/*
 * 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_TAG_HPP
#define ZT_TAG_HPP

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

#include "Constants.hpp"
#include "Credential.hpp"
#include "C25519.hpp"
#include "Address.hpp"
#include "Identity.hpp"

#define ZT_TAG_MARSHAL_SIZE_MAX (8 + 8 + 4 + 4 + 5 + 5 + 1 + 2 + ZT_SIGNATURE_BUFFER_SIZE + 2)

namespace ZeroTier {

class RuntimeEnvironment;

/**
 * A tag that can be associated with members and matched in rules
 *
 * Capabilities group rules, while tags group members subject to those
 * rules. Tag values can be matched in rules, and tags relevant to a
 * capability are presented along with it.
 *
 * E.g. a capability might be "can speak Samba/CIFS within your
 * department." This cap might have a rule to allow TCP/137 but
 * only if a given tag ID's value matches between two peers. The
 * capability is what members can do, while the tag is who they are.
 * Different departments might have tags with the same ID but different
 * values.
 *
 * Unlike capabilities tags are signed only by the issuer and are never
 * transferable.
 */
class Tag : public Credential
{
	friend class Credential;

public:
	static constexpr ZT_CredentialType credentialType() noexcept { return ZT_CREDENTIAL_TYPE_TAG; }

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

	/**
	 * @param nwid Network ID
	 * @param ts Timestamp
	 * @param issuedTo Address to which this tag was issued
	 * @param id Tag ID
	 * @param value Tag value
	 */
	ZT_INLINE Tag(const uint64_t nwid,const int64_t ts,const Address &issuedTo,const uint32_t id,const uint32_t value) noexcept :
		_id(id),
		_value(value),
		_networkId(nwid),
		_ts(ts),
		_issuedTo(issuedTo),
		_signedBy(),
		_signatureLength(0)
	{
	}

	ZT_INLINE uint32_t id() const noexcept { return _id; }
	ZT_INLINE const uint32_t &value() const noexcept { return _value; }
	ZT_INLINE uint64_t networkId() const noexcept { return _networkId; }
	ZT_INLINE int64_t timestamp() const noexcept { return _ts; }
	ZT_INLINE const Address &issuedTo() const noexcept { return _issuedTo; }
	ZT_INLINE const Address &signer() const noexcept { return _signedBy; }
	ZT_INLINE const uint8_t *signature() const noexcept { return _signature; }
	ZT_INLINE unsigned int signatureLength() const noexcept { return _signatureLength; }

	/**
	 * Sign this tag
	 *
	 * @param signer Signing identity, must have private key
	 * @return True if signature was successful
	 */
	bool sign(const Identity &signer) noexcept;

	/**
	 * Check this tag's signature
	 *
	 * @param RR Runtime environment to allow identity lookup for signedBy
	 * @param tPtr Thread pointer to be handed through to any callbacks called as a result of this call
	 */
	ZT_INLINE Credential::VerifyResult verify(const RuntimeEnvironment *RR,void *tPtr) const noexcept { return _verify(RR,tPtr,*this); }

	static constexpr int marshalSizeMax() noexcept { return ZT_TAG_MARSHAL_SIZE_MAX; }
	int marshal(uint8_t data[ZT_TAG_MARSHAL_SIZE_MAX],bool forSign = false) const noexcept;
	int unmarshal(const uint8_t *data,int len) noexcept;

	// Provides natural sort order by ID
	ZT_INLINE bool operator<(const Tag &t) const noexcept { return (_id < t._id); }

	ZT_INLINE bool operator==(const Tag &t) const noexcept { return (memcmp(this,&t,sizeof(Tag)) == 0); }
	ZT_INLINE bool operator!=(const Tag &t) const noexcept { return (memcmp(this,&t,sizeof(Tag)) != 0); }

	// For searching sorted arrays or lists of Tags by ID
	struct IdComparePredicate
	{
		ZT_INLINE bool operator()(const Tag &a,const Tag &b) const noexcept { return (a.id() < b.id()); }
		ZT_INLINE bool operator()(const uint32_t a,const Tag &b) const noexcept { return (a < b.id()); }
		ZT_INLINE bool operator()(const Tag &a,const uint32_t b) const noexcept { return (a.id() < b); }
		ZT_INLINE bool operator()(const Tag *a,const Tag *b) const noexcept { return (a->id() < b->id()); }
		ZT_INLINE bool operator()(const Tag *a,const Tag &b) const noexcept { return (a->id() < b.id()); }
		ZT_INLINE bool operator()(const Tag &a,const Tag *b) const noexcept { return (a.id() < b->id()); }
		ZT_INLINE bool operator()(const uint32_t a,const Tag *b) const noexcept { return (a < b->id()); }
		ZT_INLINE bool operator()(const Tag *a,const uint32_t b) const noexcept { return (a->id() < b); }
		ZT_INLINE bool operator()(const uint32_t a,const uint32_t b) const noexcept { return (a < b); }
	};

private:
	uint32_t _id;
	uint32_t _value;
	uint64_t _networkId;
	int64_t _ts;
	Address _issuedTo;
	Address _signedBy;
	unsigned int _signatureLength;
	uint8_t _signature[ZT_SIGNATURE_BUFFER_SIZE];
};

} // namespace ZeroTier

#endif