/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2011 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Ilya Moiseenko <iliamo@cs.ucla.edu>
 */

#include "ndn-consumer.hpp"
#include "ns3/ptr.h"
#include "ns3/log.h"
#include "ns3/simulator.h"
#include "ns3/packet.h"
#include "ns3/callback.h"
#include "ns3/string.h"
#include "ns3/boolean.h"
#include "ns3/uinteger.h"
#include "ns3/integer.h"
#include "ns3/double.h"

#include "ns3/ndn-app-face.hpp"
#include "ns3/ndn-interest.hpp"
#include "ns3/ndn-data.hpp"
#include "ns3/ndnSIM/utils/ndn-fw-hop-count-tag.hpp"
#include "ns3/ndnSIM/utils/ndn-rtt-mean-deviation.hpp"

#include <boost/ref.hpp>

#include "ns3/names.h"

NS_LOG_COMPONENT_DEFINE("ndn.Consumer");

namespace ns3 {
namespace ndn {

NS_OBJECT_ENSURE_REGISTERED(Consumer);

TypeId
Consumer::GetTypeId(void)
{
  static TypeId tid =
    TypeId("ns3::ndn::Consumer")
      .SetGroupName("Ndn")
      .SetParent<App>()
      .AddAttribute("StartSeq", "Initial sequence number", IntegerValue(0),
                    MakeIntegerAccessor(&Consumer::m_seq), MakeIntegerChecker<int32_t>())

      .AddAttribute("Prefix", "Name of the Interest", StringValue("/"),
                    MakeNameAccessor(&Consumer::m_interestName), MakeNameChecker())
      .AddAttribute("LifeTime", "LifeTime for interest packet", StringValue("2s"),
                    MakeTimeAccessor(&Consumer::m_interestLifeTime), MakeTimeChecker())

      .AddAttribute("RetxTimer",
                    "Timeout defining how frequent retransmission timeouts should be checked",
                    StringValue("50ms"),
                    MakeTimeAccessor(&Consumer::GetRetxTimer, &Consumer::SetRetxTimer),
                    MakeTimeChecker())

      .AddTraceSource("LastRetransmittedInterestDataDelay",
                      "Delay between last retransmitted Interest and received Data",
                      MakeTraceSourceAccessor(&Consumer::m_lastRetransmittedInterestDataDelay))

      .AddTraceSource("FirstInterestDataDelay",
                      "Delay between first transmitted Interest and received Data",
                      MakeTraceSourceAccessor(&Consumer::m_firstInterestDataDelay));

  return tid;
}

Consumer::Consumer()
  : m_rand(0, std::numeric_limits<uint32_t>::max())
  , m_seq(0)
  , m_seqMax(0) // don't request anything
{
  NS_LOG_FUNCTION_NOARGS();

  m_rtt = CreateObject<RttMeanDeviation>();
}

void
Consumer::SetRetxTimer(Time retxTimer)
{
  m_retxTimer = retxTimer;
  if (m_retxEvent.IsRunning()) {
    // m_retxEvent.Cancel (); // cancel any scheduled cleanup events
    Simulator::Remove(m_retxEvent); // slower, but better for memory
  }

  // schedule even with new timeout
  m_retxEvent = Simulator::Schedule(m_retxTimer, &Consumer::CheckRetxTimeout, this);
}

Time
Consumer::GetRetxTimer() const
{
  return m_retxTimer;
}

void
Consumer::CheckRetxTimeout()
{
  Time now = Simulator::Now();

  Time rto = m_rtt->RetransmitTimeout();
  // NS_LOG_DEBUG ("Current RTO: " << rto.ToDouble (Time::S) << "s");

  while (!m_seqTimeouts.empty()) {
    SeqTimeoutsContainer::index<i_timestamp>::type::iterator entry =
      m_seqTimeouts.get<i_timestamp>().begin();
    if (entry->time + rto <= now) // timeout expired?
    {
      uint32_t seqNo = entry->seq;
      m_seqTimeouts.get<i_timestamp>().erase(entry);
      OnTimeout(seqNo);
    }
    else
      break; // nothing else to do. All later packets need not be retransmitted
  }

  m_retxEvent = Simulator::Schedule(m_retxTimer, &Consumer::CheckRetxTimeout, this);
}

// Application Methods
void
Consumer::StartApplication() // Called at time specified by Start
{
  NS_LOG_FUNCTION_NOARGS();

  // do base stuff
  App::StartApplication();

  ScheduleNextPacket();
}

void
Consumer::StopApplication() // Called at time specified by Stop
{
  NS_LOG_FUNCTION_NOARGS();

  // cancel periodic packet generation
  Simulator::Cancel(m_sendEvent);

  // cleanup base stuff
  App::StopApplication();
}

void
Consumer::SendPacket()
{
  if (!m_active)
    return;

  NS_LOG_FUNCTION_NOARGS();

  uint32_t seq = std::numeric_limits<uint32_t>::max(); // invalid

  while (m_retxSeqs.size()) {
    seq = *m_retxSeqs.begin();
    m_retxSeqs.erase(m_retxSeqs.begin());
    break;
  }

  if (seq == std::numeric_limits<uint32_t>::max()) {
    if (m_seqMax != std::numeric_limits<uint32_t>::max()) {
      if (m_seq >= m_seqMax) {
        return; // we are totally done
      }
    }

    seq = m_seq++;
  }

  //
  Ptr<Name> nameWithSequence = Create<Name>(m_interestName);
  nameWithSequence->appendSeqNum(seq);
  //

  Ptr<Interest> interest = Create<Interest>();
  interest->SetNonce(m_rand.GetValue());
  interest->SetName(nameWithSequence);
  interest->SetInterestLifetime(m_interestLifeTime);

  // NS_LOG_INFO ("Requesting Interest: \n" << *interest);
  NS_LOG_INFO("> Interest for " << seq);

  WillSendOutInterest(seq);

  FwHopCountTag hopCountTag;
  interest->GetPayload()->AddPacketTag(hopCountTag);

  m_transmittedInterests(interest, this, m_face);
  m_face->ReceiveInterest(interest);

  ScheduleNextPacket();
}

///////////////////////////////////////////////////
//          Process incoming packets             //
///////////////////////////////////////////////////

void
Consumer::OnData(Ptr<const Data> data)
{
  if (!m_active)
    return;

  App::OnData(data); // tracing inside

  NS_LOG_FUNCTION(this << data);

  // NS_LOG_INFO ("Received content object: " << boost::cref(*data));

  uint32_t seq = data->GetName().get(-1).toSeqNum();
  NS_LOG_INFO("< DATA for " << seq);

  int hopCount = -1;
  FwHopCountTag hopCountTag;
  if (data->GetPayload()->PeekPacketTag(hopCountTag)) {
    hopCount = hopCountTag.Get();
  }

  SeqTimeoutsContainer::iterator entry = m_seqLastDelay.find(seq);
  if (entry != m_seqLastDelay.end()) {
    m_lastRetransmittedInterestDataDelay(this, seq, Simulator::Now() - entry->time, hopCount);
  }

  entry = m_seqFullDelay.find(seq);
  if (entry != m_seqFullDelay.end()) {
    m_firstInterestDataDelay(this, seq, Simulator::Now() - entry->time, m_seqRetxCounts[seq],
                             hopCount);
  }

  m_seqRetxCounts.erase(seq);
  m_seqFullDelay.erase(seq);
  m_seqLastDelay.erase(seq);

  m_seqTimeouts.erase(seq);
  m_retxSeqs.erase(seq);

  m_rtt->AckSeq(SequenceNumber32(seq));
}

void
Consumer::OnNack(Ptr<const Interest> interest)
{
  if (!m_active)
    return;

  App::OnNack(interest); // tracing inside

  // NS_LOG_DEBUG ("Nack type: " << interest->GetNack ());

  // NS_LOG_FUNCTION (interest->GetName ());

  // NS_LOG_INFO ("Received NACK: " << boost::cref(*interest));
  uint32_t seq = interest->GetName().get(-1).toSeqNum();
  NS_LOG_INFO("< NACK for " << seq);
  // std::cout << Simulator::Now ().ToDouble (Time::S) << "s -> " << "NACK for " << seq << "\n";

  // put in the queue of interests to be retransmitted
  // NS_LOG_INFO ("Before: " << m_retxSeqs.size ());
  m_retxSeqs.insert(seq);
  // NS_LOG_INFO ("After: " << m_retxSeqs.size ());

  m_seqTimeouts.erase(seq);

  m_rtt->IncreaseMultiplier(); // Double the next RTO ??
  ScheduleNextPacket();
}

void
Consumer::OnTimeout(uint32_t sequenceNumber)
{
  NS_LOG_FUNCTION(sequenceNumber);
  // std::cout << Simulator::Now () << ", TO: " << sequenceNumber << ", current RTO: " <<
  // m_rtt->RetransmitTimeout ().ToDouble (Time::S) << "s\n";

  m_rtt->IncreaseMultiplier(); // Double the next RTO
  m_rtt->SentSeq(SequenceNumber32(sequenceNumber),
                 1); // make sure to disable RTT calculation for this sample
  m_retxSeqs.insert(sequenceNumber);
  ScheduleNextPacket();
}

void
Consumer::WillSendOutInterest(uint32_t sequenceNumber)
{
  NS_LOG_DEBUG("Trying to add " << sequenceNumber << " with " << Simulator::Now() << ". already "
                                << m_seqTimeouts.size() << " items");

  m_seqTimeouts.insert(SeqTimeout(sequenceNumber, Simulator::Now()));
  m_seqFullDelay.insert(SeqTimeout(sequenceNumber, Simulator::Now()));

  m_seqLastDelay.erase(sequenceNumber);
  m_seqLastDelay.insert(SeqTimeout(sequenceNumber, Simulator::Now()));

  m_seqRetxCounts[sequenceNumber]++;

  m_rtt->SentSeq(SequenceNumber32(sequenceNumber), 1);
}

} // namespace ndn
} // namespace ns3