/* -*- 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