TypoScript-based language menu only showing available single news localizations

SingleRecordLocalizationMenu.php

<?php
declare(strict_types=1);

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with TYPO3 source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

namespace Causal\LbTemplate\ContentObject\Menu;

use TYPO3\CMS\Core\Database\ConnectionPool;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
use TYPO3\CMS\Frontend\ContentObject\Menu\AbstractMenuContentObject;
use TYPO3\CMS\Frontend\ContentObject\Menu\TextMenuContentObject;

/**
 * Class SingleRecordLocalizationMenu
 * @package Causal\LbTemplate\ContentObject\Menu
 *
 * Sample Usage (for a menu of localizations from a single EXT:news article):
 *
 * lib.menus.newsLanguages = HMENU
 * lib.menus.newsLanguages {
 *     special = userfunction
 *     special {
 *         userFunc = Causal\LbTemplate\ContentObject\Menu\SingleRecordLocalizationMenu->prepareLanguageMenu
 * 
 *         # configure how to fetch the single element of this page
 *         table = tx_news_domain_model_news
 *         record = TEXT
 *         record.data = GP:tx_news_pi1|news
 *
 *         # same meaning as when using "special = language"
 *         value = 0,3,1,2
 *
 *         # default language is German (sys_language_uid = 0), but it could be another uid if you have a site with
 *         # various default languages and one of the available translations is the possible default default itself
 *         # for that subsite. In that case, the trick for such case (generally-speaking, not particularly for this
 *         # menu) is to avoid using "0" in the list of values above and replace it with the corresponding "translation"
 *         defaultLanguage = 0
 *
 *         # syntax is the one (option split) typically used for a language menu
 *         overrideTitles = DE || EN || FR || IT
 *     }
 *
 *     wrap = <ul class="list-inline"> | </ul>
 *
 *     1 = TMENU
 *     1 {
 *         NO = 1
 *         NO {
 *             allWrap = <li> | </li>
 *             ATagParams = class="btn btn-default"
 *         }
 *
 *         ACT < .NO
 *         ACT.ATagParams = class="btn btn-default active"
 *     }
 * }
 *
 */
class SingleRecordLocalizationMenu /* trick to invoke protected methods */ extends AbstractMenuContentObject
{

    /**
     * @var ContentObjectRenderer
     */
    public $cObj;

    /**
     * Rendering the cObject, HMENU
     *
     * @param string $content
     * @param array $conf Array of TypoScript properties
     * @return array
     */
    public function prepareLanguageMenu(string $content, array $conf): array
    {
        if (empty($conf['table'])) {
            throw new \RuntimeException('No table specified', 1571397821);
        }
        $recordUid = $conf['record'];
        if (!empty($conf['record.'])) {
            $recordUid = $this->cObj->cObjGetSingle($conf['record'], $conf['record.']);
        }
        $recordUid = (int)$recordUid;
        if (empty($recordUid)) {
            // No menu available
            return [];
        }

        // First of all, we want TYPO3 to prepare the links to the various localizations of current page
        // "->prepareMenuItemsForLanguageMenu" is the protected method which we cannot invoke without the trick of the
        // class inheritance (or Reflection which is less-efficient)
        $menuObject = GeneralUtility::makeInstance(TextMenuContentObject::class);
        $menuObject->parent_cObj = $this->cObj;
        $fakeConf = [
            'addQueryString' => '1',
            'addQueryString.' => [
                'exclude' => 'id,L,cHash',
            ],
            '1' => 'TMENU',
        ];
        $menuObject->start($GLOBALS['TSFE']->tmpl, $GLOBALS['TSFE']->sys_page, '', $fakeConf, 1);
        $pageMenu = $menuObject->prepareMenuItemsForLanguageMenu($conf['value']);

        // Then we look for available translations of the record
        $languageUids = $this->getAvailableRecordLocalizations($conf['table'], $recordUid);
        $languageUids[] = (int)$conf['defaultLanguage'];

        // We want an associative array of $language => $position in the menu
        // and their corresponding language codes to be shown
        $orderedLanguages = array_flip(GeneralUtility::intExplode(',', $conf['value'], true));
        $languageTitles = GeneralUtility::trimExplode('||', $conf['overrideTitles']);

        // We need to override the page titles with the language code
        foreach ($pageMenu as $key => $_) {
            $pageMenu[$key]['title'] = $languageTitles[$key];
        }

        // Figure out which languages should get removed
        $removeLanguageUids = array_diff(array_keys($orderedLanguages), $languageUids);

        // Remove unwanted links
        foreach ($removeLanguageUids as $languageUid) {
            $pos = $orderedLanguages[$languageUid];
            unset($pageMenu[$pos]);
        }

        // Ensure one of the pages is "active"
        $hasActiveLanguage = false;
        foreach ($pageMenu as $key => $page) {
            $hasActiveLanguage |= $page['ITEM_STATE'] === 'ACT';
        }
        if (!$hasActiveLanguage) {
            $pos = $orderedLanguages[(int)$conf['defaultLanguage']];
            $pageMenu[$pos]['ITEM_STATE'] = 'ACT';
        }

        // Reindex the trimmed-down menu
        $pageMenu = array_values($pageMenu);

        // No need for a menu if we have no other language
        if (count($pageMenu) === 1) {
            $pageMenu = [];
        }

        return $pageMenu;
    }

    /**
     * @param string $table
     * @param int $uid
     * @return array
     */
    protected function getAvailableRecordLocalizations(string $table, int $uid): array
    {
        $rows = GeneralUtility::makeInstance(ConnectionPool::class)
            ->getConnectionForTable($table)
            ->select(
                ['sys_language_uid'],
                $table,
                [
                    'l10n_parent' => $uid,
                ]
            )
            ->fetchAll();

        $languageUids = [];
        foreach ($rows as $row) {
            $languageUids[] = $row['sys_language_uid'];
        }

        return $languageUids;
    }

}