//===----------------------------------------------------------------------===//
//
// Part of the CUDA Toolkit, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

#ifndef _CUDA_STD_ARRAY
#define _CUDA_STD_ARRAY

#include <cuda/std/detail/__config>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cuda/std/__algorithm/equal.h>
#include <cuda/std/__algorithm/fill_n.h>
#include <cuda/std/__algorithm/lexicographical_compare.h>
#include <cuda/std/__algorithm/swap_ranges.h>
#include <cuda/std/__concepts/concept_macros.h>
#include <cuda/std/__iterator/reverse_iterator.h>
#include <cuda/std/__tuple_dir/sfinae_helpers.h>
#include <cuda/std/__type_traits/conditional.h>
#include <cuda/std/__type_traits/is_array.h>
#include <cuda/std/__type_traits/is_const.h>
#include <cuda/std/__type_traits/is_constructible.h>
#include <cuda/std/__type_traits/is_move_constructible.h>
#include <cuda/std/__type_traits/is_nothrow_constructible.h>
#include <cuda/std/__type_traits/is_nothrow_move_constructible.h>
#include <cuda/std/__type_traits/is_same.h>
#include <cuda/std/__type_traits/is_swappable.h>
#include <cuda/std/__type_traits/remove_cv.h>
#include <cuda/std/__utility/integer_sequence.h>
#include <cuda/std/__utility/move.h>
#include <cuda/std/__utility/unreachable.h>
#include <cuda/std/cstdint>
#include <cuda/std/detail/libcxx/include/stdexcept>
#include <cuda/std/limits>

// standard-mandated includes
#include <cuda/std/version>

// [iterator.range]
#include <cuda/std/__iterator/access.h>
#include <cuda/std/__iterator/data.h>
#include <cuda/std/__iterator/empty.h>
#include <cuda/std/__iterator/reverse_access.h>
#include <cuda/std/__iterator/size.h>

// [array.syn]
#if _LIBCUDACXX_HAS_SPACESHIP_OPERATOR()
#  include <compare>
#endif // _LIBCUDACXX_HAS_SPACESHIP_OPERATOR()
#include <cuda/std/initializer_list>

// [tuple.helper]
#include <cuda/std/__tuple_dir/tuple_element.h>
#include <cuda/std/__tuple_dir/tuple_size.h>

#include <cuda/std/__cccl/prologue.h>

_LIBCUDACXX_BEGIN_NAMESPACE_STD

template <class _Tp, size_t _Size>
struct _CCCL_TYPE_VISIBILITY_DEFAULT array
{
  // types:
  using __self                 = array;
  using value_type             = _Tp;
  using reference              = value_type&;
  using const_reference        = const value_type&;
  using iterator               = value_type*;
  using const_iterator         = const value_type*;
  using pointer                = value_type*;
  using const_pointer          = const value_type*;
  using size_type              = size_t;
  using difference_type        = ptrdiff_t;
  using reverse_iterator       = _CUDA_VSTD::reverse_iterator<iterator>;
  using const_reverse_iterator = _CUDA_VSTD::reverse_iterator<const_iterator>;

  _Tp __elems_[_Size];

  // No explicit construct/copy/destroy for aggregate type
  _CCCL_API constexpr void fill(const value_type& __u)
  {
    _CUDA_VSTD::fill_n(__elems_, _Size, __u);
  }

  _CCCL_API constexpr void swap(array& __a) noexcept(__is_nothrow_swappable<_Tp>::value)
  {
    _CUDA_VSTD::swap_ranges(__elems_, __elems_ + _Size, __a.data());
  }

  // iterators:
  [[nodiscard]] _CCCL_API constexpr iterator begin() noexcept
  {
    return iterator(__elems_);
  }
  [[nodiscard]] _CCCL_API constexpr const_iterator begin() const noexcept
  {
    return const_iterator(__elems_);
  }
  [[nodiscard]] _CCCL_API constexpr iterator end() noexcept
  {
    return iterator(__elems_ + _Size);
  }
  [[nodiscard]] _CCCL_API constexpr const_iterator end() const noexcept
  {
    return const_iterator(__elems_ + _Size);
  }

  [[nodiscard]] _CCCL_API constexpr reverse_iterator rbegin() noexcept
  {
    return reverse_iterator(end());
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator rbegin() const noexcept
  {
    return const_reverse_iterator(end());
  }
  [[nodiscard]] _CCCL_API constexpr reverse_iterator rend() noexcept
  {
    return reverse_iterator(begin());
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator rend() const noexcept
  {
    return const_reverse_iterator(begin());
  }

  [[nodiscard]] _CCCL_API constexpr const_iterator cbegin() const noexcept
  {
    return begin();
  }
  [[nodiscard]] _CCCL_API constexpr const_iterator cend() const noexcept
  {
    return end();
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator crbegin() const noexcept
  {
    return rbegin();
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator crend() const noexcept
  {
    return rend();
  }

  // capacity:
  [[nodiscard]] _CCCL_API constexpr size_type size() const noexcept
  {
    return _Size;
  }
  [[nodiscard]] _CCCL_API constexpr size_type max_size() const noexcept
  {
    return _Size;
  }
  [[nodiscard]] _CCCL_API constexpr bool empty() const noexcept
  {
    return _Size == 0;
  }

  // element access:
  [[nodiscard]] _CCCL_API constexpr reference operator[](size_type __n) noexcept
  {
    _CCCL_ASSERT(__n < _Size, "out-of-bounds access in std::array<T, N>");
    return __elems_[__n];
  }
  [[nodiscard]] _CCCL_API constexpr const_reference operator[](size_type __n) const noexcept
  {
    _CCCL_ASSERT(__n < _Size, "out-of-bounds access in std::array<T, N>");
    return __elems_[__n];
  }

  [[nodiscard]] _CCCL_API constexpr reference at(size_type __n)
  {
    if (__n >= _Size)
    {
      _CUDA_VSTD::__throw_out_of_range("array::at");
    }
    return __elems_[__n];
  }

  [[nodiscard]] _CCCL_API constexpr const_reference at(size_type __n) const
  {
    if (__n >= _Size)
    {
      _CUDA_VSTD::__throw_out_of_range("array::at");
    }
    return __elems_[__n];
  }

  [[nodiscard]] _CCCL_API constexpr reference front() noexcept
  {
    return (*this)[0];
  }
  [[nodiscard]] _CCCL_API constexpr const_reference front() const noexcept
  {
    return (*this)[0];
  }
  [[nodiscard]] _CCCL_API constexpr reference back() noexcept
  {
    return (*this)[_Size - 1];
  }
  [[nodiscard]] _CCCL_API constexpr const_reference back() const noexcept
  {
    return (*this)[_Size - 1];
  }

  [[nodiscard]] _CCCL_API constexpr value_type* data() noexcept
  {
    return __elems_;
  }
  [[nodiscard]] _CCCL_API constexpr const value_type* data() const noexcept
  {
    return __elems_;
  }
};

_CCCL_DIAG_PUSH
_CCCL_DIAG_SUPPRESS_MSVC(4702) // Unreachable code

template <class _Tp>
struct _CCCL_TYPE_VISIBILITY_DEFAULT array<_Tp, 0>
{
  // types:
  using __self                 = array;
  using value_type             = _Tp;
  using reference              = value_type&;
  using const_reference        = const value_type&;
  using iterator               = value_type*;
  using const_iterator         = const value_type*;
  using pointer                = value_type*;
  using const_pointer          = const value_type*;
  using size_type              = size_t;
  using difference_type        = ptrdiff_t;
  using reverse_iterator       = _CUDA_VSTD::reverse_iterator<iterator>;
  using const_reverse_iterator = _CUDA_VSTD::reverse_iterator<const_iterator>;

  using _CharType = conditional_t<_CCCL_TRAIT(is_const, _Tp), const char, char>;

  struct _ArrayInStructT
  {
    _Tp __data_[1];
  };
  _CCCL_ALIGNAS_TYPE(_ArrayInStructT) _CharType __elems_[sizeof(_ArrayInStructT)];

  [[nodiscard]] _CCCL_API constexpr value_type* data() noexcept
  {
    return nullptr;
  }
  [[nodiscard]] _CCCL_API constexpr const value_type* data() const noexcept
  {
    return nullptr;
  }

  // No explicit construct/copy/destroy for aggregate type
  _CCCL_API constexpr void fill(const value_type&)
  {
    static_assert(!_CCCL_TRAIT(is_const, _Tp), "cannot fill zero-sized array of type 'const T'");
  }

  _CCCL_API constexpr void swap(array&) noexcept
  {
    static_assert(!_CCCL_TRAIT(is_const, _Tp), "cannot swap zero-sized array of type 'const T'");
  }

  // iterators:
  [[nodiscard]] _CCCL_API constexpr iterator begin() noexcept
  {
    return iterator(nullptr);
  }
  [[nodiscard]] _CCCL_API constexpr const_iterator begin() const noexcept
  {
    return const_iterator(nullptr);
  }
  [[nodiscard]] _CCCL_API constexpr iterator end() noexcept
  {
    return iterator(nullptr);
  }
  [[nodiscard]] _CCCL_API constexpr const_iterator end() const noexcept
  {
    return const_iterator(nullptr);
  }

  [[nodiscard]] _CCCL_API constexpr reverse_iterator rbegin() noexcept
  {
    return reverse_iterator(end());
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator rbegin() const noexcept
  {
    return const_reverse_iterator(end());
  }
  [[nodiscard]] _CCCL_API constexpr reverse_iterator rend() noexcept
  {
    return reverse_iterator(begin());
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator rend() const noexcept
  {
    return const_reverse_iterator(begin());
  }

  [[nodiscard]] _CCCL_API constexpr const_iterator cbegin() const noexcept
  {
    return begin();
  }
  [[nodiscard]] _CCCL_API constexpr const_iterator cend() const noexcept
  {
    return end();
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator crbegin() const noexcept
  {
    return rbegin();
  }
  [[nodiscard]] _CCCL_API constexpr const_reverse_iterator crend() const noexcept
  {
    return rend();
  }

  // capacity:
  [[nodiscard]] _CCCL_API constexpr size_type size() const noexcept
  {
    return 0;
  }
  [[nodiscard]] _CCCL_API constexpr size_type max_size() const noexcept
  {
    return 0;
  }
  [[nodiscard]] [[nodiscard]] _CCCL_API constexpr bool empty() const noexcept
  {
    return true;
  }

  // element access:
  [[nodiscard]] _CCCL_API constexpr reference operator[](size_type) noexcept
  {
    _CCCL_ASSERT(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
    _CCCL_UNREACHABLE();
    return *data();
  }

  [[nodiscard]] _CCCL_API constexpr const_reference operator[](size_type) const noexcept
  {
    _CCCL_ASSERT(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
    _CCCL_UNREACHABLE();
    return *data();
  }

  [[nodiscard]] _CCCL_API constexpr reference at(size_type)
  {
    _CUDA_VSTD::__throw_out_of_range("array<T, 0>::at");
    _CCCL_UNREACHABLE();
  }

  [[nodiscard]] _CCCL_API constexpr const_reference at(size_type) const
  {
    _CUDA_VSTD::__throw_out_of_range("array<T, 0>::at");
    _CCCL_UNREACHABLE();
  }

  [[nodiscard]] _CCCL_API constexpr reference front() noexcept
  {
    _CCCL_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
    _CCCL_UNREACHABLE();
    return *data();
  }

  [[nodiscard]] _CCCL_API constexpr const_reference front() const noexcept
  {
    _CCCL_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
    _CCCL_UNREACHABLE();
    return *data();
  }

  [[nodiscard]] _CCCL_API constexpr reference back() noexcept
  {
    _CCCL_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
    _CCCL_UNREACHABLE();
    return *data();
  }

  [[nodiscard]] _CCCL_API constexpr const_reference back() const noexcept
  {
    _CCCL_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
    _CCCL_UNREACHABLE();
    return *data();
  }
};

_CCCL_DIAG_POP

_CCCL_TEMPLATE(class _Tp, class... _Args)
_CCCL_REQUIRES((_CCCL_TRAIT(is_same, _Tp, _Args) && ...))
_CCCL_HOST_DEVICE array(_Tp, _Args...) -> array<_Tp, 1 + sizeof...(_Args)>;

template <class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr bool operator==(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
  return _CUDA_VSTD::equal(__x.begin(), __x.end(), __y.begin());
}

template <class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr bool operator!=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
  return !(__x == __y);
}

template <class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr bool operator<(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
  return _CUDA_VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
}

template <class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr bool operator>(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
  return __y < __x;
}

template <class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr bool operator<=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
  return !(__y < __x);
}

template <class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr bool operator>=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
  return !(__x < __y);
}

_CCCL_TEMPLATE(class _Tp, size_t _Size)
_CCCL_REQUIRES((_Size == 0) || __is_swappable<_Tp>::value)
_CCCL_API constexpr void swap(array<_Tp, _Size>& __x, array<_Tp, _Size>& __y) noexcept(noexcept(__x.swap(__y)))
{
  __x.swap(__y);
}

template <class _Tp, size_t _Size>
struct _CCCL_TYPE_VISIBILITY_DEFAULT tuple_size<array<_Tp, _Size>> : public integral_constant<size_t, _Size>
{};

template <size_t _Ip, class _Tp, size_t _Size>
struct _CCCL_TYPE_VISIBILITY_DEFAULT tuple_element<_Ip, array<_Tp, _Size>>
{
  static_assert(_Ip < _Size, "Index out of bounds in std::tuple_element<> (std::array)");
  using type = _Tp;
};

template <size_t _Ip, class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr _Tp& get(array<_Tp, _Size>& __a) noexcept
{
  static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array)");
  return __a.__elems_[_Ip];
}

template <size_t _Ip, class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr const _Tp& get(const array<_Tp, _Size>& __a) noexcept
{
  static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array)");
  return __a.__elems_[_Ip];
}

template <size_t _Ip, class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr _Tp&& get(array<_Tp, _Size>&& __a) noexcept
{
  static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array &&)");
  return _CUDA_VSTD::move(__a.__elems_[_Ip]);
}

template <size_t _Ip, class _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr const _Tp&& get(const array<_Tp, _Size>&& __a) noexcept
{
  static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array &&)");
  return _CUDA_VSTD::move(__a.__elems_[_Ip]);
}

template <typename _Tp, size_t _Size, size_t... _Index>
[[nodiscard]] _CCCL_API constexpr array<remove_cv_t<_Tp>, _Size>
__to_array_lvalue_impl(_Tp (&__arr)[_Size], index_sequence<_Index...>)
{
  return {{__arr[_Index]...}};
}

template <typename _Tp, size_t _Size, size_t... _Index>
[[nodiscard]] _CCCL_API constexpr array<remove_cv_t<_Tp>, _Size>
__to_array_rvalue_impl(_Tp (&&__arr)[_Size], index_sequence<_Index...>)
{
  return {{_CUDA_VSTD::move(__arr[_Index])...}};
}

template <typename _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr array<remove_cv_t<_Tp>, _Size>
to_array(_Tp (&__arr)[_Size]) noexcept(_CCCL_TRAIT(is_nothrow_constructible, _Tp, _Tp&))
{
  static_assert(!_CCCL_TRAIT(is_array, _Tp), "[array.creation]/1: to_array does not accept multidimensional arrays.");
  static_assert(_CCCL_TRAIT(is_constructible, _Tp, _Tp&),
                "[array.creation]/1: to_array requires copy constructible elements.");
  return _CUDA_VSTD::__to_array_lvalue_impl(__arr, make_index_sequence<_Size>());
}

template <typename _Tp, size_t _Size>
[[nodiscard]] _CCCL_API constexpr array<remove_cv_t<_Tp>, _Size>
to_array(_Tp (&&__arr)[_Size]) noexcept(_CCCL_TRAIT(is_nothrow_move_constructible, _Tp))
{
  static_assert(!_CCCL_TRAIT(is_array, _Tp), "[array.creation]/4: to_array does not accept multidimensional arrays.");
  static_assert(_CCCL_TRAIT(is_move_constructible, _Tp),
                "[array.creation]/4: to_array requires move constructible elements.");
  return _CUDA_VSTD::__to_array_rvalue_impl(_CUDA_VSTD::move(__arr), make_index_sequence<_Size>());
}

_LIBCUDACXX_END_NAMESPACE_STD

#include <cuda/std/__cccl/epilogue.h>

#endif // _CUDA_STD_ARRAY