/*
 *  Copyright 2008-2013 NVIDIA Corporation
 *  Modifications Copyright© 2019-2025 Advanced Micro Devices, Inc. All rights reserved.
 *
 *  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.
 */

#include <thrust/detail/config.h>

#include <thrust/detail/type_traits.h>

THRUST_SUPPRESS_DEPRECATED_PUSH

#if THRUST_CPP_DIALECT >= 2017

#  include <async/exclusive_scan/mixin.h>
#  include <async/test_policy_overloads.h>

// Verify what happens when calling the algorithm without any namespace
// qualifiers:
// - If the async entry point is available in the global namespace due to a
//   using statement, the async algorithm should be called.
// - Otherwise, ADL should resolve the call to the synchronous algo in the
//   thrust:: namespace.

namespace invoke_reference
{

template <typename input_value_type, typename output_value_type = input_value_type>
struct adl_host_synchronous
{
  template <typename InputType, typename OutputType, typename PostfixArgTuple, std::size_t... PostfixArgIndices>
  static void invoke_reference(
    InputType const& input,
    OutputType& output,
    PostfixArgTuple&& postfix_tuple,
    std::index_sequence<PostfixArgIndices...>)
  {
    // Create host versions of the input/output:
    thrust::host_vector<input_value_type> host_input(input.cbegin(), input.cend());
    thrust::host_vector<output_value_type> host_output(host_input.size());

    using OutIter = ::internal::remove_cvref_t<decltype(host_output.begin())>;

    // ADL should resolve this to the synchronous `thrust::` algorithm.
    // This is checked by ensuring that the call returns an output iterator.
    OutIter result = exclusive_scan(
      host_input.cbegin(),
      host_input.cend(),
      host_output.begin(),
      std::get<PostfixArgIndices>(THRUST_FWD(postfix_tuple))...);
    (void) result;

    // Copy back to device.
    output = host_output;
  }
};

} // namespace invoke_reference

namespace invoke_async
{

struct using_namespace
{
  template <typename PrefixArgTuple,
            std::size_t... PrefixArgIndices,
            typename InputType,
            typename OutputType,
            typename PostfixArgTuple,
            std::size_t... PostfixArgIndices>
  static auto invoke_async(
    PrefixArgTuple&& prefix_tuple,
    std::index_sequence<PrefixArgIndices...>,
    InputType const& input,
    OutputType& output,
    PostfixArgTuple&& postfix_tuple,
    std::index_sequence<PostfixArgIndices...>)
  {
    // Importing the CPO into the current namespace should unambiguously resolve
    // this call to the CPO, as opposed to resolving to the thrust:: algorithm
    // via ADL. This is verified by checking that an event is returned.
    THRUST_SUPPRESS_DEPRECATED_PUSH
    using namespace thrust::async;
    thrust::device_event e = exclusive_scan(
      std::get<PrefixArgIndices>(THRUST_FWD(prefix_tuple))...,
      input.cbegin(),
      input.cend(),
      output.begin(),
      std::get<PostfixArgIndices>(THRUST_FWD(postfix_tuple))...);
    THRUST_SUPPRESS_DEPRECATED_POP
    return e;
  }
};

struct using_cpo
{
  template <typename PrefixArgTuple,
            std::size_t... PrefixArgIndices,
            typename InputType,
            typename OutputType,
            typename PostfixArgTuple,
            std::size_t... PostfixArgIndices>
  static auto invoke_async(
    PrefixArgTuple&& prefix_tuple,
    std::index_sequence<PrefixArgIndices...>,
    InputType const& input,
    OutputType& output,
    PostfixArgTuple&& postfix_tuple,
    std::index_sequence<PostfixArgIndices...>)
  {
    // Importing the CPO into the current namespace should unambiguously resolve
    // this call to the CPO, as opposed to resolving to the thrust:: algorithm
    // via ADL. This is verified by checking that an event is returned.
    using thrust::async::exclusive_scan;
    THRUST_SUPPRESS_DEPRECATED_PUSH
    thrust::device_event e = exclusive_scan(
      std::get<PrefixArgIndices>(THRUST_FWD(prefix_tuple))...,
      input.cbegin(),
      input.cend(),
      output.begin(),
      std::get<PostfixArgIndices>(THRUST_FWD(postfix_tuple))...);
    THRUST_SUPPRESS_DEPRECATED_POP
    return e;
  }
};

} // namespace invoke_async

template <typename input_value_type,
          typename output_value_type   = input_value_type,
          typename initial_value_type  = input_value_type,
          typename alternate_binary_op = thrust::maximum<>>
struct using_namespace_invoker
    : testing::async::mixin::input::device_vector<input_value_type>
    , testing::async::mixin::output::device_vector<output_value_type>
    , testing::async::exclusive_scan::mixin::postfix_args::all_overloads<initial_value_type, alternate_binary_op>
    , invoke_reference::adl_host_synchronous<input_value_type, output_value_type>
    , invoke_async::using_namespace
    , testing::async::mixin::compare_outputs::assert_almost_equal_if_fp_quiet
{
  static std::string description()
  {
    return "importing async CPO with `using namespace thrust::async`";
  }
};

void test_using_namespace()
{
  using invoker = using_namespace_invoker<int>;
  testing::async::test_policy_overloads<invoker>::run(128);
}
DECLARE_UNITTEST(test_using_namespace);

template <typename input_value_type,
          typename output_value_type   = input_value_type,
          typename initial_value_type  = input_value_type,
          typename alternate_binary_op = thrust::maximum<>>
struct using_cpo_invoker
    : testing::async::mixin::input::device_vector<input_value_type>
    , testing::async::mixin::output::device_vector<output_value_type>
    , testing::async::exclusive_scan::mixin::postfix_args::all_overloads<initial_value_type, alternate_binary_op>
    , invoke_reference::adl_host_synchronous<input_value_type, output_value_type>
    , invoke_async::using_cpo
    , testing::async::mixin::compare_outputs::assert_almost_equal_if_fp_quiet
{
  static std::string description()
  {
    return "importing async CPO with "
           "`using namespace thrust::async::exclusive_scan`";
  }
};

void test_using_cpo()
{
  using invoker = using_cpo_invoker<int>;
  testing::async::test_policy_overloads<invoker>::run(128);
}
DECLARE_UNITTEST(test_using_cpo);

#endif // C++17

// we need to leak the suppression on clang/MSVC to suppresses warnings from the cudafe1.stub.c file
#if THRUST_HOST_COMPILER != THRUST_HOST_COMPILER_CLANG && THRUST_HOST_COMPILER != THRUST_HOST_COMPILER_MSVC
THRUST_SUPPRESS_DEPRECATED_POP
#endif // THRUST_HOST_COMPILER != THRUST_HOST_COMPILER_CLANG && THRUST_HOST_COMPILER != THRUST_HOST_COMPILER_MSVC
