Set USERDEF1 (or USERDEF2) in a language menu on record detail pages if the record is not translated. #TYPO3

MenuUtility.php

<?php
namespace BGM\BgmTheme\Utility;

/*
 * 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 this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

use TYPO3\CMS\Core\Context\Context;
use TYPO3\CMS\Core\Context\Exception\AspectNotFoundException;
use TYPO3\CMS\Core\Context\LanguageAspect;
use TYPO3\CMS\Core\Database\ConnectionPool;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Frontend\ContentObject\Menu\TextMenuContentObject;
use TYPO3\CMS\Frontend\Controller\TypoScriptFrontendController;

/**
 * Class MenuUtility
 * @package BGM\BgmTheme\Utility
 */
class MenuUtility
{
    /**
     * Check if we are on the detail view of a record and if the record is translated.
     * If the record is not translated, the ITEM_STATE of the language menu item is set to USERDEF1 or USERDEF2
     * as it is also done for pages (see AbstractMenuContentObject::prepareMenuItemsForLanguageMenu() "Checking if the
     * "disabled" state should be set.").
     *
     * TypoScript configuration example for EXT:news
     *
     * lib.languageSelector = HMENU
     * lib.languageSelector {
     *   special = language
     *   [...]
     *   1 = TMENU
     *   1 {
     *     [...]
     *     itemArrayProcFunc = BGM\BgmTheme\Utility\MenuUtility->checkForRecordTranslations
     *     itemArrayProcFunc.getParameters {
     *       # GET.PARAMETER.WITH.RECORD.UID = TABLENAME
     *       tx_news_pi1.news = tx_news_domain_model_news
     *     }
     *   }
     * }
     *
     * @see \TYPO3\CMS\Frontend\ContentObject\Menu\AbstractMenuContentObject::prepareMenuItemsForLanguageMenu()
     *
     * @param $menuArr
     * @param $conf
     * @return array
     * @throws AspectNotFoundException
     */
    public function checkForRecordTranslations($menuArr, $conf): array
    {
        $check = $this->shouldCheck($conf['getParameters.'], GeneralUtility::_GET());
        if (count($check) > 0) {
            /** @var TextMenuContentObject $parentObject */
            $parentObject = $conf['parentObj'];
            $tsFe = $this->getTypoScriptFrontendController();
            $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)
                ->getQueryBuilderForTable($check['table']);
            $context = GeneralUtility::makeInstance(Context::class);
            /** @var LanguageAspect $languageAspect */
            $languageAspect = $context->getAspect('language');
            foreach ($menuArr as &$menuItem) {
                /** current menu item language id */
                $sUid = (int)$menuItem['_PAGES_OVERLAY_LANGUAGE'];
                // Find overlay record:
                if ($sUid) {
                    $currentRecord = $queryBuilder
                        ->select('*')
                        ->from($check['table'])
                        ->where(
                            $queryBuilder->expr()->eq('uid', (int)$check['recordUid'])
                        )
                        ->execute()
                        ->fetch();
                    $overlayMode = $languageAspect->getOverlayType() === $languageAspect::OVERLAYS_MIXED ? '1' : 'hideNonTranslated';
                    $lRecs = $parentObject->__get('sys_page')->getRecordOverlay($check['table'], $currentRecord, $sUid, $overlayMode);
                } else {
                    $lRecs = [];
                }
                // Checking if the "disabled" state should be set.
                if (
                    (
                        !$parentObject->__get('conf')['special.']['special.']['normalWhenNoLanguage'] &&
                        $sUid &&
                        empty($lRecs)
                    )
                    ||
                    (
                        GeneralUtility::hideIfNotTranslated($tsFe->page['l18n_cfg']) &&
                        $sUid &&
                        empty($lRecs)
                    )
                    ||
                    (
                        GeneralUtility::hideIfDefaultLanguage($tsFe->page['l18n_cfg']) &&
                        (
                            !$sUid ||
                            empty($lRecs)
                        )
                    )
                ) {
                    $menuItem['ITEM_STATE'] = $languageAspect->getId() === $sUid ? 'USERDEF2' : 'USERDEF1';
                }
            }
        }
        return $menuArr;
    }

    /**
     * Walk through GET-Parameters and TypoScript-Configuration to check if we should do something.
     * If we should do something this function returns the tablename and uid of the record to check.
     * Else it returns false.
     *
     * @param array $configuration
     * @param array $getParameters
     * @return array
     */
    protected function shouldCheck(array $configuration, array $getParameters): array
    {
        $result = [];
        foreach ($configuration as $key => $configuredParameter) {
            $getParameterKey = $key;
            if (is_array($configuredParameter)) {
                $getParameterKey = rtrim($key, '.');
            }
            if (isset($getParameters[$getParameterKey])){
                if (
                    is_array($getParameters[$getParameterKey]) &&
                    is_array($configuredParameter)
                ) {
                    $result = $this->shouldCheck($configuredParameter, $getParameters[$getParameterKey]);
                } elseif (
                    is_string($configuredParameter) &&
                    $configuredParameter !== 0
                ) {
                    $result = [
                        'table' => $configuredParameter,
                        'recordUid' => $getParameters[$getParameterKey],
                    ];
                }
            }
        }
        return $result;
    }

    /**
     * @return TypoScriptFrontendController
     */
    protected function getTypoScriptFrontendController(): TypoScriptFrontendController
    {
        return $GLOBALS['TSFE'];
    }
}

Hi, thanks for sharing this, it's exactly what I've been looking for.
If you have time can you tell me what is line 87 doing? Because I get errors with the __get function but I don't know how to fix them, don't know what are these "$parentObject->__get('conf')". That would really help me out.