/*
 * Copyright (C) 2012 Open Source Robotics Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
*/
#include <functional>
#include "gazebo/physics/Inertial.hh"

using namespace gazebo;
using namespace physics;


/// \internal
/// \brief Private Inertial data
class gazebo::physics::InertialPrivate
{
  /// \brief Mass of the object in kg. Default is 1.0.
  public: double mass;

  /// \brief Center of gravity in the Link frame.
  /// Default is (0.0 0.0 0.0  0.0 0.0 0.0)
  public: ignition::math::Pose3d cog;

  /// \brief Principal moments of inertia in kg*m^2. Default is (1.0 1.0 1.0).
  /// These Moments of Inertia are specified in the local Inertial frame.
  /// Where principals.X() is Ixx, principals.Y() is Iyy, principals.Z() is Izz.
  public: ignition::math::Vector3d principals;

  /// \brief Product moments of inertia in kg*m^2. Default is (0.0 0.0 0.0).
  /// These MOI off-diagonals are specified in the local Inertial frame.
  /// Where products.X() is Ixy, products.Y() is Ixz and products.Z() is Iyz.
  public: ignition::math::Vector3d products;

  /// \brief Our SDF values.
  public: sdf::ElementPtr sdf;

  /// \brief An SDF pointer that allows us to only read the inertial.sdf
  /// file once, which in turns limits disk reads.
  public: static sdf::ElementPtr sdfInertial;
};

sdf::ElementPtr gazebo::physics::InertialPrivate::sdfInertial;

//////////////////////////////////////////////////
Inertial::Inertial()
  : dataPtr(new InertialPrivate)
{
  this->dataPtr->mass = 1;
  this->dataPtr->principals.Set(1, 1, 1);
  this->dataPtr->products.Set(0, 0, 0);

  if (!this->dataPtr->sdfInertial)
  {
    this->dataPtr->sdfInertial.reset(new sdf::Element);
    initFile("inertial.sdf", this->dataPtr->sdfInertial);
  }

  // This is the only time this->dataPtr->sdfInertial should be used.
  this->dataPtr->sdf = this->dataPtr->sdfInertial->Clone();
}

//////////////////////////////////////////////////
Inertial::Inertial(const double _m)
  : dataPtr(new InertialPrivate)
{
  this->dataPtr->sdf.reset(new sdf::Element);
  initFile("inertial.sdf", this->dataPtr->sdf);

  this->dataPtr->mass = _m;
  this->dataPtr->cog.Set(0, 0, 0, 0, 0, 0);
  this->dataPtr->principals.Set(1, 1, 1);
  this->dataPtr->products.Set(0, 0, 0);
}

//////////////////////////////////////////////////
Inertial::Inertial(const ignition::math::Inertiald &_inertial)
  : dataPtr(new InertialPrivate)
{
  this->dataPtr->sdf.reset(new sdf::Element);
  initFile("inertial.sdf", this->dataPtr->sdf);

  this->SetMass(_inertial.MassMatrix().Mass());
  this->SetCoG(_inertial.Pose());
  this->SetInertiaMatrix(
      _inertial.MassMatrix().Ixx(),
      _inertial.MassMatrix().Iyy(),
      _inertial.MassMatrix().Izz(),
      _inertial.MassMatrix().Ixy(),
      _inertial.MassMatrix().Ixz(),
      _inertial.MassMatrix().Iyz());
}

//////////////////////////////////////////////////
Inertial::Inertial(const Inertial &_inertial)
  : dataPtr(new InertialPrivate)
{
  this->dataPtr->sdf.reset(new sdf::Element);
  initFile("inertial.sdf", this->dataPtr->sdf);

  (*this) = _inertial;
}

//////////////////////////////////////////////////
Inertial::~Inertial()
{
  this->dataPtr->sdf.reset();
}

//////////////////////////////////////////////////
void Inertial::Load(sdf::ElementPtr _sdf)
{
  this->UpdateParameters(_sdf);
}

//////////////////////////////////////////////////
void Inertial::UpdateParameters(sdf::ElementPtr _sdf)
{
  this->dataPtr->sdf = _sdf;

  // use default pose (identity) if not specified in sdf
  ignition::math::Pose3d pose =
    this->dataPtr->sdf->Get<ignition::math::Pose3d>("pose");
  this->SetCoG(pose);
  this->dataPtr->sdf->GetElement("pose")->GetValue()->SetUpdateFunc(
      std::bind(&Inertial::Pose, this));

  // if (this->dataPtr->sdf->HasElement("inertia"))
  // Do the following whether an inertia element was specified or not.
  // Otherwise SetUpdateFunc won't get called.
  {
    sdf::ElementPtr inertiaElem = this->dataPtr->sdf->GetElement("inertia");
    this->SetInertiaMatrix(
        inertiaElem->Get<double>("ixx"),
        inertiaElem->Get<double>("iyy"),
        inertiaElem->Get<double>("izz"),
        inertiaElem->Get<double>("ixy"),
        inertiaElem->Get<double>("ixz"),
        inertiaElem->Get<double>("iyz"));

    inertiaElem->GetElement("ixx")->GetValue()->SetUpdateFunc(
        std::bind(&Inertial::IXX, this));
    inertiaElem->GetElement("iyy")->GetValue()->SetUpdateFunc(
        std::bind(&Inertial::IYY, this));
    inertiaElem->GetElement("izz")->GetValue()->SetUpdateFunc(
        std::bind(&Inertial::IZZ, this));
    inertiaElem->GetElement("ixy")->GetValue()->SetUpdateFunc(
        std::bind(&Inertial::IXY, this));
    inertiaElem->GetElement("ixz")->GetValue()->SetUpdateFunc(
        std::bind(&Inertial::IXZ, this));
    inertiaElem->GetElement("iyz")->GetValue()->SetUpdateFunc(
        std::bind(&Inertial::IYZ, this));
  }

  this->SetMass(this->dataPtr->sdf->Get<double>("mass"));
  this->dataPtr->sdf->GetElement("mass")->GetValue()->SetUpdateFunc(
      std::bind(&Inertial::Mass, this));
}

//////////////////////////////////////////////////
Inertial Inertial::operator()(
    const ignition::math::Pose3d &_frameOffset) const
{
  return Inertial::operator()(_frameOffset.Pos());
}

//////////////////////////////////////////////////
Inertial Inertial::operator()(
    const ignition::math::Vector3d &_frameOffset) const
{
  // make a copy of the current Inertial
  Inertial result(*this);

  // new CoG location after link frame offset
  result.SetCoG(result.CoG() - _frameOffset);

  // new MOI after link frame offset
  result.SetMOI(this->MOI(ignition::math::Pose3d(result.CoG(),
          ignition::math::Quaterniond::Identity)));

  return result;
}

//////////////////////////////////////////////////
void Inertial::Reset()
{
  sdf::ElementPtr inertiaElem = this->dataPtr->sdf->GetElement("inertia");

  this->dataPtr->mass = this->dataPtr->sdf->Get<double>("mass");
  this->dataPtr->cog.Set(0, 0, 0, 0, 0, 0);
  this->SetInertiaMatrix(
        inertiaElem->Get<double>("ixx"),
        inertiaElem->Get<double>("iyy"),
        inertiaElem->Get<double>("izz"),

        inertiaElem->Get<double>("ixy"),
        inertiaElem->Get<double>("ixz"),
        inertiaElem->Get<double>("iyz"));
}

//////////////////////////////////////////////////
void Inertial::SetMass(const double _m)
{
  this->dataPtr->mass = _m;
}

//////////////////////////////////////////////////
double Inertial::Mass() const
{
  return this->dataPtr->mass;
}

//////////////////////////////////////////////////
void Inertial::SetCoG(const double _cx, const double _cy, const double _cz)
{
  this->dataPtr->cog.Pos().Set(_cx, _cy, _cz);
}

//////////////////////////////////////////////////
void Inertial::SetCoG(const ignition::math::Vector3d &_c)

{
  this->dataPtr->cog.Pos() = _c;
}

//////////////////////////////////////////////////
void Inertial::SetCoG(const double _cx, const double _cy, const double _cz,
                      const double _rx, const double _ry, const double _rz)
{
  this->dataPtr->cog.Set(_cx, _cy, _cz, _rx, _ry, _rz);
}

//////////////////////////////////////////////////
void Inertial::SetCoG(const ignition::math::Pose3d &_c)
{
  this->dataPtr->cog = _c;
}

//////////////////////////////////////////////////
void Inertial::SetInertiaMatrix(
    const double ixx, const double iyy, const double izz,
    const double ixy, const double ixz, const double iyz)
{
  this->dataPtr->principals.Set(ixx, iyy, izz);
  this->dataPtr->products.Set(ixy, ixz, iyz);
}

//////////////////////////////////////////////////
const ignition::math::Vector3d &Inertial::PrincipalMoments() const
{
  return this->dataPtr->principals;
}

//////////////////////////////////////////////////
const ignition::math::Vector3d &Inertial::ProductsOfInertia() const
{
  return this->dataPtr->products;
}

//////////////////////////////////////////////////
void Inertial::SetMOI(const ignition::math::Matrix3d &_moi)
{
  /// \TODO: check symmetry of incoming _moi matrix
  this->dataPtr->principals.Set(_moi(0, 0), _moi(1, 1), _moi(2, 2));
  this->dataPtr->products.Set(_moi(0, 1), _moi(0, 2), _moi(1, 2));
}

//////////////////////////////////////////////////
ignition::math::Matrix3d Inertial::MOI() const
{
  return ignition::math::Matrix3d(
      this->dataPtr->principals.X(), this->dataPtr->products.X(),
      this->dataPtr->products.Y(),
      this->dataPtr->products.X(), this->dataPtr->principals.Y(),
      this->dataPtr->products.Z(),
      this->dataPtr->products.Y(), this->dataPtr->products.Z(),
      this->dataPtr->principals.Z());
}

//////////////////////////////////////////////////
void Inertial::Rotate(const ignition::math::Quaterniond &_rot)
{
  /// \TODO: double check what this does, if needed
  this->dataPtr->cog.Pos() = _rot.RotateVector(this->dataPtr->cog.Pos());
  this->dataPtr->cog.Rot() = _rot * this->dataPtr->cog.Rot();
}

//////////////////////////////////////////////////
Inertial &Inertial::operator=(const Inertial &_inertial)
{
  this->dataPtr->mass = _inertial.dataPtr->mass;
  this->dataPtr->cog = _inertial.dataPtr->cog;
  this->dataPtr->principals = _inertial.dataPtr->principals;
  this->dataPtr->products = _inertial.dataPtr->products;

  return *this;
}

//////////////////////////////////////////////////
Inertial Inertial::operator+(const Inertial &_inertial) const
{
  Inertial result(*this);

  // update mass with sum
  result.dataPtr->mass = this->dataPtr->mass + _inertial.dataPtr->mass;

  // compute new center of mass
  result.dataPtr->cog.Pos() =
    (this->dataPtr->cog.Pos() * this->dataPtr->mass +
     _inertial.dataPtr->cog.Pos() * _inertial.dataPtr->mass) /
    result.dataPtr->mass;

  // make a decision on the new orientation, set it to identity
  result.dataPtr->cog.Rot() = ignition::math::Quaterniond::Identity;

  // compute equivalent I for (*this) at the new CoG
  ignition::math::Matrix3d Ithis = this->MOI(result.dataPtr->cog);

  // compute equivalent I for _inertial at the new CoG
  ignition::math::Matrix3d Iparam = _inertial.MOI(result.dataPtr->cog);

  // sum up principals and products now they are at the same location
  result.SetMOI(Ithis + Iparam);

  return result;
}

//////////////////////////////////////////////////
ignition::math::Matrix3d Inertial::MOI(
    const ignition::math::Pose3d &_pose) const
{
  // get MOI as a Matrix3
  ignition::math::Matrix3d moi = this->MOI();

  // transform from new _pose to old this->dataPtr->cog,
  // specified in new _pose frame
  ignition::math::Pose3d new2Old = this->dataPtr->cog - _pose;

  // rotate moi into new cog frame
  moi = ignition::math::Matrix3d(new2Old.Rot()) * moi *
        ignition::math::Matrix3d(new2Old.Rot().Inverse());

  // parallel axis theorem to get MOI at the new cog location
  // integrating point mass at some offset
  ignition::math::Vector3d offset = new2Old.Pos();
  moi(0, 0) += (offset.Y() * offset.Y() + offset.Z() * offset.Z()) *
    this->dataPtr->mass;
  moi(0, 1) -= (offset.X() * offset.Y()) * this->dataPtr->mass;
  moi(0, 2) -= (offset.X() * offset.Z()) * this->dataPtr->mass;
  moi(1, 0) -= (offset.Y() * offset.X()) * this->dataPtr->mass;
  moi(1, 1) += (offset.X() * offset.X() + offset.Z() * offset.Z()) *
    this->dataPtr->mass;
  moi(1, 2) -= (offset.Y() * offset.Z()) * this->dataPtr->mass;
  moi(2, 0) -= (offset.Z() * offset.X()) * this->dataPtr->mass;
  moi(2, 1) -= (offset.Z() * offset.Y()) * this->dataPtr->mass;
  moi(2, 2) += (offset.X() * offset.X() + offset.Y() * offset.Y()) *
    this->dataPtr->mass;

  return moi;
}

//////////////////////////////////////////////////
const Inertial &Inertial::operator+=(const Inertial &_inertial)
{
  *this = *this + _inertial;
  return *this;
}

//////////////////////////////////////////////////
double Inertial::IXX() const
{
  return this->dataPtr->principals.X();
}

//////////////////////////////////////////////////
double Inertial::IYY() const
{
  return this->dataPtr->principals.Y();
}

//////////////////////////////////////////////////
double Inertial::IZZ() const
{
  return this->dataPtr->principals.Z();
}

//////////////////////////////////////////////////
double Inertial::IXY() const
{
  return this->dataPtr->products.X();
}

//////////////////////////////////////////////////
double Inertial::IXZ() const
{
  return this->dataPtr->products.Y();
}

//////////////////////////////////////////////////
double Inertial::IYZ() const
{
  return this->dataPtr->products.Z();
}

//////////////////////////////////////////////////
void Inertial::SetIXX(const double _v)
{
  this->dataPtr->principals.X(_v);
}

//////////////////////////////////////////////////
void Inertial::SetIYY(const double _v)
{
  this->dataPtr->principals.Y(_v);
}

//////////////////////////////////////////////////
void Inertial::SetIZZ(const double _v)
{
  this->dataPtr->principals.Z(_v);
}

//////////////////////////////////////////////////
void Inertial::SetIXY(const double _v)
{
  this->dataPtr->products.X(_v);
}

//////////////////////////////////////////////////
void Inertial::SetIXZ(const double _v)
{
  this->dataPtr->products.Y(_v);
}

//////////////////////////////////////////////////
void Inertial::SetIYZ(const double _v)
{
  this->dataPtr->products.Z(_v);
}

//////////////////////////////////////////////////
void Inertial::ProcessMsg(const msgs::Inertial &_msg)
{
  if (_msg.has_mass())
    this->SetMass(_msg.mass());
  if (_msg.has_pose())
    this->SetCoG(_msg.pose().position().x(),
                 _msg.pose().position().y(),
                 _msg.pose().position().z());
  if (_msg.has_ixx())
    this->SetIXX(_msg.ixx());
  if (_msg.has_ixy())
    this->SetIXY(_msg.ixy());
  if (_msg.has_ixz())
    this->SetIXZ(_msg.ixz());
  if (_msg.has_iyy())
    this->SetIYY(_msg.iyy());
  if (_msg.has_iyz())
    this->SetIYZ(_msg.iyz());
  if (_msg.has_izz())
    this->SetIZZ(_msg.izz());
}

//////////////////////////////////////////////////
const ignition::math::Vector3d &Inertial::CoG() const
{
  return this->dataPtr->cog.Pos();
}

//////////////////////////////////////////////////
ignition::math::Pose3d Inertial::Pose() const
{
  return ignition::math::Pose3d(this->dataPtr->cog);
}

//////////////////////////////////////////////////
ignition::math::Inertiald Inertial::Ign() const
{
  return ignition::math::Inertiald(
          ignition::math::MassMatrix3d(
            this->Mass(),
            this->PrincipalMoments(),
            this->ProductsOfInertia()),
          this->dataPtr->cog);
}

//////////////////////////////////////////////////
Inertial &Inertial::operator=(const ignition::math::Inertiald &_inertial)
{
  this->dataPtr->mass = _inertial.MassMatrix().Mass();
  this->dataPtr->cog = _inertial.Pose();
  this->dataPtr->principals = _inertial.MassMatrix().DiagonalMoments();
  this->dataPtr->products = _inertial.MassMatrix().OffDiagonalMoments();

  return *this;
}

