bbp_unspam_topic( int $topic_id )

function bbp_unspam_topic( $topic_id = 0 ) {

	// Get the topic
	$topic = bbp_get_topic( $topic_id );
	if ( empty( $topic ) )
		return $topic;

	// Bail if already not spam
	if ( bbp_get_spam_status_id() !== $topic->post_status )
		return false;

	// Execute pre unspam code
	do_action( 'bbp_unspam_topic', $topic_id );

	/** Untrash Replies *******************************************************/

	// Get the replies that were not previously trashed
	$pre_spammed_replies = get_post_meta( $topic_id, '_bbp_pre_spammed_replies', true );

	// There are replies to untrash
	if ( !empty( $pre_spammed_replies ) ) {

		// Maybe reverse the trashed replies array
		if ( is_array( $pre_spammed_replies ) )
			$pre_spammed_replies = array_reverse( $pre_spammed_replies );

		// Loop through replies
		foreach ( (array) $pre_spammed_replies as $reply ) {
			wp_untrash_post( $reply );
		}
	}

	/** Topic Tags ************************************************************/

	// Get pre-spam topic tags
	$terms = get_post_meta( $topic_id, '_bbp_spam_topic_tags', true );

	// Topic had tags before it was spammed
	if ( !empty( $terms ) ) {

		// Set the tax_input of the topic
		$topic->tax_input = array( bbp_get_topic_tag_tax_id() => $terms );

		// Delete pre-spam topic tag meta
		delete_post_meta( $topic_id, '_bbp_spam_topic_tags' );
	}

	/** Topic Status **********************************************************/

	// Get pre spam status
	$topic_status = get_post_meta( $topic_id, '_bbp_spam_meta_status', true );

	// If no previous status, default to publish
	if ( empty( $topic_status ) ) {
		$topic_status = bbp_get_public_status_id();
	}

	// Set post status to pre spam
	$topic->post_status = $topic_status;

	// Delete pre spam meta
	delete_post_meta( $topic_id, '_bbp_spam_meta_status' );

	// No revisions
	remove_action( 'pre_post_update', 'wp_save_post_revision' );

	// Update the topic
	$topic_id = wp_update_post( $topic );

	// Execute post unspam code
	do_action( 'bbp_unspammed_topic', $topic_id );

	// Return topic_id
	return $topic_id;
}