class TermTranslation

class TermTranslation extends Term {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = parent::query();
        if ($this->database
            ->schema()
            ->fieldExists('taxonomy_term_data', 'language')) {
            $query->addField('td', 'language', 'td_language');
        }
        // Get data when the i18n_mode column exists and it is not the Drupal 7
        // value I18N_MODE_NONE or I18N_MODE_LOCALIZE. Otherwise, return no data.
        // @see https://git.drupalcode.org/project/i18n/-/blob/7.x-1.x/i18n.module#L26
        if ($this->database
            ->schema()
            ->fieldExists('taxonomy_vocabulary', 'i18n_mode')) {
            $query->addField('tv', 'i18n_mode');
            $query->condition('tv.i18n_mode', [
                '0',
                '1',
            ], 'NOT IN');
        }
        else {
            $query->alwaysFalse();
        }
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        if (!parent::prepareRow($row)) {
            return FALSE;
        }
        $row->setSourceProperty('language', $row->getSourceProperty('td_language'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        $fields = [
            'language' => $this->t('Language for this term.'),
            'name_translated' => $this->t('Term name translation.'),
            'description_translated' => $this->t('Term description translation.'),
        ];
        return parent::fields() + $fields;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['language']['type'] = 'string';
        $ids['language']['alias'] = 'td';
        return parent::getIds() + $ids;
    }

}