/*
 * ZeroTier One - Network Virtualization Everywhere
 * Copyright (C) 2011-2016  ZeroTier, Inc.  https://www.zerotier.com/
 *
 * 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 <http://www.gnu.org/licenses/>.
 */

#ifndef ZT_CERTIFICATEOFOWNERSHIP_HPP
#define ZT_CERTIFICATEOFOWNERSHIP_HPP

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "Constants.hpp"
#include "C25519.hpp"
#include "Address.hpp"
#include "Identity.hpp"
#include "Buffer.hpp"
#include "InetAddress.hpp"
#include "MAC.hpp"

// Max things per CertificateOfOwnership
#define ZT_CERTIFICATEOFOWNERSHIP_MAX_THINGS 16

// Maximum size of a thing's value field in bytes
#define ZT_CERTIFICATEOFOWNERSHIP_MAX_THING_VALUE_SIZE 16

namespace ZeroTier {

class RuntimeEnvironment;

/**
 * Certificate indicating ownership of a network identifier
 */
class CertificateOfOwnership
{
public:
	enum Thing
	{
		THING_NULL = 0,
		THING_MAC_ADDRESS = 1,
		THING_IPV4_ADDRESS = 2,
		THING_IPV6_ADDRESS = 3
	};

	CertificateOfOwnership()
	{
		memset(this,0,sizeof(CertificateOfOwnership));
	}

	CertificateOfOwnership(const uint64_t nwid,const uint64_t ts,const Address &issuedTo,const uint32_t id) :
		_networkId(nwid),
		_ts(ts),
		_flags(0),
		_id(id),
		_thingCount(0),
		_issuedTo(issuedTo)
	{
	}

	inline uint64_t networkId() const { return _networkId; }
	inline uint64_t timestamp() const { return _ts; }
	inline uint32_t id() const { return _id; }
	inline unsigned int thingCount() const { return (unsigned int)_thingCount; }

	inline Thing thingType(const unsigned int i) const { return (Thing)_thingTypes[i]; }
	inline const uint8_t *thingValue(const unsigned int i) const { return _thingValues[i]; }

	inline const Address &issuedTo() const { return _issuedTo; }

	inline bool owns(const InetAddress &ip) const
	{
		if (ip.ss_family == AF_INET)
			return this->_owns(THING_IPV4_ADDRESS,&(reinterpret_cast<const struct sockaddr_in *>(&ip)->sin_addr.s_addr),4);
		if (ip.ss_family == AF_INET6)
			return this->_owns(THING_IPV6_ADDRESS,reinterpret_cast<const struct sockaddr_in6 *>(&ip)->sin6_addr.s6_addr,16);
		return false;
	}

	inline bool owns(const MAC &mac) const
	{
		uint8_t tmp[6];
		mac.copyTo(tmp,6);
		return this->_owns(THING_MAC_ADDRESS,tmp,6);
	}

	inline void addThing(const InetAddress &ip)
	{
		if (_thingCount >= ZT_CERTIFICATEOFOWNERSHIP_MAX_THINGS) return;
		if (ip.ss_family == AF_INET) {
			_thingTypes[_thingCount] = THING_IPV4_ADDRESS;
			memcpy(_thingValues[_thingCount],&(reinterpret_cast<const struct sockaddr_in *>(&ip)->sin_addr.s_addr),4);
			++_thingCount;
		} else if (ip.ss_family == AF_INET6) {
			_thingTypes[_thingCount] = THING_IPV6_ADDRESS;
			memcpy(_thingValues[_thingCount],reinterpret_cast<const struct sockaddr_in6 *>(&ip)->sin6_addr.s6_addr,16);
			++_thingCount;
		}
	}

	inline void addThing(const MAC &mac)
	{
		if (_thingCount >= ZT_CERTIFICATEOFOWNERSHIP_MAX_THINGS) return;
		_thingTypes[_thingCount] = THING_MAC_ADDRESS;
		mac.copyTo(_thingValues[_thingCount],6);
		++_thingCount;
	}

	/**
	 * @param signer Signing identity, must have private key
	 * @return True if signature was successful
	 */
	inline bool sign(const Identity &signer)
	{
		if (signer.hasPrivate()) {
			Buffer<sizeof(CertificateOfOwnership) + 64> tmp;
			_signedBy = signer.address();
			this->serialize(tmp,true);
			_signature = signer.sign(tmp.data(),tmp.size());
			return true;
		}
		return false;
	}

	/**
	 * @param RR Runtime environment to allow identity lookup for signedBy
	 * @return 0 == OK, 1 == waiting for WHOIS, -1 == BAD signature
	 */
	int verify(const RuntimeEnvironment *RR) const;

	template<unsigned int C>
	inline void serialize(Buffer<C> &b,const bool forSign = false) const
	{
		if (forSign) b.append((uint64_t)0x7f7f7f7f7f7f7f7fULL);

		b.append(_networkId);
		b.append(_ts);
		b.append(_flags);
		b.append(_id);
		b.append((uint16_t)_thingCount);
		for(unsigned int i=0,j=_thingCount;i<j;++i) {
			b.append((uint8_t)_thingTypes[i]);
			b.append(_thingValues[i],ZT_CERTIFICATEOFOWNERSHIP_MAX_THING_VALUE_SIZE);
		}

		_issuedTo.appendTo(b);
		_signedBy.appendTo(b);
		if (!forSign) {
			b.append((uint8_t)1); // 1 == Ed25519
			b.append((uint16_t)ZT_C25519_SIGNATURE_LEN); // length of signature
			b.append(_signature.data,ZT_C25519_SIGNATURE_LEN);
		}

		b.append((uint16_t)0); // length of additional fields, currently 0

		if (forSign) b.append((uint64_t)0x7f7f7f7f7f7f7f7fULL);
	}

	template<unsigned int C>
	inline unsigned int deserialize(const Buffer<C> &b,unsigned int startAt = 0)
	{
		unsigned int p = startAt;

		memset(this,0,sizeof(CertificateOfOwnership));

		_networkId = b.template at<uint64_t>(p); p += 8;
		_ts = b.template at<uint64_t>(p); p += 8;
		_flags = b.template at<uint64_t>(p); p += 8;
		_id = b.template at<uint32_t>(p); p += 4;
		_thingCount = b.template at<uint16_t>(p); p += 2;
		for(unsigned int i=0,j=_thingCount;i<j;++i) {
			if (i < ZT_CERTIFICATEOFOWNERSHIP_MAX_THINGS) {
				_thingTypes[i] = (uint8_t)b[p++];
				memcpy(_thingValues[i],b.field(p,ZT_CERTIFICATEOFOWNERSHIP_MAX_THING_VALUE_SIZE),ZT_CERTIFICATEOFOWNERSHIP_MAX_THING_VALUE_SIZE);
				p += ZT_CERTIFICATEOFOWNERSHIP_MAX_THING_VALUE_SIZE;
			}
		}

		_issuedTo.setTo(b.field(p,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); p += ZT_ADDRESS_LENGTH;
		_signedBy.setTo(b.field(p,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); p += ZT_ADDRESS_LENGTH;
		if (b[p++] == 1) {
			if (b.template at<uint16_t>(p) != ZT_C25519_SIGNATURE_LEN)
				throw std::runtime_error("invalid signature length");
			p += 2;
			memcpy(_signature.data,b.field(p,ZT_C25519_SIGNATURE_LEN),ZT_C25519_SIGNATURE_LEN); p += ZT_C25519_SIGNATURE_LEN;
		} else {
			p += 2 + b.template at<uint16_t>(p);
		}

		p += 2 + b.template at<uint16_t>(p);
		if (p > b.size())
			throw std::runtime_error("extended field overflow");

		return (p - startAt);
	}

	// Provides natural sort order by ID
	inline bool operator<(const CertificateOfOwnership &coo) const { return (_id < coo._id); }

	inline bool operator==(const CertificateOfOwnership &coo) const { return (memcmp(this,&coo,sizeof(CertificateOfOwnership)) == 0); }
	inline bool operator!=(const CertificateOfOwnership &coo) const { return (memcmp(this,&coo,sizeof(CertificateOfOwnership)) != 0); }

private:
	bool _owns(const Thing &t,const void *v,unsigned int l) const;

	uint64_t _networkId;
	uint64_t _ts;
	uint64_t _flags;
	uint32_t _id;
	uint16_t _thingCount;
	uint8_t _thingTypes[ZT_CERTIFICATEOFOWNERSHIP_MAX_THINGS];
	uint8_t _thingValues[ZT_CERTIFICATEOFOWNERSHIP_MAX_THINGS][ZT_CERTIFICATEOFOWNERSHIP_MAX_THING_VALUE_SIZE];
	Address _issuedTo;
	Address _signedBy;
	C25519::Signature _signature;
};

} // namespace ZeroTier

#endif