// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// 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.
// ------------------------------------------------------------------------

//! \addtogroup fill
//! @{

namespace fill {
struct fill_none {};
struct fill_zeros {};
struct fill_ones {};
struct fill_eye {};
struct fill_randu {};
struct fill_randn {};

template <typename fill_type>
struct fill_class {
  inline constexpr fill_class() {}
};

static constexpr fill_class<fill_none> none;
static constexpr fill_class<fill_zeros> zeros;
static constexpr fill_class<fill_ones> ones;
static constexpr fill_class<fill_eye> eye;
static constexpr fill_class<fill_randu> randu;
static constexpr fill_class<fill_randn> randn;

//

template <typename from_type, typename to_type>
struct allow_conversion {
  static constexpr bool value = true;
};

template <>
struct allow_conversion<std::complex<double>, double> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, float> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, u64> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, s64> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, u32> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, s32> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, u16> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, s16> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, u8> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<double>, s8> {
  static constexpr bool value = false;
};

template <>
struct allow_conversion<std::complex<float>, double> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, float> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, u64> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, s64> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, u32> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, s32> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, u16> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, s16> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, u8> {
  static constexpr bool value = false;
};
template <>
struct allow_conversion<std::complex<float>, s8> {
  static constexpr bool value = false;
};

//

template <typename eT>
inline bool isfinite_wrapper(eT) {
  return true;
}
template <>
inline bool isfinite_wrapper(float x) {
  return std::isfinite(x);
}
template <>
inline bool isfinite_wrapper(double x) {
  return std::isfinite(x);
}
template <typename T>
inline bool isfinite_wrapper(std::complex<T>& x) {
  return std::isfinite(x.real()) && std::isfinite(x.imag());
}

//

template <typename scalar_type1>
struct scalar_holder {
  const scalar_type1 scalar;

  inline explicit scalar_holder(const scalar_type1& in_scalar) : scalar(in_scalar) {}

  inline scalar_holder() = delete;

  template <typename scalar_type2,
            typename arma::enable_if2<allow_conversion<scalar_type1, scalar_type2>::value,
                                      int>::result = 0>
  inline operator scalar_holder<scalar_type2>() const {
    const bool ok_conversion = (std::is_integral<scalar_type2>::value &&
                                std::is_floating_point<scalar_type1>::value)
                                   ? isfinite_wrapper(scalar)
                                   : true;

    return scalar_holder<scalar_type2>(ok_conversion ? scalar_type2(scalar)
                                                     : scalar_type2(0));
  }
};

//

template <typename scalar_type>
inline typename enable_if2<is_supported_elem_type<scalar_type>::value,
                           scalar_holder<scalar_type> >::result
value(const scalar_type& in_scalar) {
  return scalar_holder<scalar_type>(in_scalar);
}
}  // namespace fill

//! @}
