/*
 * Copyright (C) 2006-2015 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2006 Hans Fugal <hans@fugal.net>
 * Copyright (C) 2007-2009 David Robillard <d@drobilla.net>
 * Copyright (C) 2009-2010 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2015-2016 Robin Gareus <robin@gareus.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef __lib_pbd_command_h__
#define __lib_pbd_command_h__

#include <string>

#include "pbd/libpbd_visibility.h"
#include "pbd/signals.h"
#include "pbd/statefuldestructible.h"

/** Base class for Undo/Redo commands and changesets */
class LIBPBD_API Command : public PBD::StatefulDestructible, public PBD::ScopedConnectionList
{
public:
	virtual ~Command() { /* NOTE: derived classes must call drop_references() */ }

	virtual void operator() () = 0;

	void set_name (const std::string& str) { _name = str; }
	const std::string& name() const { return _name; }

	virtual void undo() = 0;
	virtual void redo() { (*this)(); }

	virtual XMLNode& get_state() const;
	virtual int set_state(const XMLNode&, int /*version*/) { /* noop */ return 0; }

	virtual bool empty () const {
		return false;
	}

protected:
	Command() {}
	Command(const std::string& name) : _name(name) {}

	std::string _name;
};

#endif // __lib_pbd_command_h_
