/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2011 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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: Giuseppe Piro  <g.piro@poliba.it>

 *         Marco Miozzo <mmiozzo@cttc.es>

 */

#include <ns3/trace-fading-loss-model.h>

#include <ns3/mobility-model.h>

#include <ns3/spectrum-value.h>

#include <ns3/log.h>

#include <ns3/string.h>

#include <ns3/double.h>

#include "ns3/uinteger.h"

#include <fstream>

#include <ns3/simulator.h>

NS_LOG_COMPONENT_DEFINE ("TraceFadingLossModel");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (TraceFadingLossModel);

TraceFadingLossModel::TraceFadingLossModel ()

{

  NS_LOG_FUNCTION (this);

  SetNext (NULL);

}

TraceFadingLossModel::~TraceFadingLossModel ()

{

  m_fadingTrace.clear ();

  m_windowOffsetsMap.clear ();

  m_startVariableMap.clear ();

}

TypeId

TraceFadingLossModel::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::TraceFadingLossModel")

    .SetParent<SpectrumPropagationLossModel> ()

    .AddConstructor<TraceFadingLossModel> ()

    .AddAttribute ("TraceFilename",

                   "Name of file to load a trace from.",

                   StringValue (""),

                   MakeStringAccessor (&TraceFadingLossModel::SetTraceFileName),

                   MakeStringChecker ())

    .AddAttribute ("TraceLength",

                  "The total length of the fading trace (default value 10 s.)",

                  TimeValue (Seconds (10.0)),

                  MakeTimeAccessor (&TraceFadingLossModel::SetTraceLength),

                  MakeTimeChecker ())

    .AddAttribute ("SamplesNum",

                  "The number of samples the trace is made of (default 10000)",

                   UintegerValue (10000),

                   MakeUintegerAccessor (&TraceFadingLossModel::m_samplesNum),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("WindowSize",

                  "The size of the window for the fading trace (default value 0.5 s.)",

                  TimeValue (Seconds (0.5)),

                  MakeTimeAccessor (&TraceFadingLossModel::m_windowSize),

                  MakeTimeChecker ())

    .AddAttribute ("RbNum",

                    "The number of RB the trace is made of (default 100)",

                    UintegerValue (100),

                   MakeUintegerAccessor (&TraceFadingLossModel::m_rbNum),

                   MakeUintegerChecker<uint8_t> ())

  ;

  return tid;

}

void

TraceFadingLossModel::SetTraceFileName (std::string fileName)

{

  NS_LOG_FUNCTION (this << "Set Fading Trace " << fileName);

  m_traceFile = fileName;

}

void 

TraceFadingLossModel::SetTraceLength (Time t)

{

  m_traceLength = t;

}

void 

TraceFadingLossModel::DoStart ()

{

  LoadTrace ();

}

void

TraceFadingLossModel::LoadTrace ()

{

  NS_LOG_FUNCTION (this << "Loading Fading Trace " << m_traceFile);

  std::ifstream ifTraceFile;

  ifTraceFile.open (m_traceFile.c_str (), std::ifstream::in);

  m_fadingTrace.clear ();

  if (!ifTraceFile.good ())

    {

      NS_LOG_INFO (this << " File: " << m_traceFile);

      NS_ASSERT_MSG(ifTraceFile.good (), " Fading trace file not found");

    }

//   NS_LOG_INFO (this << " length " << m_traceLength.GetSeconds ());

//   NS_LOG_INFO (this << " RB " << (uint32_t)m_rbNum << " samples " << m_samplesNum);

  for (uint32_t i = 0; i < m_rbNum; i++)

    {

      FadingTraceSample rbTimeFadingTrace;

      for (uint32_t j = 0; j < m_samplesNum; j++)

        {

          double sample;

          ifTraceFile >> sample;

          rbTimeFadingTrace.push_back (sample);

        }

      m_fadingTrace.push_back (rbTimeFadingTrace);

    }

  m_timeGranularity = m_traceLength.GetMilliSeconds () / m_samplesNum;

  m_lastWindowUpdate = Simulator::Now ();

}

Ptr<SpectrumValue>

TraceFadingLossModel::DoCalcRxPowerSpectralDensity (

  Ptr<const SpectrumValue> txPsd,

  Ptr<const MobilityModel> a,

  Ptr<const MobilityModel> b) const

{

  NS_LOG_FUNCTION (this << *txPsd << a << b);

  std::map <ChannelRealizationId_t, int >::iterator itOff;

  ChannelRealizationId_t mobilityPair = std::make_pair (a,b);

  itOff = m_windowOffsetsMap.find (mobilityPair);

  if (itOff!=m_windowOffsetsMap.end ())

    {

      if (Simulator::Now ().GetSeconds () >= m_lastWindowUpdate.GetSeconds () + m_windowSize.GetSeconds ())

        {

          // update all the offsets

          NS_LOG_INFO ("Fading Windows Updated");

          std::map <ChannelRealizationId_t, int >::iterator itOff2;

          for (itOff2 = m_windowOffsetsMap.begin (); itOff2 != m_windowOffsetsMap.end (); itOff2++)

            {

              std::map <ChannelRealizationId_t, Ptr<UniformRandomVariable> >::iterator itVar;

              itVar = m_startVariableMap.find ((*itOff2).first);

              (*itOff2).second = (*itVar).second->GetValue ();

            }

          m_lastWindowUpdate = Simulator::Now ();

        }

    }

  else

    {

      NS_LOG_LOGIC (this << "insert new channel realization, m_windowOffsetMap.size () = " << m_windowOffsetsMap.size ());

      Ptr<UniformRandomVariable> startV = CreateObject<UniformRandomVariable> ();

      startV->SetAttribute ("Min", DoubleValue (1.0));

      startV->SetAttribute ("Max", DoubleValue ((m_traceLength.GetSeconds () - m_windowSize.GetSeconds ()) * 1000.0));

      ChannelRealizationId_t mobilityPair = std::make_pair (a,b);

      m_startVariableMap.insert (std::pair<ChannelRealizationId_t,Ptr<UniformRandomVariable> > (mobilityPair, startV));

      m_windowOffsetsMap.insert (std::pair<ChannelRealizationId_t,int> (mobilityPair, startV->GetValue ()));

    }

  Ptr<SpectrumValue> rxPsd = Copy<SpectrumValue> (txPsd);

  Values::iterator vit = rxPsd->ValuesBegin ();

  //Vector aSpeedVector = a->GetVelocity ();

  //Vector bSpeedVector = b->GetVelocity ();

  //double speed = std::sqrt (std::pow (aSpeedVector.x-bSpeedVector.x,2) + std::pow (aSpeedVector.y-bSpeedVector.y,2));

  NS_LOG_LOGIC (this << *rxPsd);

  NS_ASSERT (!m_fadingTrace.empty ());

  int now_ms = static_cast<int> (Simulator::Now ().GetMilliSeconds () * m_timeGranularity);

  int lastUpdate_ms = static_cast<int> (m_lastWindowUpdate.GetMilliSeconds () * m_timeGranularity);

  int index = ((*itOff).second + now_ms - lastUpdate_ms) % m_samplesNum;

  int subChannel = 0;

  while (vit != rxPsd->ValuesEnd ())

    {

      NS_ASSERT (subChannel < 100);

      if (*vit != 0.)

        {

          double fading = m_fadingTrace.at (subChannel).at (index);

          NS_LOG_INFO (this << " FADING now " << now_ms << " offset " << (*itOff).second << " id " << index << " fading " << fading);

          double power = *vit; // in Watt/Hz

          power = 10 * std::log10 (180000 * power); // in dB

          NS_LOG_LOGIC (this << subChannel << *vit  << power << fading);

          *vit = std::pow (10., ((power + fading) / 10)) / 180000; // in Watt

          NS_LOG_LOGIC (this << subChannel << *vit);

        }

      ++vit;

      ++subChannel;

    }

  NS_LOG_LOGIC (this << *rxPsd);

  return rxPsd;

}

int64_t

TraceFadingLossModel::AssignStreams (int64_t stream)

{

  NS_LOG_FUNCTION (this << stream);

  int64_t currentStream = stream;

  std::map <ChannelRealizationId_t, Ptr<UniformRandomVariable> >::iterator itVar;

  itVar = m_startVariableMap.begin ();

  while (itVar!=m_startVariableMap.end ())

    {

      (*itVar).second->SetStream (currentStream);

      currentStream += 1;

    }

  return (currentStream - stream);

}

} // namespace ns3