//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, 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
//
//===----------------------------------------------------------------------===//

// <chrono>
// class year_month_day;

// constexpr operator local_days() const noexcept;
//
// Returns: If ok(), returns a local_days holding a count of days from the
//   local_days epoch to *this (a negative value if *this represents a date
//   prior to the sys_days epoch). Otherwise, if y_.ok() && m_.ok() is true,
//   returns a sys_days which is offset from sys_days{y_/m_/last} by the
//   number of days d_ is offset from sys_days{y_/m_/last}.day(). Otherwise
//   the value returned is unspecified.
//
// Remarks: A local_days in the range [days{-12687428}, days{11248737}] which
//   is converted to a year_month_day shall have the same value when
//   converted back to a sys_days.
//
// [Example:
//   static_assert(year_month_day{local_days{2017y/January/0}}  == 2016y/December/31);
//   static_assert(year_month_day{local_days{2017y/January/31}} == 2017y/January/31);
//   static_assert(year_month_day{local_days{2017y/January/32}} == 2017y/February/1);
// —end example]

#include <cuda/std/cassert>
#include <cuda/std/chrono>
#include <cuda/std/type_traits>

#include "test_macros.h"

TEST_DIAG_SUPPRESS_MSVC(4307) // potential overflow
TEST_DIAG_SUPPRESS_MSVC(4308) // unsigned/signed comparisons

__host__ __device__ void RunTheExample()
{
  using namespace cuda::std::chrono;

  static_assert(year_month_day{local_days{year{2017} / January / 0}} == year{2016} / December / 31, "");
  static_assert(year_month_day{local_days{year{2017} / January / 31}} == year{2017} / January / 31, "");
  static_assert(year_month_day{local_days{year{2017} / January / 32}} == year{2017} / February / 1, "");
}

int main(int, char**)
{
  using year           = cuda::std::chrono::year;
  using month          = cuda::std::chrono::month;
  using day            = cuda::std::chrono::day;
  using local_days     = cuda::std::chrono::local_days;
  using days           = cuda::std::chrono::days;
  using year_month_day = cuda::std::chrono::year_month_day;

  static_assert(noexcept(local_days(cuda::std::declval<year_month_day>())));
  RunTheExample();

  {
    constexpr year_month_day ymd{year{1970}, month{1}, day{1}};
    constexpr local_days sd{ymd};

    static_assert(sd.time_since_epoch() == days{0}, "");
    static_assert(year_month_day{sd} == ymd, ""); // and back
  }

  {
    constexpr year_month_day ymd{year{2000}, month{2}, day{2}};
    constexpr local_days sd{ymd};

    static_assert(sd.time_since_epoch() == days{10957 + 32}, "");
    static_assert(year_month_day{sd} == ymd, ""); // and back
  }

  //  There's one more leap day between 1/1/40 and 1/1/70
  //  when compared to 1/1/70 -> 1/1/2000
  {
    constexpr year_month_day ymd{year{1940}, month{1}, day{2}};
    constexpr local_days sd{ymd};

    static_assert(sd.time_since_epoch() == days{-10957}, "");
    static_assert(year_month_day{sd} == ymd, ""); // and back
  }

  {
    year_month_day ymd{year{1939}, month{11}, day{29}};
    local_days sd{ymd};

    assert(sd.time_since_epoch() == days{-(10957 + 34)});
    assert(year_month_day{sd} == ymd); // and back
  }

  return 0;
}
