/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2011 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>
 *         Ilya Moiseenko <iliamo@cs.ucla.edu>
 */

#include "ndn-l3-protocol.hpp"

#include "ns3/packet.h"
#include "ns3/node.h"
#include "ns3/log.h"
#include "ns3/callback.h"
#include "ns3/uinteger.h"
#include "ns3/trace-source-accessor.h"
#include "ns3/object-vector.h"
#include "ns3/pointer.h"
#include "ns3/simulator.h"
#include "ns3/random-variable.h"

#include "ns3/ndn-pit.hpp"
#include "ns3/ndn-interest.hpp"
#include "ns3/ndn-data.hpp"

#include "ns3/ndn-face.hpp"
#include "ns3/ndn-forwarding-strategy.hpp"

#include "ndn-net-device-face.hpp"

#include <boost/foreach.hpp>

NS_LOG_COMPONENT_DEFINE("ndn.L3Protocol");

namespace ns3 {
namespace ndn {

const uint16_t L3Protocol::ETHERNET_FRAME_TYPE = 0x7777;
const uint16_t L3Protocol::IP_STACK_PORT = 9695;

NS_OBJECT_ENSURE_REGISTERED(L3Protocol);

TypeId
L3Protocol::GetTypeId(void)
{
  static TypeId tid =
    TypeId("ns3::ndn::L3Protocol")
      .SetGroupName("ndn")
      .SetParent<Object>()
      .AddConstructor<L3Protocol>()
      .AddAttribute("FaceList", "List of faces associated with ndn stack", ObjectVectorValue(),
                    MakeObjectVectorAccessor(&L3Protocol::m_faces),
                    MakeObjectVectorChecker<Face>());
  return tid;
}

L3Protocol::L3Protocol()
  : m_faceCounter(0)
{
  NS_LOG_FUNCTION(this);
}

L3Protocol::~L3Protocol()
{
  NS_LOG_FUNCTION(this);
}

/*
 * This method is called by AddAgregate and completes the aggregation
 * by setting the node in the ndn stack
 */
void
L3Protocol::NotifyNewAggregate()
{
  // not really efficient, but this will work only once
  if (m_node == 0) {
    m_node = GetObject<Node>();
    if (m_node != 0) {
      NS_ASSERT_MSG(m_forwardingStrategy != 0,
                    "Forwarding strategy should be aggregated before L3Protocol");
    }
  }
  if (m_forwardingStrategy == 0) {
    m_forwardingStrategy = GetObject<ForwardingStrategy>();
  }

  Object::NotifyNewAggregate();
}

void
L3Protocol::DoDispose(void)
{
  NS_LOG_FUNCTION(this);

  // for (FaceList::iterator i = m_faces.begin (); i != m_faces.end (); ++i)
  //   {
  //     *i = 0;
  //   }
  m_faces.clear();
  m_node = 0;

  // Force delete on objects
  m_forwardingStrategy = 0; // there is a reference to PIT stored in here

  Object::DoDispose();
}

uint32_t
L3Protocol::AddFace(const Ptr<Face>& face)
{
  NS_LOG_FUNCTION(this << &face);

  face->SetId(
    m_faceCounter); // sets a unique ID of the face. This ID serves only informational purposes

  // ask face to register in lower-layer stack
  face->RegisterProtocolHandlers(MakeCallback(&ForwardingStrategy::OnInterest,
                                              m_forwardingStrategy),
                                 MakeCallback(&ForwardingStrategy::OnData, m_forwardingStrategy));

  m_faces.push_back(face);
  m_faceCounter++;

  m_forwardingStrategy->AddFace(face); // notify that face is added
  return face->GetId();
}

void
L3Protocol::RemoveFace(Ptr<Face> face)
{
  NS_LOG_FUNCTION(this << boost::cref(*face));
  // ask face to register in lower-layer stack
  face->UnRegisterProtocolHandlers();
  Ptr<Pit> pit = GetObject<Pit>();

  // just to be on a safe side. Do the process in two steps
  std::list<Ptr<pit::Entry>> entriesToRemoves;
  for (Ptr<pit::Entry> pitEntry = pit->Begin(); pitEntry != 0; pitEntry = pit->Next(pitEntry)) {
    pitEntry->RemoveAllReferencesToFace(face);

    // If this face is the only for the associated FIB entry, then FIB entry will be removed soon.
    // Thus, we have to remove the whole PIT entry
    if (pitEntry->GetFibEntry()->m_faces.size() == 1
        && pitEntry->GetFibEntry()->m_faces.begin()->GetFace() == face) {
      entriesToRemoves.push_back(pitEntry);
    }
  }
  BOOST_FOREACH (Ptr<pit::Entry> removedEntry, entriesToRemoves) {
    pit->MarkErased(removedEntry);
  }

  FaceList::iterator face_it = find(m_faces.begin(), m_faces.end(), face);
  if (face_it == m_faces.end()) {
    return;
  }
  m_faces.erase(face_it);

  GetObject<Fib>()->RemoveFromAll(face);
  m_forwardingStrategy->RemoveFace(face); // notify that face is removed
}

Ptr<Face>
L3Protocol::GetFace(uint32_t index) const
{
  NS_ASSERT(0 <= index && index < m_faces.size());
  return m_faces[index];
}

Ptr<Face>
L3Protocol::GetFaceById(uint32_t index) const
{
  BOOST_FOREACH (const Ptr<Face>& face, m_faces) // this function is not supposed to be called
                                                 // often, so linear search is fine
  {
    if (face->GetId() == index)
      return face;
  }
  return 0;
}

Ptr<Face>
L3Protocol::GetFaceByNetDevice(Ptr<NetDevice> netDevice) const
{
  BOOST_FOREACH (const Ptr<Face>& face, m_faces) // this function is not supposed to be called
                                                 // often, so linear search is fine
  {
    Ptr<NetDeviceFace> netDeviceFace = DynamicCast<NetDeviceFace>(face);
    if (netDeviceFace == 0)
      continue;

    if (netDeviceFace->GetNetDevice() == netDevice)
      return face;
  }
  return 0;
}

uint32_t
L3Protocol::GetNFaces(void) const
{
  return m_faces.size();
}

} // namespace ndn
} // namespace ns3