//-----------------------------------------------------------------------------
//
//	CRC16Encap.cpp
//
//	Implementation of the Z-Wave COMMAND_CLASS_CRC_16_ENCAP
//
//	Copyright (c) 2012 Greg Satz <satz@iranger.com>
//
//	SOFTWARE NOTICE AND LICENSE
//
//	This file is part of OpenZWave.
//
//	OpenZWave 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 Foundation, either version 3 of the License,
//	or (at your option) any later version.
//
//	OpenZWave 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 Lesser General Public License for more details.
//
//	You should have received a copy of the GNU Lesser General Public License
//	along with OpenZWave.  If not, see <http://www.gnu.org/licenses/>.
//
//-----------------------------------------------------------------------------

#include "command_classes/CommandClasses.h"
#include "command_classes/CRC16Encap.h"
#include "Defs.h"
#include "Msg.h"
#include "Node.h"
#include "Driver.h"
#include "platform/Log.h"

namespace OpenZWave
{
	namespace Internal
	{
		namespace CC
		{

//
// CRC-CCITT (0x1D0F)
//
			uint16 crc16(uint8 const * data_p, uint32 const _length)
			{
				uint8 x;
				uint16 crc = 0xF6AF; // 0x1D0F with first byte 0x56;
				uint32 length = _length;

				while (length--)
				{
					x = crc >> 8 ^ *data_p++;
					x ^= x >> 4;
					crc = (crc << 8) ^ ((uint16) (x << 12)) ^ ((uint16) (x << 5)) ^ ((uint16) x);
				}
				return crc;
			}

			enum CRC16EncapCmd
			{
				CRC16EncapCmd_Encap = 0x01
			};

//-----------------------------------------------------------------------------
// <CRC16Encap::HandleMsg>
// Handle a message from the Z-Wave network
//-----------------------------------------------------------------------------
			bool CRC16Encap::HandleMsg(uint8 const* _data, uint32 const _length, uint32 const _instance	// = 1
					)
			{
				if (CRC16EncapCmd_Encap == (CRC16EncapCmd) _data[0])
				{
					Log::Write(LogLevel_Info, GetNodeId(), "Received CRC16-command from node %d", GetNodeId());

					uint16 crcM = (_data[_length - 3] << 8) + _data[_length - 2]; // crc as reported in msg
					uint16 crcC = crc16(&_data[0], _length - 3);				   // crc calculated

					if (crcM != crcC)
					{
						Log::Write(LogLevel_Info, GetNodeId(), "CRC check failed, message contains 0x%.4x but should be 0x%.4x", crcM, crcC);
						return false;
					}

					if (Node const* node = GetNodeUnsafe())
					{
						uint8 commandClassId = _data[1];

						if (CommandClass* pCommandClass = node->GetCommandClass(commandClassId))
						{
							if (!pCommandClass->IsAfterMark())
							{
								pCommandClass->HandleMsg(&_data[2], _length - 4);
							}
							else
							{
								pCommandClass->HandleIncomingMsg(&_data[2], _length - 4);
							}
						}
					}

					return true;
				}
				return false;
			}
		} // namespace CC
	} // namespace Internal
} // namespace OpenZWave