// Created by: Kirill GAVRILOV
// Copyright (c) 2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and / or modify it
// under the terms of the GNU Lesser General Public version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _NCollection_Vec3_H__
#define _NCollection_Vec3_H__

#include <cstring>
#include <cmath>
#include <NCollection_Vec2.hxx>

//! Auxiliary macros to define couple of similar access components as vector methods
#define NCOLLECTION_VEC_COMPONENTS_3D(theX, theY, theZ) \
  const NCollection_Vec3<Element_t> theX##theY##theZ() const { return NCollection_Vec3<Element_t>(theX(), theY(), theZ()); } \
  const NCollection_Vec3<Element_t> theX##theZ##theY() const { return NCollection_Vec3<Element_t>(theX(), theZ(), theY()); } \
  const NCollection_Vec3<Element_t> theY##theX##theZ() const { return NCollection_Vec3<Element_t>(theY(), theX(), theZ()); } \
  const NCollection_Vec3<Element_t> theY##theZ##theX() const { return NCollection_Vec3<Element_t>(theY(), theZ(), theX()); } \
  const NCollection_Vec3<Element_t> theZ##theY##theX() const { return NCollection_Vec3<Element_t>(theZ(), theY(), theX()); } \
  const NCollection_Vec3<Element_t> theZ##theX##theY() const { return NCollection_Vec3<Element_t>(theZ(), theX(), theY()); }

//! Generic 3-components vector.
//! To be used as RGB color pixel or XYZ 3D-point.
//! The main target for this class - to handle raw low-level arrays (from/to graphic driver etc.).
template<typename Element_t>
class NCollection_Vec3
{

public:

  //! Returns the number of components.
  static int Length()
  {
    return 3;
  }

  //! Empty constructor. Construct the zero vector.
  NCollection_Vec3()
  {
    std::memset (this, 0, sizeof(NCollection_Vec3));
  }

  //! Initialize ALL components of vector within specified value.
  explicit NCollection_Vec3 (Element_t theValue)
  {
    v[0] = v[1] = v[2] = theValue;
  }

  //! Per-component constructor.
  explicit NCollection_Vec3 (const Element_t theX,
                             const Element_t theY,
                             const Element_t theZ)
  {
    v[0] = theX;
    v[1] = theY;
    v[2] = theZ;
  }

  //! Constructor from 2-components vector.
  explicit NCollection_Vec3 (const NCollection_Vec2<Element_t>& theVec2)
  {
    v[0] = theVec2[0];
    v[1] = theVec2[1];
    v[2] = Element_t(0);
  }

  //! Copy constructor.
  NCollection_Vec3 (const NCollection_Vec3& theVec3)
  {
    std::memcpy (this, &theVec3, sizeof(NCollection_Vec3));
  }

  //! Assignment operator.
  const NCollection_Vec3& operator= (const NCollection_Vec3& theVec3)
  {
    std::memcpy (this, &theVec3, sizeof(NCollection_Vec3));
    return *this;
  }

  //! Alias to 1st component as X coordinate in XYZ.
  Element_t x() const { return v[0]; }

  //! Alias to 1st component as RED channel in RGB.
  Element_t r() const { return v[0]; }

  //! Alias to 2nd component as Y coordinate in XYZ.
  Element_t y() const { return v[1]; }

  //! Alias to 2nd component as GREEN channel in RGB.
  Element_t g() const { return v[1]; }

  //! Alias to 3rd component as Z coordinate in XYZ.
  Element_t z() const { return v[2]; }

  //! Alias to 3rd component as BLUE channel in RGB.
  Element_t b() const { return v[2]; }

  //! @return 2 components by their names in specified order (in GLSL-style)
  NCOLLECTION_VEC_COMPONENTS_2D(x, y)
  NCOLLECTION_VEC_COMPONENTS_2D(x, z)
  NCOLLECTION_VEC_COMPONENTS_2D(y, z)

  //! @return 3 components by their names in specified order (in GLSL-style)
  NCOLLECTION_VEC_COMPONENTS_3D(x, y, z)

  //! Alias to 1st component as X coordinate in XYZ.
  Element_t& x() { return v[0]; }

  //! Alias to 1st component as RED channel in RGB.
  Element_t& r() { return v[0]; }

  //! Alias to 2nd component as Y coordinate in XYZ.
  Element_t& y() { return v[1]; }

  //! Alias to 2nd component as GREEN channel in RGB.
  Element_t& g() { return v[1]; }

  //! Alias to 3rd component as Z coordinate in XYZ.
  Element_t& z() { return v[2]; }

  //! Alias to 3rd component as BLUE channel in RGB.
  Element_t& b() { return v[2]; }

  //! @return XY-components modifiable vector
  NCollection_Vec2<Element_t>& xy()
  {
    return *((NCollection_Vec2<Element_t>* )&v[0]);
  }

  //! @return YZ-components modifiable vector
  NCollection_Vec2<Element_t>& yz()
  {
    return *((NCollection_Vec2<Element_t>* )&v[1]);
  }

  //! Raw access to the data (for OpenGL exchange).
  const Element_t* GetData()    const { return v; }
        Element_t* ChangeData()       { return v; }
  operator const   Element_t*() const { return v; }
  operator         Element_t*()       { return v; }

  //! Compute per-component summary.
  NCollection_Vec3& operator+= (const NCollection_Vec3& theAdd)
  {
    v[0] += theAdd.v[0];
    v[1] += theAdd.v[1];
    v[2] += theAdd.v[2];
    return *this;
  }

  //! Compute per-component summary.
  friend NCollection_Vec3 operator+ (const NCollection_Vec3& theLeft,
                                     const NCollection_Vec3& theRight)
  {
    NCollection_Vec3 aSumm = NCollection_Vec3 (theLeft);
    return aSumm += theRight;
  }

  //! Unary -.
  NCollection_Vec3 operator-() const
  {
    return NCollection_Vec3 (-x(), -y(), -z());
  }

  //! Compute per-component subtraction.
  NCollection_Vec3& operator-= (const NCollection_Vec3& theDec)
  {
    v[0] -= theDec.v[0];
    v[1] -= theDec.v[1];
    v[2] -= theDec.v[2];
    return *this;
  }

  //! Compute per-component subtraction.
  friend NCollection_Vec3 operator- (const NCollection_Vec3& theLeft,
                                     const NCollection_Vec3& theRight)
  {
    NCollection_Vec3 aSumm = NCollection_Vec3 (theLeft);
    return aSumm -= theRight;
  }

  //! Compute per-component multiplication by scale factor.
  void Multiply (const Element_t theFactor)
  {
    v[0] *= theFactor;
    v[1] *= theFactor;
    v[2] *= theFactor;
  }

  //! Compute per-component multiplication.
  NCollection_Vec3& operator*= (const NCollection_Vec3& theRight)
  {
    v[0] *= theRight.v[0];
    v[1] *= theRight.v[1];
    v[2] *= theRight.v[2];
    return *this;
  }

  //! Compute per-component multiplication.
  friend NCollection_Vec3 operator* (const NCollection_Vec3& theLeft,
                                     const NCollection_Vec3& theRight)
  {
    NCollection_Vec3 aResult = NCollection_Vec3 (theLeft);
    return aResult *= theRight;
  }

  //! Compute per-component multiplication by scale factor.
  NCollection_Vec3& operator*= (const Element_t theFactor)
  {
    Multiply (theFactor);
    return *this;
  }

  //! Compute per-component multiplication by scale factor.
  NCollection_Vec3 operator* (const Element_t theFactor) const
  {
    return Multiplied (theFactor);
  }

  //! Compute per-component multiplication by scale factor.
  NCollection_Vec3 Multiplied (const Element_t theFactor) const
  {
    NCollection_Vec3 aCopyVec3 (*this);
    aCopyVec3 *= theFactor;
    return aCopyVec3;
  }

  //! Compute per-component division by scale factor.
  NCollection_Vec3& operator/= (const Element_t theInvFactor)
  {
    v[0] /= theInvFactor;
    v[1] /= theInvFactor;
    v[2] /= theInvFactor;
    return *this;
  }

  //! Compute per-component division by scale factor.
  NCollection_Vec3 operator/ (const Element_t theInvFactor)
  {
    NCollection_Vec3 aResult (this);
    return aResult /= theInvFactor;
  }

  //! Computes the dot product.
  Element_t Dot (const NCollection_Vec3& theOther) const
  {
    return x() * theOther.x() + y() * theOther.y() + z() * theOther.z();
  }

  //! Computes the vector modulus (magnitude, length).
  Element_t Modulus() const
  {
    return std::sqrt (x() * x() + y() * y() + z() * z());
  }

  //! Computes the square of vector modulus (magnitude, length).
  //! This method may be used for performance tricks.
  Element_t SquareModulus() const
  {
    return x() * x() + y() * y() + z() * z();
  }

  //! Normalize the vector.
  void Normalize()
  {
    Element_t aModulus = Modulus();
    if (aModulus != Element_t(0)) // just avoid divide by zero
    {
      x() = x() / aModulus;
      y() = y() / aModulus;
      z() = z() / aModulus;
    }
  }

  //! Normalize the vector.
  NCollection_Vec3 Normalized() const
  {
    NCollection_Vec3 aCopy (*this);
    aCopy.Normalize();
    return aCopy;
  }

  //! Computes the cross product.
  static NCollection_Vec3 Cross (const NCollection_Vec3& theVec1,
                                 const NCollection_Vec3& theVec2)
  {
    return NCollection_Vec3(theVec1.y() * theVec2.z() - theVec1.z() * theVec2.y(),
            theVec1.z() * theVec2.x() - theVec1.x() * theVec2.z(),
            theVec1.x() * theVec2.y() - theVec1.y() * theVec2.x());
  }

  //! Compute linear interpolation between to vectors.
  //! @param theT - interpolation coefficient 0..1;
  //! @return interpolation result.
  static NCollection_Vec3 GetLERP (const NCollection_Vec3& theFrom,
                                   const NCollection_Vec3& theTo,
                                   const Element_t         theT)
  {
    return theFrom * (Element_t(1) - theT) + theTo * theT;
  }

  //! Constuct DX unit vector.
  static NCollection_Vec3 DX()
  {
    return NCollection_Vec3 (Element_t(1), Element_t(0), Element_t(0));
  }

  //! Constuct DY unit vector.
  static NCollection_Vec3 DY()
  {
    return NCollection_Vec3 (Element_t(0), Element_t(1), Element_t(0));
  }

  //! Constuct DZ unit vector.
  static NCollection_Vec3 DZ()
  {
    return NCollection_Vec3 (Element_t(0), Element_t(0), Element_t(1));
  }

private:

  Element_t v[3]; //!< define the vector as array to avoid structure alignment issues

};

//! Optimized concretization for float type.
template<> inline NCollection_Vec3<float>& NCollection_Vec3<float>::operator/= (const float theInvFactor)
{
  Multiply (1.0f / theInvFactor);
  return *this;
}

//! Optimized concretization for double type.
template<> inline NCollection_Vec3<double>& NCollection_Vec3<double>::operator/= (const double theInvFactor)
{
  Multiply (1.0 / theInvFactor);
  return *this;
}

#endif // _NCollection_Vec3_H__