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

/*

 * Copyright (c) 2007 INRIA

 *

 * 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#include "hierarchical-mobility-model.h"

#include "ns3/pointer.h"

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (HierarchicalMobilityModel);

TypeId 

HierarchicalMobilityModel::GetTypeId (void)

{

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

    .SetParent<MobilityModel> ()

    .AddConstructor<HierarchicalMobilityModel> ()

    .AddAttribute ("Child", "The child mobility model.",

                   PointerValue (),

                   MakePointerAccessor (&HierarchicalMobilityModel::SetChild,

                                        &HierarchicalMobilityModel::GetChild),

                   MakePointerChecker<MobilityModel> ())

    .AddAttribute ("Parent", "The parent mobility model.",

                   PointerValue (),

                   MakePointerAccessor (&HierarchicalMobilityModel::SetParent,

                                        &HierarchicalMobilityModel::GetParent),

                   MakePointerChecker<MobilityModel> ())

    ;

  return tid;

}

HierarchicalMobilityModel::HierarchicalMobilityModel ()

  : m_child (0),

    m_parent (0)

{}

void 

HierarchicalMobilityModel::SetChild (Ptr<MobilityModel> model)

{

  Ptr<MobilityModel> oldChild = m_child;

  Vector pos;

  if (m_child)

    {

      pos = GetPosition ();

      m_child->TraceDisconnectWithoutContext ("CourseChange", MakeCallback (&HierarchicalMobilityModel::ChildChanged, this));

    }

  m_child = model;

  m_child->TraceConnectWithoutContext ("CourseChange", MakeCallback (&HierarchicalMobilityModel::ChildChanged, this));

  // if we had a child before, then we had a valid position before;

  // try to preserve the old absolute position.

  if (oldChild)

    {

      SetPosition (pos);

    }

}

void 

HierarchicalMobilityModel::SetParent (Ptr<MobilityModel> model)

{

  Vector pos;

  if (m_child)

    {

      pos = GetPosition ();

    }

  if (m_parent)

    {

      m_parent->TraceDisconnectWithoutContext ("CourseChange", MakeCallback (&HierarchicalMobilityModel::ParentChanged, this));

    }

  m_parent = model;

  if (m_parent)

    {

      m_parent->TraceConnectWithoutContext ("CourseChange", MakeCallback (&HierarchicalMobilityModel::ParentChanged, this));

    }

  // try to preserve the old position across parent changes

  if (m_child)

    {

      SetPosition (pos);

    }

}

Ptr<MobilityModel> 

HierarchicalMobilityModel::GetChild (void) const

{

  return m_child;

}

Ptr<MobilityModel> 

HierarchicalMobilityModel::GetParent (void) const

{

  return m_parent;

}

Vector

HierarchicalMobilityModel::DoGetPosition (void) const

{

  if (!m_parent)

    {

      return m_child->GetPosition ();

    }

  Vector parentPosition = m_parent->GetPosition ();

  Vector childPosition = m_child->GetPosition ();

  return Vector (parentPosition.x + childPosition.x,

		   parentPosition.y + childPosition.y,

		   parentPosition.z + childPosition.z);

}

void 

HierarchicalMobilityModel::DoSetPosition (const Vector &position)

{

  if (m_child == 0)

    {

      return;

    }

  // This implementation of DoSetPosition is really an arbitraty choice.

  // anything else would have been ok.

  if (m_parent)

    {

      Vector parentPosition = m_parent->GetPosition ();

      Vector childPosition (position.x - parentPosition.x,

                            position.y - parentPosition.y,

                            position.z - parentPosition.z);

      m_child->SetPosition (childPosition);

    }

  else

    {

      m_child->SetPosition (position);

    }

}

Vector

HierarchicalMobilityModel::DoGetVelocity (void) const

{

  if (m_parent)

    {

      Vector parentSpeed = m_parent->GetVelocity ();

      Vector childSpeed = m_child->GetVelocity ();

      Vector speed (parentSpeed.x + childSpeed.x,

                    parentSpeed.y + childSpeed.y,

                    parentSpeed.z + childSpeed.z);

      return speed;

    }

  else

    {

      return m_child->GetVelocity ();

    }

}

void 

HierarchicalMobilityModel::ParentChanged (Ptr<const MobilityModel> model)

{

  MobilityModel::NotifyCourseChange ();

}

void 

HierarchicalMobilityModel::ChildChanged (Ptr<const MobilityModel> model)

{

  MobilityModel::NotifyCourseChange ();

}

} // namespace ns3