/*
 * Copyright (c)2013-2020 ZeroTier, Inc.
 *
 * Use of this software is governed by the Business Source License included
 * in the LICENSE.TXT file in the project's root directory.
 *
 * Change Date: 2024-01-01
 *
 * On the date above, in accordance with the Business Source License, use
 * of this software will be governed by version 2.0 of the Apache License.
 */
/****/

#ifndef ZT_ENDPOINT_HPP
#define ZT_ENDPOINT_HPP

#include "Constants.hpp"
#include "InetAddress.hpp"
#include "Address.hpp"
#include "Utils.hpp"
#include "TriviallyCopyable.hpp"
#include "Fingerprint.hpp"

#include <cstdio>
#include <cstdlib>
#include <cstdint>
#include <cstring>

// max name size + type byte + port (for DNS name/port) + 3x 16-bit coordinate for location
#define ZT_ENDPOINT_MARSHAL_SIZE_MAX (ZT_ENDPOINT_MAX_NAME_SIZE+1+2+2+2+2)

namespace ZeroTier {

/**
 * Endpoint variant specifying some form of network endpoint
 *
 * This data structure supports a number of types that are not yet actually used:
 * DNSNAME, URL, and ETHERNET. These are present to reserve them for future use.
 */
class Endpoint : public TriviallyCopyable
{
public:
	/**
	 * Endpoint type
	 *
	 * These are set to be the same as the IDs used for trace events in ZeroTierCore.h.
	 */
	enum Type
	{
		TYPE_NIL =          ZT_TRACE_EVENT_PATH_TYPE_NIL,
		TYPE_ZEROTIER =     ZT_TRACE_EVENT_PATH_TYPE_ZEROTIER,
		TYPE_DNSNAME =      ZT_TRACE_EVENT_PATH_TYPE_DNSNAME,
		TYPE_URL =          ZT_TRACE_EVENT_PATH_TYPE_URL,
		TYPE_INETADDR_V4 =  ZT_TRACE_EVENT_PATH_TYPE_INETADDR_V4,
		TYPE_ETHERNET =     ZT_TRACE_EVENT_PATH_TYPE_ETHERNET,
		TYPE_INETADDR_V6 =  ZT_TRACE_EVENT_PATH_TYPE_INETADDR_V6
	};

	/**
	 * Protocol identifiers for INETADDR endpoint types
	 *
	 * Most of these are reserved for future use.
	 */
	enum Protocol
	{
		PROTO_UDP_ZT =      0,
		PROTO_TCP_ZT =      1,
		PROTO_IP_ZT =       2
	};

	ZT_INLINE Endpoint() noexcept { memoryZero(this); }

	explicit Endpoint(const InetAddress &sa,const Protocol proto = PROTO_UDP_ZT) noexcept;

	explicit ZT_INLINE Endpoint(const Address &zt,const uint8_t identityHash[ZT_IDENTITY_HASH_SIZE]) noexcept :
		_t(TYPE_ZEROTIER)
	{
		_v.zt.address = zt.toInt();
		memcpy(_v.zt.hash,identityHash,ZT_IDENTITY_HASH_SIZE);
	}

	explicit ZT_INLINE Endpoint(const char *name,const int port) noexcept :
		_t(TYPE_DNSNAME)
	{
		_v.dns.port = port;
		Utils::scopy(_v.dns.name,sizeof(_v.dns.name),name);
	}

	explicit ZT_INLINE Endpoint(const char *url) noexcept :
		_t(TYPE_URL)
	{
		Utils::scopy(_v.url,sizeof(_v.url),url);
	}

	/**
	 * @return InetAddress or NIL if not of this type
	 */
	ZT_INLINE const InetAddress &inetAddr() const noexcept { return ((_t == TYPE_INETADDR_V4) || (_t == TYPE_INETADDR_V6)) ? asInetAddress(_v.in.sa) : InetAddress::NIL; }

	/**
	 * @return Protocol for INETADDR types, undefined for other endpoint types
	 */
	ZT_INLINE Protocol inetAddrProto() const noexcept { return (Protocol)_v.in.proto; }

	/**
	 * @return DNS name or empty string if not of this type
	 */
	ZT_INLINE const char *dnsName() const noexcept { return (_t == TYPE_DNSNAME) ? _v.dns.name : ""; }

	/**
	 * @return Port associated with DNS name or -1 if not of this type
	 */
	ZT_INLINE int dnsPort() const noexcept { return (_t == TYPE_DNSNAME) ? _v.dns.port : -1; }

	/**
	 * @return ZeroTier address or NIL if not of this type
	 */
	ZT_INLINE Address ztAddress() const noexcept { return Address((_t == TYPE_ZEROTIER) ? _v.zt.address : (uint64_t)0); }

	/**
	 * @return 384-bit hash of identity keys or NULL if not of this type
	 */
	ZT_INLINE const Fingerprint &ztFingerprint() const noexcept { return *reinterpret_cast<const Fingerprint *>(&_v.zt); }

	/**
	 * @return URL or empty string if not of this type
	 */
	ZT_INLINE const char *url() const noexcept { return (_t == TYPE_URL) ? _v.url : ""; }

	/**
	 * @return Ethernet address or NIL if not of this type
	 */
	ZT_INLINE MAC ethernet() const noexcept { return (_t == TYPE_ETHERNET) ? MAC(_v.eth) : MAC(); }

	/**
	 * @return Endpoint type or NIL if unset/empty
	 */
	ZT_INLINE Type type() const noexcept { return _t; }

	ZT_INLINE operator bool() const noexcept { return _t != TYPE_NIL; }

	bool operator==(const Endpoint &ep) const noexcept;
	ZT_INLINE bool operator!=(const Endpoint &ep) const noexcept { return (!(*this == ep)); }
	bool operator<(const Endpoint &ep) const noexcept;
	ZT_INLINE bool operator>(const Endpoint &ep) const noexcept { return (ep < *this); }
	ZT_INLINE bool operator<=(const Endpoint &ep) const noexcept { return !(ep < *this); }
	ZT_INLINE bool operator>=(const Endpoint &ep) const noexcept { return !(*this < ep); }

	static constexpr int marshalSizeMax() noexcept { return ZT_ENDPOINT_MARSHAL_SIZE_MAX; }
	int marshal(uint8_t data[ZT_ENDPOINT_MARSHAL_SIZE_MAX]) const noexcept;
	int unmarshal(const uint8_t *restrict data,int len) noexcept;

private:
	Type _t;
	int _l[3]; // X,Y,Z location in kilometers from the nearest gravitational center of mass
	union {
		struct {
			sockaddr_storage sa;
			uint8_t proto;
		} in;
		struct {
			uint16_t port;
			char name[ZT_ENDPOINT_MAX_NAME_SIZE];
		} dns;
		ZT_Fingerprint zt;
		char url[ZT_ENDPOINT_MAX_NAME_SIZE];
		uint64_t eth;
	} _v;
};

} // namespace ZeroTier

#endif