/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2013-2017, Regents of the University of California.
 *
 * This file is part of ChronoShare, a decentralized file sharing application over NDN.
 *
 * ChronoShare 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.
 *
 * ChronoShare 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 copies of the GNU General Public License along with
 * ChronoShare, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ChronoShare authors and contributors.
 */

#ifndef CHRONOSHARE_SRC_FETCHER_HPP
#define CHRONOSHARE_SRC_FETCHER_HPP

#include "core/chronoshare-common.hpp"

#include <ndn-cxx/face.hpp>

#include <set>
#include <thread>
#include <mutex>
#include <boost/intrusive/list.hpp>

namespace ndn {
namespace chronoshare {

class FetchManager;

class Fetcher
{
public:
  typedef std::function<void(Name& deviceName, Name& baseName, uint64_t seq, shared_ptr<Data> data)> SegmentCallback;
  typedef std::function<void(Name& deviceName, Name& baseName)> FinishCallback;
  typedef std::function<void(Fetcher&, const Name& deviceName, const Name& baseName)> OnFetchCompleteCallback;
  typedef std::function<void(Fetcher&)> OnFetchFailedCallback;

  Fetcher(Face& face,
          const SegmentCallback& segmentCallback, // callback passed by caller of FetchManager
          const FinishCallback& finishCallback,   // callback passed by caller of FetchManager
          const OnFetchCompleteCallback& onFetchComplete,
          const OnFetchFailedCallback& onFetchFailed, // callbacks provided by FetchManager
          const Name& deviceName, const Name& name, int64_t minSeqNo, int64_t maxSeqNo,
          time::milliseconds timeout = time::seconds(30), // this time is not precise, but sets min bound
                                                          // actual time depends on how fast Interests timeout
          const Name& forwardingHint = Name());
  virtual ~Fetcher();

  bool
  IsActive() const;

  bool
  IsTimedWait() const
  {
    return m_timedwait;
  }

  void
  RestartPipeline();

  void
  SetForwardingHint(const Name& forwardingHint);

  const Name&
  GetForwardingHint() const
  {
    return m_forwardingHint;
  }

  const Name&
  GetName() const
  {
    return m_name;
  }

  const Name&
  GetDeviceName() const
  {
    return m_deviceName;
  }

  time::seconds
  GetRetryPause() const
  {
    return m_retryPause;
  }

  void
  SetRetryPause(time::seconds pause)
  {
    m_retryPause = pause;
  }

  const time::steady_clock::TimePoint&
  GetNextScheduledRetry() const
  {
    return m_nextScheduledRetry;
  }

  void
  SetNextScheduledRetry(const time::steady_clock::TimePoint& nextScheduledRetry)
  {
    m_nextScheduledRetry = nextScheduledRetry;
  }

private:
  void
  FillPipeline();

  void
  OnData(uint64_t seqno, const Interest& interest, Data& data);

  void
  OnTimeout(uint64_t seqno, const Interest& interest);

public:
  boost::intrusive::list_member_hook<> m_managerListHook;

private:
  Face& m_face;

  SegmentCallback m_segmentCallback;
  OnFetchCompleteCallback m_onFetchComplete;
  OnFetchFailedCallback m_onFetchFailed;

  FinishCallback m_finishCallback;

  bool m_active;
  bool m_timedwait;

  Name m_name;
  Name m_deviceName;
  Name m_forwardingHint;

  time::milliseconds m_maximumNoActivityPeriod;

  int64_t m_minSendSeqNo;
  int64_t m_maxInOrderRecvSeqNo;
  std::set<int64_t> m_outOfOrderRecvSeqNo;
  std::set<int64_t> m_inActivePipeline;

  // int64_t m_minSeqNo;
  int64_t m_maxSeqNo;

  uint32_t m_pipeline;
  uint32_t m_activePipeline;
  // double m_rto;
  // double m_maxRto;
  bool m_slowStart;
  uint32_t m_threshold;
  uint32_t m_roundCount;

  time::steady_clock::TimePoint m_lastPositiveActivity;

  time::seconds m_retryPause; // pause to stop trying to fetch(for fetch-manager)
  time::steady_clock::TimePoint m_nextScheduledRetry;

  std::mutex m_seqNoMutex;

  boost::asio::io_service& m_ioService;
};

typedef shared_ptr<Fetcher> FetcherPtr;

inline bool
Fetcher::IsActive() const
{
  return m_active;
}

} // namespace chronoshare
} // namespace ndn

#endif // CHRONOSHARE_SRC_FETCHER_HPP