/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2012 University of California, Los Angeles
 *
 * 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: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 */
// ndn-simple.cc
#include "ns3/core-module.h"
#include "ns3/network-module.h"
#include "ns3/point-to-point-module.h"
#include "ns3/ndnSIM-module.h"

using namespace ns3;

/**
 * This scenario simulates a very simple network topology:
 *
 *
 *      +----------+     1Mbps      +--------+     1Mbps      +----------+
 *      | consumer | <------------> | router | <------------> | producer |
 *      +----------+         10ms   +--------+          10ms  +----------+
 *
 * This scenario demonstrates how to use content store that responds to Freshness parameter set in ContentObjects.
 * That is, if producer set Freshness field to 2 seconds, the corresponding content object will not be cached
 * more than 2 seconds (can be cached for a shorter time, if entry is evicted earlier)
 * 
 *     NS_LOG=DumbRequester ./waf --run ndn-simple-with-content-freshness
 */

int 
main (int argc, char *argv[])
{
  // setting default parameters for PointToPoint links and channels
  Config::SetDefault ("ns3::PointToPointNetDevice::DataRate", StringValue ("1Mbps"));
  Config::SetDefault ("ns3::PointToPointChannel::Delay", StringValue ("10ms"));
  Config::SetDefault ("ns3::DropTailQueue::MaxPackets", StringValue ("20"));

  // Read optional command-line parameters (e.g., enable visualizer with ./waf --run=<> --visualize
  CommandLine cmd;
  cmd.Parse (argc, argv);

  // Creating nodes
  NodeContainer nodes;
  nodes.Create (3);

  // Connecting nodes using two links
  PointToPointHelper p2p;
  p2p.Install (nodes.Get (0), nodes.Get (1));
  p2p.Install (nodes.Get (1), nodes.Get (2));

  // Install CCNx stack on all nodes
  ndn::StackHelper ccnxHelper;
  ccnxHelper.SetDefaultRoutes (true);
  ccnxHelper.SetContentStore ("ns3::ndn::cs::Freshness::Lru",
                              "MaxSize", "2"); // allow just 2 entries to be cached
  ccnxHelper.InstallAll ();

  // Installing applications

  // Consumer
  ndn::AppHelper consumerHelper ("DumbRequester");

  // /*
  //   1) at time 1 second requests Data from a producer that does not specify freshness
  //   2) at time 10 seconds requests the same Data packet as client 1

  //   3) at time 2 seconds requests Data from a producer that specifies freshness set to 2 seconds
  //   4) at time 12 seconds requests the same Data packet as client 3

  //   Expectation:
  //   Interests from 1, 3 and 4 will reach producers
  //   Interset from 2 will be served from cache
  //  */

  ApplicationContainer apps;
  
  consumerHelper.SetPrefix ("/no-freshness");
  apps = consumerHelper.Install (nodes.Get (0));
  apps.Start (Seconds (0.1));
  apps.Stop  (Seconds (10.0));

  consumerHelper.SetPrefix ("/with-freshness");
  apps = consumerHelper.Install (nodes.Get (0));
  apps.Start (Seconds (20.1));
  apps.Stop  (Seconds (30.0));
  
  // Producer
  ndn::AppHelper producerHelper ("ns3::ndn::Producer");
  producerHelper.SetAttribute ("PayloadSize", StringValue("1024"));

  producerHelper.SetAttribute ("Freshness", TimeValue (Seconds (0))); // unlimited freshness
  producerHelper.SetPrefix ("/no-freshness");
  producerHelper.Install (nodes.Get (2)); // last node

  producerHelper.SetAttribute ("Freshness", TimeValue (Seconds (2.0))); // freshness 2 seconds (!!! freshness granularity is 1 seconds !!!)
  producerHelper.SetPrefix ("/with-freshness");
  producerHelper.Install (nodes.Get (2)); // last node
                               
  Simulator::Stop (Seconds (30.0));

  Simulator::Run ();
  Simulator::Destroy ();

  return 0;
}