/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
#include <base/system.h>

#include <string.h> /* strlen */

#include "e_config.h"
#include "e_engine.h"
#include "e_network.h"
#include "e_huffman.h"

void CNetRecvUnpacker::Clear()
{
	m_Valid = false;
}

void CNetRecvUnpacker::Start(const NETADDR *pAddr, CNetConnection *pConnection, int ClientID)
{
	m_Addr = *pAddr;
	m_pConnection = pConnection;
	m_ClientID = ClientID;
	m_CurrentChunk = 0;
	m_Valid = true;
}

/* TODO: rename this function */
int CNetRecvUnpacker::FetchChunk(CNetChunk *pChunk)
{
	CNetChunkHeader Header;
	unsigned char *pEnd = m_Data.m_aChunkData + m_Data.m_DataSize;
	
	while(1)
	{
		unsigned char *pData = m_Data.m_aChunkData;
		
		/* check for old data to unpack */
		if(!m_Valid || m_CurrentChunk >= m_Data.m_NumChunks)
		{
			Clear();
			return 0;
		}
		
		/* TODO: add checking here so we don't read too far */
		for(int i = 0; i < m_CurrentChunk; i++)
		{
			pData = Header.Unpack(pData);
			pData += Header.m_Size;
		}
		
		/* unpack the header */
		pData = Header.Unpack(pData);
		m_CurrentChunk++;
		
		if(pData+Header.m_Size > pEnd)
		{
			Clear();
			return 0;
		}
		
		/* handle sequence stuff */
		if(m_pConnection && (Header.m_Flags&NET_CHUNKFLAG_VITAL))
		{
			if(Header.m_Sequence == (m_pConnection->m_Ack+1)%NET_MAX_SEQUENCE)
			{
				/* in sequence */
				m_pConnection->m_Ack = (m_pConnection->m_Ack+1)%NET_MAX_SEQUENCE;
			}
			else
			{
				/* old packet that we already got */
				if(CNetBase::IsSeqInBackroom(Header.m_Sequence, m_pConnection->m_Ack))
					continue;

				/* out of sequence, request resend */
				if(config.debug)
					dbg_msg("conn", "asking for resend %d %d", Header.m_Sequence, (m_pConnection->m_Ack+1)%NET_MAX_SEQUENCE);
				m_pConnection->SignalResend();
				continue; /* take the next chunk in the packet */
			}
		}
		
		/* fill in the info */
		pChunk->m_ClientID = m_ClientID;
		pChunk->m_Address = m_Addr;
		pChunk->m_Flags = 0;
		pChunk->m_DataSize = Header.m_Size;
		pChunk->m_pData = pData;
		return 1;
	}
}

/* packs the data tight and sends it */
void CNetBase::SendPacketConnless(NETSOCKET Socket, NETADDR *pAddr, const void *pData, int DataSize)
{
	unsigned char aBuffer[NET_MAX_PACKETSIZE];
	aBuffer[0] = 0xff;
	aBuffer[1] = 0xff;
	aBuffer[2] = 0xff;
	aBuffer[3] = 0xff;
	aBuffer[4] = 0xff;
	aBuffer[5] = 0xff;
	mem_copy(&aBuffer[6], pData, DataSize);
	net_udp_send(Socket, pAddr, aBuffer, 6+DataSize);
}

void CNetBase::SendPacket(NETSOCKET Socket, NETADDR *pAddr, CNetPacketConstruct *pPacket)
{
	unsigned char aBuffer[NET_MAX_PACKETSIZE];
	int CompressedSize = -1;
	int FinalSize = -1;

	/* log the data */
	if(ms_DataLogSent)
	{
		int type = 1;
		io_write(ms_DataLogSent, &type, sizeof(type));
		io_write(ms_DataLogSent, &pPacket->m_DataSize, sizeof(pPacket->m_DataSize));
		io_write(ms_DataLogSent, &pPacket->m_aChunkData, pPacket->m_DataSize);
		io_flush(ms_DataLogSent);
	}
	
	/* compress */
	CompressedSize = huffman_compress(&ms_HuffmanState, pPacket->m_aChunkData, pPacket->m_DataSize, &aBuffer[3], NET_MAX_PACKETSIZE-4);

	/* check if the compression was enabled, successful and good enough	*/
	if(CompressedSize > 0 && CompressedSize < pPacket->m_DataSize)
	{
		FinalSize = CompressedSize;
		pPacket->m_Flags |= NET_PACKETFLAG_COMPRESSION;
	}
	else
	{
		/* use uncompressed data */
		FinalSize = pPacket->m_DataSize;
		mem_copy(&aBuffer[3], pPacket->m_aChunkData, pPacket->m_DataSize);
		pPacket->m_Flags &= ~NET_PACKETFLAG_COMPRESSION;
	}

	/* set header and send the packet if all things are good */
	if(FinalSize >= 0)
	{
		FinalSize += NET_PACKETHEADERSIZE;
		aBuffer[0] = ((pPacket->m_Flags<<4)&0xf0)|((pPacket->m_Ack>>8)&0xf);
		aBuffer[1] = pPacket->m_Ack&0xff;
		aBuffer[2] = pPacket->m_NumChunks;
		net_udp_send(Socket, pAddr, aBuffer, FinalSize);

		/* log raw socket data */
		if(ms_DataLogSent)
		{
			int type = 0;
			io_write(ms_DataLogSent, &type, sizeof(type));
			io_write(ms_DataLogSent, &FinalSize, sizeof(FinalSize));
			io_write(ms_DataLogSent, aBuffer, FinalSize);
			io_flush(ms_DataLogSent);
		}
	}
}

/* TODO: rename this function */
int CNetBase::UnpackPacket(unsigned char *pBuffer, int Size, CNetPacketConstruct *pPacket)
{
	/* check the size */
	if(Size < NET_PACKETHEADERSIZE || Size > NET_MAX_PACKETSIZE)
	{
		dbg_msg("", "packet too small, %d", Size);
		return -1;
	}

	/* log the data */
	if(ms_DataLogRecv)
	{
		int type = 0;
		io_write(ms_DataLogRecv, &type, sizeof(type));
		io_write(ms_DataLogRecv, &Size, sizeof(Size));
		io_write(ms_DataLogRecv, pBuffer, Size);
		io_flush(ms_DataLogRecv);
	}
	
	/* read the packet */
	pPacket->m_Flags = pBuffer[0]>>4;
	pPacket->m_Ack = ((pBuffer[0]&0xf)<<8) | pBuffer[1];
	pPacket->m_NumChunks = pBuffer[2];
	pPacket->m_DataSize = Size - NET_PACKETHEADERSIZE;

	if(pPacket->m_Flags&NET_PACKETFLAG_CONNLESS)
	{
		if(Size < 6)
		{
			dbg_msg("", "connection less packet too small, %d", Size);
			return -1;
		}
			
		pPacket->m_Flags = NET_PACKETFLAG_CONNLESS;
		pPacket->m_Ack = 0;
		pPacket->m_NumChunks = 0;
		pPacket->m_DataSize = Size - 6;
		mem_copy(pPacket->m_aChunkData, &pBuffer[6], pPacket->m_DataSize);
	}
	else
	{
		if(pPacket->m_Flags&NET_PACKETFLAG_COMPRESSION)
			pPacket->m_DataSize = huffman_decompress(&ms_HuffmanState, &pBuffer[3], pPacket->m_DataSize, pPacket->m_aChunkData, sizeof(pPacket->m_aChunkData));
		else
			mem_copy(pPacket->m_aChunkData, &pBuffer[3], pPacket->m_DataSize);
	}

	/* check for errors */	
	if(pPacket->m_DataSize < 0)
	{
		if(config.debug)
			dbg_msg("network", "error during packet decoding");
		return -1;
	}

	/* log the data */
	if(ms_DataLogRecv)
	{
		int type = 1;
		io_write(ms_DataLogRecv, &type, sizeof(type));
		io_write(ms_DataLogRecv, &pPacket->m_DataSize, sizeof(pPacket->m_DataSize));
		io_write(ms_DataLogRecv, pPacket->m_aChunkData, pPacket->m_DataSize);
		io_flush(ms_DataLogRecv);
	}
		
	/* return success */
	return 0;
}


void CNetBase::SendControlMsg(NETSOCKET Socket, NETADDR *pAddr, int Ack, int ControlMsg, const void *pExtra, int ExtraSize)
{
	CNetPacketConstruct Construct;
	Construct.m_Flags = NET_PACKETFLAG_CONTROL;
	Construct.m_Ack = Ack;
	Construct.m_NumChunks = 0;
	Construct.m_DataSize = 1+ExtraSize;
	Construct.m_aChunkData[0] = ControlMsg;
	mem_copy(&Construct.m_aChunkData[1], pExtra, ExtraSize);
	
	/* send the control message */
	CNetBase::SendPacket(Socket, pAddr, &Construct);
}



unsigned char *CNetChunkHeader::Pack(unsigned char *pData)
{
	pData[0] = ((m_Flags&3)<<6)|((m_Size>>4)&0x3f);
	pData[1] = (m_Size&0xf);
	if(m_Flags&NET_CHUNKFLAG_VITAL)
	{
		pData[1] |= (m_Sequence>>2)&0xf0;
		pData[2] = m_Sequence&0xff;
		return pData + 3;
	}
	return pData + 2;
}

unsigned char *CNetChunkHeader::Unpack(unsigned char *pData)
{
	m_Flags = (pData[0]>>6)&3;
	m_Size = ((pData[0]&0x3f)<<4) | (pData[1]&0xf);
	m_Sequence = -1;
	if(m_Flags&NET_CHUNKFLAG_VITAL)
	{
		m_Sequence = ((pData[1]&0xf0)<<2) | pData[2];
		return pData + 3;
	}
	return pData + 2;
}


int CNetBase::IsSeqInBackroom(int Seq, int Ack)
{
	int Bottom = (Ack-NET_MAX_SEQUENCE/2);
	if(Bottom < 0)
	{
		if(Seq <= Ack)
			return 1;
		if(Seq >= (Bottom + NET_MAX_SEQUENCE))
			return 1;
	}
	else
	{
		if(Seq <= Ack && Seq >= Bottom)
			return 1;
	}
	
	return 0;
}

IOHANDLE CNetBase::ms_DataLogSent = 0;
IOHANDLE CNetBase::ms_DataLogRecv = 0;
HUFFMAN_STATE CNetBase::ms_HuffmanState;


void CNetBase::OpenLog(const char *pSentLog, const char *pRecvLog)
{
	if(pSentLog)
	{
		ms_DataLogSent = engine_openfile(pSentLog, IOFLAG_WRITE);
		if(ms_DataLogSent)
			dbg_msg("network", "logging sent packages to '%s'", pSentLog);
		else
			dbg_msg("network", "failed to open for logging '%s'", pSentLog);
	}
	
	if(pRecvLog)
	{
		ms_DataLogRecv = engine_openfile(pRecvLog, IOFLAG_WRITE);
		if(ms_DataLogRecv)
			dbg_msg("network", "logging recv packages to '%s'", pRecvLog);
		else
			dbg_msg("network", "failed to open for logging '%s'", pRecvLog);
	}
}

int CNetBase::Compress(const void *pData, int DataSize, void *pOutput, int OutputSize)
{
	return huffman_compress(&ms_HuffmanState, pData, DataSize, pOutput, OutputSize);
}

int CNetBase::Decompress(const void *pData, int DataSize, void *pOutput, int OutputSize)
{
	return huffman_decompress(&ms_HuffmanState, pData, DataSize, pOutput, OutputSize);
}


static const unsigned gs_aFreqTable[256+1] = {
	1<<30,4545,2657,431,1950,919,444,482,2244,617,838,542,715,1814,304,240,754,212,647,186,
	283,131,146,166,543,164,167,136,179,859,363,113,157,154,204,108,137,180,202,176,
	872,404,168,134,151,111,113,109,120,126,129,100,41,20,16,22,18,18,17,19,
	16,37,13,21,362,166,99,78,95,88,81,70,83,284,91,187,77,68,52,68,
	59,66,61,638,71,157,50,46,69,43,11,24,13,19,10,12,12,20,14,9,
	20,20,10,10,15,15,12,12,7,19,15,14,13,18,35,19,17,14,8,5,
	15,17,9,15,14,18,8,10,2173,134,157,68,188,60,170,60,194,62,175,71,
	148,67,167,78,211,67,156,69,1674,90,174,53,147,89,181,51,174,63,163,80,
	167,94,128,122,223,153,218,77,200,110,190,73,174,69,145,66,277,143,141,60,
	136,53,180,57,142,57,158,61,166,112,152,92,26,22,21,28,20,26,30,21,
	32,27,20,17,23,21,30,22,22,21,27,25,17,27,23,18,39,26,15,21,
	12,18,18,27,20,18,15,19,11,17,33,12,18,15,19,18,16,26,17,18,
	9,10,25,22,22,17,20,16,6,16,15,20,14,18,24,335,1517};

void CNetBase::Init()
{
	huffman_init(&ms_HuffmanState, gs_aFreqTable);
}