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

//

// Copyright (c) 2006 Georgia Tech Research Corporation

//

// 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: George F. Riley<riley@ece.gatech.edu>

//

// ns3 - On/Off Data Source Application class

// George F. Riley, Georgia Tech, Spring 2007

// Adapted from ApplicationOnOff in GTNetS.

#include "ns3/log.h"

#include "ns3/address.h"

#include "ns3/node.h"

#include "ns3/nstime.h"

#include "ns3/data-rate.h"

#include "ns3/random-variable.h"

#include "ns3/socket.h"

#include "ns3/simulator.h"

#include "ns3/socket-factory.h"

#include "ns3/packet.h"

#include "ns3/uinteger.h"

#include "ns3/trace-source-accessor.h"

#include "onoff-application.h"

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

NS_LOG_COMPONENT_DEFINE ("OnOffApplication");

using namespace std;

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (OnOffApplication);

TypeId

OnOffApplication::GetTypeId (void)

{

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

    .SetParent<Application> ()

    .AddConstructor<OnOffApplication> ()

    .AddAttribute ("DataRate", "The data rate in on state.",

                   DataRateValue (DataRate ("500kb/s")),

                   MakeDataRateAccessor (&OnOffApplication::m_cbrRate),

                   MakeDataRateChecker ())

    .AddAttribute ("PacketSize", "The size of packets sent in on state",

                   UintegerValue (512),

                   MakeUintegerAccessor (&OnOffApplication::m_pktSize),

                   MakeUintegerChecker<uint32_t> (1))

    .AddAttribute ("Remote", "The address of the destination",

                   AddressValue (),

                   MakeAddressAccessor (&OnOffApplication::m_peer),

                   MakeAddressChecker ())

    .AddAttribute ("OnTime", "A RandomVariable used to pick the duration of the 'On' state.",

                   RandomVariableValue (ConstantVariable (1.0)),

                   MakeRandomVariableAccessor (&OnOffApplication::m_onTime),

                   MakeRandomVariableChecker ())

    .AddAttribute ("OffTime", "A RandomVariable used to pick the duration of the 'Off' state.",

                   RandomVariableValue (ConstantVariable (1.0)),

                   MakeRandomVariableAccessor (&OnOffApplication::m_offTime),

                   MakeRandomVariableChecker ())

    .AddAttribute ("MaxBytes", 

                   "The total number of bytes to send. Once these bytes are sent, "

                   "no packet is sent again, even in on state. The value zero means "

                   "that there is no limit.",

                   UintegerValue (0),

                   MakeUintegerAccessor (&OnOffApplication::m_maxBytes),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("Protocol", "The type of protocol to use.",

                   TypeIdValue (UdpSocketFactory::GetTypeId ()),

                   MakeTypeIdAccessor (&OnOffApplication::m_tid),

                   MakeTypeIdChecker ())

    .AddTraceSource ("Tx", "A new packet is created and is sent",

                     MakeTraceSourceAccessor (&OnOffApplication::m_txTrace))

    ;

  return tid;

}

OnOffApplication::OnOffApplication ()

{

  NS_LOG_FUNCTION_NOARGS ();

  m_socket = 0;

  m_connected = false;

  m_residualBits = 0;

  m_lastStartTime = Seconds (0);

  m_totBytes = 0;

}

OnOffApplication::~OnOffApplication()

{

  NS_LOG_FUNCTION_NOARGS ();

}

void 

OnOffApplication::SetMaxBytes(uint32_t maxBytes)

{

  NS_LOG_FUNCTION (this << maxBytes);

  m_maxBytes = maxBytes;

}

void

OnOffApplication::DoDispose (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_socket = 0;

  // chain up

  Application::DoDispose ();

}

// Application Methods

void OnOffApplication::StartApplication() // Called at time specified by Start

{

  NS_LOG_FUNCTION_NOARGS ();

  // Create the socket if not already

  if (!m_socket)

    {

      m_socket = Socket::CreateSocket (GetNode(), m_tid);

      m_socket->Bind ();

      m_socket->Connect (m_peer);

    }

  // Insure no pending event

  CancelEvents ();

  // If we are not yet connected, there is nothing to do here

  // The ConnectionComplete upcall will start timers at that time

  //if (!m_connected) return;

  ScheduleStartEvent();

}

void OnOffApplication::StopApplication() // Called at time specified by Stop

{

  NS_LOG_FUNCTION_NOARGS ();

  CancelEvents ();

  if(m_socket != 0)

    {

      m_socket->Close ();

    }

  else

    {

      NS_LOG_WARN("OnOffApplication found null socket to close in StopApplication");

    }

}

void OnOffApplication::CancelEvents ()

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_sendEvent.IsRunning ())

    { // Cancel the pending send packet event

      // Calculate residual bits since last packet sent

      Time delta(Simulator::Now() - m_lastStartTime);

      m_residualBits += (uint32_t)(m_cbrRate.GetBitRate() * delta.GetSeconds());

    }

  Simulator::Cancel(m_sendEvent);

  Simulator::Cancel(m_startStopEvent);

}

// Event handlers

void OnOffApplication::StartSending()

{

  NS_LOG_FUNCTION_NOARGS ();

  ScheduleNextTx();  // Schedule the send packet event

}

void OnOffApplication::StopSending()

{

  NS_LOG_FUNCTION_NOARGS ();

}

// Private helpers

void OnOffApplication::ScheduleNextTx()

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_maxBytes == 0 || m_totBytes < m_maxBytes)

    {

      uint32_t bits = m_pktSize * 8 - m_residualBits;

      NS_LOG_LOGIC ("bits = " << bits);

      Time nextTime(Seconds (bits / 

        static_cast<double>(m_cbrRate.GetBitRate()))); // Time till next packet

      NS_LOG_LOGIC ("nextTime = " << nextTime);

      m_sendEvent = Simulator::Schedule(nextTime, 

                                        &OnOffApplication::SendPacket, this);

    }

  else

    { // All done, cancel any pending events

      StopApplication();

    }

}

void OnOffApplication::ScheduleStartEvent()

{  // Schedules the event to start sending data (switch to the "On" state)

  NS_LOG_FUNCTION_NOARGS ();

  Time offInterval = Seconds(m_offTime.GetValue());

  NS_LOG_LOGIC ("start at " << offInterval);

  m_startStopEvent = Simulator::Schedule(offInterval, &OnOffApplication::StartSending, this);

}

void OnOffApplication::ScheduleStopEvent()

{  // Schedules the event to stop sending data (switch to "Off" state)

  NS_LOG_FUNCTION_NOARGS ();

  Time onInterval = Seconds(m_onTime.GetValue());

  NS_LOG_LOGIC ("stop at " << onInterval);

}

void OnOffApplication::SendPacket()

{

  NS_LOG_FUNCTION_NOARGS ();

  NS_LOG_LOGIC ("sending packet at " << Simulator::Now());

  NS_ASSERT (m_sendEvent.IsExpired ());

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

  m_txTrace (packet);

  m_socket->Send (packet);

  m_totBytes += m_pktSize;

  m_lastStartTime = Simulator::Now();

  m_residualBits = 0;

  ScheduleNextTx();

}

void OnOffApplication::ConnectionSucceeded(Ptr<Socket>)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_connected = true;

  ScheduleStartEvent();

}

void OnOffApplication::ConnectionFailed(Ptr<Socket>)

{

  NS_LOG_FUNCTION_NOARGS ();

  cout << "OnOffApplication, Connection Failed" << endl;

}

} // Namespace ns3