bbp_get_forum_last_reply_url( int $forum_id )

	function bbp_get_forum_last_reply_url( $forum_id = 0 ) {
		$forum_id = bbp_get_forum_id( $forum_id );

		// If forum has replies, get the last reply and use its url
		$reply_id = bbp_get_forum_last_reply_id( $forum_id );
		if ( !empty( $reply_id ) ) {
			$reply_url = bbp_get_reply_url( $reply_id );

		// No replies, so look for topics and use last permalink
		} else {
			$reply_url = bbp_get_forum_last_topic_permalink( $forum_id );

			// No topics either, so set $reply_url as empty string
			if ( empty( $reply_url ) ) {
				$reply_url = '';
			}
		}

		// Filter and return
		return apply_filters( 'bbp_get_forum_last_reply_url', $reply_url, $forum_id );
	}