/*
  This file is part of Ingen.
  Copyright 2007-2015 David Robillard <http://drobilla.net/>

  Ingen is free software: you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free
  Software Foundation, either version 3 of the License, or any later version.

  Ingen 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 Affero General Public License for details.

  You should have received a copy of the GNU Affero General Public License
  along with Ingen.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef INGEN_GUI_THREADEDLOADER_HPP
#define INGEN_GUI_THREADEDLOADER_HPP

#include "ingen/FilePath.hpp"
#include "raul/Semaphore.hpp"

#include <sigc++/functors/slot.h>

#include <list>
#include <memory>
#include <mutex>
#include <optional>
#include <thread>

namespace raul {
class Path;
class Symbol;
} // namespace raul

namespace ingen {

class Interface;
class Parser;
class Properties;
class URI;

namespace client {
class GraphModel;
} // namespace client

namespace gui {

class App;

/** Thread for loading graph files.
 *
 * This is a seperate thread so it can send all the loading message without
 * blocking everything else, so the app can respond to the incoming events
 * caused as a result of the graph loading, while the graph loads.
 *
 * Implemented as a slave with a list of closures (events) which processes
 * all events in the (mutex protected) list each time it's whipped.
 *
 * \ingroup GUI
 */
class ThreadedLoader
{
public:
	ThreadedLoader(App&            app,
	               std::shared_ptr<Interface> engine);

	~ThreadedLoader();

	void load_graph(bool                               merge,
	                const FilePath&                    file_path,
	                const std::optional<raul::Path>&   engine_parent,
	                const std::optional<raul::Symbol>& engine_symbol,
	                const std::optional<Properties>&   engine_data);

	void save_graph(const std::shared_ptr<const client::GraphModel>& model,
	                const URI&                                       uri);

	std::shared_ptr<Parser> parser();

private:
	void load_graph_event(const FilePath&                    file_path,
	                      const std::optional<raul::Path>&   engine_parent,
	                      const std::optional<raul::Symbol>& engine_symbol,
	                      const std::optional<Properties>&   engine_data);

	void
	save_graph_event(const std::shared_ptr<const client::GraphModel>& model,
	                 const URI&                                       uri);

	/** Returns nothing and takes no parameters (because they have all been bound) */
	using Closure = sigc::slot<void>;

	void run();

	App&                       _app;
	raul::Semaphore            _sem{0};
	std::shared_ptr<Interface> _engine;
	std::mutex                 _mutex;
	std::list<Closure>         _events;
	bool                       _exit_flag{false};
	std::thread                _thread;
};

} // namespace gui
} // namespace ingen

#endif // INGEN_GUI_LOADERRTHREAD_HPP