class Term

class Term extends FieldableEntity {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = $this->select('taxonomy_term_data', 'td')
            ->fields('td')
            ->distinct()
            ->orderBy('tid');
        $query->leftJoin('taxonomy_vocabulary', 'tv', '[td].[vid] = [tv].[vid]');
        $query->addField('tv', 'machine_name');
        if ($this->getDatabase()
            ->schema()
            ->fieldExists('taxonomy_vocabulary', 'i18n_mode')) {
            $query->addField('tv', 'i18n_mode');
        }
        if (isset($this->configuration['bundle'])) {
            $query->condition('tv.machine_name', (array) $this->configuration['bundle'], 'IN');
        }
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        $fields = [
            'tid' => $this->t('The term ID.'),
            'vid' => $this->t('Existing term VID'),
            'machine_name' => $this->t('Vocabulary machine name'),
            'name' => $this->t('The name of the term.'),
            'description' => $this->t('The term description.'),
            'weight' => $this->t('Weight'),
            'parent' => $this->t("The Drupal term IDs of the term's parents."),
            'format' => $this->t("Format of the term description."),
        ];
        return $fields;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        $tid = $row->getSourceProperty('tid');
        $vocabulary = $row->getSourceProperty('machine_name');
        $default_language = (array) $this->variableGet('language_default', [
            'language' => 'en',
        ]);
        // If this entity was translated using Entity Translation, we need to get
        // its source language to get the field values in the right language.
        // The translations will be migrated by the d7_node_entity_translation
        // migration.
        $translatable_vocabularies = array_keys(array_filter($this->variableGet('entity_translation_taxonomy', [])));
        $entity_translatable = $this->isEntityTranslatable('taxonomy_term') && in_array($vocabulary, $translatable_vocabularies, TRUE);
        if ($entity_translatable) {
            $source_language = $this->getEntityTranslationSourceLanguage('taxonomy_term', $tid);
            $language = $entity_translatable && $source_language ? $source_language : $default_language['language'];
        }
        // If this is an i18n translation use the default language when i18n_mode
        // is localized.
        if ($row->get('i18n_mode')) {
            $language = $row->get('i18n_mode') === '1' ? $default_language['language'] : $row->get('language');
        }
        $language = $language ?? $default_language['language'];
        $row->setSourceProperty('language', $language);
        // Get Field API field values.
        foreach ($this->getFields('taxonomy_term', $vocabulary) as $field_name => $field) {
            // Ensure we're using the right language if the entity and the field are
            // translatable.
            $field_language = $entity_translatable && $field['translatable'] ? $language : NULL;
            $row->setSourceProperty($field_name, $this->getFieldValues('taxonomy_term', $field_name, $tid, NULL, $field_language));
        }
        // Find parents for this row.
        $parents = $this->select('taxonomy_term_hierarchy', 'th')
            ->fields('th', [
            'parent',
            'tid',
        ])
            ->condition('tid', $row->getSourceProperty('tid'))
            ->execute()
            ->fetchCol();
        $row->setSourceProperty('parent', $parents);
        // If the term name or term description were replaced by real fields using
        // the Drupal 7 Title module, use the fields value instead of the term name
        // or term description.
        if ($this->moduleExists('title')) {
            $name_field = $row->getSourceProperty('name_field');
            if (isset($name_field[0]['value'])) {
                $row->setSourceProperty('name', $name_field[0]['value']);
            }
            $description_field = $row->getSourceProperty('description_field');
            if (isset($description_field[0]['value'])) {
                $row->setSourceProperty('description', $description_field[0]['value']);
            }
            if (isset($description_field[0]['format'])) {
                $row->setSourceProperty('format', $description_field[0]['format']);
            }
        }
        return parent::prepareRow($row);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['tid']['type'] = 'integer';
        return $ids;
    }

}