/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2024,  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_CHANNEL_HPP
#define NFD_DAEMON_FACE_CHANNEL_HPP

#include "channel-log.hpp"
#include "face-common.hpp"

#include <functional>

namespace nfd::face {

/** \brief Represents a channel that listens on a local endpoint.
 *  \sa FaceSystem
 *
 *  A channel can listen on a local endpoint and initiate outgoing connection from a local endpoint.
 *  A channel creates Face objects and retains shared ownership of them.
 */
class Channel : public std::enable_shared_from_this<Channel>, noncopyable
{
public:
  virtual
  ~Channel();

  const FaceUri&
  getUri() const noexcept
  {
    return m_uri;
  }

  /**
   * \brief Returns the default MTU for all faces created by this channel.
   */
  size_t
  getDefaultMtu() const noexcept
  {
    return m_defaultMtu;
  }

  /**
   * \brief Returns whether the channel is listening.
   */
  virtual bool
  isListening() const = 0;

  /**
   * \brief Returns the number of faces in the channel.
   */
  virtual size_t
  size() const = 0;

protected:
  void
  setUri(const FaceUri& uri) noexcept;

  void
  setDefaultMtu(size_t mtu) noexcept;

private:
  FaceUri m_uri;
  size_t m_defaultMtu = ndn::MAX_NDN_PACKET_SIZE;
};

/** \brief Prototype for the callback that is invoked when a face is created
 *         (in response to an incoming connection or after a connection is established).
 */
using FaceCreatedCallback = std::function<void(const shared_ptr<Face>&)>;

/** \brief Prototype for the callback that is invoked when a face fails to be created.
 */
using FaceCreationFailedCallback = std::function<void(uint32_t status, const std::string& reason)>;

/** \brief Invokes a callback when a face is closed.
 *  \param face the face
 *  \param f the callback to be invoked when the face enters CLOSED state
 *
 *  This function connects a callback to the afterStateChange signal of \p face,
 *  and invokes \p f when the state becomes CLOSED.
 */
void
connectFaceClosedSignal(Face& face, std::function<void()> f);

} // namespace nfd::face

#endif // NFD_DAEMON_FACE_CHANNEL_HPP