/*
  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_CLIENT_THREADEDSIGCLIENTINTERFACE_HPP
#define INGEN_CLIENT_THREADEDSIGCLIENTINTERFACE_HPP

#include <stdint.h>

#include <string>

#undef nil
#include <sigc++/sigc++.h>
#include <glibmm/thread.h>

#include "ingen/Atom.hpp"
#include "ingen/Interface.hpp"
#include "ingen/client/SigClientInterface.hpp"
#include "ingen/ingen.h"
#include "raul/SRSWQueue.hpp"

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

namespace Ingen {

class Interface;

namespace Client {

/** A LibSigC++ signal emitting interface for clients to use.
 *
 * This emits signals (possibly) in a different thread than the ClientInterface
 * functions are called.  It must be explicitly driven with the emit_signals()
 * function, which fires all enqueued signals up until the present.  You can
 * use this in a GTK idle callback for receiving thread safe engine signals.
 *
 * @ingroup IngenClient
 */
class INGEN_API ThreadedSigClientInterface : public SigClientInterface
{
public:
	explicit ThreadedSigClientInterface(uint32_t queue_size)
		: _sigs(queue_size)
		, response_slot(_signal_response.make_slot())
		, error_slot(_signal_error.make_slot())
		, put_slot(_signal_put.make_slot())
		, connection_slot(_signal_connection.make_slot())
		, object_deleted_slot(_signal_object_deleted.make_slot())
		, object_moved_slot(_signal_object_moved.make_slot())
		, object_copied_slot(_signal_object_copied.make_slot())
		, disconnection_slot(_signal_disconnection.make_slot())
		, disconnect_all_slot(_signal_disconnect_all.make_slot())
		, property_change_slot(_signal_property_change.make_slot())
	{}

	virtual Raul::URI uri() const { return Raul::URI("ingen:/clients/sig_queue"); }

	void bundle_begin()
	{ push_sig(bundle_begin_slot); }

	void bundle_end()
	{ push_sig(bundle_end_slot); }

	void response(int32_t id, Status status, const std::string& subject)
	{ push_sig(sigc::bind(response_slot, id, status, subject)); }

	void error(const std::string& msg)
	{ push_sig(sigc::bind(error_slot, msg)); }

	void put(const Raul::URI&  path,
	         const Properties& properties,
	         Resource::Graph   ctx = Resource::Graph::DEFAULT)
	{ push_sig(sigc::bind(put_slot, path, properties, ctx)); }

	void delta(const Raul::URI&  path,
	           const Properties& remove,
	           const Properties& add,
	           Resource::Graph   ctx = Resource::Graph::DEFAULT)
	{ push_sig(sigc::bind(delta_slot, path, remove, add, ctx)); }

	void connect(const Raul::Path& tail, const Raul::Path& head)
	{ push_sig(sigc::bind(connection_slot, tail, head)); }

	void del(const Raul::URI& uri)
	{ push_sig(sigc::bind(object_deleted_slot, uri)); }

	void move(const Raul::Path& old_path, const Raul::Path& new_path)
	{ push_sig(sigc::bind(object_moved_slot, old_path, new_path)); }

	void copy(const Raul::URI& old_uri, const Raul::URI& new_uri)
	{ push_sig(sigc::bind(object_copied_slot, old_uri, new_uri)); }

	void disconnect(const Raul::Path& tail, const Raul::Path& head)
	{ push_sig(sigc::bind(disconnection_slot, tail, head)); }

	void disconnect_all(const Raul::Path& graph, const Raul::Path& path)
	{ push_sig(sigc::bind(disconnect_all_slot, graph, path)); }

	void set_property(const Raul::URI& subject,
	                  const Raul::URI& key,
	                  const Atom&      value,
	                  Resource::Graph  ctx = Resource::Graph::DEFAULT)
	{ push_sig(sigc::bind(property_change_slot, subject, key, value, ctx)); }

	/** Process all queued events - Called from GTK thread to emit signals. */
	bool emit_signals() {
		// Process a limited number of events, to prevent locking the GTK
		// thread indefinitely while processing continually arriving events

		size_t num_processed = 0;
		while (!_sigs.empty() && num_processed++ < (_sigs.capacity() * 3 / 4)) {
			Closure& ev = _sigs.front();
			ev();
			ev.disconnect();
			_sigs.pop();
		}

		_mutex.lock();
		_cond.broadcast();
		_mutex.unlock();

		return true;
	}

private:
	void push_sig(Closure ev) {
		bool success = false;
		while (!success) {
			success = _sigs.push(ev);
			if (!success) {
				_mutex.lock();
				_cond.wait(_mutex);
				_mutex.unlock();
			}
		}
	}

	Glib::Mutex _mutex;
	Glib::Cond  _cond;

	Raul::SRSWQueue<Closure> _sigs;

	using Graph = Resource::Graph;
	using Path  = Raul::Path;
	using URI   = Raul::URI;

	sigc::slot<void>                                     bundle_begin_slot;
	sigc::slot<void>                                     bundle_end_slot;
	sigc::slot<void, int32_t, Status, std::string>       response_slot;
	sigc::slot<void, std::string>                        error_slot;
	sigc::slot<void, URI, URI, Raul::Symbol>             new_plugin_slot;
	sigc::slot<void, URI, Properties, Graph>             put_slot;
	sigc::slot<void, URI, Properties, Properties, Graph> delta_slot;
	sigc::slot<void, Path, Path>                         connection_slot;
	sigc::slot<void, URI>                                object_deleted_slot;
	sigc::slot<void, Path, Path>                         object_moved_slot;
	sigc::slot<void, URI, URI>                           object_copied_slot;
	sigc::slot<void, Path, Path>                         disconnection_slot;
	sigc::slot<void, Path, Path>                         disconnect_all_slot;
	sigc::slot<void, URI, URI, Atom, Graph>              property_change_slot;
};

} // namespace Client
} // namespace Ingen

#endif