/*
 * Copyright (C) 2018 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.
 *
*/
#ifndef GZ_MATH_BOX_HH_
#define GZ_MATH_BOX_HH_

#include <optional>
#include <gz/math/config.hh>
#include <gz/math/MassMatrix3.hh>
#include <gz/math/Material.hh>
#include <gz/math/Plane.hh>
#include <gz/math/Vector3.hh>

#include "gz/math/detail/WellOrderedVector.hh"

#include <set>

namespace gz::math
{
  // Inline bracket to help doxygen filtering.
  inline namespace GZ_MATH_VERSION_NAMESPACE {
  /// \brief This is the type used for deduplicating and returning the set of
  /// intersections.
  template<typename T>
  using IntersectionPoints = std::set<Vector3<T>, WellOrderedVectors<T>>;

  /// \class Box Box.hh gz/math/Box.hh
  /// \brief A representation of a box. All units are in meters.
  ///
  /// The box class supports defining a size and material properties.
  /// See Material for more on material properties.
  ///
  /// By default, a box's size (length, width, and height)  is zero.
  ///
  /// See AxisAlignedBox for an axis aligned box implementation.
  template<typename Precision>
  class Box
  {
    /// \brief Default constructor.
    public: Box() = default;

    /// \brief Construct a box with specified dimensions.
    /// \param[in] _length Length of the box in meters.
    /// \param[in] _width Width of the box in meters.
    /// \param[in] _height Height of the box in meters.
    public: Box(const Precision _length,
                const Precision _width,
                const Precision _height);

    /// \brief Construct a box with specified dimensions and a material.
    /// \param[in] _length Length of the box in meters.
    /// \param[in] _width Width of the box in meters.
    /// \param[in] _height Height of the box.
    /// \param[in] _mat Material property for the box.
    public: Box(const Precision _length, const Precision _width,
                const Precision _height,
                const gz::math::Material &_mat);

    /// \brief Construct a box with specified dimensions, in vector form.
    /// \param[in] _size Size of the box. The vector _size has the following
    /// mapping:
    ///
    /// * _size[0] == length in meters
    /// * _size[1] == width in meters
    /// * _size[2] == height in meters
    public: explicit Box(const Vector3<Precision> &_size);

    /// \brief Construct a box with specified dimensions, in vector form
    /// and a material.
    /// \param[in] _size Size of the box. The vector _size has the following
    /// mapping:
    ///
    /// * _size[0] == length in meters
    /// * _size[1] == width in meters
    /// * _size[2] == height in meters
    /// \param[in] _mat Material property for the box.
    public: Box(const Vector3<Precision> &_size,
                const gz::math::Material &_mat);

    /// \brief Get the size of the box.
    /// \return Size of the box in meters.
    public: math::Vector3<Precision> Size() const;

    /// \brief Set the size of the box.
    /// \param[in] _size Size of the box. The vector _size has the following
    /// mapping:
    ///
    /// * _size[0] == lengt in metersh
    /// * _size[1] == widt in metersh
    /// * _size[2] == heigh in meterst
    public: void SetSize(const math::Vector3<Precision> &_size);

    /// \brief Set the size of the box.
    /// \param[in] _length Length of the box in meters.
    /// \param[in] _width Width of the box in meters.
    /// \param[in] _height Height of the box in meters.
    public: void SetSize(const Precision _length,
                         const Precision _width,
                         const Precision _height);

    /// \brief Equality test operator.
    /// \param[in] _b Box to test.
    /// \return True if equal.
    public: bool operator==(const Box<Precision> &_b) const;

    /// \brief Inequality test operator.
    /// \param[in] _b Box to test.
    /// \return True if not equal.
    public: bool operator!=(const Box<Precision> &_b) const;

    /// \brief Get the material associated with this box.
    /// \return The material assigned to this box.
    public: const gz::math::Material &Material() const;

    /// \brief Set the material associated with this box.
    /// \param[in] _mat The material assigned to this box.
    public: void SetMaterial(const gz::math::Material &_mat);

    /// \brief Get the volume of the box in m^3.
    /// \return Volume of the box in m^3.
    public: Precision Volume() const;

    /// \brief Get the volume of the box below a plane.
    /// \param[in] _plane The plane which cuts the box, expressed in the box's
    /// frame.
    /// \return Volume below the plane in m^3.
    public: Precision VolumeBelow(const Plane<Precision> &_plane) const;

    /// \brief Center of volume below the plane. This is useful when
    /// calculating where buoyancy should be applied, for example.
    /// \param[in] _plane The plane which cuts the box, expressed in the box's
    /// frame.
    /// \return Center of volume, in box's frame.
    public: std::optional<Vector3<Precision>>
      CenterOfVolumeBelow(const Plane<Precision> &_plane) const;

    /// \brief All the vertices which are on or below the plane.
    /// \param[in] _plane The plane which cuts the box, expressed in the box's
    /// frame.
    /// \return Box vertices which are below the plane, expressed in the box's
    /// frame.
    public: IntersectionPoints<Precision>
      VerticesBelow(const Plane<Precision> &_plane) const;

    /// \brief Compute the box's density given a mass value. The
    /// box is assumed to be solid with uniform density. This
    /// function requires the box's size to be set to
    /// values greater than zero. The Material of the box is ignored.
    /// \param[in] _mass Mass of the box, in kg. This value should be
    /// greater than zero.
    /// \return Density of the box in kg/m^3. A negative value is
    /// returned if the size or _mass is <= 0.
    public: Precision DensityFromMass(const Precision _mass) const;

    /// \brief Set the density of this box based on a mass value.
    /// Density is computed using
    /// double DensityFromMass(const double _mass) const. The
    /// box is assumed to be solid with uniform density. This
    /// function requires the box's size to be set to
    /// values greater than zero. The existing Material density value is
    /// overwritten only if the return value from this true.
    /// \param[in] _mass Mass of the box, in kg. This value should be
    /// greater than zero.
    /// \return True if the density was set. False is returned if the
    /// box's size or the _mass value are <= 0.
    /// \sa double DensityFromMass(const double _mass) const
    public: bool SetDensityFromMass(const Precision _mass);

    /// \brief Get the mass matrix for this box. This function
    /// is only meaningful if the box's size and material
    /// have been set.
    /// \param[out] _massMat The computed mass matrix will be stored
    /// here.
    /// \return False if computation of the mass matrix failed, which
    /// could be due to an invalid size (<=0) or density (<=0).
    public: bool MassMatrix(MassMatrix3<Precision> &_massMat) const;

    /// \brief Get the mass matrix for this box. This function
    /// is only meaningful if the box's size and material
    /// have been set.
    /// \return The computed mass matrix if parameters are valid
    /// (radius > 0), (length > 0), and (density > 0). Otherwise
    /// std::nullopt is returned.
    public: std::optional< MassMatrix3<Precision> > MassMatrix() const;

    /// \brief Get intersection between a plane and the box's edges.
    /// Edges contained on the plane are ignored.
    /// \param[in] _plane The plane against which we are testing intersection.
    /// \returns A list of points along the edges of the box where the
    /// intersection occurs.
    public: IntersectionPoints<Precision> Intersections(
      const Plane<Precision> &_plane) const;

    /// \brief Size of the box.
    private: Vector3<Precision> size = Vector3<Precision>::Zero;

    /// \brief The box's material.
    private: gz::math::Material material;
  };

  /// \typedef Box<int> Boxi
  /// \brief Box with integer precision.
  typedef Box<int> Boxi;

  /// \typedef Box<double> Boxd
  /// \brief Box with double precision.
  typedef Box<double> Boxd;

  /// \typedef Box<float> Boxf
  /// \brief Box with float precision.
  typedef Box<float> Boxf;
  }  // namespace GZ_MATH_VERSION_NAMESPACE
}  // namespace gz::math
#include "gz/math/detail/Box.hh"
#endif  // GZ_MATH_BOX_HH_
