/**
 * Copyright (c) 2019-2022 polistern
 * Copyright (c) 2017 The I2P Project
 * Copyright (c) 2013-2015 The Anoncoin Core developers
 * Copyright (c) 2012-2013 giv
 *
 * Distributed under the MIT software license, see the accompanying
 * file LICENSE or http://www.opensource.org/licenses/mit-license.php.
 *
 * See full documentation about SAM at http://www.i2p2.i2p/samv3.html
 */

#include <ctime>
#include <cstdlib>
#include <cstring>

#include "i2psam.h"

#define PORT_ZERO 0
#define I2P_MIN_DESTINATION_SIZE 521

namespace SAM
{

#ifdef WIN32
int I2pSocket::instances_ = 0;

void I2pSocket::initWSA()
{
    WSADATA wsadata;
    int ret = WSAStartup(MAKEWORD(2, 2), &wsadata);
    if (ret != NO_ERROR)
        print_error("Failed to initialize winsock library");
}

void I2pSocket::freeWSA()
{
    WSACleanup();
}
#endif // WIN32

I2pSocket::I2pSocket(const std::string &SAMHost, uint16_t SAMPort)
    : socket_(INVALID_SOCKET), SAMHost_(SAMHost), SAMPort_(SAMPort) {
#ifdef WIN32
  if (instances_++ == 0)
      initWSA();
#endif // WIN32

  memset(&servAddr_, 0, sizeof(servAddr_));

  servAddr_.sin_family = AF_INET;
  servAddr_.sin_addr.s_addr = inet_addr(SAMHost.c_str());
  servAddr_.sin_port = htons(SAMPort);
  bootstrapI2P();
}

I2pSocket::I2pSocket(const sockaddr_in &addr)
    : socket_(INVALID_SOCKET), servAddr_(addr)
{
#ifdef WIN32
  if (instances_++ == 0)
      initWSA();
#endif // WIN32
  bootstrapI2P();
}

I2pSocket::I2pSocket(const I2pSocket &rhs)
    : socket_(INVALID_SOCKET), servAddr_(rhs.servAddr_)
{
#ifdef WIN32
  if (instances_++ == 0)
      initWSA();
#endif // WIN32
  bootstrapI2P();
}

I2pSocket::~I2pSocket()
{
  close();

#ifdef WIN32
  if (--instances_ == 0)
      freeWSA();
#endif // WIN32
}

void I2pSocket::bootstrapI2P()
{
  init();
  if (isOk())
    handshake();
}

void I2pSocket::init()
{
  /**
   * Here is where the only real OS socket is called for creation to talk with the router,
   * the value returned is stored in our variable socket_  which holds the connection
   * to our stream for everything else
   */
  socket_ = socket(AF_INET, SOCK_STREAM, 0);
  if (socket_ == INVALID_SOCKET)
    {
      print_error("Failed to create socket");
      return;
    }

  if (connect(socket_, (const sockaddr *) &servAddr_, sizeof(servAddr_)) == SOCKET_ERROR)
    {
      close();
      print_error("Failed to connect to SAM");
      return;
    }
}

SOCKET I2pSocket::release()
{
  SOCKET temp = socket_;
  socket_ = INVALID_SOCKET;
  return temp;
}

// If the handshake works, we're talking to a valid I2P router.
void I2pSocket::handshake()
{
  this->write(Message::hello(minVer_, maxVer_));
  const std::string answer = this->read();
  const Message::eStatus answerStatus = Message::checkAnswer(answer);
  if (answerStatus == Message::OK)
    version_ = Message::getValue(answer, "VERSION");
  else
    print_error("Handshake failed");
}

void I2pSocket::write(const std::string &msg)
{
  if (!isOk())
    {
      print_error("Failed to send data because socket is closed");
      return;
    }
#ifdef DEBUG_ON_STDOUT
  std::cout << "Send: " << msg << std::endl;
#endif // DEBUG_ON_STDOUT
  ssize_t sentBytes = send(socket_, msg.c_str(), msg.length(), 0);
  if (sentBytes == SOCKET_ERROR)
    {
      close();
      print_error("Failed to send data");
      return;
    }
  if (sentBytes == 0)
    {
      close();
      print_error("I2pSocket was closed");
      return;
    }
}

std::string I2pSocket::read()
{
  if (!isOk())
    {
      print_error("Failed to read data because socket is closed");
      return std::string();
    }
  char buffer[SAM_BUFSIZE];
  memset(buffer, 0, SAM_BUFSIZE);
  ssize_t recievedBytes = recv(socket_, buffer, SAM_BUFSIZE, 0);
  if (recievedBytes == SOCKET_ERROR)
    {
      close();
      print_error("Failed to receive data");
      return std::string();
    }
  if (recievedBytes == 0)
    {
      close();
      print_error("I2pSocket was closed");
    }
#ifdef DEBUG_ON_STDOUT
  std::cout << "Reply: " << buffer << std::endl;
#endif // DEBUG_ON_STDOUT
  return std::string(buffer);
}

void I2pSocket::close()
{
  if (socket_ != INVALID_SOCKET)
    {
#ifdef WIN32
      ::closesocket(socket_);
#else
      ::close(socket_);
#endif // WIN32
      socket_ = INVALID_SOCKET;
    }
}

bool I2pSocket::isOk() const { return socket_ != INVALID_SOCKET; }

const std::string &I2pSocket::getHost() const { return SAMHost_; }

uint16_t I2pSocket::getPort() const { return SAMPort_; }

const std::string &I2pSocket::getVersion() const { return version_; }

const sockaddr_in &I2pSocket::getAddress() const { return servAddr_; }

//-----------------------------------------------------------------------------

SAMSession::SAMSession(
    const std::string &nickname,
    const std::string &SAMHost       /*= SAM_DEFAULT_ADDRESS*/,
    uint16_t SAMPort                 /*= SAM_DEFAULT_PORT_TCP*/,
    const std::string &i2pOptions    /*= SAM_DEFAULT_I2P_OPTIONS*/,
    const std::string &signatureType /*= SAM_SIGNATURE_TYPE */)
    : socket_(SAMHost, SAMPort),
      nickname_(nickname),
      sessionID_(generateSessionID()),
      i2pOptions_(i2pOptions),
      isSick_(false)
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a brand new SAM stream session (" << sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

SAMSession::SAMSession(SAMSession& rhs)
    : socket_(rhs.socket_),
      nickname_(rhs.nickname_),
      sessionID_(generateSessionID()),
      myDestination_(rhs.myDestination_),
      i2pOptions_(rhs.i2pOptions_),
      isSick_(false)
{
    rhs.fallSick();
    rhs.socket_.close();
#ifdef DEBUG_ON_STDOUT
    std::cout << "Created a new SAM session (" << sessionID_ << ")  from another (" << rhs.sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

/*static*/
std::string SAMSession::generateSessionID()
{
  static const int minSessionIDLength = 5;
  static const int maxSessionIDLength = 9;
  static const char sessionIDAlphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  int length = minSessionIDLength - 1;
  std::string result;

  srand(time(nullptr));

  while (length < minSessionIDLength)
    length = rand() % maxSessionIDLength;

  while (length-- > 0)
    result += sessionIDAlphabet[rand() % (sizeof(sessionIDAlphabet) - 1)];

#ifdef DEBUG_ON_STDOUT
  std::cout << "Generated session ID: " << result << std::endl;
#endif // DEBUG_ON_STDOUT
  return result;
}

RequestResult<const std::string> SAMSession::namingLookup(const std::string &name) const
{
  typedef RequestResult<const std::string> ResultType;
  typedef Message::Answer<const std::string> AnswerType;

  std::unique_ptr<I2pSocket> newSocket(new I2pSocket(socket_));
  const AnswerType answer = namingLookup(*newSocket, name);
  switch (answer.status)
    {
      case Message::OK:
        return ResultType(answer.value);
      case Message::EMPTY_ANSWER:
      case Message::CLOSED_SOCKET:
        fallSick();
        break;
      default:
        break;
    }
  return ResultType();
}

RequestResult<const FullDestination> SAMSession::destGenerate() const
{
  typedef RequestResult<const FullDestination> ResultType;
  typedef Message::Answer<const FullDestination> AnswerType;

  std::unique_ptr<I2pSocket> newSocket(new I2pSocket(socket_));
  const AnswerType answer = destGenerate(*newSocket);
  switch (answer.status)
    {
      case Message::OK:
        return ResultType(answer.value);
      case Message::EMPTY_ANSWER:
      case Message::CLOSED_SOCKET:
        fallSick();
        break;
      default:
        break;
    }
  return ResultType();
}

FullDestination SAMSession::createSession(const std::string& destination)
{
  return createSession(destination, SAM_SIGNATURE_TYPE);
}

FullDestination SAMSession::createSession(const std::string& destination, const std::string& sigType)
{
  return createSession(destination, sigType, i2pOptions_);
}

void SAMSession::fallSick() const { isSick_ = true; }

/*static*/
Message::Answer<const std::string> SAMSession::rawRequest(I2pSocket &socket, const std::string &requestStr)
{
  typedef Message::Answer<const std::string> AnswerType;

  if (!socket.isOk())
    return AnswerType(Message::CLOSED_SOCKET);
  socket.write(requestStr);
  const std::string answer = socket.read();
  const Message::eStatus status = Message::checkAnswer(answer);
  return AnswerType(status, answer);
}

/*static*/
Message::Answer<const std::string> SAMSession::request(I2pSocket &socket,
                                                          const std::string &requestStr,
                                                          const std::string &keyOnSuccess)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType answer = rawRequest(socket, requestStr);
  return (answer.status == Message::OK) ? AnswerType(answer.status, Message::getValue(answer.value, keyOnSuccess))
                                        : answer;
}

/*static*/
Message::eStatus SAMSession::request(I2pSocket &socket, const std::string &requestStr)
{
  return rawRequest(socket, requestStr).status;
}

/*static*/
Message::Answer<const std::string> SAMSession::namingLookup(I2pSocket &socket, const std::string &name)
{
  return request(socket, Message::namingLookup(name), "VALUE");
}

/*static*/
Message::Answer<const FullDestination> SAMSession::destGenerate(I2pSocket &socket)
{
  // while answer for a DEST GENERATE request doesn't contain a "RESULT" field we parse it manually
  typedef Message::Answer<const FullDestination> ResultType;

  if (!socket.isOk())
    return ResultType(Message::CLOSED_SOCKET, FullDestination());
  socket.write(Message::destGenerate());
  const std::string answer = socket.read();
  const std::string pub = Message::getValue(answer, "PUB");
  const std::string priv = Message::getValue(answer, "PRIV");
  return (!pub.empty() && !priv.empty()) ? ResultType(Message::OK, FullDestination(pub, priv, /*isGenerated*/ true))
                                         : ResultType(Message::EMPTY_ANSWER, FullDestination());
}

const std::string &SAMSession::getNickname() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getNickname: " << nickname_ << std::endl;
#endif // DEBUG_ON_STDOUT
  return nickname_;
}

const std::string &SAMSession::getSessionID() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getSessionID: " << sessionID_ << std::endl;
#endif // DEBUG_ON_STDOUT
  return sessionID_;
}

const std::string &SAMSession::getOptions() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getOptions: " << i2pOptions_ << std::endl;
#endif // DEBUG_ON_STDOUT
  return i2pOptions_;
}

const FullDestination &SAMSession::getMyDestination() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getMyDestination: " << myDestination_.priv << std::endl;
#endif // DEBUG_ON_STDOUT
  return myDestination_;
}

bool SAMSession::isSick() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "isSick: " << isSick_ << std::endl;
#endif // DEBUG_ON_STDOUT
  return isSick_;
}

const sockaddr_in &SAMSession::getSAMAddress() const
{
#ifdef DEBUG_ON_STDOUT
  // std::cout << "getSAMAddress: " << socket_.getAddress() << std::endl;
  std::cout << "getSAMAddress: not yet parsed" << std::endl;
#endif // DEBUG_ON_STDOUT
  return socket_.getAddress();
}

const std::string &SAMSession::getSAMHost() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getSAMHost: " << socket_.getHost() << std::endl;
#endif // DEBUG_ON_STDOUT
  return socket_.getHost();
}

uint16_t SAMSession::getSAMPort() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getSAMPort: " << socket_.getPort() << std::endl;
#endif // DEBUG_ON_STDOUT
  return socket_.getPort();
}

const std::string &SAMSession::getSAMVersion() const
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "getSAMVersion: " << socket_.getVersion() << std::endl;
#endif // DEBUG_ON_STDOUT
  return socket_.getVersion();
}

const std::string &SAMSession::getSAMMinVer() const { return socket_.minVer_; }

const std::string &SAMSession::getSAMMaxVer() const { return socket_.maxVer_; }

//-----------------------------------------------------------------------------

StreamSession::StreamSession(
    const std::string &nickname,
    const std::string &SAMHost       /*= SAM_DEFAULT_ADDRESS*/,
    uint16_t SAMPort                 /*= SAM_DEFAULT_PORT_TCP*/,
    const std::string &destination   /*= SAM_GENERATE_MY_DESTINATION*/,
    const std::string &i2pOptions    /*= SAM_DEFAULT_I2P_OPTIONS*/,
    const std::string &signatureType /*= SAM_SIGNATURE_TYPE */)
    : SAMSession(nickname, SAMHost, SAMPort, i2pOptions, signatureType)
{
  myDestination_ = createStreamSession(destination);
#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a brand new SAM stream session (" << sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

StreamSession::StreamSession(StreamSession &rhs)
    : SAMSession(rhs)
{
  rhs.fallSick();
  rhs.socket_.close();
  (void) createStreamSession(myDestination_.priv);

  for (const auto &forwardedStream : rhs.forwardedStreams_)
    forward(forwardedStream.host, forwardedStream.port, forwardedStream.silent);

#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a new SAM stream session (" << sessionID_ << ")  from another (" << rhs.sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

StreamSession::~StreamSession()
{
  stopForwardingAll();
#ifdef DEBUG_ON_STDOUT
  std::cout << "Closing SAM stream session (" << sessionID_ << ") ..." << std::endl;
#endif // DEBUG_ON_STDOUT
}

RequestResult<std::unique_ptr<I2pSocket>> StreamSession::accept(bool silent)
{
  typedef RequestResult<std::unique_ptr<I2pSocket>> ResultType;

  std::unique_ptr<I2pSocket> streamSocket(new I2pSocket(socket_));
  const Message::eStatus status = accept(*streamSocket, sessionID_, silent);
  switch (status)
    {
      case Message::OK:
        return ResultType(std::move(streamSocket));
      case Message::EMPTY_ANSWER:
      case Message::CLOSED_SOCKET:
      case Message::INVALID_ID:
      case Message::I2P_ERROR:
        fallSick();
        break;
      default:
        break;
    }
  return ResultType();
}

RequestResult<std::unique_ptr<I2pSocket>> StreamSession::connect(const std::string &destination, bool silent)
{
  typedef RequestResult<std::unique_ptr<I2pSocket>> ResultType;

  std::unique_ptr<I2pSocket> streamSocket(new I2pSocket(socket_));
  const Message::eStatus status = connect(*streamSocket, sessionID_, destination, silent);

  if (silent)
    return ResultType(std::move(streamSocket));
  
  switch (status)
    {
      case Message::OK:
        return ResultType(std::move(streamSocket));
      case Message::EMPTY_ANSWER:
      case Message::CLOSED_SOCKET:
      case Message::INVALID_ID:
      case Message::I2P_ERROR:
        fallSick();
        break;
      default:
        break;
    }
  return ResultType();
}

RequestResult<void> StreamSession::forward(const std::string &host, uint16_t port, bool silent)
{
  typedef RequestResult<void> ResultType;

  std::unique_ptr<I2pSocket> newSocket(new I2pSocket(socket_));
  const Message::eStatus status = forward(*newSocket, sessionID_, host, port, silent);
  switch (status)
    {
      case Message::OK:
        forwardedStreams_.push_back(ForwardedStream(newSocket.get(), host, port, silent));
        newSocket.release(); // release after successful push_back only
        return ResultType(true);
      case Message::EMPTY_ANSWER:
      case Message::CLOSED_SOCKET:
      case Message::INVALID_ID:
      case Message::I2P_ERROR:
        fallSick();
        break;
      default:
        break;
    }
  return ResultType();
}

FullDestination StreamSession::createStreamSession(const std::string &destination)
{
   return createStreamSession(destination, SAM_SIGNATURE_TYPE);
}

FullDestination StreamSession::createStreamSession(const std::string& destination, const std::string& sigType)
{
    return createStreamSession(destination, sigType, i2pOptions_);
}

FullDestination StreamSession::createStreamSession(const std::string& destination, const std::string& sigType, const std::string& i2pOptions)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType
      answer = createStreamSession(socket_, sessionID_, nickname_, destination, i2pOptions, sigType);
  if (answer.status != Message::OK)
    {
      fallSick();
      return FullDestination();
    }
  return FullDestination(answer.value.c_str(), answer.value, (destination == SAM_GENERATE_MY_DESTINATION));
}

FullDestination StreamSession::createSession(const std::string& destination, const std::string& sigType, const std::string& i2pOptions)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType
      answer = createStreamSession(socket_, sessionID_, nickname_, destination, i2pOptions, sigType);
  if (answer.status != Message::OK)
    {
      fallSick();
      return FullDestination();
    }
  return FullDestination(answer.value.c_str(), answer.value, (destination == SAM_GENERATE_MY_DESTINATION));
}

void StreamSession::stopForwarding(const std::string &host, uint16_t port)
{
  for (auto it = forwardedStreams_.begin(); it != forwardedStreams_.end();)
    {
      if (it->port == port && it->host == host)
        {
          delete (it->socket);
          it = forwardedStreams_.erase(it);
        }
      else
        ++it;
    }
}

void StreamSession::stopForwardingAll()
{
  for (auto &forwardedStream : forwardedStreams_)
    delete (forwardedStream.socket);
  forwardedStreams_.clear();
  socket_.close();
}

/*static*/
Message::Answer<const std::string> StreamSession::createStreamSession(I2pSocket &socket,
                                                                      const std::string &sessionID,
                                                                      const std::string &nickname,
                                                                      const std::string &destination,
                                                                      const std::string &options,
                                                                      const std::string &signatureType)
{
  return request(socket,
                 Message::sessionCreate(Message::sssStream, sessionID, nickname, destination, options, signatureType),
                 "DESTINATION");
}

/*static*/
Message::eStatus StreamSession::accept(I2pSocket &socket, const std::string &sessionID, bool silent)
{
  return request(socket, Message::streamAccept(sessionID, silent));
}

/*static*/
Message::eStatus StreamSession::connect(I2pSocket &socket,
                                        const std::string &sessionID,
                                        const std::string &destination,
                                        bool silent)
{
  return request(socket, Message::streamConnect(sessionID, destination, silent));
}

/*static*/
Message::eStatus StreamSession::forward(I2pSocket &socket,
                                        const std::string &sessionID,
                                        const std::string &host,
                                        uint16_t port,
                                        bool silent)
{
  return request(socket, Message::streamForward(sessionID, host, port, silent));
}

//--------------------------------------------------------------------------------------------------

DatagramSession::DatagramSession(
    const std::string &nickname,
    const std::string &SAMHost       /* = SAM_DEFAULT_ADDRESS*/,
    uint16_t SAMPortTCP              /*= SAM_DEFAULT_PORT_TCP*/,
    uint16_t SAMPortUDP              /*= SAM_DEFAULT_PORT_UDP*/,
    const std::string &listenAddress /*= SAM_DEFAULT_ADDRESS*/,
    uint16_t ClientPortUDP           /*= SAM_DEFAULT_CLIENT_UDP*/,
    const std::string &destination   /*= SAM_GENERATE_MY_DESTINATION*/,
    const std::string &i2pOptions    /*= SAM_DEFAULT_I2P_OPTIONS*/,
    const std::string &signatureType /*= SAM_SIGNATURE_TYPE*/)
    : SAMSession(nickname, SAMHost, SAMPortTCP, i2pOptions, signatureType)
{
  listenAddress_ = listenAddress;
  listenPortUDP_ = ClientPortUDP;
  SAMPortUDP_ = SAMPortUDP;
  myDestination_ = createDatagramSession(destination);
#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a brand new SAM datagram session (" << sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

DatagramSession::DatagramSession(DatagramSession &rhs)
    : SAMSession(rhs),
      listenAddress_(rhs.listenAddress_), listenPortUDP_(rhs.listenPortUDP_), SAMPortUDP_(rhs.SAMPortUDP_)
{
  myDestination_ = rhs.myDestination_;
  rhs.fallSick();
  rhs.socket_.close();
  (void) createDatagramSession(myDestination_.priv);

#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a new SAM datagram session (" << sessionID_ << ")  from another (" << rhs.sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

DatagramSession::~DatagramSession()
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "Closing SAM datagram session (" << sessionID_ << ") ..." << std::endl;
#endif // DEBUG_ON_STDOUT
}

FullDestination DatagramSession::createDatagramSession(const std::string& destination)
{
  return createDatagramSession(destination, SAM_SIGNATURE_TYPE);
}

FullDestination DatagramSession::createDatagramSession(const std::string& destination, const std::string& sigType)
{
  return createDatagramSession(destination, sigType, i2pOptions_);
}

FullDestination DatagramSession::createDatagramSession(const std::string& destination, const std::string& sigType, const std::string& i2pOptions)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType answer = createDatagramSession(socket_, sessionID_, nickname_, listenPortUDP_, listenAddress_, destination, i2pOptions, sigType);
  if (answer.status != Message::OK)
    {
      fallSick();
      return FullDestination();
    }
  return FullDestination(answer.value.c_str(), answer.value, (destination == SAM_GENERATE_MY_DESTINATION));
}

FullDestination DatagramSession::createSession(const std::string& destination, const std::string& sigType, const std::string& i2pOptions)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType answer = createDatagramSession(socket_, sessionID_, nickname_, listenPortUDP_, listenAddress_, destination, i2pOptions, sigType);
  if (answer.status != Message::OK)
    {
      fallSick();
      return FullDestination();
    }
  return FullDestination(answer.value.c_str(), answer.value, (destination == SAM_GENERATE_MY_DESTINATION));
}

/*static*/
Message::Answer<const std::string> DatagramSession::createDatagramSession(I2pSocket &socket,
                                                                          const std::string &sessionID,
                                                                          const std::string &nickname,
                                                                          const uint16_t port,
                                                                          const std::string &host,
                                                                          const std::string &destination,
                                                                          const std::string &options,
                                                                          const std::string &signatureType)
{
  return request(socket,
                 Message::sessionCreate(Message::sssDatagram,
                                        sessionID,
                                        nickname,
                                        port,
                                        host,
                                        destination,
                                        options,
                                        signatureType),
                 "DESTINATION");
}

//--------------------------------------------------------------------------------------------------

RawSession::RawSession(
    const std::string &nickname,
    const std::string &SAMHost       /* = SAM_DEFAULT_ADDRESS*/,
    uint16_t SAMPortTCP              /* = SAM_DEFAULT_PORT_TCP*/,
    uint16_t SAMPortUDP              /* = SAM_DEFAULT_PORT_UDP*/,
    const std::string &listenAddress /* = SAM_DEFAULT_ADDRESS*/,
    uint16_t ClientPortUDP           /* = SAM_DEFAULT_CLIENT_UDP*/,
    const std::string &destination   /* = SAM_GENERATE_MY_DESTINATION*/,
    const std::string &i2pOptions    /* = SAM_DEFAULT_I2P_OPTIONS*/,
    const std::string &signatureType /* = SAM_SIGNATURE_TYPE*/)
    : SAMSession(nickname, SAMHost, SAMPortTCP, i2pOptions, signatureType),
      listenAddress_(listenAddress), listenPortUDP_(ClientPortUDP), SAMPortUDP_(SAMPortUDP)
{
  myDestination_ = createRawSession(destination);
#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a brand new SAM datagram session (" << sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

RawSession::RawSession(RawSession &rhs)
    : SAMSession(rhs),
      listenAddress_(rhs.listenAddress_), listenPortUDP_(rhs.listenPortUDP_), SAMPortUDP_(rhs.SAMPortUDP_)
{
  myDestination_ = rhs.myDestination_;
  rhs.fallSick();
  rhs.socket_.close();
  (void) createRawSession(myDestination_.priv);
#ifdef DEBUG_ON_STDOUT
  std::cout << "Created a new SAM datagram session (" << sessionID_ << ")  from another (" << rhs.sessionID_ << ")" << std::endl;
#endif // DEBUG_ON_STDOUT
}

RawSession::~RawSession()
{
#ifdef DEBUG_ON_STDOUT
  std::cout << "Closing SAM datagram session (" << sessionID_ << ") ..." << std::endl;
#endif // DEBUG_ON_STDOUT
}

FullDestination RawSession::createRawSession(const std::string& destination)
{
    return createRawSession(destination, SAM_SIGNATURE_TYPE);
}

FullDestination RawSession::createRawSession(const std::string& destination, const std::string& sigType)
{
    return createRawSession(destination, sigType, i2pOptions_);
}

FullDestination RawSession::createRawSession(const std::string& destination, const std::string& sigType, const std::string& i2pOptions)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType answer = createRawSession(socket_, sessionID_, nickname_, listenPortUDP_, listenAddress_, destination, i2pOptions, sigType);
  if (answer.status != Message::OK)
    {
      fallSick();
      return FullDestination();
    }
  return FullDestination(answer.value.c_str(), answer.value, (destination == SAM_GENERATE_MY_DESTINATION));
}

FullDestination RawSession::createSession(const std::string& destination, const std::string& sigType, const std::string& i2pOptions)
{
  typedef Message::Answer<const std::string> AnswerType;

  const AnswerType answer = createRawSession(socket_, sessionID_, nickname_, listenPortUDP_, listenAddress_, destination, i2pOptions, sigType);
  if (answer.status != Message::OK)
    {
      fallSick();
      return FullDestination();
    }
  return FullDestination(answer.value.c_str(), answer.value, (destination == SAM_GENERATE_MY_DESTINATION));
}

/*static*/
Message::Answer<const std::string> RawSession::createRawSession(I2pSocket &socket,
                                                                const std::string &sessionID,
                                                                const std::string &nickname,
                                                                const uint16_t port,
                                                                const std::string &host,
                                                                const std::string &destination,
                                                                const std::string &options,
                                                                const std::string &signatureType)
{
  return request(socket, Message::sessionCreate(Message::sssRaw, sessionID, nickname, port, host, destination, options, signatureType), "DESTINATION");
}

//-----------------------------------------------------------------------------

std::string Message::hello(const std::string &minVer, const std::string &maxVer)
{
  /**
   * ->  HELLO VERSION
   *        MIN=$min
   *        MAX=$max
   *
   * <-  HELLO REPLY
   *        RESULT=OK
   *        VERSION=$version
   */

  static const char *helloFormat = "HELLO VERSION MIN=%s MAX=%s\n";
  return createSAMRequest(helloFormat, minVer.c_str(), maxVer.c_str());
}

std::string Message::sessionCreate(SessionStyle style,
                                   const std::string &sessionID,
                                   const std::string &nickname,
                                   const std::string &destination   /*= SAM_GENERATE_MY_DESTINATION*/,
                                   const std::string &options       /*= ""*/,
                                   const std::string &signatureType /*= SAM_SIGNATURE_TYPE*/)
{
  /**
   * ->  SESSION CREATE
   *        STYLE={STREAM,DATAGRAM,RAW}
   *        ID={$nickname}
   *        DESTINATION={$private_destination_key,TRANSIENT}
   *        [option=value]*
   *
   * <-  SESSION STATUS
   *        RESULT=OK
   *        DESTINATION=$private_destination_key
   */

  std::string sessionStyle;
  switch (style)
    {
      case sssStream:sessionStyle = "STREAM";
        break;
      case sssDatagram:sessionStyle = "DATAGRAM";
        break;
      case sssRaw:sessionStyle = "RAW";
        break;
    }

  static const char *sessionCreateFormat =
      "SESSION CREATE STYLE=%s ID=%s DESTINATION=%s SIGNATURE_TYPE=%s inbound.nickname=%s %s\n"; // we add inbound.nickname option
  return createSAMRequest(sessionCreateFormat,
                          sessionStyle.c_str(),
                          sessionID.c_str(),
                          destination.c_str(),
                          signatureType.c_str(),
                          nickname.c_str(),
                          options.c_str());
}

std::string Message::sessionCreate(SessionStyle style,
                                   const std::string &sessionID,
                                   const std::string &nickname,
                                   const uint16_t port,
                                   const std::string &host,
                                   const std::string &destination   /*= SAM_GENERATE_MY_DESTINATION*/,
                                   const std::string &options       /*= ""*/,
                                   const std::string &signatureType /*= SAM_SIGNATURE_TYPE*/)
{
  /**
   * ->  SESSION CREATE
   *        STYLE={STREAM,DATAGRAM,RAW}
   *        ID={$nickname}
   *        DESTINATION={$private_destination_key,TRANSIENT}
   *        [SIGNATURE_TYPE=value] # SAM 3.1 or higher only, for DESTINATION=TRANSIENT only, default DSA_SHA1
   *        [PORT=$port]           # Required for DATAGRAM and RAW, invalid for STREAM
   *        [HOST=$host]           # Optional for DATAGRAM and RAW, invalid for STREAM
   *        [FROM_PORT=nnn]        # SAM 3.2 or higher only, default 0
   *        [TO_PORT=nnn]          # SAM 3.2 or higher only, default 0
   *        [PROTOCOL=nnn]         # SAM 3.2 or higher only, for STYLE=RAW only, default 18
   *        [HEADER={true,false}]  # SAM 3.2 or higher only, for STYLE=RAW only, default false
   *        [option=value]*        # I2CP and streaming options
   *
   * <-  SESSION STATUS
   *        RESULT=OK
   *        DESTINATION=$private_destination_key
   */

  std::string sessionStyle;
  switch (style)
    {
      case sssStream:sessionStyle = "STREAM";
        break;
      case sssDatagram:sessionStyle = "DATAGRAM";
        break;
      case sssRaw:sessionStyle = "RAW";
        break;
    }
  // we add inbound.nickname option
  static const char *sessionCreateFormat =
      "SESSION CREATE STYLE=%s ID=%s DESTINATION=%s SIGNATURE_TYPE=%s PORT=%s HOST=%s inbound.nickname=%s %s\n";
  return createSAMRequest(sessionCreateFormat,
                          sessionStyle.c_str(),
                          sessionID.c_str(),
                          destination.c_str(),
                          signatureType.c_str(),
                          std::to_string(port).c_str(),
                          host.c_str(),
                          nickname.c_str(),
                          options.c_str());
}

std::string Message::streamAccept(const std::string &sessionID,
                                  bool silent /*= false*/)
{
  /**
   * -> STREAM ACCEPT
   *       ID={$nickname}
   *       [SILENT={true,false}]
   *
   * <- STREAM STATUS
   *       RESULT=$result
   *       [MESSAGE=...]
   */

  static const char *streamAcceptFormat = "STREAM ACCEPT ID=%s SILENT=%s\n";
  return createSAMRequest(streamAcceptFormat,
                          sessionID.c_str(),
                          silent ? "true" : "false");
}

std::string Message::streamConnect(const std::string &sessionID,
                                   const std::string &destination,
                                   bool silent /*= false*/)
{
  /**
   * -> STREAM CONNECT
   *       ID={$nickname}
   *       DESTINATION=$peer_public_base64_key
   *       [SILENT={true,false}]
   *
   * <- STREAM STATUS
   *       RESULT=$result
   *       [MESSAGE=...]
   */

  static const char *streamConnectFormat = "STREAM CONNECT ID=%s DESTINATION=%s SILENT=%s\n";
  return createSAMRequest(streamConnectFormat,
                          sessionID.c_str(),
                          destination.c_str(),
                          silent ? "true" : "false");
}

std::string Message::streamForward(const std::string &sessionID,
                                   const std::string &host,
                                   uint16_t port,
                                   bool silent /*= false*/)
{
  /**
   * -> STREAM FORWARD
   *       ID={$nickname}
   *       PORT={$port}
   *       [HOST={$host}]
   *       [SILENT={true,false}]
   *
   * <- STREAM STATUS
   *       RESULT=$result
   *       [MESSAGE=...]
   */
  static const char *streamForwardFormat = "STREAM FORWARD ID=%s PORT=%u HOST=%s SILENT=%s\n";
  return createSAMRequest(streamForwardFormat,
                          sessionID.c_str(),
                          (unsigned) port,
                          host.c_str(),
                          silent ? "true" : "false");
}

std::string Message::datagramSend(const std::string &nickname, const std::string &destination)
{
  /**
   * 3.0                          # As of SAM 3.2, any "3.x" is allowed. Prior to that, "3.0" is required.
   * {$nickname}
   * {$destination}
   * [FROM_PORT=nnn]              # SAM 3.2 or higher only, default 0
   * [TO_PORT=nnn]                # SAM 3.2 or higher only, default 0
   * [PROTOCOL=nnn]               # SAM 3.2 or higher only, only for RAW sessions, default 18
   * [SEND_TAGS=nnn]              # SAM 3.3 or higher only, number of session tags to send
   *                              # Overrides crypto.tagsToSend I2CP session option
   *                              # Default is router-dependent (40 for Java router)
   * [TAG_THRESHOLD=nnn]          # SAM 3.3 or higher only, low session tag threshold
   *                              # Overrides crypto.lowTagThreshold I2CP session option
   *                              # Default is router-dependent (30 for Java router)
   * [EXPIRES=nnn]                # SAM 3.3 or higher only, expiration from now in seconds
   *                              # Overrides clientMessageTimeout I2CP session option (which is in ms)
   *                              # Default is router-dependent (60 for Java router)
   * [SEND_LEASESET={true,false}] # SAM 3.3 or higher only, whether to send our leaseset
   *                              # Overrides shouldBundleReplyInfo I2CP session option
   *                              # Default is true
   * \n
   * {$datagram_payload}
   */
  static const char *datagramSendFormat = "3.0 %s %s\n";
  return createSAMRequest(datagramSendFormat, nickname.c_str(), destination.c_str());
}

std::string Message::namingLookup(const std::string &name)
{
  /**
   * -> NAMING LOOKUP
   *       NAME=$name
   *
   * <- NAMING REPLY
   *       RESULT=OK
   *       NAME=$name
   *       VALUE=$base64key
   */

  static const char *namingLookupFormat = "NAMING LOOKUP NAME=%s\n";
  return createSAMRequest(namingLookupFormat,
                          name.c_str());
}

std::string Message::destGenerate()
{
  /**
   * -> DEST GENERATE
   *
   * <- DEST REPLY
   *       PUB=$pubkey
   *       PRIV=$privkey
   */

  static const char *destGenerateFormat = "DEST GENERATE\n";
  return createSAMRequest(destGenerateFormat);
}

#define SAM_MAKESTRING(X) SAM_MAKESTRING2(X)
#define SAM_MAKESTRING2(X) #X

#define SAM_CHECK_RESULT(value)          \
    if (result == SAM_MAKESTRING(value)) \
    return value

Message::eStatus Message::checkAnswer(const std::string &answer) {
  if (answer.empty())
    return EMPTY_ANSWER;

  const std::string result = getValue(answer, "RESULT");

  SAM_CHECK_RESULT(OK);
  SAM_CHECK_RESULT(DUPLICATED_DEST);
  SAM_CHECK_RESULT(DUPLICATED_ID);
  SAM_CHECK_RESULT(I2P_ERROR);
  SAM_CHECK_RESULT(INVALID_ID);
  SAM_CHECK_RESULT(INVALID_KEY);
  SAM_CHECK_RESULT(CANT_REACH_PEER);
  SAM_CHECK_RESULT(TIMEOUT);
  SAM_CHECK_RESULT(NOVERSION);
  SAM_CHECK_RESULT(KEY_NOT_FOUND);
  SAM_CHECK_RESULT(PEER_NOT_FOUND);
  SAM_CHECK_RESULT(ALREADY_ACCEPTING);

  return CANNOT_PARSE_ERROR;
}

#undef SAM_CHECK_RESULT
#undef SAM_MAKESTRING2
#undef SAM_MAKESTRING

std::string Message::getValue(const std::string &answer, const std::string &key) {
  if (key.empty())
    return std::string();

  const std::string keyPattern = key + "=";
  size_t valueStart = answer.find(keyPattern);
  if (valueStart == std::string::npos)
    return std::string();

  valueStart += keyPattern.length();
  size_t valueEnd = answer.find_first_of(' ', valueStart);
  if (valueEnd == std::string::npos)
    valueEnd = answer.find_first_of('\n', valueStart);
  return answer.substr(valueStart, valueEnd - valueStart);
}

} // namespace SAM

// C interface

extern "C"
{

#include "i2psam-c.h"

struct i2psam_stream_session { SAM::StreamSession *impl = nullptr; };

struct i2psam_socket { std::unique_ptr<SAM::I2pSocket> impl; };

struct i2psam_destination
{
  char *pub;
  char *priv;
};

struct i2psam_stream_session *i2psam_stream_session_new(struct i2psam_stream_settings *settings)
{
  struct i2psam_stream_session *session = new i2psam_stream_session;
  session->impl = new SAM::StreamSession(settings->nickname,
                                         settings->samhost,
                                         settings->samport,
                                         settings->destination,
                                         settings->i2cp_opts);
  return session;
}

void i2psam_stream_session_free(struct i2psam_stream_session *session)
{
  delete session->impl;
  delete session;
}

const char *i2psam_get_samhost(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getSAMHost().c_str());
}

uint16_t i2psam_get_samport(struct i2psam_stream_session *session)
{
  return session->impl->getSAMPort();
}

const char *i2psam_get_nickname(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getNickname().c_str());
}

const char *i2psam_get_session_id(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getSessionID().c_str());
}

const char *i2psam_get_sam_min_version(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getSAMMinVer().c_str());
}

const char *i2psam_get_sam_max_version(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getSAMMaxVer().c_str());
}

const char *i2psam_get_sam_version(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getSAMVersion().c_str());
}

const char *i2psam_get_i2cp_options(struct i2psam_stream_session *session)
{
  return strdup(session->impl->getOptions().c_str());
}

int i2psam_is_sick(struct i2psam_stream_session *session)
{
  if (session->impl->isSick())
    return 1;
  else
    return 0;
}

struct i2psam_socket *i2psam_accept(struct i2psam_stream_session *session, int silent)
{
  auto result = session->impl->accept(silent);
  if (result.isOk)
    {
      struct i2psam_socket *socket = new i2psam_socket;
      socket->impl = std::move(result.value);
      return socket;
    }
  else
    return nullptr;
}

struct i2psam_socket *i2psam_connect(struct i2psam_stream_session *session, const char *destination, int silent)
{
  auto result = session->impl->connect(destination, silent != 0);
  if (result.isOk)
    {
      struct i2psam_socket *socket = new i2psam_socket;
      socket->impl = std::move(result.value);
      return socket;
    }
  else
    return nullptr;
}

int i2psam_forward(struct i2psam_stream_session *session, const char *host, uint16_t port, int silent)
{
  std::string remote(host);
  auto result = session->impl->forward(host, port, silent);

  if (result.isOk)
    return 0;
  else
    return -1;
}

const char *i2psam_namelookup(struct i2psam_stream_session *session, const char *name)
{
  auto result = session->impl->namingLookup(name);

  if (result.isOk)
    return strdup(result.value.c_str());
  else
    return nullptr;
}

struct i2psam_destination *i2psam_dest_generate(struct i2psam_stream_session *session)
{
  auto result = session->impl->destGenerate();
  if (result.isOk)
    {
      struct i2psam_destination *dest = new i2psam_destination;
      dest->pub = strdup(result.value.pub.c_str());
      dest->priv = strdup(result.value.priv.c_str());
      return dest;
    }
  else
    return nullptr;
}

void i2psam_stop_forwarding(struct i2psam_stream_session *session, const char *host, uint16_t port)
{
  session->impl->stopForwarding(host, port);
}

void i2psam_stop_forwarding_all(struct i2psam_stream_session *session)
{
  session->impl->stopForwardingAll();
}

struct i2psam_destination *i2psam_get_my_destination(struct i2psam_stream_session *session)
{
  struct i2psam_destination *dest = new i2psam_destination;
  const auto &mydest = session->impl->getMyDestination();
  dest->pub = strdup(mydest.pub.c_str());
  dest->priv = strdup(mydest.priv.c_str());
  return dest;
}

void i2psam_write(struct i2psam_socket *sock, const char *data, size_t dlen)
{
  const std::string buf(data, dlen);
  sock->impl->write(buf);
}

char *i2psam_read(struct i2psam_socket *sock, size_t *dlen)
{
  std::string buf = sock->impl->read();
  size_t sz = sizeof(char) * buf.size();
  *dlen = sz;
  if (sz)
    {
      char *ret = (char *) malloc(sz);
      memcpy(ret, buf.c_str(), sz);
      return ret;
    }
  else
    return nullptr;
}

void i2psam_socket_close(struct i2psam_socket *sock) { sock->impl->close(); }

int i2psam_socket_is_ok(struct i2psam_socket *sock)
{
  if (sock->impl->isOk())
    return 1;
  else
    return 0;
}

void i2psam_socket_free(struct i2psam_socket *sock) { delete sock; }

const char *i2psam_destination_priv(struct i2psam_destination *dest)
{
  return strdup(dest->priv);
}

const char *i2psam_destination_pub(struct i2psam_destination *dest)
{
  return strdup(dest->pub);
}

void i2psam_destination_free(struct i2psam_destination *dest)
{
  free(dest->pub);
  free(dest->priv);
  delete dest;
}

} // extern "C"