//  Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.

// urfd -- The universal reflector
// Copyright © 2021 Thomas A. Early N7TAE
//
// 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 3 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, see <https://www.gnu.org/licenses/>.

#include "Main.h"
#include "DCSProtocol.h"
#include "Clients.h"
#include "Reflector.h"


////////////////////////////////////////////////////////////////////////////////////////
// constructor


CProtocol::CProtocol() : keep_running(true) {}


////////////////////////////////////////////////////////////////////////////////////////
// destructor

CProtocol::~CProtocol()
{
	// kill threads
	Close();

	// empty queue
	m_Queue.Lock();
	while ( !m_Queue.empty() )
	{
		m_Queue.pop();
	}
	m_Queue.Unlock();
}

////////////////////////////////////////////////////////////////////////////////////////
// initialization

bool CProtocol::Initialize(const char *type, const EProtocol ptype, const uint16_t port, const bool has_ipv4, const bool has_ipv6)
{
	// init reflector apparent callsign
	m_ReflectorCallsign = g_Reflector.GetCallsign();

	// reset stop flag
	keep_running = true;

	// update the reflector callsign
	if (type)
		m_ReflectorCallsign.PatchCallsign(0, (const uint8_t *)type, 3);

	// create our sockets
#ifdef LISTEN_IPV4
	if (has_ipv4)
	{
		CIp ip4(AF_INET, port, LISTEN_IPV4);
		if ( ip4.IsSet() )
		{
			if (! m_Socket4.Open(ip4))
				return false;
		}
		std::cout << "Listening on " << ip4 << std::endl;
	}
#endif

#ifdef LISTEN_IPV6
	if (has_ipv6)
	{
		CIp ip6(AF_INET6, port, LISTEN_IPV6);
		if ( ip6.IsSet() )
		{
			if (! m_Socket6.Open(ip6))
			{
				m_Socket4.Close();
				return false;
			}
			std::cout << "Listening on " << ip6 << std::endl;
		}
	}
#endif

	try {
		m_Future = std::async(std::launch::async, &CProtocol::Thread, this);
	}
	catch (const std::exception &e)
	{
		std::cerr << "Could not start protocol on port " << port << ": " << e.what() << std::endl;
		m_Socket4.Close();
		m_Socket6.Close();
		return false;
	}

	return true;
}

void CProtocol::Thread()
{
	while (keep_running)
	{
		Task();
	}
}

void CProtocol::Close(void)
{
	keep_running = false;
	if ( m_Future.valid() )
	{
		m_Future.get();
	}
	m_Socket4.Close();
	m_Socket6.Close();
}

////////////////////////////////////////////////////////////////////////////////////////
// packet encoding helpers

bool CProtocol::EncodeDvPacket(const CPacket &packet, CBuffer *buffer) const
{
	if ( packet.IsDvFrame() )
	{
		if ( packet.IsLastPacket() )
			return EncodeDvLastFramePacket((CDvLastFramePacket &)packet, buffer);
		else
			return EncodeDvFramePacket((CDvFramePacket &)packet, buffer);
	}
	if ( packet.IsDvHeader() )
		return EncodeDvHeaderPacket((CDvHeaderPacket &)packet, buffer);

	std::cerr << "Can't encode an unknown packet type!" << std::endl;
	return false;
}

////////////////////////////////////////////////////////////////////////////////////////
// streams helpers

void CProtocol::OnDvFramePacketIn(std::unique_ptr<CDvFramePacket> &Frame, const CIp *Ip)
{
	// find the stream
	auto stream = GetStream(Frame->GetStreamId(), Ip);
	if ( stream )
	{
		//std::cout << "DV frame" << "from "  << *Ip << std::endl;
		// and push
		stream->Lock();
		stream->Push(std::move(Frame));
		stream->Unlock();
	}
	// else
	// {
	// 	std::cout << "Orphaned Frame with ID " << Frame->GetStreamId() << " on " << *Ip << std::endl;
	// }
}

void CProtocol::OnDvLastFramePacketIn(std::unique_ptr<CDvLastFramePacket> &Frame, const CIp *Ip)
{
	// find the stream
	auto stream = GetStream(Frame->GetStreamId(), Ip);
	if ( stream )
	{
		// push
		stream->Lock();
		stream->Push(std::move(Frame));
		stream->Unlock();

		// Don't close yet, this stops the last packet relfection bug that was fixed in upstream by the same change.
		// Don't close the stream yet but rely on CheckStreamsTimeout
        	// mechanism, so the stream will be closed after the queues have
        	// been sinked out. This avoid last packets to be send back
        	// to transmitting client (master)

	}
	// else
	// {
	// 	std::cout << "Orphaned Last Frame with ID " << Frame->GetStreamId() << " on " << *Ip << std::endl;
	// }
}

////////////////////////////////////////////////////////////////////////////////////////
// stream handle helpers

std::shared_ptr<CPacketStream> CProtocol::GetStream(uint16_t uiStreamId, const CIp *Ip)
{
	for ( auto it=m_Streams.begin(); it!=m_Streams.end(); it++ )
	{
		if ( (*it)->GetStreamId() == uiStreamId )
		{
			// if Ip not nullptr, also check if IP match
			if ( (Ip != nullptr) && ((*it)->GetOwnerIp() != nullptr) )
			{
				if ( *Ip == *((*it)->GetOwnerIp()) )
				{
					return *it;
				}
			}
		}
	}
	// done
	return nullptr;
}

void CProtocol::CheckStreamsTimeout(void)
{
	for ( auto it=m_Streams.begin(); it!=m_Streams.end(); )
	{
		// time out ?
		(*it)->Lock();
		if ( (*it)->IsExpired() )
		{
			// yes, close it
			(*it)->Unlock();
			g_Reflector.CloseStream(*it);
			// and remove it
			it = m_Streams.erase(it);
		}
		else
		{
			(*it++)->Unlock();
		}
	}
}

////////////////////////////////////////////////////////////////////////////////////////
// syntax helper

bool CProtocol::IsNumber(char c) const
{
	return ((c >= '0') && (c <= '9'));
}

bool CProtocol::IsLetter(char c) const
{
	return ((c >= 'A') && (c <= 'Z'));
}

bool CProtocol::IsSpace(char c) const
{
	return (c == ' ');
}

////////////////////////////////////////////////////////////////////////////////////////
// DestId to Module helper

char CProtocol::DmrDstIdToModule(uint32_t tg) const
{
	return ((char)((tg % 26)-1) + 'A');
}

uint32_t CProtocol::ModuleToDmrDestId(char m) const
{
	return (uint32_t)(m - 'A')+1;
}

////////////////////////////////////////////////////////////////////////////////////////
// Receivers

bool CProtocol::Receive6(CBuffer &buf, CIp &ip, int time_ms)
{
	return m_Socket6.Receive(buf, ip, time_ms);
}

bool CProtocol::Receive4(CBuffer &buf, CIp &ip, int time_ms)
{
	return m_Socket4.Receive(buf, ip, time_ms);
}

bool CProtocol::ReceiveDS(CBuffer &buf, CIp &ip, int time_ms)
{
	auto fd4 = m_Socket4.GetSocket();
	auto fd6 = m_Socket6.GetSocket();

	if (fd4 < 0)
	{
		if (fd6 < 0)
			return false;
		return m_Socket6.Receive(buf, ip, time_ms);
	}
	else if (fd6 < 0)
		return m_Socket4.Receive(buf, ip, time_ms);

	fd_set fset;
	FD_ZERO(&fset);
	FD_SET(fd4, &fset);
	FD_SET(fd6, &fset);
	int max = (fd4 > fd6) ? fd4 : fd6;
	struct timeval tv;
	tv.tv_sec = time_ms / 1000;
	tv.tv_usec = (time_ms % 1000) * 1000;

	auto rval = select(max+1, &fset, 0, 0, &tv);
	if (rval <= 0)
	{
		if (rval < 0)
			std::cerr << "ReceiveDS select error: " << strerror(errno) << std::endl;
		return false;
	}

	if (FD_ISSET(fd4, &fset))
		return m_Socket4.ReceiveFrom(buf, ip);
	else
		return m_Socket6.ReceiveFrom(buf, ip);
}

////////////////////////////////////////////////////////////////////////////////////////
// dual stack senders

void CProtocol::Send(const CBuffer &buf, const CIp &Ip) const
{
	switch (Ip.GetFamily())
	{
	case AF_INET:
		m_Socket4.Send(buf, Ip);
		break;
	case AF_INET6:
		m_Socket6.Send(buf, Ip);
		break;
	default:
		std::cerr << "Wrong family: " << Ip.GetFamily() << std::endl;
		break;
	}
}

void CProtocol::Send(const char *buf, const CIp &Ip) const
{
	switch (Ip.GetFamily())
	{
	case AF_INET:
		m_Socket4.Send(buf, Ip);
		break;
	case AF_INET6:
		m_Socket6.Send(buf, Ip);
		break;
	default:
		std::cerr << "ERROR: wrong family: " << Ip.GetFamily() << std::endl;
		break;
	}
}

void CProtocol::Send(const CBuffer &buf, const CIp &Ip, uint16_t port) const
{
	switch (Ip.GetFamily())
	{
	case AF_INET:
		m_Socket4.Send(buf, Ip, port);
		break;
	case AF_INET6:
		m_Socket6.Send(buf, Ip, port);
		break;
	default:
		std::cerr << "Wrong family: " << Ip.GetFamily() << " on port " << port << std::endl;
		break;
	}
}

void CProtocol::Send(const char *buf, const CIp &Ip, uint16_t port) const
{
	switch (Ip.GetFamily())
	{
	case AF_INET:
		m_Socket4.Send(buf, Ip, port);
		break;
	case AF_INET6:
		m_Socket6.Send(buf, Ip, port);
		break;
	default:
		std::cerr << "Wrong family: " << Ip.GetFamily() << " on port " << port << std::endl;
		break;
	}
}