Exclude a bbPress Forum, all of it's Topics, and all Replies for those Topics from SearchWP results

gistfile1.php

<?php

// exclude anything to do with Forum ID 133643 from search results in SearchWP
function my_exclude_private_bbpress_forum_and_children( $ids, $engine, $terms ) {
	$forum_id = 133643;

	// exclude Topics from that Forum
	$topic_args = array(
		'post_type' => 'topic',
		'posts_per_page' => -1,
		'fields' => 'ids',
		'post_parent' => $forum_id,
		'suppress_filters' => true,
	);
	$topic_ids = new WP_Query( $topic_args );
	$topic_ids = $topic_ids->posts;

	// if there are no posts we get array( 0 => '0' ) back
	if ( 1 == count( $topic_ids ) && $topic_ids[0] == 0 ) {
		$topic_ids = array();
	}

	// exclude Replies to those Topics
	$reply_args = array(
		'post_type' => 'reply',
		'posts_per_page' => -1,
		'fields' => 'ids',
		'post_parent__in' => $topic_ids,
		'suppress_filters' => true,
	);
	$reply_ids = new WP_Query( $reply_args );
	$reply_ids = $reply_ids->posts;

	// if there are no posts we get array( 0 => '0' ) back
	if ( 1 == count( $reply_ids ) && $reply_ids[0] == 0 ) {
		$reply_ids = array();
	}

	$ids = array_merge( $ids, array( $forum_id ), $topic_ids, $reply_ids );

	return $ids;
}

add_filter( 'searchwp_exclude', 'my_exclude_private_bbpress_forum_and_children', 10, 3 );