/*
 *  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/extrema.h>

#include <unittest/unittest.h>

#ifdef THRUST_TEST_DEVICE_SIDE
template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
__global__ void minmax_element_kernel(ExecutionPolicy exec, Iterator1 first, Iterator1 last, Iterator2 result)
{
  *result = thrust::minmax_element(exec, first, last);
}

template <typename ExecutionPolicy, typename Iterator1, typename Iterator2, typename BinaryPredicate>
__global__ void
minmax_element_kernel(ExecutionPolicy exec, Iterator1 first, Iterator1 last, BinaryPredicate pred, Iterator2 result)
{
  *result = thrust::minmax_element(exec, first, last, pred);
}

template <typename ExecutionPolicy>
void TestMinMaxElementDevice(ExecutionPolicy exec)
{
  size_t n = 1000;

  thrust::host_vector<int> h_data   = unittest::random_samples<int>(n);
  thrust::device_vector<int> d_data = h_data;

  typename thrust::host_vector<int>::iterator h_min;
  typename thrust::host_vector<int>::iterator h_max;
  typename thrust::device_vector<int>::iterator d_min;
  typename thrust::device_vector<int>::iterator d_max;

  using pair_type =
    thrust::pair<typename thrust::device_vector<int>::iterator, typename thrust::device_vector<int>::iterator>;

  thrust::device_vector<pair_type> d_result(1);

  h_min = thrust::minmax_element(h_data.begin(), h_data.end()).first;
  h_max = thrust::minmax_element(h_data.begin(), h_data.end()).second;

  d_min = thrust::minmax_element(d_data.begin(), d_data.end()).first;
  d_max = thrust::minmax_element(d_data.begin(), d_data.end()).second;

  minmax_element_kernel<<<1, 1>>>(exec, d_data.begin(), d_data.end(), d_result.begin());
  {
    cudaError_t const err = cudaDeviceSynchronize();
    ASSERT_EQUAL(cudaSuccess, err);
  }

  d_min = ((pair_type) d_result[0]).first;
  d_max = ((pair_type) d_result[0]).second;

  ASSERT_EQUAL(h_min - h_data.begin(), d_min - d_data.begin());
  ASSERT_EQUAL(h_max - h_data.begin(), d_max - d_data.begin());

  h_max = thrust::minmax_element(h_data.begin(), h_data.end(), thrust::greater<int>()).first;
  h_min = thrust::minmax_element(h_data.begin(), h_data.end(), thrust::greater<int>()).second;

  minmax_element_kernel<<<1, 1>>>(exec, d_data.begin(), d_data.end(), thrust::greater<int>(), d_result.begin());
  {
    cudaError_t const err = cudaDeviceSynchronize();
    ASSERT_EQUAL(cudaSuccess, err);
  }

  d_max = ((pair_type) d_result[0]).first;
  d_min = ((pair_type) d_result[0]).second;

  ASSERT_EQUAL(h_min - h_data.begin(), d_min - d_data.begin());
  ASSERT_EQUAL(h_max - h_data.begin(), d_max - d_data.begin());
}

void TestMinMaxElementDeviceSeq()
{
  TestMinMaxElementDevice(thrust::seq);
}
DECLARE_UNITTEST(TestMinMaxElementDeviceSeq);

void TestMinMaxElementDeviceDevice()
{
  TestMinMaxElementDevice(thrust::device);
}
DECLARE_UNITTEST(TestMinMaxElementDeviceDevice);
#endif

void TestMinMaxElementCudaStreams()
{
  using Vector = thrust::device_vector<int>;

  Vector data(6);
  data[0] = 3;
  data[1] = 5;
  data[2] = 1;
  data[3] = 2;
  data[4] = 5;
  data[5] = 1;

  cudaStream_t s;
  cudaStreamCreate(&s);

  ASSERT_EQUAL(*thrust::minmax_element(thrust::cuda::par.on(s), data.begin(), data.end()).first, 1);
  ASSERT_EQUAL(*thrust::minmax_element(thrust::cuda::par.on(s), data.begin(), data.end()).second, 5);
  ASSERT_EQUAL(thrust::minmax_element(thrust::cuda::par.on(s), data.begin(), data.end()).first - data.begin(), 2);
  ASSERT_EQUAL(thrust::minmax_element(thrust::cuda::par.on(s), data.begin(), data.end()).second - data.begin(), 1);

  cudaStreamDestroy(s);
}
DECLARE_UNITTEST(TestMinMaxElementCudaStreams);

void TestMinMaxElementDevicePointer()
{
  using Vector = thrust::device_vector<int>;
  using T      = Vector::value_type;

  Vector data(6);
  data[0] = 3;
  data[1] = 5;
  data[2] = 1;
  data[3] = 2;
  data[4] = 5;
  data[5] = 1;

  T* raw_ptr = thrust::raw_pointer_cast(data.data());
  size_t n   = data.size();
  ASSERT_EQUAL(thrust::minmax_element(thrust::device, raw_ptr, raw_ptr + n).first - raw_ptr, 2);
  ASSERT_EQUAL(thrust::minmax_element(thrust::device, raw_ptr, raw_ptr + n).second - raw_ptr, 1);
}
DECLARE_UNITTEST(TestMinMaxElementDevicePointer);
