/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * @file os_abstraction.h Network stuff has many things that needs to be
 *                        included and/or implemented by default.
 *                        All those things are in this file.
 */

#ifndef NETWORK_CORE_OS_ABSTRACTION_H
#define NETWORK_CORE_OS_ABSTRACTION_H

/* Include standard stuff per OS */

/* Windows stuff */
#if defined(_WIN32)
#include <errno.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <windows.h>

#define GET_LAST_ERROR() WSAGetLastError()
#undef EWOULDBLOCK
#define EWOULDBLOCK WSAEWOULDBLOCK
/* Windows has some different names for some types */
typedef unsigned long in_addr_t;

/* Handle cross-compilation with --build=*-*-cygwin --host=*-*-mingw32 */
#if defined(__MINGW32__) && !defined(AI_ADDRCONFIG)
#	define AI_ADDRCONFIG               0x00000400
#endif

#if !(defined(__MINGW32__) || defined(__CYGWIN__))
	/* Windows has some different names for some types */
	typedef SSIZE_T ssize_t;
	typedef int socklen_t;
#	define IPPROTO_IPV6 41
#endif /* !(__MINGW32__ && __CYGWIN__) */

#if defined(__MINGW32__)
#ifndef AI_ADDRCONFIG
#define AI_ADDRCONFIG 0x400
#endif
#ifndef IPPROTO_IPV6
#define IPPROTO_IPV6 41
#endif
#ifndef IPV6_V6ONLY
#define IPV6_V6ONLY 27
#endif
#endif /* __MINGW32__ */

#endif /* _WIN32 */

/* UNIX stuff */
#if defined(UNIX) && !defined(__OS2__)
#	if defined(OPENBSD) || defined(__NetBSD__)
#		define AI_ADDRCONFIG 0
#	endif
#	define SOCKET int
#	define INVALID_SOCKET -1
#	define ioctlsocket ioctl
#	define closesocket close
#	define GET_LAST_ERROR() (errno)
#	define SD_RECEIVE SHUT_RD
#	define SD_SEND SHUT_WR
#	define SD_BOTH SHUT_RDWR
/* Need this for FIONREAD on solaris */
#	define BSD_COMP

/* Includes needed for UNIX-like systems */
#	include <unistd.h>
#	include <sys/ioctl.h>
#	include <sys/socket.h>
#	include <netinet/in.h>
#	include <netinet/tcp.h>
#	include <arpa/inet.h>
#	include <net/if.h>
/* According to glibc/NEWS, <ifaddrs.h> appeared in glibc-2.3. */
#	if !defined(__sgi__) && !defined(SUNOS) && !defined(__INNOTEK_LIBC__) \
	   && !(defined(__GLIBC__) && (__GLIBC__ <= 2) && (__GLIBC_MINOR__ <= 2)) && !defined(__dietlibc__) && !defined(HPUX)
/* If for any reason ifaddrs.h does not exist on your system, comment out
 *   the following two lines and an alternative way will be used to fetch
 *   the list of IPs from the system. */
#		include <ifaddrs.h>
#		define HAVE_GETIFADDRS
#	endif
#	if !defined(INADDR_NONE)
#		define INADDR_NONE 0xffffffff
#	endif

#	if defined(__GLIBC__) && (__GLIBC__ <= 2) && (__GLIBC_MINOR__ <= 1)
		typedef uint32_t in_addr_t;
#	endif

#	include <errno.h>
#	include <sys/time.h>
#	include <netdb.h>

#   if defined(__EMSCRIPTEN__)
/* Emscripten doesn't support AI_ADDRCONFIG and errors out on it. */
#		undef AI_ADDRCONFIG
#		define AI_ADDRCONFIG 0
/* Emscripten says it supports FD_SETSIZE fds, but it really only supports 64.
 * https://github.com/emscripten-core/emscripten/issues/1711 */
#		undef FD_SETSIZE
#		define FD_SETSIZE 64
#   endif
#endif /* UNIX */

/* OS/2 stuff */
#if defined(__OS2__)
#	define SOCKET int
#	define INVALID_SOCKET -1
#	define ioctlsocket ioctl
#	define closesocket close
#	define GET_LAST_ERROR() (sock_errno())
#	define SD_RECEIVE SHUT_RD
#	define SD_SEND SHUT_WR
#	define SD_BOTH SHUT_RDWR

/* Includes needed for OS/2 systems */
#	include <types.h>
#	include <unistd.h>
#	include <sys/ioctl.h>
#	include <sys/socket.h>
#	include <netinet/in.h>
#	include <netinet/tcp.h>
#	include <arpa/inet.h>
#	include <net/if.h>
#	include <errno.h>
#	include <sys/time.h>
#	include <netdb.h>
#	include <nerrno.h>
#	define INADDR_NONE 0xffffffff
#	include "../../3rdparty/os2/getaddrinfo.h"
#	include "../../3rdparty/os2/getnameinfo.h"

#define IPV6_V6ONLY 27

/*
 * IPv6 address
 */
struct in6_addr {
	union {
		uint8_t  __u6_addr8[16];
		uint16_t __u6_addr16[8];
		uint32_t __u6_addr32[4];
	} __u6_addr; /* 128-bit IP6 address */
};

#define s6_addr   __u6_addr.__u6_addr8

struct sockaddr_in6 {
	uint8_t         sin6_len;       /* length of this struct */
	sa_family_t     sin6_family;    /* AF_INET6 */
	in_port_t       sin6_port;      /* Transport layer port # */
	uint32_t        sin6_flowinfo;  /* IP6 flow information */
	struct in6_addr sin6_addr;      /* IP6 address */
	uint32_t        sin6_scope_id;  /* scope zone index */
};

typedef int socklen_t;
#if !defined(__INNOTEK_LIBC__)
typedef unsigned long in_addr_t;
#endif /* __INNOTEK_LIBC__ */

#endif /* OS/2 */

#ifdef __EMSCRIPTEN__
/**
 * Emscripten doesn't set 'addrlen' for accept(), getsockname(), getpeername()
 * and recvfrom(), which confuses other functions and causes them to crash.
 * This function needs to be called after these four functions to make sure
 * 'addrlen' is patched up.
 *
 * https://github.com/emscripten-core/emscripten/issues/12996
 *
 * @param address The address returned by those four functions.
 * @return The correct value for addrlen.
 */
static inline socklen_t FixAddrLenForEmscripten(struct sockaddr_storage &address)
{
	switch (address.ss_family) {
		case AF_INET6: return sizeof(struct sockaddr_in6);
		case AF_INET: return sizeof(struct sockaddr_in);
		default: NOT_REACHED();
	}
}
#endif

/**
 * Try to set the socket into non-blocking mode.
 * @param d The socket to set the non-blocking more for.
 * @return True if setting the non-blocking mode succeeded, otherwise false.
 */
static inline bool SetNonBlocking(SOCKET d)
{
#ifdef __EMSCRIPTEN__
	return true;
#else
#	ifdef _WIN32
	u_long nonblocking = 1;
#	else
	int nonblocking = 1;
#	endif
	return ioctlsocket(d, FIONBIO, &nonblocking) == 0;
#endif
}

/**
 * Try to set the socket into blocking mode.
 * @param d The socket to set the blocking more for.
 * @return True if setting the blocking mode succeeded, otherwise false.
 */
static inline bool SetBlocking(SOCKET d)
{
#ifdef _WIN32
	u_long nonblocking = 0;
#else
	int nonblocking = 0;
#endif
	return ioctlsocket(d, FIONBIO, &nonblocking) == 0;
}

/**
 * Try to set the socket to not delay sending.
 * @param d The socket to disable the delaying for.
 * @return True if disabling the delaying succeeded, otherwise false.
 */
static inline bool SetNoDelay(SOCKET d)
{
#ifdef __EMSCRIPTEN__
	return true;
#else
	/* XXX should this be done at all? */
	int b = 1;
	/* The (const char*) cast is needed for windows */
	return setsockopt(d, IPPROTO_TCP, TCP_NODELAY, (const char*)&b, sizeof(b)) == 0;
#endif
}


/**
 * Try to shutdown the socket in one or both directions.
 * @param d The socket to disable the delaying for.
 * @param read Whether to shutdown the read direction.
 * @param write Whether to shutdown the write direction.
 * @param linger_timeout The socket linger timeout.
 * @return True if successful
 */
static inline bool ShutdownSocket(SOCKET d, bool read, bool write, uint linger_timeout)
{
	if (!read && !write) return true;
#ifdef _WIN32
	LINGER ln = { 1U, (uint16) linger_timeout };
#else
	struct linger ln = { 1, (int) linger_timeout };
#endif

	setsockopt(d, SOL_SOCKET, SO_LINGER, (const char*)&ln, sizeof(ln));

	int how = SD_BOTH;
	if (!read) how = SD_SEND;
	if (!write) how = SD_RECEIVE;
	return shutdown(d, how) == 0;
}

/* Make sure these structures have the size we expect them to be */
assert_compile(sizeof(in_addr)  ==  4); ///< IPv4 addresses should be 4 bytes.
assert_compile(sizeof(in6_addr) == 16); ///< IPv6 addresses should be 16 bytes.

#endif /* NETWORK_CORE_OS_ABSTRACTION_H */