/*
 * 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_DICTIONARY_HPP
#define ZT_DICTIONARY_HPP

#include "Constants.hpp"
#include "Utils.hpp"
#include "Address.hpp"
#include "Buf.hpp"
#include "FCV.hpp"
#include "SHA512.hpp"
#include "Fingerprint.hpp"
#include "Containers.hpp"

namespace ZeroTier {

class Identity;

/**
 * A simple key-value store for short keys
 *
 * This data structure is used for network configurations, node meta-data,
 * and other open-definition protocol objects. It consists of a key-value
 * store with short (max: 7 characters) keys that map to strings, blobs,
 * or integers with the latter being by convention in hex format.
 *
 * If this seems a little odd, it is. It dates back to the very first alpha
 * versions of ZeroTier and if it were redesigned today we'd use some kind
 * of simple or standardized binary encoding. Nevertheless it is efficient
 * and it works so there is no need to change it and break backward
 * compatibility.
 * 
 * Use of the append functions is faster than building and then encoding a
 * dictionary for creating outbound packets.
 */
class Dictionary
{
public:
	Dictionary();

	/**
	 * Get a reference to a value
	 *
	 * @param k Key to look up
	 * @return Reference to value
	 */
	Vector<uint8_t> &operator[](const char *k);

	/**
	 * Get a const reference to a value
	 *
	 * @param k Key to look up
	 * @return Reference to value or to empty vector if not found
	 */
	const Vector<uint8_t> &operator[](const char *k) const;

	/**
	 * Add a boolean as '1' or '0'
	 */
	void add(const char *k,bool v);

	/**
	 * Add an integer as a hexadecimal string value
	 */
	ZT_INLINE void add(const char *const k,const uint64_t v) { char buf[17]; add(k,Utils::hex(v,buf)); }
	ZT_INLINE void add(const char *const k,const int64_t v) { char buf[17]; add(k,Utils::hex((uint64_t)v,buf)); }
	ZT_INLINE void add(const char *const k,const uint32_t v) { char buf[17]; add(k,Utils::hex((uint64_t)v,buf)); }
	ZT_INLINE void add(const char *const k,const int32_t v) { char buf[17]; add(k,Utils::hex((uint64_t)v,buf)); }
	ZT_INLINE void add(const char *const k,const uint16_t v) { char buf[17]; add(k,Utils::hex((uint64_t)v,buf)); }
	ZT_INLINE void add(const char *const k,const int16_t v) { char buf[17]; add(k,Utils::hex((uint64_t)v,buf)); }

	/**
	 * Add an address in 10-digit hex string format
	 */
	void add(const char *k,const Address &v);

	/**
	 * Add a C string as a value
	 */
	void add(const char *k,const char *v);

	/**
	 * Add a binary blob as a value
	 */
	void add(const char *k,const void *data,unsigned int len);

	/**
	 * Get a boolean
	 *
	 * @param k Key to look up
	 * @param dfl Default value (default: false)
	 * @return Value of key or default if not found
	 */
	bool getB(const char *k,bool dfl = false) const;

	/**
	 * Get an integer
	 *
	 * @param k Key to look up
	 * @param dfl Default value (default: 0)
	 * @return Value of key or default if not found
	 */
	uint64_t getUI(const char *k,uint64_t dfl = 0) const;

	/**
	 * Get a C string
	 *
	 * If the buffer is too small the string will be truncated, but the
	 * buffer will always end in a terminating null no matter what.
	 *
	 * @param k Key to look up
	 * @param v Buffer to hold string
	 * @param cap Maximum size of string (including terminating null)
	 */
	char *getS(const char *k,char *v,unsigned int cap) const;

	/**
	 * Get an object supporting the marshal/unmarshal interface pattern
	 * 
	 * @param k Key to look up
	 * @param obj Object to unmarshal() into
	 * @return True if unmarshal was successful
	 */
	template<typename T>
	ZT_INLINE bool getO(const char *k,T &obj) const
	{
		const Vector<uint8_t> &d = (*this)[k];
		if (d.empty())
			return false;
		return (obj.unmarshal(d.data(),(unsigned int)d.size()) > 0);
	}

	/**
	 * Sign this identity
	 *
	 * This adds two fields:
	 *   "@Si" contains the fingerprint (address followed by hash) of the signer
	 *   "@Ss" contains the signature
	 *
	 * @param signer Signing identity (must contain secret)
	 * @return True if signature was successful
	 */
	bool sign(const Identity &signer);

	/**
	 * Get the signer's fingerprint for this dictionary or a NIL fingerprint if not signed.
	 *
	 * @return Signer
	 */
	Fingerprint signer() const;

	/**
	 * Verify this identity's signature
	 *
	 * @param signer
	 * @return
	 */
	bool verify(const Identity &signer) const;

	/**
	 * Erase all entries in dictionary
	 */
	void clear();

	/**
	 * @return Number of entries
	 */
	ZT_INLINE unsigned int size() const noexcept { return m_entries.size(); }

	/**
	 * @return True if dictionary is not empty
	 */
	ZT_INLINE bool empty() const noexcept { return m_entries.empty(); }

	/**
	 * Encode to a string in the supplied vector
	 *
	 * @param out String encoded dictionary
	 * @param omitSignatureFields If true omit the signature fields from encoding (default: false)
	 */
	void encode(Vector<uint8_t> &out,bool omitSignatureFields = false) const;

	/**
	 * Decode a string encoded dictionary
	 *
	 * This will decode up to 'len' but will also abort if it finds a
	 * null/zero as this could be a C string.
	 *
	 * @param data Data to decode
	 * @param len Length of data
	 * @return True if dictionary was formatted correctly and valid, false on error
	 */
	bool decode(const void *data,unsigned int len);

	/**
	 * Append a key=value pair to a buffer (vector or FCV)
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param v Value
	 */
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const bool v)
	{
		s_appendKey(out,k);
		out.push_back((uint8_t)(v ? '1' : '0'));
		out.push_back((uint8_t)'\n');
	}

	/**
	 * Append a key=value pair to a buffer (vector or FCV)
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param v Value
	 */
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const Address v)
	{
		s_appendKey(out,k);
		const uint64_t a = v.toInt();
		static_assert(ZT_ADDRESS_LENGTH_HEX == 10,"this must be rewritten for any change in address length");
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 36U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 32U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 28U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 24U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 20U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 16U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 12U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 8U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[(a >> 4U) & 0xfU]);
		out.push_back((uint8_t)Utils::HEXCHARS[a & 0xfU]);
		out.push_back((uint8_t)'\n');
	}

	/**
	 * Append a key=value pair to a buffer (vector or FCV)
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param v Value
	 */
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const uint64_t v)
	{
		char buf[17];
		Utils::hex(v,buf);
		unsigned int i = 0;
		while (buf[i])
			out.push_back((uint8_t)buf[i++]);
		out.push_back((uint8_t)'\n');
	}

	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const int64_t v) { append(out,k,(uint64_t)v); }
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const uint32_t v) { append(out,k,(uint64_t)v); }
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const int32_t v) { append(out,k,(uint64_t)v); }
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const uint16_t v) { append(out,k,(uint64_t)v); }
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const int16_t v) { append(out,k,(uint64_t)v); }
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const uint8_t v) { append(out,k,(uint64_t)v); }
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const int8_t v) { append(out,k,(uint64_t)v); }

	/**
	 * Append a key=value pair to a buffer (vector or FCV)
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param v Value
	 */
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const char *v)
	{
		if ((v)&&(*v)) {
			s_appendKey(out,k);
			while (*v)
				s_appendValueByte(out,(uint8_t)*(v++));
			out.push_back((uint8_t)'\n');
		}
	}

	/**
	 * Append a key=value pair to a buffer (vector or FCV)
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param v Value
	 * @param vlen Value length in bytes
	 */
	template<typename V>
	ZT_INLINE static void append(V &out,const char *const k,const void *const v,const unsigned int vlen)
	{
		s_appendKey(out,k);
		for(unsigned int i=0;i<vlen;++i)
			s_appendValueByte(out,reinterpret_cast<const uint8_t *>(v)[i]);
		out.push_back((uint8_t)'\n');
	}

	/**
	 * Append a packet ID as raw bytes in the provided byte order
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param pid Packet ID
	 */
	template<typename V>
	static ZT_INLINE void appendPacketId(V &out,const char *const k,const uint64_t pid)
	{
		append(out,k,&pid,8);
	}

	/**
	 * Append key=value with any object implementing the correct marshal interface
	 * 
	 * @param out Buffer
	 * @param k Key (must be <= 8 characters)
	 * @param v Marshal-able object
	 * @return Bytes appended or negative on error (return value of marshal())
	 */
	template<typename V,typename T>
	static ZT_INLINE int appendObject(V &out,const char *const k,const T &v)
	{
		uint8_t tmp[4096]; // large enough for any current object
		if (T::marshalSizeMax() > sizeof(tmp))
			return -1;
		const int mlen = v.marshal(tmp);
		if (mlen > 0)
			append(out,k,tmp,(unsigned int)mlen);
		return mlen;
	}

private:
	template<typename V>
	ZT_INLINE static void s_appendValueByte(V &out,const uint8_t c)
	{
		switch(c) {
			case 0:
				out.push_back(92); // backslash
				out.push_back(48);
				break;
			case 10:
				out.push_back(92);
				out.push_back(110);
				break;
			case 13:
				out.push_back(92);
				out.push_back(114);
				break;
			case 61:
				out.push_back(92);
				out.push_back(101);
				break;
			case 92:
				out.push_back(92);
				out.push_back(92);
				break;
			default:
				out.push_back(c);
				break;
		}
	}

	template<typename V>
	ZT_INLINE static void s_appendKey(V &out,const char *const k)
	{
		for(unsigned int i=0;i<7;++i) {
			const char kc = k[i];
			if (kc == 0)
				break;
			if ((kc >= 33)&&(kc <= 126)&&(kc != 61)&&(kc != 92)) // printable ASCII with no spaces, equals, or backslash
				out.push_back((uint8_t)kc);
		}
		out.push_back((uint8_t)'=');
	}

	ZT_INLINE static FCV<char,8> &s_key(FCV<char,8> &buf,const char *k) noexcept
	{
		buf.clear();
		for(unsigned int i=0;i<7;++i) {
			const char kc = k[i];
			if (kc == 0)
				break;
			if ((kc >= 33)&&(kc <= 126)&&(kc != 61)&&(kc != 92)) // printable ASCII with no spaces, equals, or backslash
				buf.push_back(kc);
		}
		buf.push_back(0);
		return buf;
	}

	SortedMap< FCV<char,8>,Vector<uint8_t> > m_entries;
};

} // namespace ZeroTier

#endif