bbp_update_reply_walker( int $reply_id, string $last_active_time = '', int $forum_id, int $topic_id, bool $refresh = true )

function bbp_update_reply_walker( $reply_id, $last_active_time = '', $forum_id = 0, $topic_id = 0, $refresh = true ) {

	// Verify the reply ID
	$reply_id = bbp_get_reply_id( $reply_id );

	// Reply was passed
	if ( !empty( $reply_id ) ) {

		// Get the topic ID if none was passed
		if ( empty( $topic_id ) ) {
			$topic_id = bbp_get_reply_topic_id( $reply_id );
		}

		// Get the forum ID if none was passed
		if ( empty( $forum_id ) ) {
			$forum_id = bbp_get_reply_forum_id( $reply_id );
		}
	}

	// Set the active_id based on topic_id/reply_id
	$active_id = empty( $reply_id ) ? $topic_id : $reply_id;

	// Setup ancestors array to walk up
	$ancestors = array_values( array_unique( array_merge( array( $topic_id, $forum_id ), (array) get_post_ancestors( $topic_id ) ) ) );

	// If we want a full refresh, unset any of the possibly passed variables
	if ( true === $refresh )
		$forum_id = $topic_id = $reply_id = $active_id = $last_active_time = 0;

	// Walk up ancestors
	if ( !empty( $ancestors ) ) {
		foreach ( $ancestors as $ancestor ) {

			// Reply meta relating to most recent reply
			if ( bbp_is_reply( $ancestor ) ) {
				// @todo - hierarchical replies

			// Topic meta relating to most recent reply
			} elseif ( bbp_is_topic( $ancestor ) ) {

				// Last reply and active ID's
				bbp_update_topic_last_reply_id ( $ancestor, $reply_id  );
				bbp_update_topic_last_active_id( $ancestor, $active_id );

				// Get the last active time if none was passed
				$topic_last_active_time = $last_active_time;
				if ( empty( $last_active_time ) ) {
					$topic_last_active_time = get_post_field( 'post_date', bbp_get_topic_last_active_id( $ancestor ) );
				}

				// Only update if reply is published
				if ( bbp_is_reply_published( $reply_id ) ) {
					bbp_update_topic_last_active_time( $ancestor, $topic_last_active_time );
				}

				// Counts
				bbp_update_topic_voice_count       ( $ancestor );
				bbp_update_topic_reply_count       ( $ancestor );
				bbp_update_topic_reply_count_hidden( $ancestor );

			// Forum meta relating to most recent topic
			} elseif ( bbp_is_forum( $ancestor ) ) {

				// Last topic and reply ID's
				bbp_update_forum_last_topic_id( $ancestor, $topic_id );
				bbp_update_forum_last_reply_id( $ancestor, $reply_id );

				// Last Active
				bbp_update_forum_last_active_id( $ancestor, $active_id );

				// Get the last active time if none was passed
				$forum_last_active_time = $last_active_time;
				if ( empty( $last_active_time ) ) {
					$forum_last_active_time = get_post_field( 'post_date', bbp_get_forum_last_active_id( $ancestor ) );
				}

				// Only update if reply is published
				if ( bbp_is_reply_published( $reply_id ) ) {
					bbp_update_forum_last_active_time( $ancestor, $forum_last_active_time );
				}

				// Counts
				bbp_update_forum_reply_count( $ancestor );
			}
		}
	}
}