// portable/Packet.h
// Copyright 2016/1/16 Robin.Rowe@cinepaint.org
// License open source MIT/BSD

#ifndef Packet_h
#define Packet_h

#include <memory.h>
#include <string>
#include <stdio.h>
#include "PacketSizer.h"
#include "../SoftLock.h"
#include "../StdFile.h"
#include "../../xxhash/xxhash.h"
/*
#if 1
#define TRACE(msg) puts("ERROR: " msg); Dump()
#else
#define TRACE(msg)
#endif
*/
#ifndef _WIN32
typedef int SOCKET;
#endif

namespace portable 
{

struct PacketHeader
{	typedef XXH64_hash_t hash_t;
	hash_t hash;
	unsigned packetSize;
	unsigned packetId;
	bool isGood;
	PacketHeader()
	{	Reset();
	}
	void Reset()
	{	hash = 0;
		packetSize = 0;
		packetId = 0;
		isGood = false;
	}
	void ResetWrite()
	{	packetSize = GetSize();
		packetId = 0;
	}
	unsigned GetSize() const
	{	return sizeof(XXH64_hash_t) + 2 * sizeof(unsigned);
	}
	void Read(const char* data)
	{	Reset();
		memcpy(&hash, data, sizeof(XXH64_hash_t));
		data += sizeof(XXH64_hash_t);
		memcpy(&packetSize,data,sizeof(packetSize));
		data += sizeof(packetSize);
		memcpy(&packetId, data,sizeof(packetId));
		isGood = true;
//		Dump();
	}
	void WriteHash(char* data, XXH64_hash_t packetHash)
	{	hash = packetHash;
		memcpy(data,(const char*) &hash,sizeof(hash));
//		Dump();
	}
	void WriteSizeId(char* data)
	{	data += sizeof(XXH64_hash_t);
		memcpy(data,(const char*) &packetSize, sizeof(packetSize));
		data += sizeof(packetSize);
		memcpy(data,(const char*) &packetId, sizeof(packetId));
		isGood = true;
	}
	void Dump() const
	{	printf("packet id #%u size=%u hash=%llx\n",packetId,packetSize,hash);
	}
};

class Packet
{protected:
	char* const buffer;
	typedef unsigned T;
	char* packet;
	const unsigned bufsize;
#if 0
	bool IsEmpty() const
	{	const bool isEmpty = packet >= buffer + bufsize;
//		std::cout << "isEmpty = "<<isEmpty << std::endl;
		return isEmpty;
	}
#endif
public:			
	PacketHeader header;
	AtomicMutex ownership;
	Packet(const PacketSizer& sizer)
	:	buffer(sizer.buffer)
	,	bufsize(sizer.bufsize)
	{	Reset();
	}
	Packet(char* buffer,unsigned bufsize)
	:	buffer(buffer)
	,	bufsize(bufsize)
	{	Reset();
	}
	virtual void Reset()
	{	packet=buffer;
		header.Reset();
	}
	virtual bool IsGood() const
	{	if(GetPacketSize()>GetCapacity())
		{	return false;
		}
		if(!GetPacketSize())
		{	return false;
		}
		return true;
	}
	unsigned GetPacketId() const
	{	return header.packetId;
	}
#pragma warning(disable: 4458)
	void SetPacketId(unsigned packetId)
	{	header.packetId = packetId;
	}
	const char* GetPayload() const // Whole packet except hash
	{	return packet+sizeof(PacketHeader::hash_t);
	}
	T GetPayloadSize() const
	{	const T size = GetPacketSize();
		if(!size)
		{	return 0;
		}
		return size - sizeof(PacketHeader::hash_t);
	}
	T GetCapacity() const
	{	return bufsize;
	}
	T GetPacketSize() const
	{	if(bufsize<header.packetSize)
		{	printf("ERROR: packet size overflow, bufsize %u < %u\n",bufsize, header.packetSize);
			return 0;
		}	
		return header.packetSize;
	}
	T GetPacketSize(unsigned bytes) const
	{	const unsigned fullSize = GetPacketSize();
		if(!fullSize)
		{	return 0;
		}
		if(fullSize>bufsize)
		{	printf("ERROR overflow: packetSize %u > bufSize %u\n",fullSize,bufsize);
			return false;
		}
		if(fullSize > bytes)
		{//	stats.fragments++;
			return 0;
		}
		return fullSize;
	}
	const char* GetPacket() const
	{	return packet;
	}
	void Dump() const
	{	printf("Dump Packet: size = %d, bufsize = %d",header.packetSize,bufsize);
	}
	virtual bool Skip(unsigned length)
	{	(void) length;
		return true;
	}
	PacketHeader::hash_t CalcHash() const
	{	const unsigned long long seed = 0;
		const char* payload = GetPayload();
		const unsigned payloadSize = GetPayloadSize();
		if(!payloadSize)
		{	return 0;
		}
		const XXH64_hash_t hash = XXH64(payload,payloadSize,seed);
		return hash;
	}
	PacketHeader::hash_t GetHash() const
	{	if(header.hash == 0xcdcdcdcdcdcdcdcdull)
		{	puts("Invalid memory");
		}
		if(!header.hash)
		{	puts("zero hash");
		}
		return header.hash;
	}
};

}

#endif