/*

 * Copyright (c) 2009 University of Washington

 *

 * 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

 */

#include <iostream>

#include <fstream>

#include <vector>

#include <string>

#include "ns3/log.h"

#include "ns3/callback.h"

#include "ns3/abort.h"

#include "ns3/test.h"

#include "ns3/pcap-file.h"

#include "ns3/config.h"

#include "ns3/string.h"

#include "ns3/uinteger.h"

#include "ns3/double.h"

#include "ns3/data-rate.h"

#include "ns3/inet-socket-address.h"

#include "ns3/internet-stack-helper.h"

#include "ns3/ipv4-address-helper.h"

#include "ns3/tcp-socket-factory.h"

#include "ns3/yans-wifi-helper.h"

#include "ns3/propagation-loss-model.h"

#include "ns3/propagation-delay-model.h"

#include "ns3/yans-wifi-channel.h"

#include "ns3/yans-wifi-phy.h"

#include "ns3/wifi-net-device.h"

#include "ns3/mobility-helper.h"

#include "ns3/constant-position-mobility-model.h"

#include "ns3/nqos-wifi-mac-helper.h"

#include "ns3/simulator.h"

NS_LOG_COMPONENT_DEFINE ("WifiInterferenceTestSuite");

using namespace ns3;

class WifiInterferenceTestCase : public TestCase

{

public:

  WifiInterferenceTestCase ();

  virtual ~WifiInterferenceTestCase ();

private:

  virtual void DoRun (void);

  void ReceivePacket (Ptr<Socket> socket);

  static void GenerateTraffic (Ptr<Socket> socket, uint32_t pktSize, uint32_t pktCount, Time pktInterval);

  void PrintEndSync (std::string context, uint32_t dataRate, double snr, double per);

  double WifiSimpleInterference (std::string phyMode, double Prss, double Irss, double delta, uint32_t PpacketSize, 

                                 uint32_t IpacketSize, bool verbose, InternetStackHelper internet);

  double m_PER;

  double m_SNR;

  uint32_t m_DataRate;

};

// Add some help text to this case to describe what it is intended to test

WifiInterferenceTestCase::WifiInterferenceTestCase  ()

  : TestCase ("Test interference calculation when interfering frame exactly overlaps intended frame")

{

}

WifiInterferenceTestCase::~WifiInterferenceTestCase ()

{

}

static inline std::string

PrintReceivedPacket (Ptr<Socket> socket)

{

  Address addr;

  socket->GetSockName (addr);

  InetSocketAddress iaddr = InetSocketAddress::ConvertFrom (addr);

  std::ostringstream oss;

  oss << "Received one packet!  Socket: " << iaddr.GetIpv4 () << " port: " << iaddr.GetPort ();

  return oss.str ();

}

void

WifiInterferenceTestCase::ReceivePacket (Ptr<Socket> socket)

{

  NS_LOG_UNCOND (PrintReceivedPacket (socket));

}

void 

WifiInterferenceTestCase::GenerateTraffic (Ptr<Socket> socket, uint32_t pktSize, uint32_t pktCount, Time pktInterval)

{

  if (pktCount > 0)

    {

      socket->Send (Create<Packet> (pktSize));

      Simulator::Schedule (pktInterval, &WifiInterferenceTestCase::GenerateTraffic, socket, pktSize, pktCount-1, pktInterval);

    }

  else

    {

      socket->Close ();

    }

}

void 

WifiInterferenceTestCase::PrintEndSync (std::string context, uint32_t dataRate, double snr, double per)

{

  NS_LOG_UNCOND ("EndSync:  Received frame with dataRate=" << dataRate << ", SNR=" << snr << ", PER =" << per);

  m_PER = per;

  m_SNR = snr;

  m_DataRate = dataRate;

}

double 

WifiInterferenceTestCase::WifiSimpleInterference (std::string phyMode,double Prss, double Irss, double delta, uint32_t PpacketSize, uint32_t IpacketSize, bool verbose, InternetStackHelper internet)

{

  uint32_t numPackets = 1;

  double interval = 1.0; // seconds

  double startTime = 10.0; // seconds

  double distanceToRx = 100.0; // meters

  double offset = 91;  // This is a magic number used to set the 

  // transmit power, based on other configuration

  m_PER = 0;

  m_SNR = 0;

  m_DataRate = 0;

  // Convert to time object

  Time interPacketInterval = Seconds (interval);

  // disable fragmentation for frames below 2200 bytes

  Config::SetDefault ("ns3::WifiRemoteStationManager::FragmentationThreshold", StringValue ("2200"));

  // turn off RTS/CTS for frames below 2200 bytes

  Config::SetDefault ("ns3::WifiRemoteStationManager::RtsCtsThreshold", StringValue ("2200"));

  // Fix non-unicast data rate to be the same as that of unicast

  Config::SetDefault ("ns3::WifiRemoteStationManager::NonUnicastMode", 

                      StringValue (phyMode));

  NodeContainer c;

  c.Create (3);

  // The below set of helpers will help us to put together the wifi NICs we want

  WifiHelper wifi;

  wifi.SetStandard (WIFI_PHY_STANDARD_80211b);

  YansWifiPhyHelper wifiPhy =  YansWifiPhyHelper::Default ();

  // This is one parameter that matters when using FixedRssLossModel

  // set it to zero; otherwise, gain will be added

  wifiPhy.Set ("RxGain", DoubleValue (0) ); 

  wifiPhy.Set ("CcaMode1Threshold", DoubleValue (0.0) );

  // ns-3 supports RadioTap and Prism tracing extensions for 802.11b

  wifiPhy.SetPcapDataLinkType (YansWifiPhyHelper::DLT_IEEE802_11_RADIO); 

  YansWifiChannelHelper wifiChannel;

  wifiChannel.SetPropagationDelay ("ns3::ConstantSpeedPropagationDelayModel");

  wifiChannel.AddPropagationLoss ("ns3::LogDistancePropagationLossModel");

  wifiPhy.SetChannel (wifiChannel.Create ());

  // Add a non-QoS upper mac, and disable rate control

  NqosWifiMacHelper wifiMac = NqosWifiMacHelper::Default ();

  wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager",

                                "DataMode",StringValue (phyMode),

                                "ControlMode",StringValue (phyMode));

  // Set it to adhoc mode

  wifiMac.SetType ("ns3::AdhocWifiMac");

  NetDeviceContainer devices = wifi.Install (wifiPhy, wifiMac, c.Get (0));

  // This will disable these sending devices from detecting a signal 

  // so that they do not backoff

  wifiPhy.Set ("EnergyDetectionThreshold", DoubleValue (0.0) );

  wifiPhy.Set ("TxGain", DoubleValue (offset + Prss) ); 

  devices.Add (wifi.Install (wifiPhy, wifiMac, c.Get (1)));

  wifiPhy.Set ("TxGain", DoubleValue (offset + Irss) ); 

  devices.Add (wifi.Install (wifiPhy, wifiMac, c.Get (2)));

  // Note that with FixedRssLossModel, the positions below are not 

  // used for received signal strength. 

  MobilityHelper mobility;

  Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator> ();

  positionAlloc->Add (Vector (0.0, 0.0, 0.0));

  positionAlloc->Add (Vector (distanceToRx, 0.0, 0.0));

  positionAlloc->Add (Vector (-1*distanceToRx, 0.0, 0.0));

  mobility.SetPositionAllocator (positionAlloc);

  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");

  mobility.Install (c);

  // InternetStackHelper internet;

  internet.Install (c);

  Ipv4AddressHelper ipv4;

  NS_LOG_INFO ("Assign IP Addresses.");

  ipv4.SetBase ("10.1.1.0", "255.255.255.0");

  Ipv4InterfaceContainer i = ipv4.Assign (devices);

  TypeId tid = TypeId::LookupByName ("ns3::UdpSocketFactory");

  Ptr<Socket> recvSink = Socket::CreateSocket (c.Get (0), tid);

  InetSocketAddress local = InetSocketAddress (Ipv4Address ("10.1.1.1"), 80);

  recvSink->Bind (local);

  recvSink->SetRecvCallback (MakeCallback (&WifiInterferenceTestCase::ReceivePacket, this));

  Ptr<Socket> source = Socket::CreateSocket (c.Get (1), tid);

  InetSocketAddress remote = InetSocketAddress (Ipv4Address ("255.255.255.255"), 80);

  source->Connect (remote);

  // Interferer will send to a different port; we will not see a

  // "Received packet" message

  Ptr<Socket> interferer = Socket::CreateSocket (c.Get (2), tid);

  InetSocketAddress interferingAddr = InetSocketAddress (Ipv4Address ("255.255.255.255"), 49000);

  interferer->Connect (interferingAddr);

  Config::Connect ("/NodeList/0/DeviceList/0/$ns3::WifiNetDevice/Phy/$ns3::YansWifiPhy/EndSync", MakeCallback (&WifiInterferenceTestCase::PrintEndSync, this)); 

  // Tracing

//  wifiPhy.EnablePcap ("wifi-simple-interference", devices.Get (0));

  Simulator::ScheduleWithContext (source->GetNode ()->GetId (),

                                  Seconds (startTime), &GenerateTraffic,

                                  source, PpacketSize, numPackets, interPacketInterval);

  Simulator::ScheduleWithContext (interferer->GetNode ()->GetId (),

                                  Seconds (startTime + delta/1000000.0), &GenerateTraffic,

                                  interferer, IpacketSize, numPackets, interPacketInterval);

  Simulator::Run ();

  Simulator::Destroy ();

  return m_PER;

}

void

WifiInterferenceTestCase::DoRun (void)

{

  std::string phyMode ("DsssRate1Mbps");

  double Prss = -90;  // -dBm

  double Irss = -90;  // -dBm

  double delta = 0;  // microseconds

  uint32_t PpacketSize = 1000; // bytes

  uint32_t IpacketSize = 1000; // bytes

  bool verbose = false;

  double PER, PER1, PER2;

  InternetStackHelper internet;

  // Compute the packet error rate (PER) when delta=0 microseconds.  This

  // means that the interferer arrives at exactly the same time as the

  // intended packet

  PER = WifiSimpleInterference (phyMode,Prss,Irss,delta,PpacketSize,IpacketSize,verbose,internet);

  // Now rerun this test case and compute the PER when the delta time between

  // arrival of the intended frame and interferer is 1 microsecond.

  delta = 1;

  PER1 = WifiSimpleInterference (phyMode,Prss,Irss,delta,PpacketSize,IpacketSize,verbose,internet);

  // Now rerun this test case and compute the PER when the delta time between

  // arrival of the intended frame and interferer is 2 microseconds.

  delta = 2;

  PER2 = WifiSimpleInterference (phyMode,Prss,Irss,delta,PpacketSize,IpacketSize,verbose,internet);

  double PERDiff1 = PER - PER1;

  double PERDiff2 = PER1 - PER2;

  NS_TEST_ASSERT_MSG_EQ (PERDiff1, PERDiff2, 

                         "The PER difference due to 1 microsecond difference in arrival shouldn't depend on absolute arrival");

}

class WifiInterferenceTestSuite : public TestSuite

{

public:

  WifiInterferenceTestSuite ();

};

WifiInterferenceTestSuite::WifiInterferenceTestSuite ()

  : TestSuite ("ns3-wifi-interference", UNIT)

{

}

static WifiInterferenceTestSuite wifiInterferenceTestSuite;