/*
 *  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/device_vector.h>
#include <thrust/extrema.h>
#include <thrust/functional.h>
#include <thrust/host_vector.h>
#include <thrust/iterator/discard_iterator.h>
#include <thrust/iterator/retag.h>
#include <thrust/merge.h>
#include <thrust/sort.h>
#include <thrust/unique.h>

#include "test_param_fixtures.hpp"
#include "test_utils.hpp"

TESTS_DEFINE(MergeTests, FullTestsParams);
TESTS_DEFINE(PrimitiveMergeTests, NumericalTestsParams);

TEST(MergeTests, UsingHip)
{
  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  ASSERT_EQ(THRUST_DEVICE_SYSTEM, THRUST_DEVICE_SYSTEM_HIP);
}

TYPED_TEST(MergeTests, MergeSimple)
{
  using Vector = typename TestFixture::input_type;
  using Policy = typename TestFixture::execution_policy;

  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  const Vector a{0, 2, 4}, b{0, 3, 3, 4};
  const Vector ref{0, 0, 2, 3, 3, 4, 4};

  Vector result(7);

  const auto end = thrust::merge(Policy{}, a.begin(), a.end(), b.begin(), b.end(), result.begin());

  EXPECT_EQ(result.end(), end);
  ASSERT_EQ(ref, result);
}

template <typename InputIterator1, typename InputIterator2, typename OutputIterator>
OutputIterator
merge(my_system& system, InputIterator1, InputIterator1, InputIterator2, InputIterator2, OutputIterator result)
{
  system.validate_dispatch();
  return result;
}

TEST(MergeTests, MergeDispatchExplicit)
{
  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  thrust::device_vector<int> vec(1);

  my_system sys(0);
  thrust::merge(sys, vec.begin(), vec.begin(), vec.begin(), vec.begin(), vec.begin());

  ASSERT_EQ(true, sys.is_valid());
}

template <typename InputIterator1, typename InputIterator2, typename OutputIterator>
OutputIterator merge(my_tag, InputIterator1, InputIterator1, InputIterator2, InputIterator2, OutputIterator result)
{
  *result = 13;
  return result;
}

TEST(MergeTests, MergeDispatchImplicit)
{
  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  thrust::device_vector<int> vec(1);

  thrust::merge(thrust::retag<my_tag>(vec.begin()),
                thrust::retag<my_tag>(vec.begin()),
                thrust::retag<my_tag>(vec.begin()),
                thrust::retag<my_tag>(vec.begin()),
                thrust::retag<my_tag>(vec.begin()));

  ASSERT_EQ(13, vec.front());
}

TYPED_TEST(PrimitiveMergeTests, MergeWithRandomData)
{
  using T = typename TestFixture::input_type;

  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  for (auto size : get_sizes())
  {
    SCOPED_TRACE(testing::Message() << "with size= " << size);

    const size_t expanded_sizes[]   = {0, 1, size / 2, size, size + 1, 2 * size};
    const size_t num_expanded_sizes = sizeof(expanded_sizes) / sizeof(size_t);

    for (auto seed : get_seeds())
    {
      SCOPED_TRACE(testing::Message() << "with seed= " << seed);

      const thrust::host_vector<T> random = get_random_data<unsigned short int>(
        size + *thrust::max_element(expanded_sizes, expanded_sizes + num_expanded_sizes), 0, 255, seed);
      thrust::host_vector<T> h_a(random.begin(), random.begin() + size);
      thrust::host_vector<T> h_b(random.begin() + size, random.end());

      thrust::stable_sort(h_a.begin(), h_a.end());
      thrust::stable_sort(h_b.begin(), h_b.end());

      const thrust::device_vector<T> d_a = h_a;
      const thrust::device_vector<T> d_b = h_b;

      for (size_t i = 0; i < num_expanded_sizes; i++)
      {
        const size_t expanded_size = expanded_sizes[i];

        thrust::host_vector<T> h_result(size + expanded_size);
        thrust::device_vector<T> d_result(size + expanded_size);

        const auto h_end =
          thrust::merge(h_a.begin(), h_a.end(), h_b.begin(), h_b.begin() + expanded_size, h_result.begin());
        h_result.resize(h_end - h_result.begin());

        const auto d_end =
          thrust::merge(d_a.begin(), d_a.end(), d_b.begin(), d_b.begin() + expanded_size, d_result.begin());
        d_result.resize(d_end - d_result.begin());

        ASSERT_EQ(h_result, d_result);
      }
    }
  }
}

TYPED_TEST(PrimitiveMergeTests, MergeToDiscardIterator)
{
  using T = typename TestFixture::input_type;

  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  for (auto size : get_sizes())
  {
    SCOPED_TRACE(testing::Message() << "with size= " << size);

    for (auto seed : get_seeds())
    {
      SCOPED_TRACE(testing::Message() << "with seed= " << seed);

      thrust::host_vector<T> h_a =
        get_random_data<T>(size, get_default_limits<T>::min(), get_default_limits<T>::max(), seed);
      thrust::host_vector<T> h_b = get_random_data<T>(
        size, get_default_limits<T>::min(), get_default_limits<T>::max(), seed + seed_value_addition);

      thrust::stable_sort(h_a.begin(), h_a.end());
      thrust::stable_sort(h_b.begin(), h_b.end());

      const thrust::device_vector<T> d_a = h_a;
      const thrust::device_vector<T> d_b = h_b;

      const auto h_result =
        thrust::merge(h_a.begin(), h_a.end(), h_b.begin(), h_b.end(), thrust::make_discard_iterator());

      const auto d_result =
        thrust::merge(d_a.begin(), d_a.end(), d_b.begin(), d_b.end(), thrust::make_discard_iterator());

      thrust::discard_iterator<> reference(2 * size);

      ASSERT_EQ(reference, h_result);
      ASSERT_EQ(reference, d_result);
    }
  }
}

TYPED_TEST(PrimitiveMergeTests, MergeDescending)
{
  using T = typename TestFixture::input_type;

  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  for (auto size : get_sizes())
  {
    SCOPED_TRACE(testing::Message() << "with size= " << size);

    for (auto seed : get_seeds())
    {
      SCOPED_TRACE(testing::Message() << "with seed= " << seed);

      thrust::host_vector<T> h_a =
        get_random_data<T>(size, get_default_limits<T>::min(), get_default_limits<T>::max(), seed);
      thrust::host_vector<T> h_b = get_random_data<T>(
        size, get_default_limits<T>::min(), get_default_limits<T>::max(), seed + seed_value_addition);

      thrust::stable_sort(h_a.begin(), h_a.end(), thrust::greater<T>());
      thrust::stable_sort(h_b.begin(), h_b.end(), thrust::greater<T>());

      const thrust::device_vector<T> d_a = h_a;
      const thrust::device_vector<T> d_b = h_b;

      thrust::host_vector<T> h_result(h_a.size() + h_b.size());
      thrust::device_vector<T> d_result(d_a.size() + d_b.size());

      const auto h_end =
        thrust::merge(h_a.begin(), h_a.end(), h_b.begin(), h_b.end(), h_result.begin(), thrust::greater<T>());

      const auto d_end =
        thrust::merge(d_a.begin(), d_a.end(), d_b.begin(), d_b.end(), d_result.begin(), thrust::greater<T>());

      ASSERT_EQ(h_result, d_result);
      ASSERT_TRUE(h_end == h_result.end());
      ASSERT_TRUE(d_end == d_result.end());
    }
  }
}

template <class T>
__global__ THRUST_HIP_LAUNCH_BOUNDS_DEFAULT void
MergeKernel(int const N, const T* inA_array, const T* inB_array, T* out_array)
{
  if (threadIdx.x == 0)
  {
    thrust::device_ptr<const int> inA_begin(inA_array);
    thrust::device_ptr<const int> inA_end(inA_array + N);
    thrust::device_ptr<const int> inB_begin(inB_array);
    thrust::device_ptr<const int> inB_end(inB_array + N);
    thrust::device_ptr<int> out_begin(out_array);

    thrust::merge(thrust::hip::par, inA_begin, inA_end, inB_begin, inB_end, out_begin);
  }
}
TEST(PrimitiveMergeTests, TestMergeDevice)
{
  using T = int;

  SCOPED_TRACE(testing::Message() << "with device_id= " << test::set_device_from_ctest());

  for (auto size : get_sizes())
  {
    SCOPED_TRACE(testing::Message() << "with size= " << size);

    for (auto seed : get_seeds())
    {
      SCOPED_TRACE(testing::Message() << "with seed= " << seed);

      thrust::host_vector<T> h_a =
        get_random_data<T>(size, get_default_limits<T>::min(), get_default_limits<T>::max(), seed);
      thrust::host_vector<T> h_b = get_random_data<T>(
        size, get_default_limits<T>::min(), get_default_limits<T>::max(), seed + seed_value_addition);

      thrust::stable_sort(h_a.begin(), h_a.end(), thrust::greater<T>());
      thrust::stable_sort(h_b.begin(), h_b.end(), thrust::greater<T>());

      const thrust::device_vector<T> d_a = h_a;
      const thrust::device_vector<T> d_b = h_b;

      thrust::host_vector<T> h_result(h_a.size() + h_b.size());
      thrust::device_vector<T> d_result(d_a.size() + d_b.size());

      thrust::merge(h_a.begin(), h_a.end(), h_b.begin(), h_b.end(), h_result.begin());

      hipLaunchKernelGGL(
        MergeKernel,
        dim3(1, 1, 1),
        dim3(128, 1, 1),
        0,
        0,
        size,
        thrust::raw_pointer_cast(&d_a[0]),
        thrust::raw_pointer_cast(&d_b[0]),
        thrust::raw_pointer_cast(&d_result[0]));
      HIP_CHECK(hipGetLastError());

      ASSERT_EQ(h_result, d_result);
    }
  }
}