function bbp_toggle_topic_handler( $action = '' ) {

	// Bail if required GET actions aren't passed
	if ( empty( $_GET['topic_id'] ) ) {
		return;
	}

	// What's the topic id?
	$topic_id = bbp_get_topic_id( (int) $_GET['topic_id'] );

	// Get possible topic-handler toggles
	$toggles = bbp_get_topic_toggles( $topic_id );

	// Bail if actions aren't meant for this function
	if ( ! in_array( $action, $toggles, true ) ) {
		return;
	}

	// Make sure topic exists
	$topic = bbp_get_topic( $topic_id );
	if ( empty( $topic ) ) {
		bbp_add_error( 'bbp_toggle_topic_missing', __( '<strong>ERROR</strong>: This topic could not be found or no longer exists.', 'bbpress' ) );
		return;
	}

	// What is the user doing here?
	if ( ! current_user_can( 'edit_topic', $topic_id ) || ( 'bbp_toggle_topic_trash' === $action && ! current_user_can( 'delete_topic', $topic_id ) ) ) {
		bbp_add_error( 'bbp_toggle_topic_permission', __( '<strong>ERROR</strong>: You do not have permission to do that.', 'bbpress' ) );
		return;
	}

	// Sub-action?
	$sub_action = ! empty( $_GET['sub_action'] )
		? sanitize_key( $_GET['sub_action'] )
		: false;

	// Preliminary array
	$post_data = array( 'ID' => $topic_id );

	// Do the topic toggling
	$retval = bbp_toggle_topic( array(
		'id'         => $topic_id,
		'action'     => $action,
		'sub_action' => $sub_action,
		'data'       => $post_data
	) );

	// Do additional topic toggle actions
	do_action( 'bbp_toggle_topic_handler', $retval['status'], $post_data, $action );

	// No errors
	if ( ( false !== $retval['status'] ) && ! is_wp_error( $retval['status'] ) ) {
		bbp_redirect( $retval['redirect_to'] );

	// Handle errors
	} else {
		bbp_add_error( 'bbp_toggle_topic', $retval['message'] );
	}
}