/***************************************************************************
 *   Copyright (C) 2005 by Joris Guisson                                   *
 *   joris.guisson@gmail.com                                               *
 *                                                                         *
 *   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.          *
 ***************************************************************************/
#include "socketgroup.h"
#include <math.h>
#include <util/log.h>
#include <util/functions.h>
#include "trafficshapedsocket.h"
		
using namespace bt;

namespace net
{

	SocketGroup::SocketGroup(Uint32 limit,Uint32 assured_rate) : limit(limit),assured_rate(assured_rate)
	{
		prev_run_time = bt::CurrentTime();
		group_allowance = 0;
		group_assured = 0;
	}


	SocketGroup::~SocketGroup()
	{}

	void SocketGroup::processUnlimited(bool up,bt::TimeStamp now)
	{
		std::list<TrafficShapedSocket*>::iterator i = sockets.begin();
		while (i != sockets.end())
		{
			TrafficShapedSocket* s = *i;
			if (s)
			{
				if (up)
					s->write(0,now);
				else
					s->read(0,now);
			}
			++i;
		}
	}
	
	bool SocketGroup::processLimited(bool up,bt::TimeStamp now,Uint32 & allowance)
	{
		Uint32 bslot = allowance / sockets.size() + 1;
	
		std::list<TrafficShapedSocket*>::iterator itr = sockets.begin();
		
		// while we can send and there are sockets left to send
		while (sockets.size() > 0 && allowance > 0)
		{
			Uint32 as = bslot;
			if (as > allowance)
				as = allowance;
			
			TrafficShapedSocket* s = *itr;
			if (s)
			{
				Uint32 ret = 0;
				if (up)
					ret = s->write(as,now);
				else
					ret = s->read(as,now);
				
				// if this socket did what it was supposed to do, 
				// it can have another go if stuff is leftover
				// if it doesn't, we erase it from the list
				if (ret != as) 
					itr = sockets.erase(itr);
				else
					++itr;
			
				if (ret > allowance)
					allowance = 0;
				else
					allowance -= ret;
			}
			else
			{
				// 0 pointer so just erase
				itr = sockets.erase(itr);
			}

			// wrap around if necessary
			if (itr == sockets.end())
				itr = sockets.begin();
		}
		
		return sockets.size() > 0;
	}
	
	bool SocketGroup::download(Uint32 & global_allowance,bt::TimeStamp now)
	{
		return process(false,now,global_allowance);	
	}
	
	bool SocketGroup::upload(Uint32 & global_allowance,bt::TimeStamp now)
	{
		return process(true,now,global_allowance);
	}
	
	void SocketGroup::calcAllowance(bt::TimeStamp now)
	{
		if (limit > 0)
			group_allowance = (Uint32)ceil(1.0 * limit * (now - prev_run_time) * 0.001);
		else
			group_allowance = 0;
		
		if (assured_rate > 0)
			group_assured = (Uint32)ceil(1.0 * assured_rate * (now - prev_run_time) * 0.001);
		else
			group_assured = 0;
		
		prev_run_time = now;
	}
	
	bool SocketGroup::process(bool up,bt::TimeStamp now,Uint32 & global_allowance)
	{
		if (limit > 0)
		{	
			if (group_allowance == 0)
			{
				clear();
				return false;
			}
			
			bool ret = false;
			if (global_allowance == 0)
			{
				Uint32 p = group_allowance;
				ret = processLimited(up,now,p);
				group_allowance = p;
			}
			else if (global_allowance <= group_allowance)
			{
				Uint32 tmp = global_allowance;	
				ret = processLimited(up,now,tmp);
				
				Uint32 done = (global_allowance - tmp);
				if (group_allowance < done)
					group_allowance = 0;
				else
					group_allowance -= done;
				
				global_allowance = tmp;
			}
			else
			{
				Uint32 p = group_allowance;
				ret = processLimited(up,now,p);
				
				Uint32 done = (group_allowance - p);
				if (global_allowance < done)
					global_allowance = 0;
				else
					global_allowance -= done;
				
				group_allowance = p;
			}
			
			// if group allowance is used up, this group can no longer do anything
			if (group_allowance == 0)
			{
				clear();
				return false;
			}
			else
				return ret;
		}
		else if (global_allowance > 0)
		{
			return processLimited(up,now,global_allowance);
		}
		else
		{
			processUnlimited(up,now);
			return false;
		}
	}
		


}
