/* -*- 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_FW_ASF_STRATEGY_HPP
#define NFD_DAEMON_FW_ASF_STRATEGY_HPP

#include "strategy.hpp"
#include "asf-measurements.hpp"
#include "asf-probing-module.hpp"
#include "process-nack-traits.hpp"
#include "retx-suppression-exponential.hpp"

namespace nfd::fw {
namespace asf {

/**
 * \brief Adaptive SRTT-based forwarding strategy.
 *
 * \see Vince Lehman, Ashlesh Gawande, Rodrigo Aldecoa, Dmitri Krioukov, Beichuan Zhang,
 *      Lixia Zhang, and Lan Wang, "An Experimental Investigation of Hyperbolic Routing
 *      with a Smart Forwarding Plane in NDN", NDN Technical Report NDN-0042, 2016.
 *      https://named-data.net/publications/techreports/ndn-0042-1-asf/
 */
class AsfStrategy : public Strategy, public ProcessNackTraits<AsfStrategy>
{
public:
  explicit
  AsfStrategy(Forwarder& forwarder, const Name& name = getStrategyName());

  static const Name&
  getStrategyName();

public: // triggers
  void
  afterReceiveInterest(const Interest& interest, const FaceEndpoint& ingress,
                       const shared_ptr<pit::Entry>& pitEntry) override;

  void
  beforeSatisfyInterest(const Data& data, const FaceEndpoint& ingress,
                        const shared_ptr<pit::Entry>& pitEntry) override;

  void
  afterReceiveNack(const lp::Nack& nack, const FaceEndpoint& ingress,
                   const shared_ptr<pit::Entry>& pitEntry) override;

private:
  pit::OutRecord*
  forwardInterest(const Interest& interest, Face& outFace, const fib::Entry& fibEntry,
                  const shared_ptr<pit::Entry>& pitEntry);

  void
  sendProbe(const Interest& interest, const FaceEndpoint& ingress, const Face& faceToUse,
            const fib::Entry& fibEntry, const shared_ptr<pit::Entry>& pitEntry);

  Face*
  getBestFaceForForwarding(const Interest& interest, const Face& inFace,
                           const fib::Entry& fibEntry, const shared_ptr<pit::Entry>& pitEntry,
                           bool isNewInterest = true);

  void
  onTimeoutOrNack(const Name& interestName, FaceId faceId, bool isNack);

  void
  sendNoRouteNack(Face& face, const shared_ptr<pit::Entry>& pitEntry);

private:
  AsfMeasurements m_measurements{getMeasurements()};

NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  struct FaceStatsForwardingCompare
  {
    bool
    operator()(const FaceStats& lhs, const FaceStats& rhs) const noexcept;
  };
  using FaceStatsForwardingSet = std::set<FaceStats, FaceStatsForwardingCompare>;

  std::unique_ptr<RetxSuppressionExponential> m_retxSuppression;
  ProbingModule m_probing{m_measurements};
  size_t m_nMaxTimeouts = 3;

  friend ProcessNackTraits<AsfStrategy>;
};

} // namespace asf

using asf::AsfStrategy;

} // namespace nfd::fw

#endif // NFD_DAEMON_FW_ASF_STRATEGY_HPP