                $alreadyEntered = $this->retrieveTagDescFromWikipedia($tag_id, $datafromwiki, $wikilink[$lang], $lang, $lang, $erfasst_von);
            }

        }

        foreach (self::LANGUAGES_MAIN_DESC as $sprache) {

            if ($alreadyEntered === true) break;
            if (!isset($wikilink[$sprache]) || !isset($wikilinkterm[$sprache]) || !is_string($wikilinkterm[$sprache])) continue;

            $datafromwiki = MD_STD::runCurl("https://" . $sprache . ".wikipedia.org/w/api.php?action=parse&page=" . urlencode((string)$wikilinkterm[$sprache]) . "&prop=text&section=0&format=json", 10000);
            $datafromwiki = json_decode($datafromwiki, true)['parse']['text']['*'];

            # Process data retrieved from wikipedia
            if ($datafromwiki = self::_cleanWikidataInput((string)$datafromwiki)) {
                $alreadyEntered = $this->retrieveTagDescFromWikipedia($tag_id, $datafromwiki, $wikilink[$sprache], $lang, "$sprache", $erfasst_von);
            }

        }

        $nodaLinks = [
            "wikidata" => $wikidata_id,
        ];
        foreach (self::P_IDS_NODA_TAGS as $vocabName => $pId) {
            if ($vocabName === 'loc') continue;
            if (isset($data['claims'][$pId])) $nodaLinks[$vocabName] = $data['claims'][$pId][0]['mainsnak']['datavalue']['value'];
        }

        $this->writeNodaLinksTag($nodaLinks, $tag_id, $erfasst_von);

        // Get translations
        if (!empty($data)) $this->getWikidataTranslationsForTag($data, $tag_id);

    }

    /**
     * Function for fetching translations from wikidata.
     *
     * @param array<mixed> $data   Entity data fetched from wikidata.
     * @param integer      $tag_id Tag ID.
     *
     * @return void
     */
    public function getWikidataTranslationsForTag(array $data, int $tag_id) {

        $checkagainstLanguage = self::LANGUAGES_TO_CHECK;

        $insertStmt = $this->_mysqli_noda->do_prepare("CALL nodaInsertTagTranslation(?, ?, ?, ?, ?)");

        list($languagesToFetch, $wikilinks) = self::getWikidataWikipediaTranslationSources($checkagainstLanguage, $data);

        try {
            $contents = MD_STD::runCurlMulti($languagesToFetch, 10000);
        }
        catch (TypeError $e) {
            throw new MDExpectedException("Failed to initialize a request. Try pressing F5 to run the requests again.");
        }

        $this->_mysqli_noda->autocommit(false);

        foreach ($checkagainstLanguage as $lang) {

            if (!empty($languagesToFetch[$lang]) && !empty($data['sitelinks'][$lang . 'wiki'])) {

                $url = $languagesToFetch[$lang];

                $wikilink = $wikilinks[$lang];
                if (!empty($contents[$lang])) {

                    $descFromWiki = $contents[$lang];
                    $descFromWiki = json_decode($descFromWiki, true)['parse']['text']['*'];

                    if (!empty($descFromWiki)) {

                        # Process data retrieved from wikipedia
                        $tDescription = self::_cleanWikidataInput((string)$descFromWiki);

                        if (substr($tDescription, -1) == chr(10)) {
                            $tDescription = substr($tDescription, 0, strlen($tDescription) - 1);
                        }

                        $tDescription = '"' . $tDescription . '" - (' . $data['labels'][$lang]['language'] . '.wikipedia.org ' . date('d.m.Y') . ')';
                        $tDescription = str_replace("'", "´", MD_STD::preg_replace_str("/\&\#91\;[0-9]\&\#93\;/", '', $tDescription));

                    }
                    else {
                        $tDescription = "";
                    }

                }
                else {
                    $tDescription = "";
                }

                $tLang = self::_cleanWikidataInput((string)$data['labels'][$lang]['language']);
                $tLabel = self::_cleanWikidataInput((string)$data['labels'][$lang]['value']);

                if (in_array($tLang, self::LANGUAGES_TO_CAPITALIZE, true)) {
                    $tLabel = ucfirst(trim($tLabel));
                    $tDescription = ucfirst(trim($tDescription));
                }

                try {
                    $insertStmt->bind_param("issss", $tag_id, $tLang, $tLabel, $tDescription, $wikilink);
                    $insertStmt->execute();
                }
                catch (MDMysqliInvalidEncodingError $e) {
                }

            }
            else if (!empty($data['labels'][$lang]['value']) and !empty($data['descriptions'][$lang])) {

                $wikilink = "";

                if (in_array($lang, self::LANGUAGES_TO_CAPITALIZE, true)) {
                    $data['labels'][$lang]['value'] = ucfirst(trim($data['labels'][$lang]['value']));
                    $data['descriptions'][$lang]['value'] = ucfirst(trim($data['descriptions'][$lang]['value']));
                }

                $insertStmt->bind_param("issss", $tag_id, $data['labels'][$lang]['language'], $data['labels'][$lang]['value'], $data['descriptions'][$lang]['value'], $wikilink);
                $insertStmt->execute();
            }

        }

        $this->_mysqli_noda->commit();
        $this->_mysqli_noda->autocommit(true);

        $insertStmt->close();
        unset($insertStmt);

    }

    /**
     * Function for generating a wikidata results list.
     *
     * @param array<array<mixed>> $wikidata_data Wikidata data.
     * @param string              $link          Links.
     * @param string              $searchTerm    Search term.
     * @param string              $lang          Language.
     *
     * @return void
     */
    public static function generateWikidataResultsList(array $wikidata_data, string $link, string $searchTerm, string $lang):void {

        if (count($wikidata_data['search']) === 0) {
            echo '<p class="icons iconsAlert alert"><b>' . ucfirst($searchTerm) . '</b>  not found in Wikidata</p>';
            return;
        }

        echo '
        <main id="wikidataResultsList">';

        foreach ($wikidata_data['search'] as $result) {

            if ((isset($result['description']) and $result['description'] == '') or (isset($result['label']) and $result['label'] == '') or !isset($result['label']) or (isset($result['description']) and $result['description'] == 'Wikipedia disambiguation page') or (isset($result['description']) and $result['description'] == 'Wikimedia disambiguation page')) continue;

            echo '<div><a href="' . $link . 'suchbegriff=' . $searchTerm . '&wikidata_id=' . $result['id'] . '&lang=' . $lang . '">
                <h4 class="icons iconsTag">' . $result['id'] . '</h4>';
            echo '<p class="wikidataSummary">' . $result['label'];
            if (!empty($result['match'])) echo " (<span class='icons iconsTranslate'>{$result['match']['language']}: {$result['match']['text']}</span>)";
            echo '</p>';
            if (!empty($result['description'])) echo '<p>' . $result['description'] . '</p>';
            echo '</a><a class="icons iconsEye" target="_blank" href="https://www.wikidata.org/wiki/' . $result['id'] . '">Wikidata page</a></div>';

        }

        echo '
        </main>';

    }

    /**
     * Function generates HTML head for wikidata fetchers.
     *
     * @param string  $lang     User language.
     * @param boolean $implyEnd If set to true, the end string will be echoed at the end of the script execution.
     *
     * @return string
     */
    public static function generateHTMLHeadForWikidataFetcher(string $lang, bool $implyEnd = true):string {
        $output = "<!DOCTYPE html><html class=\"getWikidata\" lang=\"{$lang}\">
    <head>
        <title>Get Wikidata</title>
        <meta name=\"viewport\" content=\"width=device-width, initial-scale=1\" />
        <link rel=\"manifest\" href=\"../manifest.webmanifest\" />
        <meta name=\"theme-color\" content=\"#0b1728\" />
        <link rel=\"shortcut icon\" sizes=\"16x16 32x32\" href=\"../img/mdlogo-nodac.svg.png\" />
        <link rel=\"apple-touch-icon\" sizes=\"256x256\" href=\"../img/mdterm-256px.png\" />
        <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\"/>";
        if (defined("MAIN_CSS_FILE")) {
            $output .= "<link rel=\"stylesheet\" type=\"text/css\" href=\"" . htmlspecialchars(MAIN_CSS_FILE) . "\">";
        }
        $output .= "
        <meta name=\"description\" content=\"Fetch information from Wikidata.\" />
    </head>
    <body>";

        if ($implyEnd === true) {
            register_shutdown_function(function() :void {
                echo printHTMLEnd();
            });
        }

        return MD_STD::minimizeHTMLString($output);

    }

    /**
     * Function generate header for wikidata fetcher pages.
     *
     * @param MDTlLoader $tlLoader   Translation variable.
     * @param string     $additional Additional info.
     * @param string     $searchTerm Search term.
     *
     * @return string
     */
    public static function generateWikidataFetcherHeader(MDTlLoader $tlLoader, string $additional = "", string $searchTerm = ""):string {

        if (empty($searchTerm) and !empty($_GET['suchbegriff'])) {
            $searchTerm = $_GET['suchbegriff'];
        }

        $output = '
        <header>
            <h1><img src="../img/wikidata.png" alt="Logo: Wikidata" />' . $tlLoader->tl("wiki", "wiki", "fetch_from_wikidata");
        $output .= ': ' . $searchTerm;
        $output .= '</h1>';
        $output .= $additional;
        $output .= '</header>';
        return $output;

    }

    /**
     * Constructor.
     *
     * @param MDMysqli $mysqli_noda DB connection.
     *
     * @return void
     */
    public function __construct(MDMysqli $mysqli_noda) {

        $this->_mysqli_noda = $mysqli_noda;

    }
}