/* -*- 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: Marco Miozzo <marco.miozzo@cttc.es>        // original version

 * Modification: Dizhi Zhou <dizhi.zhou@gmail.com>    // modify codes related to downlink scheduler

 */

#include <ns3/log.h>

#include <ns3/pointer.h>

#include <ns3/integer.h>

#include <ns3/simulator.h>

#include <ns3/lte-amc.h>

#include <ns3/tdtbfq-ff-mac-scheduler.h>

#include <ns3/lte-vendor-specific-parameters.h>

NS_LOG_COMPONENT_DEFINE ("TdTbfqFfMacScheduler");

// value for SINR outside the range defined by LTE, used to indicate that there

// is no CQI for this element

#define NO_SINR -5000

namespace ns3 {

int TdTbfqType0AllocationRbg[4] = {

  10,       // RGB size 1

  26,       // RGB size 2

  63,       // RGB size 3

  110       // RGB size 4

};  // see table 7.1.6.1-1 of 36.213

NS_OBJECT_ENSURE_REGISTERED (TdTbfqFfMacScheduler);

class TdTbfqSchedulerMemberCschedSapProvider : public FfMacCschedSapProvider

{

public:

  TdTbfqSchedulerMemberCschedSapProvider (TdTbfqFfMacScheduler* scheduler);

  // inherited from FfMacCschedSapProvider

  virtual void CschedCellConfigReq (const struct CschedCellConfigReqParameters& params);

  virtual void CschedUeConfigReq (const struct CschedUeConfigReqParameters& params);

  virtual void CschedLcConfigReq (const struct CschedLcConfigReqParameters& params);

  virtual void CschedLcReleaseReq (const struct CschedLcReleaseReqParameters& params);

  virtual void CschedUeReleaseReq (const struct CschedUeReleaseReqParameters& params);

private:

  TdTbfqSchedulerMemberCschedSapProvider ();

  TdTbfqFfMacScheduler* m_scheduler;

};

TdTbfqSchedulerMemberCschedSapProvider::TdTbfqSchedulerMemberCschedSapProvider ()

{

}

TdTbfqSchedulerMemberCschedSapProvider::TdTbfqSchedulerMemberCschedSapProvider (TdTbfqFfMacScheduler* scheduler) : m_scheduler (scheduler)

{

}

void

TdTbfqSchedulerMemberCschedSapProvider::CschedCellConfigReq (const struct CschedCellConfigReqParameters& params)

{

  m_scheduler->DoCschedCellConfigReq (params);

}

void

TdTbfqSchedulerMemberCschedSapProvider::CschedUeConfigReq (const struct CschedUeConfigReqParameters& params)

{

  m_scheduler->DoCschedUeConfigReq (params);

}

void

TdTbfqSchedulerMemberCschedSapProvider::CschedLcConfigReq (const struct CschedLcConfigReqParameters& params)

{

  m_scheduler->DoCschedLcConfigReq (params);

}

void

TdTbfqSchedulerMemberCschedSapProvider::CschedLcReleaseReq (const struct CschedLcReleaseReqParameters& params)

{

  m_scheduler->DoCschedLcReleaseReq (params);

}

void

TdTbfqSchedulerMemberCschedSapProvider::CschedUeReleaseReq (const struct CschedUeReleaseReqParameters& params)

{

  m_scheduler->DoCschedUeReleaseReq (params);

}

class TdTbfqSchedulerMemberSchedSapProvider : public FfMacSchedSapProvider

{

public:

  TdTbfqSchedulerMemberSchedSapProvider (TdTbfqFfMacScheduler* scheduler);

  // inherited from FfMacSchedSapProvider

  virtual void SchedDlRlcBufferReq (const struct SchedDlRlcBufferReqParameters& params);

  virtual void SchedDlPagingBufferReq (const struct SchedDlPagingBufferReqParameters& params);

  virtual void SchedDlMacBufferReq (const struct SchedDlMacBufferReqParameters& params);

  virtual void SchedDlTriggerReq (const struct SchedDlTriggerReqParameters& params);

  virtual void SchedDlRachInfoReq (const struct SchedDlRachInfoReqParameters& params);

  virtual void SchedDlCqiInfoReq (const struct SchedDlCqiInfoReqParameters& params);

  virtual void SchedUlTriggerReq (const struct SchedUlTriggerReqParameters& params);

  virtual void SchedUlNoiseInterferenceReq (const struct SchedUlNoiseInterferenceReqParameters& params);

  virtual void SchedUlSrInfoReq (const struct SchedUlSrInfoReqParameters& params);

  virtual void SchedUlMacCtrlInfoReq (const struct SchedUlMacCtrlInfoReqParameters& params);

  virtual void SchedUlCqiInfoReq (const struct SchedUlCqiInfoReqParameters& params);

private:

  TdTbfqSchedulerMemberSchedSapProvider ();

  TdTbfqFfMacScheduler* m_scheduler;

};

TdTbfqSchedulerMemberSchedSapProvider::TdTbfqSchedulerMemberSchedSapProvider ()

{

}

TdTbfqSchedulerMemberSchedSapProvider::TdTbfqSchedulerMemberSchedSapProvider (TdTbfqFfMacScheduler* scheduler)

  : m_scheduler (scheduler)

{

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedDlRlcBufferReq (const struct SchedDlRlcBufferReqParameters& params)

{

  m_scheduler->DoSchedDlRlcBufferReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedDlPagingBufferReq (const struct SchedDlPagingBufferReqParameters& params)

{

  m_scheduler->DoSchedDlPagingBufferReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedDlMacBufferReq (const struct SchedDlMacBufferReqParameters& params)

{

  m_scheduler->DoSchedDlMacBufferReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedDlTriggerReq (const struct SchedDlTriggerReqParameters& params)

{

  m_scheduler->DoSchedDlTriggerReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedDlRachInfoReq (const struct SchedDlRachInfoReqParameters& params)

{

  m_scheduler->DoSchedDlRachInfoReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedDlCqiInfoReq (const struct SchedDlCqiInfoReqParameters& params)

{

  m_scheduler->DoSchedDlCqiInfoReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedUlTriggerReq (const struct SchedUlTriggerReqParameters& params)

{

  m_scheduler->DoSchedUlTriggerReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedUlNoiseInterferenceReq (const struct SchedUlNoiseInterferenceReqParameters& params)

{

  m_scheduler->DoSchedUlNoiseInterferenceReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedUlSrInfoReq (const struct SchedUlSrInfoReqParameters& params)

{

  m_scheduler->DoSchedUlSrInfoReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedUlMacCtrlInfoReq (const struct SchedUlMacCtrlInfoReqParameters& params)

{

  m_scheduler->DoSchedUlMacCtrlInfoReq (params);

}

void

TdTbfqSchedulerMemberSchedSapProvider::SchedUlCqiInfoReq (const struct SchedUlCqiInfoReqParameters& params)

{

  m_scheduler->DoSchedUlCqiInfoReq (params);

}

TdTbfqFfMacScheduler::TdTbfqFfMacScheduler ()

  :   m_cschedSapUser (0),

    m_schedSapUser (0),

    m_timeWindow (99.0),

    m_nextRntiUl (0)

{

  m_amc = CreateObject <LteAmc> ();

  m_cschedSapProvider = new TdTbfqSchedulerMemberCschedSapProvider (this);

  m_schedSapProvider = new TdTbfqSchedulerMemberSchedSapProvider (this);

}

TdTbfqFfMacScheduler::~TdTbfqFfMacScheduler ()

{

  NS_LOG_FUNCTION (this);

}

void

TdTbfqFfMacScheduler::DoDispose ()

{

  NS_LOG_FUNCTION (this);

  delete m_cschedSapProvider;

  delete m_schedSapProvider;

}

TypeId

TdTbfqFfMacScheduler::GetTypeId (void)

{

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

    .SetParent<FfMacScheduler> ()

    .AddConstructor<TdTbfqFfMacScheduler> ()

    .AddAttribute ("CqiTimerThreshold",

                   "The number of TTIs a CQI is valid (default 1000 - 1 sec.)",

                   UintegerValue (1000),

                   MakeUintegerAccessor (&TdTbfqFfMacScheduler::m_cqiTimersThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("DebtLimit",

                   "Flow debt limit (default -625000 bytes)",

                   IntegerValue (-625000),

                   MakeIntegerAccessor (&TdTbfqFfMacScheduler::m_debtLimit),

                   MakeIntegerChecker<int> ())

    .AddAttribute ("CreditLimit",

                   "Flow credit limit (default 625000 bytes)",

                   UintegerValue (625000),

                   MakeUintegerAccessor (&TdTbfqFfMacScheduler::m_creditLimit),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("TokenPoolSize",

                   "The maximum value of flow token pool (default 1 bytes)",

                   UintegerValue (1),

                   MakeUintegerAccessor (&TdTbfqFfMacScheduler::m_tokenPoolSize),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("CreditableThreshold",

                   "Threshold of flow credit (default 0 bytes)",

                   UintegerValue (0),

                   MakeUintegerAccessor (&TdTbfqFfMacScheduler::m_creditableThreshold),

                   MakeUintegerChecker<uint32_t> ())

  ;

  return tid;

}

void

TdTbfqFfMacScheduler::SetFfMacCschedSapUser (FfMacCschedSapUser* s)

{

  m_cschedSapUser = s;

}

void

TdTbfqFfMacScheduler::SetFfMacSchedSapUser (FfMacSchedSapUser* s)

{

  m_schedSapUser = s;

}

FfMacCschedSapProvider*

TdTbfqFfMacScheduler::GetFfMacCschedSapProvider ()

{

  return m_cschedSapProvider;

}

FfMacSchedSapProvider*

TdTbfqFfMacScheduler::GetFfMacSchedSapProvider ()

{

  return m_schedSapProvider;

}

void

TdTbfqFfMacScheduler::DoCschedCellConfigReq (const struct FfMacCschedSapProvider::CschedCellConfigReqParameters& params)

{

  NS_LOG_FUNCTION (this);

  // Read the subset of parameters used

  m_cschedCellConfig = params;

  FfMacCschedSapUser::CschedUeConfigCnfParameters cnf;

  cnf.m_result = SUCCESS;

  m_cschedSapUser->CschedUeConfigCnf (cnf);

  return;

}

void

TdTbfqFfMacScheduler::DoCschedUeConfigReq (const struct FfMacCschedSapProvider::CschedUeConfigReqParameters& params)

{

  NS_LOG_FUNCTION (this << " RNTI " << params.m_rnti << " txMode " << (uint16_t)params.m_transmissionMode);

  std::map <uint16_t,uint8_t>::iterator it = m_uesTxMode.find (params.m_rnti);

  if (it == m_uesTxMode.end ())

    {

      m_uesTxMode.insert (std::pair <uint16_t, double> (params.m_rnti, params.m_transmissionMode));

    }

  else

    {

      (*it).second = params.m_transmissionMode;

    }

  return;

}

void

TdTbfqFfMacScheduler::DoCschedLcConfigReq (const struct FfMacCschedSapProvider::CschedLcConfigReqParameters& params)

{

  NS_LOG_FUNCTION (this << " New LC, rnti: "  << params.m_rnti);

  std::map <uint16_t, tdtbfqsFlowPerf_t>::iterator it;

  for (uint16_t i = 0; i < params.m_logicalChannelConfigList.size (); i++)

    {

      it = m_flowStatsDl.find (params.m_rnti);

      if (it == m_flowStatsDl.end ())

        {

          uint64_t mbrDlInBytes = params.m_logicalChannelConfigList.at (i).m_eRabMaximulBitrateDl / 8;   // byte/s

          uint64_t mbrUlInBytes = params.m_logicalChannelConfigList.at (i).m_eRabMaximulBitrateUl / 8;   // byte/s

          tdtbfqsFlowPerf_t flowStatsDl;

          flowStatsDl.flowStart = Simulator::Now ();

          flowStatsDl.packetArrivalRate = 0;

          flowStatsDl.tokenGenerationRate = mbrDlInBytes;

          flowStatsDl.tokenPoolSize = 0;

          flowStatsDl.maxTokenPoolSize = m_tokenPoolSize;

          flowStatsDl.counter = 0;

          flowStatsDl.burstCredit = m_creditLimit; // bytes

          flowStatsDl.debtLimit = m_debtLimit; // bytes

          flowStatsDl.creditableThreshold = m_creditableThreshold;

          m_flowStatsDl.insert (std::pair<uint16_t, tdtbfqsFlowPerf_t> (params.m_rnti, flowStatsDl));

          tdtbfqsFlowPerf_t flowStatsUl;

          flowStatsUl.flowStart = Simulator::Now ();

          flowStatsUl.packetArrivalRate = 0;

          flowStatsUl.tokenGenerationRate = mbrUlInBytes;

          flowStatsUl.tokenPoolSize = 0;

          flowStatsUl.maxTokenPoolSize = m_tokenPoolSize;

          flowStatsUl.counter = 0;

          flowStatsUl.burstCredit = m_creditLimit;  // bytes

          flowStatsUl.debtLimit = m_debtLimit;  // bytes

          flowStatsUl.creditableThreshold = m_creditableThreshold;

          m_flowStatsUl.insert (std::pair<uint16_t, tdtbfqsFlowPerf_t> (params.m_rnti, flowStatsUl));

        }

      else

        {

          NS_LOG_ERROR ("RNTI already exists");

        }

    }

  return;

}

void

TdTbfqFfMacScheduler::DoCschedLcReleaseReq (const struct FfMacCschedSapProvider::CschedLcReleaseReqParameters& params)

{

  NS_FATAL_ERROR ("unimplemented");

  return;

}

void

TdTbfqFfMacScheduler::DoCschedUeReleaseReq (const struct FfMacCschedSapProvider::CschedUeReleaseReqParameters& params)

{

  NS_FATAL_ERROR ("unimplemented");

  return;

}

void

TdTbfqFfMacScheduler::DoSchedDlRlcBufferReq (const struct FfMacSchedSapProvider::SchedDlRlcBufferReqParameters& params)

{

  NS_LOG_FUNCTION (this << params.m_rnti << (uint32_t) params.m_logicalChannelIdentity);

  // API generated by RLC for updating RLC parameters on a LC (tx and retx queues)

  std::map <LteFlowId_t, FfMacSchedSapProvider::SchedDlRlcBufferReqParameters>::iterator it;

  LteFlowId_t flow (params.m_rnti, params.m_logicalChannelIdentity);

  it =  m_rlcBufferReq.find (flow);

  if (it == m_rlcBufferReq.end ())

    {

      m_rlcBufferReq.insert (std::pair <LteFlowId_t, FfMacSchedSapProvider::SchedDlRlcBufferReqParameters> (flow, params));

    }

  else

    {

      (*it).second = params;

    }

  return;

}

void

TdTbfqFfMacScheduler::DoSchedDlPagingBufferReq (const struct FfMacSchedSapProvider::SchedDlPagingBufferReqParameters& params)

{

  NS_FATAL_ERROR ("unimplemented");

  return;

}

void

TdTbfqFfMacScheduler::DoSchedDlMacBufferReq (const struct FfMacSchedSapProvider::SchedDlMacBufferReqParameters& params)

{

  NS_FATAL_ERROR ("unimplemented");

  return;

}

int

TdTbfqFfMacScheduler::GetRbgSize (int dlbandwidth)

{

  for (int i = 0; i < 4; i++)

    {

      if (dlbandwidth < TdTbfqType0AllocationRbg[i])

        {

          return (i + 1);

        }

    }

  return (-1);

}

int 

TdTbfqFfMacScheduler::LcActivePerFlow (uint16_t rnti)

{

  std::map <LteFlowId_t, FfMacSchedSapProvider::SchedDlRlcBufferReqParameters>::iterator it;

  int lcActive = 0;

  for (it = m_rlcBufferReq.begin (); it != m_rlcBufferReq.end (); it++)

    {

      if (((*it).first.m_rnti == rnti) && (((*it).second.m_rlcTransmissionQueueSize > 0)

                                           || ((*it).second.m_rlcRetransmissionQueueSize > 0)

                                           || ((*it).second.m_rlcStatusPduSize > 0) ))

        {

          lcActive++;

        }

      if ((*it).first.m_rnti > rnti)

        {

          break;

        }

    }

  return (lcActive);

}

void

TdTbfqFfMacScheduler::DoSchedDlTriggerReq (const struct FfMacSchedSapProvider::SchedDlTriggerReqParameters& params)

{

  NS_LOG_FUNCTION (this << " Frame no. " << (params.m_sfnSf >> 4) << " subframe no. " << (0xF & params.m_sfnSf));

  // API generated by RLC for triggering the scheduling of a DL subframe

  // evaluate the relative channel quality indicator for each UE per each RBG 

  // (since we are using allocation type 0 the small unit of allocation is RBG)

  // Resource allocation type 0 (see sec 7.1.6.1 of 36.213)

  RefreshDlCqiMaps ();

  // update token pool, counter and bank size

  std::map <uint16_t, tdtbfqsFlowPerf_t>::iterator itStats;

  for (itStats = m_flowStatsDl.begin (); itStats != m_flowStatsDl.end (); itStats++)

    {

      if ( (*itStats).second.tokenGenerationRate / 1000 +  (*itStats).second.tokenPoolSize > (*itStats).second.maxTokenPoolSize )     

        {

          (*itStats).second.counter +=  (*itStats).second.tokenGenerationRate / 1000 - ( (*itStats).second.maxTokenPoolSize -  (*itStats).second.tokenPoolSize );

          (*itStats).second.tokenPoolSize = (*itStats).second.maxTokenPoolSize;

          bankSize += (*itStats).second.tokenGenerationRate / 1000 - ( (*itStats).second.maxTokenPoolSize -  (*itStats).second.tokenPoolSize );  

        }

      else

        {

          (*itStats).second.tokenPoolSize += (*itStats).second.tokenGenerationRate / 1000;

        }

    }

  int rbgSize = GetRbgSize (m_cschedCellConfig.m_dlBandwidth);

  int rbgNum = m_cschedCellConfig.m_dlBandwidth / rbgSize;

  std::map <uint16_t, std::vector <uint16_t> > allocationMap;

  // select UE with largest metric

  std::map <uint16_t, tdtbfqsFlowPerf_t>::iterator it;

  std::map <uint16_t, tdtbfqsFlowPerf_t>::iterator itMax = m_flowStatsDl.end ();

  bool firstRnti = true;

  for (it = m_flowStatsDl.begin (); it != m_flowStatsDl.end (); it++)

    {

      if (LcActivePerFlow ((*it).first) == 0)

        {

          continue;

        }

      double metric = ( ( (double)(*it).second.counter ) / ( (double)(*it).second.tokenGenerationRate ) );  

      if (firstRnti == true)

        {

          metricMax = metric;

          itMax = it;

          firstRnti = false;

          continue;

        }

      if (metric > metricMax)

        {

          metricMax = metric;

          itMax = it;

        }

    } // end for m_flowStatsDl

  if (itMax == m_flowStatsDl.end ())

    {

      // no UE available for downlink 

      return;

    }