/***************************************************************************
 *   Copyright (C) 2009 by Lothar May                                      *
 *                                                                         *
 *   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.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include <core/timermanager.h>


using namespace std;


TimerManager::TimerManager(boost::shared_ptr<boost::asio::io_service> ioService)
: m_ioService(ioService), m_curTimerId(0)
{
}

unsigned
TimerManager::RegisterTimer(unsigned timeoutMsec, boost::function<void()> timerHandler, bool autoRestart)
{
	// Register a new timer callback.
	boost::recursive_mutex::scoped_lock lock(m_timerMutex);
	// Use a unique id for each timer.
	unsigned id = GetNextTimerId();
	boost::shared_ptr<TimerData> data(new TimerData);
	data->timer.reset(
				new boost::asio::deadline_timer(*m_ioService, boost::posix_time::milliseconds(timeoutMsec)));
	data->id = id;
	data->userHandler = timerHandler;
	data->durationMsec = timeoutMsec;
	data->autoRestart = autoRestart;
	data->cancelled = false;
	data->timer->async_wait(boost::bind(&TimerManager::Handler, this, boost::asio::placeholders::error, data));
	m_timerMap.insert(TimerMap::value_type(id, data));

	return id;
}

bool
TimerManager::UnregisterTimer(unsigned timerId)
{
	// Remove a timer callback from the map.
	boost::recursive_mutex::scoped_lock lock(m_timerMutex);
	bool unregistered = false;
	TimerMap::iterator pos = m_timerMap.find(timerId);
	if (pos != m_timerMap.end())
	{
		pos->second->cancelled = true;
		m_timerMap.erase(pos);
		unregistered = true;
	}
	return unregistered;
}

void
TimerManager::Handler(const boost::system::error_code &ec, boost::shared_ptr<TimerManager::TimerData> data)
{
	boost::recursive_mutex::scoped_lock lock(m_timerMutex);
	if (!ec && data && !data->cancelled)
	{
		data->userHandler();
		if (data->autoRestart)
		{
			data->timer.reset(
				new boost::asio::deadline_timer(*m_ioService, boost::posix_time::milliseconds(data->durationMsec)));
			data->timer->async_wait(boost::bind(&TimerManager::Handler, this, boost::asio::placeholders::error, data));
		}
		else
			UnregisterTimer(data->id);
	}
}

/*void
TimerManager::Process()
{
	boost::recursive_mutex::scoped_lock lock(m_timerMutex);
	bool timerOccurred;
	do
	{
		timerOccurred = false;
		TimerMap::iterator i = m_timerMap.begin();
		if (i != m_timerMap.end())
		{
			// Check whether the timer occured.
			unsigned currentTicks = static_cast<unsigned>(m_softwareTimer.elapsed().total_milliseconds());
			unsigned timerTicks = i->first;
			if (currentTicks >= timerTicks)
			{
				// Grab a copy of the timer.
				TimerData timer = i->second;
				// Remove the timer, re-add if it is repeating.
				m_timerMap.erase(i);
				if (timer.repeat)
				{
					// Re-add the repeating timer.
					// Try to be precise.
					unsigned absoluteTimer = currentTicks + timer.msec;
					unsigned tickDiff = currentTicks - timerTicks;
					if (absoluteTimer >= tickDiff)
						absoluteTimer -= tickDiff;
					m_timerMap.insert(
						TimerMap::value_type(absoluteTimer, timer));
				}

				// The callback may register/unregister a timer (a recursive mutex is used).
				timer.handler();
				timerOccurred = true;
			}
		}
	} while (timerOccurred);
}*/

unsigned
TimerManager::GetNextTimerId()
{
	++m_curTimerId;
	if (m_curTimerId == 0) // Id 0 is invalid.
		++m_curTimerId;
	return m_curTimerId;
}