bbp_get_reply_ancestor_id( in $reply_id )

	function bbp_get_reply_ancestor_id( $reply_id = 0 ) {

		// Validation
		$reply_id = bbp_get_reply_id( $reply_id );
		if ( empty( $reply_id ) )
			return false;

		// Find highest reply ancestor
		$ancestor_id = $reply_id;
		while ( $parent_id = bbp_get_reply_to( $ancestor_id ) ) {
			if ( empty( $parent_id ) || ( $parent_id === $ancestor_id ) || ( bbp_get_reply_topic_id( $reply_id ) === $parent_id ) || ( $parent_id === $reply_id ) ) {
				break;
			}
			$ancestor_id = $parent_id;
		}

		return (int) $ancestor_id;
	}