/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2015-2022,  Arizona Board of Regents.
 *
 * This file is part of ndn-tools (Named Data Networking Essential Tools).
 * See AUTHORS.md for complete list of ndn-tools authors and contributors.
 *
 * ndn-tools 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.
 *
 * ndn-tools 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
 * ndn-tools, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Eric Newberry <enewberry@email.arizona.edu>
 * @author Jerald Paul Abraham <jeraldabraham@email.arizona.edu>
 */

#ifndef NDN_TOOLS_PING_SERVER_PING_SERVER_HPP
#define NDN_TOOLS_PING_SERVER_PING_SERVER_HPP

#include "core/common.hpp"

#include <ndn-cxx/util/signal.hpp>

namespace ndn::ping::server {

/**
 * @brief Options for PingServer
 */
struct Options
{
  Name prefix;                              //!< prefix to register
  time::milliseconds freshnessPeriod = 1_s; //!< data freshness period
  size_t nMaxPings = 0;                     //!< max number of pings to satisfy (0 == no limit)
  size_t payloadSize = 0;                   //!< response payload size (0 == no payload)
  bool wantTimestamp = false;               //!< print timestamp when response sent
  bool wantQuiet = false;                   //!< suppress printing per-packet log message
};

/**
 * @brief NDN modular ping server
 */
class PingServer : noncopyable
{
public:
  PingServer(Face& face, KeyChain& keyChain, const Options& options);

  /**
   * @brief Signals when Interest received
   *
   * @param name incoming interest name
   */
  util::Signal<PingServer, Name> afterReceive;

  /**
   * @brief Signals when finished pinging
   */
  util::Signal<PingServer> afterFinish;

  /** @brief starts ping server
   *
   *  If options.shouldLimitSatisfied is false, this method does not return unless there's an error.
   *  Otherwise, this method returns when options.nMaxPings Interests are processed.
   */
  void
  run();

  /**
   * @brief starts the Interest filter
   *
   * @note This method is non-blocking and caller need to call face.processEvents()
   */
  void
  start();

  /**
   * @brief Unregister set interest filter
   */
  void
  stop();

  /**
   * @brief gets the number of pings received
   */
  size_t
  getNPings() const;

private:
  /**
   * @brief Called when interest received
   *
   * @param interest incoming interest
   */
  void
  onInterest(const Interest& interest);

private:
  const Options& m_options;
  Face& m_face;
  KeyChain& m_keyChain;
  size_t m_nPings = 0;
  Block m_payload;
  RegisteredPrefixHandle m_registeredPrefix;
};

} // namespace ndn::ping::server

#endif // NDN_TOOLS_PING_SERVER_PING_SERVER_HPP