/*
 * Copyright (C) 2004-2015 L2J Server
 * 
 * This file is part of L2J Server.
 * 
 * L2J Server 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 3 of the License, or
 * (at your option) any later version.
 * 
 * L2J Server 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, see <http://www.gnu.org/licenses/>.
 */
package com.l2jserver.gameserver.network;

import com.l2jserver.Config;

public class ClientStats
{
	public int processedPackets = 0;
	public int droppedPackets = 0;
	public int unknownPackets = 0;
	public int totalQueueSize = 0;
	public int maxQueueSize = 0;
	public int totalBursts = 0;
	public int maxBurstSize = 0;
	public int shortFloods = 0;
	public int longFloods = 0;
	public int totalQueueOverflows = 0;
	public int totalUnderflowExceptions = 0;
	
	private final int[] _packetsInSecond;
	private long _packetCountStartTick = 0;
	private int _head;
	private int _totalCount = 0;
	
	private int _floodsInMin = 0;
	private long _floodStartTick = 0;
	private int _unknownPacketsInMin = 0;
	private long _unknownPacketStartTick = 0;
	private int _overflowsInMin = 0;
	private long _overflowStartTick = 0;
	private int _underflowReadsInMin = 0;
	private long _underflowReadStartTick = 0;
	
	private volatile boolean _floodDetected = false;
	private volatile boolean _queueOverflowDetected = false;
	
	private final int BUFFER_SIZE;
	
	public ClientStats()
	{
		BUFFER_SIZE = Config.CLIENT_PACKET_QUEUE_MEASURE_INTERVAL;
		_packetsInSecond = new int[BUFFER_SIZE];
		_head = BUFFER_SIZE - 1;
	}
	
	/**
	 * @return true if incoming packet need to be dropped
	 */
	protected final boolean dropPacket()
	{
		final boolean result = _floodDetected || _queueOverflowDetected;
		if (result)
		{
			droppedPackets++;
		}
		return result;
	}
	
	/**
	 * Later during flood returns true (and send ActionFailed) once per second.
	 * @param queueSize
	 * @return true if flood detected first and ActionFailed packet need to be sent.
	 */
	protected final boolean countPacket(int queueSize)
	{
		processedPackets++;
		totalQueueSize += queueSize;
		if (maxQueueSize < queueSize)
		{
			maxQueueSize = queueSize;
		}
		if (_queueOverflowDetected && (queueSize < 2))
		{
			_queueOverflowDetected = false;
		}
		
		return countPacket();
	}
	
	/**
	 * @return Counts unknown packets and return true if threshold is reached.
	 */
	protected final boolean countUnknownPacket()
	{
		unknownPackets++;
		
		final long tick = System.currentTimeMillis();
		if ((tick - _unknownPacketStartTick) > 60000)
		{
			_unknownPacketStartTick = tick;
			_unknownPacketsInMin = 1;
			return false;
		}
		
		_unknownPacketsInMin++;
		return _unknownPacketsInMin > Config.CLIENT_PACKET_QUEUE_MAX_UNKNOWN_PER_MIN;
	}
	
	/**
	 * @param count - current number of processed packets in burst
	 * @return burst length and return true if execution of the queue need to be aborted.
	 */
	protected final boolean countBurst(int count)
	{
		if (count > maxBurstSize)
		{
			maxBurstSize = count;
		}
		
		if (count < Config.CLIENT_PACKET_QUEUE_MAX_BURST_SIZE)
		{
			return false;
		}
		
		totalBursts++;
		return true;
	}
	
	/**
	 * @return Counts queue overflows and return true if threshold is reached.
	 */
	protected final boolean countQueueOverflow()
	{
		_queueOverflowDetected = true;
		totalQueueOverflows++;
		
		final long tick = System.currentTimeMillis();
		if ((tick - _overflowStartTick) > 60000)
		{
			_overflowStartTick = tick;
			_overflowsInMin = 1;
			return false;
		}
		
		_overflowsInMin++;
		return _overflowsInMin > Config.CLIENT_PACKET_QUEUE_MAX_OVERFLOWS_PER_MIN;
	}
	
	/**
	 * @return Counts underflow exceptions and return true if threshold is reached.
	 */
	protected final boolean countUnderflowException()
	{
		totalUnderflowExceptions++;
		
		final long tick = System.currentTimeMillis();
		if ((tick - _underflowReadStartTick) > 60000)
		{
			_underflowReadStartTick = tick;
			_underflowReadsInMin = 1;
			return false;
		}
		
		_underflowReadsInMin++;
		return _underflowReadsInMin > Config.CLIENT_PACKET_QUEUE_MAX_UNDERFLOWS_PER_MIN;
	}
	
	/**
	 * @return true if maximum number of floods per minute is reached.
	 */
	protected final boolean countFloods()
	{
		return _floodsInMin > Config.CLIENT_PACKET_QUEUE_MAX_FLOODS_PER_MIN;
	}
	
	private final boolean longFloodDetected()
	{
		return (_totalCount / BUFFER_SIZE) > Config.CLIENT_PACKET_QUEUE_MAX_AVERAGE_PACKETS_PER_SECOND;
	}
	
	/**
	 * Later during flood returns true (and send ActionFailed) once per second.
	 * @return true if flood detected first and ActionFailed packet need to be sent.
	 */
	private final synchronized boolean countPacket()
	{
		_totalCount++;
		final long tick = System.currentTimeMillis();
		if ((tick - _packetCountStartTick) > 1000)
		{
			_packetCountStartTick = tick;
			
			// clear flag if no more flooding during last seconds
			if (_floodDetected && !longFloodDetected() && (_packetsInSecond[_head] < (Config.CLIENT_PACKET_QUEUE_MAX_PACKETS_PER_SECOND / 2)))
			{
				_floodDetected = false;
			}
			
			// wrap head of the buffer around the tail
			if (_head <= 0)
			{
				_head = BUFFER_SIZE;
			}
			_head--;
			
			_totalCount -= _packetsInSecond[_head];
			_packetsInSecond[_head] = 1;
			return _floodDetected;
		}
		
		final int count = ++_packetsInSecond[_head];
		if (!_floodDetected)
		{
			if (count > Config.CLIENT_PACKET_QUEUE_MAX_PACKETS_PER_SECOND)
			{
				shortFloods++;
			}
			else if (longFloodDetected())
			{
				longFloods++;
			}
			else
			{
				return false;
			}
			
			_floodDetected = true;
			if ((tick - _floodStartTick) > 60000)
			{
				_floodStartTick = tick;
				_floodsInMin = 1;
			}
			else
			{
				_floodsInMin++;
			}
			
			return true; // Return true only in the beginning of the flood
		}
		
		return false;
	}
}