/*
 *   Copyright (C) 2006-2016,2018,2020 by Jonathan Naylor G4KLX
 *
 *   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 2 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, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "UDPSocket.h"

#include <cassert>

#if !defined(_WIN32) && !defined(_WIN64)
#include <cerrno>
#include <cstring>
#endif

#if defined(HAVE_LOG_H)
#include "Log.h"
#else
#define LogError(fmt, ...)	::fprintf(stderr, fmt "\n", ## __VA_ARGS__)
#define LogInfo(fmt, ...)	::fprintf(stderr, fmt "\n", ## __VA_ARGS__)
#endif

CUDPSocket::CUDPSocket(const std::string& address, unsigned int port)
{
#if defined(_WIN32) || defined(_WIN64)
	WSAData data;
	int wsaRet = ::WSAStartup(MAKEWORD(2, 2), &data);
	if (wsaRet != 0)
		LogError("Error from WSAStartup");
#endif
	for (int i = 0; i < UDP_SOCKET_MAX; i++) {
		m_address[i] = "";
		m_port[i] = 0U;
		m_af[i] = 0U;
		m_fd[i] = -1;
	}

	m_address[0] = address;
	m_port[0] = port;
	m_counter = 0U;
}

CUDPSocket::CUDPSocket(unsigned int port)
{
	CUDPSocket("", port);
}

CUDPSocket::CUDPSocket()
{
	CUDPSocket("", 0U);
}

CUDPSocket::~CUDPSocket()
{
#if defined(_WIN32) || defined(_WIN64)
	::WSACleanup();
#endif
}

int CUDPSocket::lookup(const std::string& hostname, unsigned int port, sockaddr_storage &addr, unsigned int &address_length)
{
	struct addrinfo hints;

	::memset(&hints, 0, sizeof(hints));

	return lookup(hostname, port, addr, address_length, hints);
}

int CUDPSocket::lookup(const std::string& hostname, unsigned int port, sockaddr_storage &addr, unsigned int &address_length, struct addrinfo &hints)
{
	int err;
	std::string portstr = std::to_string(port);
	struct addrinfo *res;

	/* port is always digits, no needs to lookup service */
	hints.ai_flags |= AI_NUMERICSERV;

	err = getaddrinfo(hostname.empty() ? NULL : hostname.c_str(), portstr.c_str(), &hints, &res);
	if (err) {
		sockaddr_in *paddr = (sockaddr_in *)&addr;
		::memset(paddr, 0, address_length = sizeof(sockaddr_in));
		paddr->sin_family = AF_INET;
		paddr->sin_port = htons(port);
		paddr->sin_addr.s_addr = htonl(INADDR_NONE);
		LogError("Cannot find address for host %s", hostname.c_str());
		return err;
	}

	::memcpy(&addr, res->ai_addr, address_length = res->ai_addrlen);

	freeaddrinfo(res);
	return 0;
}

bool CUDPSocket::match(const sockaddr_storage &addr1, const sockaddr_storage &addr2)
{
	if (addr1.ss_family != addr2.ss_family)
		return false;

	switch (addr1.ss_family) {
	case AF_INET:
		struct sockaddr_in *in_1, *in_2;
		in_1 = (struct sockaddr_in *)&addr1;
		in_2 = (struct sockaddr_in *)&addr2;
		return ( (in_1->sin_addr.s_addr == in_2->sin_addr.s_addr) &&
			 (in_1->sin_port == in_2->sin_port) );
	case AF_INET6:
		struct sockaddr_in6 *in6_1, *in6_2;
		in6_1 = (struct sockaddr_in6 *)&addr1;
		in6_2 = (struct sockaddr_in6 *)&addr2;
		return ( IN6_ARE_ADDR_EQUAL(&in6_1->sin6_addr, &in6_2->sin6_addr) &&
			 (in6_1->sin6_port == in6_2->sin6_port) );
	default:
		return false;
	}
}

bool CUDPSocket::match_addr(const sockaddr_storage &addr1, const sockaddr_storage &addr2)
{
	if (addr1.ss_family != addr2.ss_family)
		return false;

	switch (addr1.ss_family) {
	case AF_INET:
		struct sockaddr_in *in_1, *in_2;
		in_1 = (struct sockaddr_in *)&addr1;
		in_2 = (struct sockaddr_in *)&addr2;
		return (in_1->sin_addr.s_addr == in_2->sin_addr.s_addr);
	case AF_INET6:
		struct sockaddr_in6 *in6_1, *in6_2;
		in6_1 = (struct sockaddr_in6 *)&addr1;
		in6_2 = (struct sockaddr_in6 *)&addr2;
		return IN6_ARE_ADDR_EQUAL(&in6_1->sin6_addr, &in6_2->sin6_addr);
	default:
		return false;
	}
}

bool CUDPSocket::isnone(const sockaddr_storage &addr)
{
	struct sockaddr_in *in = (struct sockaddr_in *)&addr;

	return ( (addr.ss_family == AF_INET) &&
		 (in->sin_addr.s_addr == htonl(INADDR_NONE)) );
}

bool CUDPSocket::open()
{
	return open(0, AF_UNSPEC, m_address[0], m_port[0]);
}

bool CUDPSocket::open(const unsigned int af)
{
	return open(0, af, m_address[0], m_port[0]);
}

bool CUDPSocket::open(const unsigned int index, const unsigned int af, const std::string& address, const unsigned int port)
{
	int err, fd;
	sockaddr_storage addr;
	unsigned int addrlen;
	struct addrinfo hints;

	::memset(&hints, 0, sizeof(hints));
	hints.ai_flags = AI_PASSIVE;
	hints.ai_family = af;

	/* to determine protocol family, call lookup() first. */
	err = lookup(address, port, addr, addrlen, hints);
	if (err) {
		LogError("The local address is invalid - %s", address.c_str());
		return false;
	}

	fd = ::socket(addr.ss_family, SOCK_DGRAM, 0);
	if (fd < 0) {
#if defined(_WIN32) || defined(_WIN64)
		LogError("Cannot create the UDP socket, err: %lu", ::GetLastError());
#else
		LogError("Cannot create the UDP socket, err: %d", errno);
#endif
		return false;
	}

	m_address[index] = address;
	m_port[index] = port;
	m_af[index] = addr.ss_family;
	m_fd[index] = fd;

	if (port > 0U) {
		int reuse = 1;
		if (::setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&reuse, sizeof(reuse)) == -1) {
#if defined(_WIN32) || defined(_WIN64)
			LogError("Cannot set the UDP socket option, err: %lu", ::GetLastError());
#else
			LogError("Cannot set the UDP socket option, err: %d", errno);
#endif
			return false;
		}

		if (::bind(fd, (sockaddr*)&addr, addrlen) == -1) {
#if defined(_WIN32) || defined(_WIN64)
			LogError("Cannot bind the UDP address, err: %lu", ::GetLastError());
#else
			LogError("Cannot bind the UDP address, err: %d", errno);
#endif
			return false;
		}

		LogInfo("Opening UDP port on %u", port);
	}

	return true;
}

int CUDPSocket::read(unsigned char* buffer, unsigned int length, sockaddr_storage& address, unsigned int &address_length)
{
	assert(buffer != NULL);
	assert(length > 0U);

	// Check that the readfrom() won't block
	int i, n;
	struct pollfd pfd[UDP_SOCKET_MAX];
	for (i = n = 0; i < UDP_SOCKET_MAX; i++) {
		if (m_fd[i] >= 0) {
			pfd[n].fd = m_fd[i];
			pfd[n].events = POLLIN;
			n++;
		}
	}

	// no socket descriptor to receive
	if (n == 0)
		return 0;

	// Return immediately
#if defined(_WIN32) || defined(_WIN64)
	int ret = WSAPoll(pfd, n, 0);
#else
	int ret = ::poll(pfd, n, 0);
#endif
	if (ret < 0) {
#if defined(_WIN32) || defined(_WIN64)
		LogError("Error returned from UDP poll, err: %lu", ::GetLastError());
#else
		LogError("Error returned from UDP poll, err: %d", errno);
#endif
		return -1;
	}

	int index;
	for (i = 0; i < n; i++) {
		// round robin
	  	index = (i + m_counter) % n;
		if (pfd[index].revents & POLLIN)
			break;
	}
	if (i == n)
		return 0;

#if defined(_WIN32) || defined(_WIN64)
	int size = sizeof(sockaddr_storage);
#else
	socklen_t size = sizeof(sockaddr_storage);
#endif

#if defined(_WIN32) || defined(_WIN64)
	int len = ::recvfrom(pfd[index].fd, (char*)buffer, length, 0, (sockaddr *)&address, &size);
#else
	ssize_t len = ::recvfrom(pfd[index].fd, (char*)buffer, length, 0, (sockaddr *)&address, &size);
#endif
	if (len <= 0) {
#if defined(_WIN32) || defined(_WIN64)
		LogError("Error returned from recvfrom, err: %lu", ::GetLastError());
#else
		LogError("Error returned from recvfrom, err: %d", errno);
#endif
		return -1;
	}

	m_counter++;
	address_length = size;
	return len;
}

bool CUDPSocket::write(const unsigned char* buffer, unsigned int length, const sockaddr_storage& address, unsigned int address_length)
{
	assert(buffer != NULL);
	assert(length > 0U);

	bool result = false;

	for (int i = 0; i < UDP_SOCKET_MAX; i++) {
		if (m_fd[i] < 0 || m_af[i] != address.ss_family)
			continue;

#if defined(_WIN32) || defined(_WIN64)
		int ret = ::sendto(m_fd[i], (char *)buffer, length, 0, (sockaddr *)&address, address_length);
#else
		ssize_t ret = ::sendto(m_fd[i], (char *)buffer, length, 0, (sockaddr *)&address, address_length);
#endif

		if (ret < 0) {
#if defined(_WIN32) || defined(_WIN64)
			LogError("Error returned from sendto, err: %lu", ::GetLastError());
#else
			LogError("Error returned from sendto, err: %d", errno);
#endif
		} else {
#if defined(_WIN32) || defined(_WIN64)
			if (ret == int(length))
				result = true;
#else
			if (ret == ssize_t(length))
				result = true;
#endif
		}
	}

	return result;
}

void CUDPSocket::close()
{
	for (int i = 0; i < UDP_SOCKET_MAX; i++)
		close(m_fd[i]);
}

void CUDPSocket::close(const unsigned int index)
{
 	if (m_fd[index] >= 0) {
#if defined(_WIN32) || defined(_WIN64)
		::closesocket(m_fd[index]);
#else
		::close(m_fd[index]);
#endif
		m_fd[index] = -1;
	}
}