How to get attachment urls after saving topic

I want insert details of topics into the database after the topic is saved. Which hook should I use so that the attachment url is available?

I am using code similar to this:

function add_news_after_topic_save( $post_id )
{
    global $wpdb;

    $args = array( 'post_type' => 'attachment', 'post_parent' => $post_id );
    $attachments = get_posts($args);

    if ($attachments) {
	foreach ( $attachments as $attachment ) {
		$attached_url = get_the_attachment_link( $attachment->ID , false );
	}
    }

    $message = 'New topic added in Forum_Name <img src="' . $attached_url . '" alt="" />';
		$url = bbp_get_topic_permalink();
		$matches = array('nid' => $nid);
		$data = array('news' => '<a href=\''.$url.'\'>'.$message.'</a>');

    $wpdb->update( "$wpdb->news", $data, $matches);

}
add_action("bbp_new_topic", "add_news_after_topic_save", 10, 4);

I have tried various different hooks but don’t seem to be able to retrieve the attachment urls successfully. Can you advise?

Thanks in advance

https://wordpress.org/plugins/bbpress-multi-image-uploader/