bp_document_update_activity_privacy( int $activity_id, string $privacy = '' )

function bp_document_update_activity_privacy( $activity_id = 0, $privacy = '' ) {
	global $wpdb, $bp;

	if ( empty( $activity_id ) || empty( $privacy ) ) {
		return;
	}

	// Update privacy for the documents which are uploaded in root of the documents.
	$document_ids = bp_activity_get_meta( $activity_id, 'bp_document_ids', true );
	if ( ! empty( $document_ids ) ) {
		$document_ids = explode( ',', $document_ids );
		if ( ! empty( $document_ids ) ) {
			foreach ( $document_ids as $id ) {
				$document = new BP_Document( $id );
				if ( empty( $document->folder_id ) ) {
					$q = $wpdb->prepare( "UPDATE {$bp->document->table_name} SET privacy = %s WHERE id = %d", $privacy, $id );
					$wpdb->query( $q );
				}
			}
		}
	}
}