#pragma once

#ifndef TCG_NUMERIC_OPS_H

#define TCG_NUMERIC_OPS_H

// tcg includes

#include "traits.h"

#include "macros.h"

// STD includes

#include <cmath></cmath>

#include <limits></limits>

/*!

  \file     tcg_numeric_ops.h

  \brief    This file contains small function snippets to manipulate scalars

            or numerical objects.

*/

//***************************************************************************

//    Numerical Operations

//***************************************************************************

namespace tcg {

/*!

  Contains small function snippets to manipulate scalars

  or numerical objects.

*/

namespace numeric_ops {

template <typename scalar=""></typename>

// inline Scalar NaN() {return (std::numeric_limits<scalar>::quiet_NaN)();}</scalar>

inline Scalar NaN() {

  return (std::numeric_limits<scalar>::max)();</scalar>

}

//-------------------------------------------------------------------------------------------

/*!

  Calculates the sign of a scalar.

  \remark  This function returns the \a integral values \p 1 in case the input

  value is

           \a positive, \p -1 in case it's negative, and \p 0 in case it's \a

  exactly \p 0.

  \return  The sign of the input scalar.

*/

template <typename scalar=""></typename>

inline int sign(Scalar val, Scalar tol = 0) {

  return (val > tol) ? 1 : (val < -tol) ? -1 : 0;

}

//-------------------------------------------------------------------------------------------

//! Computes the nearest integer not greater in magnitude than the given value

template <typename scalar=""></typename>

Scalar trunc(Scalar val) {

  return (val < 0) ? std::ceil(val) : std::floor(val);

}

//! Computes the nearest integer \b strictly not greater in magnitude than the

//! given value

template <typename scalar=""></typename>

Scalar truncStrict(Scalar val) {

  return (val < 0) ? std::floor(val + 1) : std::ceil(val - 1);

}

//! Computes the nearest integer not lesser in magnitude than the given value

template <typename scalar=""></typename>

Scalar grow(Scalar val) {

  return (val < 0) ? std::floor(val) : std::ceil(val);

}

//! Computes the nearest integer \b strictly not lesser in magnitude than the

//! given value

template <typename scalar=""></typename>

Scalar growStrict(Scalar val) {

  return (val < 0) ? std::ceil(val - 1) : std::floor(val + 1);

}

//-------------------------------------------------------------------------------------------

template <typename scalar=""></typename>

inline bool areNear(Scalar a, Scalar b, Scalar tolerance) {

  return (std::abs(b - a) < tolerance);

}

//-------------------------------------------------------------------------------------------

template <typename scalar=""></typename>

inline typename std::enable_if::value,

                                Scalar>::type

mod(Scalar val, Scalar mod) {

  Scalar m = val % mod;

  return (m >= 0) ? m : m + mod;

}

template <typename scalar=""></typename>

inline

    typename std::enable_if<tcg::is_floating_point<scalar>::value, Scalar>::type</tcg::is_floating_point<scalar>

    mod(Scalar val, Scalar mod) {

  Scalar m = fmod(val, mod);

  return (m >= 0) ? m : m + mod;

}

//-------------------------------------------------------------------------------------------

template <typename scalar=""></typename>

inline Scalar mod(Scalar val, Scalar a, Scalar b) {

  return a + mod(val - a, b - a);

}

//-------------------------------------------------------------------------------------------

//! Returns the modular shift value with minimal abs:  <tt>mod(val2, m) =</tt>

//! mod(val1 + shift, m)

template <typename scalar=""></typename>

inline Scalar modShift(Scalar val1, Scalar val2, Scalar m) {

  Scalar shift1 = mod(val2 - val1, m), shift2 = m - shift1;

  return (shift2 < shift1) ? -shift2 : shift1;

}

//-------------------------------------------------------------------------------------------

//! Returns the modular shift value with minimal abs:  <tt>mod(val2, a, b) =</tt>

//! mod(val1 + shift, a, b)

template <typename scalar=""></typename>

inline Scalar modShift(Scalar val1, Scalar val2, Scalar a, Scalar b) {

  return modShift(val1 - a, val2 - a, b - a);

}

//-------------------------------------------------------------------------------------------

/*!

  Returns the \a quotient associated to the remainder calculated with mod().

  \return  Integral quotient of the division of \p val by \p d.

*/

template <typename scalar=""></typename>

inline typename std::enable_if::value,

                                Scalar>::type

div(Scalar val, Scalar d) {

  TCG_STATIC_ASSERT(-3 / 5 == 0);

  TCG_STATIC_ASSERT(3 / -5 == 0);

  return (val < 0 || d < 0) ? (val / d) - 1 : val / d;

}

/*!

  Returns the \a quotient associated to the remainder calculated with mod().

  \return  Integral quotient of the division of \p val by \p d.

*/

template <typename scalar=""></typename>

inline

    typename std::enable_if<tcg::is_floating_point<scalar>::value, Scalar>::type</tcg::is_floating_point<scalar>

    div(Scalar val, Scalar d) {

  return std::floor(val / d);

}

//-------------------------------------------------------------------------------------------

/*!

  Returns the \a quotient associated to the remainder calculated with mod().

  \return  Integral quotient of the division of \p val by <tt>(b-a)</tt>.

*/

template <typename scalar=""></typename>

inline Scalar div(Scalar val, Scalar a, Scalar b) {

  return div(val - a, b - a);

}

//-------------------------------------------------------------------------------------------

//! Linear interpolation of values \p v0 and \p v1 with parameter \p t.

template <typename scalar="" t,="" typename=""></typename>

inline T lerp(const T &v0, const T &v1, Scalar t) {

  return (1 - t) * v0 + t * v1;

}

//-------------------------------------------------------------------------------------------

/*!

  \brief Computes the second degree Bezier curve of control points \p c0, \p c1

  and \p c2

         at parameter \p t.

*/

template <typename scalar="" t,="" typename=""></typename>

inline T bezier(const T &c0, const T &c1, const T &c2, Scalar t) {

  Scalar one_t = 1 - t, t_one_t = t * one_t;  // 3  Scalar-Scalar products

  return (one_t * one_t) * c0 + (t_one_t + t_one_t) * c1 +

         (t * t) * c2;  // 3  Scalar-T products

  // return (c0 * one_t + c1 * t) * one_t + (c1 * one_t + c2 * t) * t;

  // // 6 Scalar-T products

}

//-------------------------------------------------------------------------------------------

//! \deprecated

template <typename uscalar=""></typename>

inline UScalar GE_2Power(UScalar val) {

  if (!val) return 0;

  --val;

  UScalar i;

  for (i = 0; val; ++i) val = val >> 1;

  return 1 << i;

}

}

}  // namespace tcg::numeric_ops

#endif  // TCG_NUMERIC_OPS_H