class Comment

class Comment extends FieldableEntity {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = $this->select('comment', 'c')
            ->fields('c');
        $query->innerJoin('node', 'n', '[c].[nid] = [n].[nid]');
        $query->addField('n', 'type', 'node_type');
        $query->orderBy('c.created');
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        $cid = $row->getSourceProperty('cid');
        $node_type = $row->getSourceProperty('node_type');
        $comment_type = 'comment_node_' . $node_type;
        $row->setSourceProperty('comment_type', 'comment_node_' . $node_type);
        // 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_comment_entity_translation
        // migration.
        $entity_translatable = $this->isEntityTranslatable('comment') && (int) $this->variableGet('language_content_type_' . $node_type, 0) === 4;
        $source_language = $this->getEntityTranslationSourceLanguage('comment', $cid);
        $language = $entity_translatable && $source_language ? $source_language : $row->getSourceProperty('language');
        // Get Field API field values.
        foreach ($this->getFields('comment', $comment_type) 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('comment', $field_name, $cid, NULL, $field_language));
        }
        // If the comment subject was replaced by a real field using the Drupal 7
        // Title module, use the field value instead of the comment subject.
        if ($this->moduleExists('title')) {
            $subject_field = $row->getSourceProperty('subject_field');
            if (isset($subject_field[0]['value'])) {
                $row->setSourceProperty('subject', $subject_field[0]['value']);
            }
        }
        return parent::prepareRow($row);
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return [
            'cid' => $this->t('Comment ID.'),
            'pid' => $this->t('Parent comment ID. If set to 0, this comment is not a reply to an existing comment.'),
            'nid' => $this->t('The {node}.nid to which this comment is a reply.'),
            'uid' => $this->t('The {users}.uid who authored the comment. If set to 0, this comment was created by an anonymous user.'),
            'subject' => $this->t('The comment title.'),
            'comment' => $this->t('The comment body.'),
            'hostname' => $this->t("The author's host name."),
            'created' => $this->t('The time that the comment was created, as a Unix timestamp.'),
            'changed' => $this->t('The time that the comment was edited by its author, as a Unix timestamp.'),
            'status' => $this->t('The published status of a comment. (0 = Published, 1 = Not Published)'),
            'format' => $this->t('The {filter_formats}.format of the comment body.'),
            'thread' => $this->t("The vancode representation of the comment's place in a thread."),
            'name' => $this->t("The comment author's name. Uses {users}.name if the user is logged in, otherwise uses the value typed into the comment form."),
            'mail' => $this->t("The comment author's email address from the comment form, if user is anonymous, and the 'Anonymous users may/must leave their contact information' setting is turned on."),
            'homepage' => $this->t("The comment author's home page address from the comment form, if user is anonymous, and the 'Anonymous users may/must leave their contact information' setting is turned on."),
            'language' => $this->t('The comment language.'),
            'type' => $this->t("The {node}.type to which this comment is a reply."),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['cid']['type'] = 'integer';
        return $ids;
    }

}