wp_filter_comment

 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param array $commentdata {
 *     Array of arguments for inserting a new comment.
 *
 *     @type string     $comment_agent        The HTTP user agent of the `$comment_author` when
 *                                            the comment was submitted. Default empty.
 *     @type int|string $comment_approved     Whether the comment has been approved. Default 1.
 *     @type string     $comment_author       The name of the author of the comment. Default empty.
 *     @type string     $comment_author_email The email address of the `$comment_author`. Default empty.
 *     @type string     $comment_author_IP    The IP address of the `$comment_author`. Default empty.
 *     @type string     $comment_author_url   The URL address of the `$comment_author`. Default empty.
 *     @type string     $comment_content      The content of the comment. Default empty.
 *     @type string     $comment_date         The date the comment was submitted. To set the date
 *                                            manually, `$comment_date_gmt` must also be specified.
 *                                            Default is the current time.
 *     @type string     $comment_date_gmt     The date the comment was submitted in the GMT timezone.
 *                                            Default is `$comment_date` in the site's GMT timezone.
 *     @type int        $comment_karma        The karma of the comment. Default 0.
 *     @type int        $comment_parent       ID of this comment's parent, if any. Default 0.
 *     @type int        $comment_post_ID      ID of the post that relates to the comment, if any.
 *                                            Default 0.
 *     @type string     $comment_type         Comment type. Default 'comment'.
 *     @type array      $comment_meta         Optional. Array of key/value pairs to be stored in commentmeta for the
 *                                            new comment.
 *     @type int        $user_id              ID of the user who submitted the comment. Default 0.
 * }
 * @return int|false The new comment's ID on success, false on failure.
 */
function wp_insert_comment( $commentdata ) {
	global $wpdb;
	$data = wp_unslash( $commentdata );

	$comment_author       = ! isset( $data['comment_author'] ) ? '' : $data['comment_author'];
	$comment_author_email = ! isset( $data['comment_author_email'] ) ? '' : $data['comment_author_email'];
	$comment_author_url   = ! isset( $data['comment_author_url'] ) ? '' : $data['comment_author_url'];
	$comment_author_IP    = ! isset( $data['comment_author_IP'] ) ? '' : $data['comment_author_IP'];

	$comment_date     = ! isset( $data['comment_date'] ) ? current_time( 'mysql' ) : $data['comment_date'];
	$comment_date_gmt = ! isset( $data['comment_date_gmt'] ) ? get_gmt_from_date( $comment_date ) : $data['comment_date_gmt'];

	$comment_post_ID  = ! isset( $data['comment_post_ID'] ) ? 0 : $data['comment_post_ID'];
	$comment_content  = ! isset( $data['comment_content'] ) ? '' : $data['comment_content'];
	$comment_karma    = ! isset( $data['comment_karma'] ) ? 0 : $data['comment_karma'];
	$comment_approved = ! isset( $data['comment_approved'] ) ? 1 : $data['comment_approved'];
	$comment_agent    = ! isset( $data['comment_agent'] ) ? '' : $data['comment_agent'];
	$comment_type     = empty( $data['comment_type'] ) ? 'comment' : $data['comment_type'];
	$comment_parent   = ! isset( $data['comment_parent'] ) ? 0 : $data['comment_parent'];

	$user_id = ! isset( $data['user_id'] ) ? 0 : $data['user_id'];