//
// Created by Grishka on 10.04.17.
//

#include "NetworkSocketWinsock.h"
#include <winsock2.h>
#include <ws2tcpip.h>
#include <IPHlpApi.h>
#include <assert.h>
#include "../../logging.h"
#include "../../VoIPController.h"

using namespace tgvoip;

NetworkSocketWinsock::NetworkSocketWinsock() : lastRecvdV4(0){
	needUpdateNat64Prefix=true;
	nat64Present=false;
	switchToV6at=0;
	isV4Available=false;

	DWORD version=GetVersion();
	isAtLeastVista=LOBYTE(LOWORD(version))>=6; // Vista is 6.0, XP is 5.1 and 5.2

	WSADATA wsaData;
	WSAStartup(MAKEWORD(2, 2), &wsaData);
	LOGD("Initialized winsock, version %d.%d", wsaData.wHighVersion, wsaData.wVersion);
}

NetworkSocketWinsock::~NetworkSocketWinsock(){

}

void NetworkSocketWinsock::SetMaxPriority(){
	
}

void NetworkSocketWinsock::Send(NetworkPacket *packet){
	sockaddr_in6 addr;
	IPv4Address* v4addr=dynamic_cast<IPv4Address*>(packet->address);
	if(v4addr){
		if(!isAtLeastVista){
			sockaddr_in _addr;
			_addr.sin_family=AF_INET;
			_addr.sin_addr.s_addr=v4addr->GetAddress();
			_addr.sin_port=htons(packet->port);
			int res=sendto(fd, (char*)packet->data, packet->length, 0, (sockaddr*)&_addr, sizeof(_addr));
			if(res==SOCKET_ERROR){
				int error=WSAGetLastError();
				LOGE("error sending: %d", error);
			}
			return;
		}
		if(needUpdateNat64Prefix && !isV4Available && VoIPController::GetCurrentTime()>switchToV6at && switchToV6at!=0){
			LOGV("Updating NAT64 prefix");
			nat64Present=false;
			addrinfo* addr0;
			int res=getaddrinfo("ipv4only.arpa", NULL, NULL, &addr0);
			if(res!=0){
				LOGW("Error updating NAT64 prefix: %d / %s", res, gai_strerror(res));
			}else{
				addrinfo* addrPtr;
				unsigned char* addr170=NULL;
				unsigned char* addr171=NULL;
				for(addrPtr=addr0;addrPtr;addrPtr=addrPtr->ai_next){
					if(addrPtr->ai_family==AF_INET6){
						sockaddr_in6* translatedAddr=(sockaddr_in6*)addrPtr->ai_addr;
						uint32_t v4part=*((uint32_t*)&translatedAddr->sin6_addr.s6_addr[12]);
						if(v4part==0xAA0000C0 && !addr170){
							addr170=translatedAddr->sin6_addr.s6_addr;
						}
						if(v4part==0xAB0000C0 && !addr171){
							addr171=translatedAddr->sin6_addr.s6_addr;
						}
						char buf[INET6_ADDRSTRLEN];
						//LOGV("Got translated address: %s", inet_ntop(AF_INET6, &translatedAddr->sin6_addr, buf, sizeof(buf)));
					}
				}
				if(addr170 && addr171 && memcmp(addr170, addr171, 12)==0){
					nat64Present=true;
					memcpy(nat64Prefix, addr170, 12);
					char buf[INET6_ADDRSTRLEN];
					//LOGV("Found nat64 prefix from %s", inet_ntop(AF_INET6, addr170, buf, sizeof(buf)));
				}else{
					LOGV("Didn't find nat64");
				}
				freeaddrinfo(addr0);
			}
			needUpdateNat64Prefix=false;
		}
		memset(&addr, 0, sizeof(sockaddr_in6));
		addr.sin6_family=AF_INET6;
		*((uint32_t*)&addr.sin6_addr.s6_addr[12])=v4addr->GetAddress();
		if(nat64Present)
			memcpy(addr.sin6_addr.s6_addr, nat64Prefix, 12);
		else
			addr.sin6_addr.s6_addr[11]=addr.sin6_addr.s6_addr[10]=0xFF;

	}else{
		IPv6Address* v6addr=dynamic_cast<IPv6Address*>(packet->address);
		assert(v6addr!=NULL);
		if(!isAtLeastVista){
			return;
		}
	}
	addr.sin6_port=htons(packet->port);
	
	//WSABUF wsaBuf;
	//wsaBuf.buf=(char*) packet->data;
	//wsaBuf.len=packet->length;
	//int res=WSASendTo(fd, &wsaBuf, 1, NULL, 0, (const sockaddr*)&addr, sizeof(addr), NULL, NULL);
	int res=sendto(fd, (char*)packet->data, packet->length, 0, (sockaddr*)&addr, sizeof(addr));
	if(res==SOCKET_ERROR){
		int error=WSAGetLastError();
		LOGE("error sending: %d", error);
		if(error==WSAENETUNREACH && !isV4Available && VoIPController::GetCurrentTime()<switchToV6at){
			switchToV6at=VoIPController::GetCurrentTime();
			LOGI("Network unreachable, trying NAT64");
		}
	}
}

void NetworkSocketWinsock::Receive(NetworkPacket *packet){
	sockaddr_in6 srcAddr;
	sockaddr_in srcAddr4;
	sockaddr* addr;
	int addrLen;
	if(isAtLeastVista){
		addr=(sockaddr*)&srcAddr;
		addrLen=sizeof(srcAddr);
	}else{
		addr=(sockaddr*)&srcAddr4;
		addrLen=sizeof(srcAddr4);
	}
	//DWORD len;
	//WSABUF buf;
	//buf.buf=(char*) packet->data;
	//buf.len=packet->length;
	//int res=WSARecvFrom(fd, &buf, 1, &len, 0, (sockaddr*) &srcAddr, &addrLen, NULL, NULL);
	int res=recvfrom(fd, (char*)packet->data, packet->length, 0, addr, &addrLen);
	if(res!=SOCKET_ERROR)
		packet->length=(size_t) res;
	else{
		packet->length=0;
		int error=WSAGetLastError();
		LOGE("error receiving: %d", error);
		return;
	}
	//LOGV("Received %d bytes from %s:%d at %.5lf", len, inet_ntoa(srcAddr.sin_addr), ntohs(srcAddr.sin_port), GetCurrentTime());
	if(addr->sa_family==AF_INET){
		packet->port=srcAddr4.sin_port;
		lastRecvdV4=IPv4Address(srcAddr4.sin_addr.s_addr);
		packet->address=&lastRecvdV4;
	}else{
		packet->port=srcAddr.sin6_port;
		if(!isV4Available && IN6_IS_ADDR_V4MAPPED(&srcAddr.sin6_addr)){
			isV4Available=true;
			LOGI("Detected IPv4 connectivity, will not try IPv6");
		}
		if(IN6_IS_ADDR_V4MAPPED(&srcAddr.sin6_addr) || (nat64Present && memcmp(nat64Prefix, srcAddr.sin6_addr.s6_addr, 12)==0)){
			in_addr v4addr=*((in_addr *)&srcAddr.sin6_addr.s6_addr[12]);
			lastRecvdV4=IPv4Address(v4addr.s_addr);
			packet->address=&lastRecvdV4;
		}
	}
}

void NetworkSocketWinsock::Open(){
	fd=socket(isAtLeastVista ? AF_INET6 : AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if(fd==INVALID_SOCKET){
		int error=WSAGetLastError();
		LOGE("error creating socket: %d", error);
		failed=true;
		return;
	}
	
	int res;
	if(isAtLeastVista){
		DWORD flag=0;
		res=setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&flag, sizeof(flag));
		if(res==SOCKET_ERROR){
			LOGE("error enabling dual stack socket: %d", WSAGetLastError());
			failed=true;
			return;
		}
	}

	SetMaxPriority();

	int tries=0;
	sockaddr* addr;
	sockaddr_in addr4;
	sockaddr_in6 addr6;
	int addrLen;
	if(isAtLeastVista){
		//addr.sin6_addr.s_addr=0;
		memset(&addr6, 0, sizeof(sockaddr_in6));
		//addr.sin6_len=sizeof(sa_family_t);
		addr6.sin6_family=AF_INET6;
		addr=(sockaddr*)&addr6;
		addrLen=sizeof(addr6);
	}else{
		sockaddr_in addr4;
		addr4.sin_addr.s_addr=0;
		addr4.sin_family=AF_INET;
		addr=(sockaddr*)&addr4;
		addrLen=sizeof(addr4);
	}
	for(tries=0;tries<10;tries++){
		uint16_t port=htons(GenerateLocalPort());
		if(isAtLeastVista)
			((sockaddr_in6*)addr)->sin6_port=port;
		else
			((sockaddr_in*)addr)->sin_port=port;
		res=::bind(fd, addr, addrLen);
		LOGV("trying bind to port %u", ntohs(port));
		if(res<0){
			LOGE("error binding to port %u: %d / %s", ntohs(port), errno, strerror(errno));
		}else{
			break;
		}
	}
	if(tries==10){
		if(isAtLeastVista)
			((sockaddr_in6*)addr)->sin6_port=0;
		else
			((sockaddr_in*)addr)->sin_port=0;
		res=::bind(fd, addr, addrLen);
		if(res<0){
			LOGE("error binding to port %u: %d / %s", 0, errno, strerror(errno));
			//SetState(STATE_FAILED);
			return;
		}
	}
	getsockname(fd, addr, (socklen_t*) &addrLen);
	uint16_t localUdpPort;
	if(isAtLeastVista)
		localUdpPort=ntohs(((sockaddr_in6*)addr)->sin6_port);
	else
		localUdpPort=ntohs(((sockaddr_in*)addr)->sin_port);
	LOGD("Bound to local UDP port %u", ntohs(localUdpPort));

	needUpdateNat64Prefix=true;
	isV4Available=false;
	switchToV6at=VoIPController::GetCurrentTime()+ipv6Timeout;
}

void NetworkSocketWinsock::Close(){
	closesocket(fd);
}

void NetworkSocketWinsock::OnActiveInterfaceChanged(){
	needUpdateNat64Prefix=true;
	isV4Available=false;
	switchToV6at=VoIPController::GetCurrentTime()+ipv6Timeout;
}

std::string NetworkSocketWinsock::GetLocalInterfaceInfo(IPv4Address *v4addr, IPv6Address *v6addr){
	IP_ADAPTER_ADDRESSES* addrs=(IP_ADAPTER_ADDRESSES*)malloc(15*1024);
	ULONG size=15*1024;
	ULONG flags=GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER | GAA_FLAG_SKIP_FRIENDLY_NAME;
	
	ULONG res=GetAdaptersAddresses(AF_UNSPEC, flags, NULL, addrs, &size);
	if(res==ERROR_BUFFER_OVERFLOW){
		addrs=(IP_ADAPTER_ADDRESSES*)realloc(addrs, size);
		res=GetAdaptersAddresses(AF_UNSPEC, flags, NULL, addrs, &size);
	}

	ULONG bestMetric=0;
	std::string bestName("");

	if(res==ERROR_SUCCESS){
		IP_ADAPTER_ADDRESSES* current=addrs;
		while(current){
			char* name=current->AdapterName;
			LOGV("Adapter '%s':", name);
			IP_ADAPTER_UNICAST_ADDRESS* curAddr=current->FirstUnicastAddress;
			if(current->OperStatus!=IfOperStatusUp){
				LOGV("-> (down)");
				current=current->Next;
				continue;
			}
			if(current->IfType==IF_TYPE_SOFTWARE_LOOPBACK){
				LOGV("-> (loopback)");
				current=current->Next;
				continue;
			}
			if(isAtLeastVista)
				LOGV("v4 metric: %u, v6 metric: %u", current->Ipv4Metric, current->Ipv6Metric);
			while(curAddr){
				sockaddr* addr=curAddr->Address.lpSockaddr;
				if(addr->sa_family==AF_INET && v4addr){
					sockaddr_in* ipv4=(sockaddr_in*)addr;
					LOGV("-> V4: %s", V4AddressToString(ipv4->sin_addr.s_addr).c_str());
					uint32_t ip=ntohl(ipv4->sin_addr.s_addr);
					if((ip & 0xFFFF0000)!=0xA9FE0000){
						if(isAtLeastVista){
							if(current->Ipv4Metric>bestMetric){
								bestMetric=current->Ipv4Metric;
								bestName=std::string(current->AdapterName);
								*v4addr=IPv4Address(ipv4->sin_addr.s_addr);
							}
						}else{
							bestName=std::string(current->AdapterName);
							*v4addr=IPv4Address(ipv4->sin_addr.s_addr);
						}
					}
				}else if(addr->sa_family==AF_INET6 && v6addr){
					sockaddr_in6* ipv6=(sockaddr_in6*)addr;
					LOGV("-> V6: %s", V6AddressToString(ipv6->sin6_addr.s6_addr).c_str());
					if(!IN6_IS_ADDR_LINKLOCAL(&ipv6->sin6_addr)){
						*v6addr=IPv6Address(ipv6->sin6_addr.s6_addr);
					}
				}
				curAddr=curAddr->Next;
			}
			current=current->Next;
		}
	}

	free(addrs);
	return bestName;
}

uint16_t NetworkSocketWinsock::GetLocalPort(){
	if(!isAtLeastVista){
		sockaddr_in addr;
		size_t addrLen=sizeof(sockaddr_in);
		getsockname(fd, (sockaddr*)&addr, (socklen_t*)&addrLen);
		return ntohs(addr.sin_port);
	}
	sockaddr_in6 addr;
	size_t addrLen=sizeof(sockaddr_in6);
	getsockname(fd, (sockaddr*)&addr, (socklen_t*) &addrLen);
	return ntohs(addr.sin6_port);
}

std::string NetworkSocketWinsock::V4AddressToString(uint32_t address){
	char buf[INET_ADDRSTRLEN];
	sockaddr_in addr;
	ZeroMemory(&addr, sizeof(addr));
	addr.sin_family=AF_INET;
	addr.sin_addr.s_addr=address;
	DWORD len=sizeof(buf);
	WSAAddressToStringA((sockaddr*)&addr, sizeof(addr), NULL, buf, &len);
	return std::string(buf);
}

std::string NetworkSocketWinsock::V6AddressToString(unsigned char *address){
	char buf[INET6_ADDRSTRLEN];
	sockaddr_in6 addr;
	ZeroMemory(&addr, sizeof(addr));
	addr.sin6_family=AF_INET6;
	memcpy(addr.sin6_addr.s6_addr, address, 16);
	DWORD len=sizeof(buf);
	WSAAddressToStringA((sockaddr*)&addr, sizeof(addr), NULL, buf, &len);
	return std::string(buf);
}

uint32_t NetworkSocketWinsock::StringToV4Address(std::string address){
	sockaddr_in addr;
	ZeroMemory(&addr, sizeof(addr));
	addr.sin_family=AF_INET;
	int size=sizeof(addr);
	WSAStringToAddressA((char*)address.c_str(), AF_INET, NULL, (sockaddr*)&addr, &size);
	return addr.sin_addr.s_addr;
}

void NetworkSocketWinsock::StringToV6Address(std::string address, unsigned char *out){
	sockaddr_in6 addr;
	ZeroMemory(&addr, sizeof(addr));
	addr.sin6_family=AF_INET6;
	int size=sizeof(addr);
	WSAStringToAddressA((char*)address.c_str(), AF_INET6, NULL, (sockaddr*)&addr, &size);
	memcpy(out, addr.sin6_addr.s6_addr, 16);
}