class Comment

class Comment extends DrupalSqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = $this->select('comments', 'c')
            ->fields('c', [
            'cid',
            'pid',
            'nid',
            'uid',
            'subject',
            'comment',
            'hostname',
            'timestamp',
            'status',
            'thread',
            'name',
            'mail',
            'homepage',
            'format',
        ]);
        $query->innerJoin('node', 'n', '[c].[nid] = [n].[nid]');
        $query->fields('n', [
            'type',
            'language',
        ]);
        $query->orderBy('c.timestamp');
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        // In D6, status=0 means published, while in D8 means the opposite.
        $row->setSourceProperty('status', !$row->getSourceProperty('status'));
        // If node did not have a language, use site default language as a fallback.
        if (!$row->getSourceProperty('language')) {
            $language_default = $this->variableGet('language_default', NULL);
            $language = $language_default ? $language_default->language : 'en';
            $row->setSourceProperty('language', $language);
        }
        return parent::prepareRow($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."),
            'timestamp' => $this->t('The time that the comment was created, or last 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."),
            'type' => $this->t("The {node}.type to which this comment is a reply."),
            'language' => $this->t("The {node}.language to which this comment is a reply. Site default language is used as a fallback if node does not have a language."),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['cid']['type'] = 'integer';
        return $ids;
    }

}