/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * 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
 *
 * Authors: Joe Kopena <tjkopena@cs.drexel.edu>
 *
 * These applications are used in the WiFi Distance Test experiment,
 * described and implemented in test02.cc.  That file should be in the
 * same place as this file.  The applications have two very simple
 * jobs, they just generate and receive packets.  We could use the
 * standard Application classes included in the NS-3 distribution.
 * These have been written just to change the behavior a little, and
 * provide more examples.
 *
 */

#include <ostream>

#include "ns3/core-module.h"
#include "ns3/common-module.h"
#include "ns3/simulator-module.h"
#include "ns3/node-module.h"
#include "ns3/internet-stack-module.h"

#include "ns3/stats-module.h"

#include "wifi-example-apps.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("WiFiDistanceApps");

TypeId
Sender::GetTypeId(void)
{
  static TypeId tid = TypeId ("Sender")
    .SetParent<Application> ()
    .AddConstructor<Sender> ()
    .AddAttribute ("PacketSize", "The size of packets transmitted.",
                   UintegerValue(64),
                   MakeUintegerAccessor(&Sender::m_pktSize),
                   MakeUintegerChecker<uint32_t>(1))
    .AddAttribute("Destination", "Target host address.",
                  Ipv4AddressValue("255.255.255.255"),
                  MakeIpv4AddressAccessor(&Sender::m_destAddr),
                  MakeIpv4AddressChecker())
    .AddAttribute("Port", "Destination app port.",
                  UintegerValue(1603),
                  MakeUintegerAccessor(&Sender::m_destPort),
                  MakeUintegerChecker<uint32_t>())
    .AddAttribute("NumPackets", "Total number of packets to send.",
                  UintegerValue(30),
                  MakeUintegerAccessor(&Sender::m_numPkts),
                  MakeUintegerChecker<uint32_t>(1))
    .AddAttribute ("Interval", "Delay between transmissions.",
                   RandomVariableValue(ConstantVariable(0.5)),
                   MakeRandomVariableAccessor(&Sender::m_interval),
                   MakeRandomVariableChecker())
    .AddTraceSource ("Tx", "A new packet is created and is sent",
                     MakeTraceSourceAccessor (&Sender::m_txTrace))
    ;
  return tid;
}


Sender::Sender()
{
  NS_LOG_FUNCTION_NOARGS ();
  m_socket = 0;
}

Sender::~Sender()
{
  NS_LOG_FUNCTION_NOARGS ();
}

void
Sender::DoDispose (void)
{
  NS_LOG_FUNCTION_NOARGS ();

  m_socket = 0;
  // chain up
  Application::DoDispose ();
}

void Sender::StartApplication()
{
  NS_LOG_FUNCTION_NOARGS ();

  if (m_socket == 0) {
      Ptr<SocketFactory> socketFactory = GetNode()->GetObject<SocketFactory>
        (UdpSocketFactory::GetTypeId());
      m_socket = socketFactory->CreateSocket ();
      m_socket->Bind ();
  }

  m_count = 0;

  Simulator::Cancel(m_sendEvent);
  m_sendEvent = Simulator::ScheduleNow(&Sender::SendPacket, this);

  // end Sender::StartApplication
}

void Sender::StopApplication()
{
  NS_LOG_FUNCTION_NOARGS ();
  Simulator::Cancel(m_sendEvent);
  // end Sender::StopApplication
}
  
void Sender::SendPacket()
{
  // NS_LOG_FUNCTION_NOARGS ();
  NS_LOG_INFO("Sending packet at " << Simulator::Now() << " to " <<
              m_destAddr);

  Ptr<Packet> packet = Create<Packet>(m_pktSize);

  TimestampTag timestamp;
  timestamp.SetTimestamp(Simulator::Now());
  packet->AddByteTag (timestamp);

  // Could connect the socket since the address never changes; using SendTo
  // here simply because all of the standard apps do not.
  m_socket->SendTo(packet, 0, InetSocketAddress(m_destAddr, m_destPort));

  // Report the event to the trace.
  m_txTrace(packet);

  if (++m_count < m_numPkts) {
    m_sendEvent = Simulator::Schedule(Seconds(m_interval.GetValue()),
                                      &Sender::SendPacket, this);
  }

  // end Sender::SendPacket
}




//----------------------------------------------------------------------
//-- Receiver
//------------------------------------------------------
TypeId
Receiver::GetTypeId(void)
{
  static TypeId tid = TypeId ("Receiver")
    .SetParent<Application> ()
    .AddConstructor<Receiver> ()
    .AddAttribute("Port", "Listening port.",
                  UintegerValue(1603),
                  MakeUintegerAccessor(&Receiver::m_port),
                  MakeUintegerChecker<uint32_t>())
    ;
  return tid;
}

Receiver::Receiver() :
  m_calc(0),
  m_delay(0)
{
  NS_LOG_FUNCTION_NOARGS ();
  m_socket = 0;
}

Receiver::~Receiver()
{
  NS_LOG_FUNCTION_NOARGS ();
}

void
Receiver::DoDispose (void)
{
  NS_LOG_FUNCTION_NOARGS ();

  m_socket = 0;
  // chain up
  Application::DoDispose ();
}

void
Receiver::StartApplication()
{
  NS_LOG_FUNCTION_NOARGS ();

  if (m_socket == 0) {
      Ptr<SocketFactory> socketFactory = GetNode()->GetObject<SocketFactory>
        (UdpSocketFactory::GetTypeId());
      m_socket = socketFactory->CreateSocket();
      InetSocketAddress local = 
        InetSocketAddress(Ipv4Address::GetAny(), m_port);
      m_socket->Bind(local);
  }

  m_socket->SetRecvCallback(MakeCallback(&Receiver::Receive, this));

  // end Receiver::StartApplication
}

void
Receiver::StopApplication()
{
  NS_LOG_FUNCTION_NOARGS ();

  if (m_socket != 0) {
      m_socket->SetRecvCallback(MakeNullCallback<void, Ptr<Socket> > ());
  }

  // end Receiver::StopApplication
}

void
Receiver::SetCounter(Ptr<CounterCalculator<> > calc)
{
  m_calc = calc;
  // end Receiver::SetCounter
}
void
Receiver::SetDelayTracker(Ptr<TimeMinMaxAvgTotalCalculator> delay)
{
  m_delay = delay;
  // end Receiver::SetDelayTracker
}

void
Receiver::Receive(Ptr<Socket> socket)
{
  // NS_LOG_FUNCTION (this << socket << packet << from);

  Ptr<Packet> packet;
  Address from;
  while (packet = socket->RecvFrom(from)) {
    if (InetSocketAddress::IsMatchingType (from)) {
      InetSocketAddress address = InetSocketAddress::ConvertFrom (from);
      NS_LOG_INFO ("Received " << packet->GetSize() << " bytes from " << 
                   address.GetIpv4());
    }

    TimestampTag timestamp;
    // Should never not be found since the sender is adding it, but
    // you never know.
    if (packet->FindFirstMatchingByteTag(timestamp)) {
      Time tx = timestamp.GetTimestamp();

      if (m_delay != 0) {
        m_delay->Update(Simulator::Now() - tx);
      }
    }

    if (m_calc != 0) {
      m_calc->Update();
    }

    // end receiving packets
  }

  // end Receiver::Receive
}




//----------------------------------------------------------------------
//-- TimestampTag
//------------------------------------------------------
TypeId 
TimestampTag::GetTypeId(void)
{
  static TypeId tid = TypeId ("TimestampTag")
    .SetParent<Tag> ()
    .AddConstructor<TimestampTag> ()
    .AddAttribute ("Timestamp",
                   "Some momentous point in time!",
                   EmptyAttributeValue(),
                   MakeTimeAccessor(&TimestampTag::GetTimestamp),
                   MakeTimeChecker())
    ;
  return tid;
}
TypeId 
TimestampTag::GetInstanceTypeId(void) const
{
  return GetTypeId ();
}

uint32_t 
TimestampTag::GetSerializedSize (void) const
{
  return 8;
}
void 
TimestampTag::Serialize (TagBuffer i) const
{
  int64_t t = m_timestamp.GetNanoSeconds();
  i.Write((const uint8_t *)&t, 8);
}
void 
TimestampTag::Deserialize (TagBuffer i)
{
  int64_t t;
  i.Read((uint8_t *)&t, 8);
  m_timestamp = NanoSeconds(t);
}

void
TimestampTag::SetTimestamp(Time time)
{
  m_timestamp = time;
}
Time
TimestampTag::GetTimestamp(void) const
{
  return m_timestamp;
}

void 
TimestampTag::Print(std::ostream &os) const
{
  os << "t=" << m_timestamp;
}