/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014,  Regents of the University of California,
 *                      Arizona Board of Regents,
 *                      Colorado State University,
 *                      University Pierre & Marie Curie, Sorbonne University,
 *                      Washington University in St. Louis,
 *                      Beijing Institute of Technology,
 *                      The University of Memphis
 *
 * This file is part of NFD (Named Data Networking Forwarding Daemon).
 * See AUTHORS.md for complete list of NFD authors and contributors.
 *
 * NFD 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.
 *
 * NFD 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
 * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef NFD_DAEMON_FACE_DATAGRAM_FACE_HPP
#define NFD_DAEMON_FACE_DATAGRAM_FACE_HPP

#include "face.hpp"
#include "core/logger.hpp"

namespace nfd {

class Unicast {};
class Multicast {};

template<class Protocol, class Type = Unicast>
class DatagramFace : public Face
{
public:
  typedef Protocol protocol;

  /** \brief Construct datagram face
   *
   * \param socket      Protocol-specific socket for the created face
   * \param isOnDemand  If true, the face can be closed after it remains
   *                    unused for a certain amount of time
   */
  DatagramFace(const FaceUri& remoteUri, const FaceUri& localUri,
               const shared_ptr<typename protocol::socket>& socket,
               bool isOnDemand);

  virtual
  ~DatagramFace();

  // from Face
  virtual void
  sendInterest(const Interest& interest);

  virtual void
  sendData(const Data& data);

  virtual void
  close();

  void
  receiveDatagram(const uint8_t* buffer,
                  size_t nBytesReceived,
                  const boost::system::error_code& error);

  /**
   * \brief Set m_hasBeenUsedRecently to false
   */
  void
  resetRecentUsage();

  bool
  hasBeenUsedRecently() const;

  void
  setOnDemand(bool isOnDemand);

protected:
  void
  handleSend(const boost::system::error_code& error,
             size_t nBytesSent,
             const Block& payload);

  void
  handleReceive(const boost::system::error_code& error,
                size_t nBytesReceived);

  void
  keepFaceAliveUntilAllHandlersExecuted(const shared_ptr<Face>& face);

  void
  closeSocket();

protected:
  shared_ptr<typename protocol::socket> m_socket;
  uint8_t m_inputBuffer[ndn::MAX_NDN_PACKET_SIZE];
  bool m_hasBeenUsedRecently;

  NFD_LOG_INCLASS_DECLARE();
};


template<class T, class U>
inline
DatagramFace<T, U>::DatagramFace(const FaceUri& remoteUri, const FaceUri& localUri,
                                 const shared_ptr<typename DatagramFace::protocol::socket>& socket,
                                 bool isOnDemand)
  : Face(remoteUri, localUri)
  , m_socket(socket)
{
  setOnDemand(isOnDemand);

  m_socket->async_receive(boost::asio::buffer(m_inputBuffer, ndn::MAX_NDN_PACKET_SIZE), 0,
                          bind(&DatagramFace<T, U>::handleReceive, this, _1, _2));
}

template<class T, class U>
inline
DatagramFace<T, U>::~DatagramFace()
{
}

template<class T, class U>
inline void
DatagramFace<T, U>::sendInterest(const Interest& interest)
{
  this->onSendInterest(interest);
  const Block& payload = interest.wireEncode();
  m_socket->async_send(boost::asio::buffer(payload.wire(), payload.size()),
                       bind(&DatagramFace<T, U>::handleSend, this, _1, _2, payload));

  // anything else should be done here?
}

template<class T, class U>
inline void
DatagramFace<T, U>::sendData(const Data& data)
{
  this->onSendData(data);
  const Block& payload = data.wireEncode();
  m_socket->async_send(boost::asio::buffer(payload.wire(), payload.size()),
                       bind(&DatagramFace<T, U>::handleSend, this, _1, _2, payload));

  // anything else should be done here?
}

template<class T, class U>
inline void
DatagramFace<T, U>::handleSend(const boost::system::error_code& error,
                               size_t nBytesSent,
                               const Block& payload)
// 'payload' is unused; it's needed to retain the underlying Buffer
{
  if (error != 0) {
    if (error == boost::system::errc::operation_canceled) // when socket is closed by someone
      return;

    if (!m_socket->is_open()) {
      fail("Tunnel closed");
      return;
    }

    NFD_LOG_WARN("[id:" << this->getId()
                  << ",uri:" << this->getRemoteUri()
                  << "] Send operation failed, closing socket: "
                  << error.category().message(error.value()));

    closeSocket();

    if (error == boost::asio::error::eof) {
      fail("Tunnel closed");
    }
    else {
      fail("Send operation failed, closing socket: " +
             error.category().message(error.value()));
    }
    return;
  }

  NFD_LOG_TRACE("[id:" << this->getId()
                << ",uri:" << this->getRemoteUri()
                << "] Successfully sent: " << nBytesSent << " bytes");
  this->getMutableCounters().getNOutBytes() += nBytesSent;
}

template<class T, class U>
inline void
DatagramFace<T, U>::close()
{
  if (!m_socket->is_open())
    return;

  NFD_LOG_INFO("[id:" << this->getId()
               << ",uri:" << this->getRemoteUri()
               << "] Close tunnel");

  closeSocket();
  fail("Close tunnel");
}

template<class T, class U>
inline void
DatagramFace<T, U>::handleReceive(const boost::system::error_code& error,
                                  size_t nBytesReceived)
{
  NFD_LOG_DEBUG("handleReceive: " << nBytesReceived);
  receiveDatagram(m_inputBuffer, nBytesReceived, error);
  if (m_socket->is_open())
    m_socket->async_receive(boost::asio::buffer(m_inputBuffer, ndn::MAX_NDN_PACKET_SIZE), 0,
                            bind(&DatagramFace<T, U>::handleReceive, this, _1, _2));
}

template<class T, class U>
inline void
DatagramFace<T, U>::receiveDatagram(const uint8_t* buffer,
                                    size_t nBytesReceived,
                                    const boost::system::error_code& error)
{
  if (error != 0 || nBytesReceived == 0) {
    if (error == boost::system::errc::operation_canceled) // when socket is closed by someone
      return;

    // this should be unnecessary, but just in case
    if (!m_socket->is_open()) {
      fail("Tunnel closed");
      return;
    }

    NFD_LOG_WARN("[id:" << this->getId()
                 << ",uri:" << this->getRemoteUri()
                 << "] Receive operation failed: "
                 << error.category().message(error.value()));

    closeSocket();

    if (error == boost::asio::error::eof) {
      fail("Tunnel closed");
    }
    else {
      fail("Receive operation failed, closing socket: " +
             error.category().message(error.value()));
    }
    return;
  }

  NFD_LOG_TRACE("[id:" << this->getId()
                << ",uri:" << this->getRemoteUri()
                << "] Received: " << nBytesReceived << " bytes");
  this->getMutableCounters().getNInBytes() += nBytesReceived;

  Block element;
  bool isOk = Block::fromBuffer(buffer, nBytesReceived, element);
  if (!isOk)
    {
      NFD_LOG_WARN("[id:" << this->getId()
                   << ",uri:" << this->getRemoteUri()
                   << "] Failed to parse incoming packet");
      // This message won't extend the face lifetime
      return;
    }

  if (element.size() != nBytesReceived)
    {
      NFD_LOG_WARN("[id:" << this->getId()
                   << ",uri:" << this->getRemoteUri()
                   << "] Received datagram size and decoded "
                   << "element size don't match");
      // This message won't extend the face lifetime
      return;
    }

  if (!this->decodeAndDispatchInput(element))
    {
      NFD_LOG_WARN("[id:" << this->getId()
                   << ",uri:" << this->getRemoteUri()
                   << "] Received unrecognized block of type ["
                   << element.type() << "]");
      // This message won't extend the face lifetime
      return;
    }

  m_hasBeenUsedRecently = true;
}


template<class T, class U>
inline void
DatagramFace<T, U>::keepFaceAliveUntilAllHandlersExecuted(const shared_ptr<Face>& face)
{
}

template<class T, class U>
inline void
DatagramFace<T, U>::closeSocket()
{
  NFD_LOG_DEBUG("[id:" << this->getId()
                << ",uri:" << this->getRemoteUri()
                << "] closeSocket");

  boost::asio::io_service& io = m_socket->get_io_service();

  // use the non-throwing variants and ignore errors, if any
  boost::system::error_code error;
  m_socket->shutdown(protocol::socket::shutdown_both, error);
  m_socket->close(error);
  // after this, handlers will be called with an error code

  // ensure that the Face object is alive at least until all pending
  // handlers are dispatched
  io.post(bind(&DatagramFace<T, U>::keepFaceAliveUntilAllHandlersExecuted,
               this, this->shared_from_this()));
}

template<class T, class U>
inline void
DatagramFace<T, U>::setOnDemand(bool isOnDemand)
{
  Face::setOnDemand(isOnDemand);
}

template<class T, class U>
inline void
DatagramFace<T, U>::resetRecentUsage()
{
  m_hasBeenUsedRecently = false;
}

template<class T, class U>
inline bool
DatagramFace<T, U>::hasBeenUsedRecently() const
{
  return m_hasBeenUsedRecently;
}

} // namespace nfd

#endif // NFD_DAEMON_FACE_DATAGRAM_FACE_HPP