/*  PCSX2 - PS2 Emulator for PCs
 *  Copyright (C) 2002-2010  PCSX2 Dev Team
 *
 *  PCSX2 is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU Lesser General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  PCSX2 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 PCSX2.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include <list>
#include <mutex>

// --------------------------------------------------------------------------------------
//  EventSource< template EvtType >
// --------------------------------------------------------------------------------------

template <typename ListenerType>
class EventSource
{
public:
	typedef typename ListenerType::EvtParams EvtParams;
	typedef typename std::list<ListenerType*> ListenerList;
	typedef typename ListenerList::iterator ListenerIterator;

protected:
	typedef typename ListenerList::const_iterator ConstIterator;

	ListenerList m_listeners;

	// This is a cached copy of the listener list used to handle standard dispatching, which
	// allows for self-modification of the EventSource's listener list by the listeners.
	// Translation: The dispatcher uses this copy instead, to avoid iterator invalidation.
	ListenerList m_cache_copy;
	bool m_cache_valid;

	std::mutex m_listeners_lock;

public:
	EventSource()
	{
		m_cache_valid = false;
	}

	virtual ~EventSource() = default;

	virtual ListenerIterator Add(ListenerType& listener);
	virtual void Remove(ListenerType& listener);
	virtual void Remove(const ListenerIterator& listenerHandle);

	void Add(ListenerType* listener)
	{
		if (listener == NULL)
			return;
		Add(*listener);
	}

	void Remove(ListenerType* listener)
	{
		if (listener == NULL)
			return;
		Remove(*listener);
	}

	void Dispatch(const EvtParams& params);

protected:
	virtual ListenerIterator _AddFast_without_lock(ListenerType& listener);
	virtual void _DispatchRaw(ListenerIterator iter, const ListenerIterator& iend, const EvtParams& params);
};

// --------------------------------------------------------------------------------------
//  IEventDispatcher
// --------------------------------------------------------------------------------------
// This class is used as a base interface for EventListeners.  It allows the listeners to do
// customized dispatching of several event types into "user friendly" function overrides.
//
template <typename EvtParams>
class IEventDispatcher
{
protected:
	IEventDispatcher() {}

public:
	virtual ~IEventDispatcher() = default;
	virtual void DispatchEvent(const EvtParams& params) = 0;
};