/* -*- 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
 *
 */

#include "ns3/core-module.h"
#include "ns3/simulator-module.h"
#include "ns3/node-module.h"
#include "ns3/helper-module.h"

// Network topology (default)
//
//        n2 n3 n4              .
//         \ | /                .
//          \|/                 .
//     n1--- n0---n5            .
//          /|\                 .
//         / | \                .
//        n8 n7 n6              .
//


using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("Star");

int 
main (int argc, char *argv[])
{

  //
  // Set up some default values for the simulation.
  //
  Config::SetDefault ("ns3::OnOffApplication::PacketSize", UintegerValue (137));

  // ??? try and stick 15kb/s into the data rate
  Config::SetDefault ("ns3::OnOffApplication::DataRate", StringValue ("14kb/s"));

  //
  // Default number of nodes in the star.  Overridable by command line argument.
  //
  uint32_t nNodes = 9;

  CommandLine cmd;
  cmd.AddValue("nNodes", "Number of nodes to place in the star", nNodes);
  cmd.Parse (argc, argv);

  NS_LOG_INFO ("Create nodes.");
  NodeContainer hubNode;
  NodeContainer spokeNodes;
  hubNode.Create (1);
  Ptr<Node> hub = hubNode.Get (0);
  spokeNodes.Create (nNodes - 1);

  NS_LOG_INFO ("Install internet stack on all nodes.");
  InternetStackHelper internet;
  internet.Install (NodeContainer (hubNode, spokeNodes));

  PointToPointHelper pointToPoint;
  pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));
  pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms"));

  NS_LOG_INFO ("Build star topology.");
  NetDeviceContainer hubDevices, spokeDevices;
  pointToPoint.InstallStar (hubNode.Get (0), spokeNodes, hubDevices, spokeDevices);

  NS_LOG_INFO ("Assign IP Addresses.");
  Ipv4AddressHelper address;

  //
  // Assign IPv4 interfaces and IP addresses to the devices we previously
  // created.  Keep track of the resulting addresses, one for the addresses
  // of the hub node, and one for addresses on the spoke nodes.  Despite the
  // name of the class, what is visible to clients is really the address.
  //
  Ipv4InterfaceContainer hubAddresses;
  Ipv4InterfaceContainer spokeAddresses;

  for(uint32_t i = 0; i < spokeNodes.GetN (); ++i)
  {
    std::ostringstream subnet;
    subnet << "10.1.1." << (i << 2);
    NS_LOG_INFO ("Assign IP Addresses for point-to-point subnet " << subnet.str ());
    address.SetBase (subnet.str ().c_str (), "255.255.255.252");
    hubAddresses.Add (address.Assign (hubDevices.Get (i)));
    spokeAddresses.Add (address.Assign (spokeDevices.Get (i)));
  }

  NS_LOG_INFO ("Create applications.");
  //
  // Create a packet sink on the star "hub" to receive packets.  
  // 
  uint16_t port = 50000;
  Address hubLocalAddress (InetSocketAddress (Ipv4Address::GetAny (), port));
  PacketSinkHelper packetSinkHelper ("ns3::TcpSocketFactory", hubLocalAddress);
  ApplicationContainer hubApp = packetSinkHelper.Install (hubNode);
  hubApp.Start (Seconds (1.0));
  hubApp.Stop (Seconds (10.0));

  //
  // Create OnOff applications to send TCP to the hub, one on each spoke node.
  //
  OnOffHelper onOffHelper ("ns3::TcpSocketFactory", Address ());
  onOffHelper.SetAttribute ("OnTime", RandomVariableValue (ConstantVariable (1)));
  onOffHelper.SetAttribute ("OffTime", RandomVariableValue (ConstantVariable (0)));

  ApplicationContainer spokeApps;

  for (uint32_t i = 0; i < spokeNodes.GetN (); ++i)
    {
      AddressValue remoteAddress (InetSocketAddress (hubAddresses.GetAddress (i), port));
      onOffHelper.SetAttribute ("Remote", remoteAddress);
      spokeApps.Add (onOffHelper.Install (spokeNodes.Get (i)));
  }
  spokeApps.Start (Seconds (1.0));
  spokeApps.Stop (Seconds (10.0));

  NS_LOG_INFO ("Enable static global routing.");
  //
  // Turn on global static routing so we can actually be routed across the star.
  //
  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  NS_LOG_INFO ("Enable pcap tracing.");
  //
  // Do pcap tracing on all point-to-point devices on all nodes.
  //
  PointToPointHelper::EnablePcapAll ("star");

  NS_LOG_INFO ("Run Simulation.");
  Simulator::Run ();
  Simulator::Destroy ();
  NS_LOG_INFO ("Done.");

  return 0;
}