function bbp_logout_url( $url = '', $redirect_to = '' ) {

	// If there is no redirect in the URL, let's add one...
	if ( ! strstr( $url, 'redirect_to' ) ) {

		// Get the forum root, to maybe use as a default
		$forum_root = bbp_get_root_url();

		// No redirect passed, so check referer and fallback to request uri
		if ( empty( $redirect_to ) ) {

			// Check for a valid referer
			$redirect_to = wp_get_referer();

			// Fallback to request uri if invalid referer
			if ( false === $redirect_to ) {
				$redirect_to = bbp_get_url_scheme() . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
			}
		}

		// Filter the $redirect_to destination
		$filtered  = apply_filters( 'bbp_logout_url_redirect_to', $redirect_to );

		// Validate $redirect_to, default to root
		$validated = wp_validate_redirect( $filtered, $forum_root );

		// Assemble $redirect_to and add it (encoded) to full $url
		$appended  = add_query_arg( array( 'loggedout'   => 'true'   ), $validated );
		$encoded   = urlencode( $appended );
		$url       = add_query_arg( array( 'redirect_to' => $encoded ), $url       );
	}

	// Filter & return
	return apply_filters( 'bbp_logout_url', $url, $redirect_to );
}