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

/*

 * Copyright (c) 2006,2007 INRIA

 * All rights reserved.

 *

 * 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 "random-walk-2d-mobility-model.h"

#include "ns3/default-value.h"

#include "ns3/time-default-value.h"

#include "ns3/rectangle-default-value.h"

#include "ns3/random-variable-default-value.h"

#include "ns3/simulator.h"

#include "ns3/debug.h"

#include <cmath>

NS_DEBUG_COMPONENT_DEFINE ("RandomWalk2d");

namespace ns3 {

const ClassId RandomWalk2dMobilityModel::cid = 

  MakeClassId<RandomWalk2dMobilityModel> ("RandomWalk2dMobilityModel", RandomWalk2dMobilityModel::iid);

static EnumDefaultValue<RandomWalk2dMobilityModelParameters::Mode> 

g_mode ("RandomWalk2dMode",

        "The mode indicates the condition used to "

        "change the current speed and direction",

        RandomWalk2dMobilityModelParameters::MODE_DISTANCE, "Distance",

        RandomWalk2dMobilityModelParameters::MODE_TIME, "Time",

        0, 0);

static IntegerDefaultValue<double>

g_modeDistance ("RandomWalk2dDistance",

                "Change current direction and speed after moving this distance.",

                2.0);

static TimeDefaultValue

g_modeTime ("RandomWalk2dTime",

             "Change current direction and speed after moving for this delay.",

             Seconds (1.0));

static RandomVariableDefaultValue

g_speed ("RandomWalk2dSpeed",

         "A random variable used to pick the speed.",

         "Uniform:2:4");

static RandomVariableDefaultValue

g_direction ("RandomWalk2dDirection",

             "A random variable used to pick the direction (gradients).",

             "Uniform:0.0:6.283184");

static RectangleDefaultValue

g_rectangle ("RandomWalk2dBounds",

             "Bounds of the area to cruise.",

             0.0, 0.0, 100.0, 100.0);

RandomWalk2dMobilityModelParameters::RandomWalk2dMobilityModelParameters ()

  : m_mode (g_mode.GetValue ()),

    m_modeDistance (g_modeDistance.GetValue ()),

    m_modeTime (g_modeTime.GetValue ()),

    m_speed (g_speed.GetCopy ()),

    m_direction (g_direction.GetCopy ()),

    m_bounds (g_rectangle.GetValue ())

{}

RandomWalk2dMobilityModelParameters::~RandomWalk2dMobilityModelParameters ()

{

  delete m_speed;

  delete m_direction;

  m_speed = 0;

  m_direction = 0;

}

Ptr<RandomWalk2dMobilityModelParameters> 

RandomWalk2dMobilityModelParameters::GetCurrent (void)

{

  static Ptr<RandomWalk2dMobilityModelParameters> parameters = 0;

  if (parameters == 0 ||

      g_speed.IsDirty () ||

      g_direction.IsDirty () ||

      g_mode.IsDirty () ||

      g_modeDistance.IsDirty () ||

      g_modeTime.IsDirty () ||

      g_rectangle.IsDirty ())

    {

      parameters = Create<RandomWalk2dMobilityModelParameters> ();

    }

  return parameters;

}

RandomWalk2dMobilityModel::RandomWalk2dMobilityModel ()

  : m_parameters (RandomWalk2dMobilityModelParameters::GetCurrent ())

{

  SetInterfaceId (RandomWalk2dMobilityModel::iid);

  m_event = Simulator::ScheduleNow (&RandomWalk2dMobilityModel::Start, this);

}

void

RandomWalk2dMobilityModel::Start (void)

{

  double speed = m_parameters->m_speed->GetValue ();

  double direction = m_parameters->m_direction->GetValue ();

  Speed vector (std::cos (direction) * speed,

                std::sin (direction) * speed,

                0.0);

  m_helper.Reset (vector);

  Time delayLeft;

  if (m_parameters->m_mode == RandomWalk2dMobilityModelParameters::MODE_TIME)

    {

      delayLeft = m_parameters->m_modeTime;

    }

  else

    {

      delayLeft = Seconds (m_parameters->m_modeDistance / speed); 

    }

  DoWalk (delayLeft);

}

void

RandomWalk2dMobilityModel::DoWalk (Time delayLeft)

{

  Position position = m_helper.GetCurrentPosition ();

  Speed speed = m_helper.GetSpeed ();

  Position nextPosition = position;

  nextPosition.x += speed.dx * delayLeft.GetSeconds ();

  nextPosition.y += speed.dy * delayLeft.GetSeconds ();

  if (m_parameters->m_bounds.IsInside (nextPosition))

    {

      m_event = Simulator::Schedule (delayLeft, &RandomWalk2dMobilityModel::Start, this);

    }

  else

    {

      nextPosition = m_parameters->m_bounds.CalculateIntersection (position, speed);

      Time delay = Seconds ((nextPosition.x - position.x) / speed.dx);

      m_event = Simulator::Schedule (delay, &RandomWalk2dMobilityModel::Rebound, this,

                                     delayLeft - delay);      

    }  

  NotifyCourseChange ();

}

void

RandomWalk2dMobilityModel::Rebound (Time delayLeft)

{

  Position position = m_helper.GetCurrentPosition (m_parameters->m_bounds);

  Speed speed = m_helper.GetSpeed ();

  switch (m_parameters->m_bounds.GetClosestSide (position))

    {

    case Rectangle::RIGHT:

    case Rectangle::LEFT:

      speed.dx = - speed.dx;

      break;

    case Rectangle::TOP:

    case Rectangle::BOTTOM:

      speed.dy = - speed.dy;

      break;

    }

  m_helper.Reset (speed);

  DoWalk (delayLeft);

}

void

RandomWalk2dMobilityModel::DoDispose (void)

{

  m_parameters = 0;

  // chain up

  MobilityModel::DoDispose ();

}

Position

RandomWalk2dMobilityModel::DoGet (void) const

{

  return m_helper.GetCurrentPosition (m_parameters->m_bounds);

}

void

RandomWalk2dMobilityModel::DoSet (const Position &position)

{

  NS_ASSERT (m_parameters->m_bounds.IsInside (position));

  m_helper.InitializePosition (position);

  Simulator::Remove (m_event);

  m_event = Simulator::ScheduleNow (&RandomWalk2dMobilityModel::Start, this);

}

} // namespace ns3