/*
 *  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/iterator/reverse_iterator.h>
#include <thrust/scan.h>
#include <thrust/sequence.h>

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

TESTS_DEFINE(ReverseIteratorTests, FullTestsParams);

TESTS_DEFINE(PrimitiveReverseIteratorTests, NumericalTestsParams);

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

  ASSERT_EQ(THRUST_DEVICE_SYSTEM, THRUST_DEVICE_SYSTEM_HIP);
}

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

  thrust::host_vector<int> h_v(1, 13);

  thrust::reverse_iterator<thrust::host_vector<int>::iterator> h_iter0(h_v.end());
  thrust::reverse_iterator<thrust::host_vector<int>::iterator> h_iter1(h_iter0);

  ASSERT_EQ(h_iter0, h_iter1);
  ASSERT_EQ(*h_iter0, *h_iter1);

  thrust::device_vector<int> d_v(1, 13);

  thrust::reverse_iterator<thrust::device_vector<int>::iterator> d_iter2(d_v.end());
  thrust::reverse_iterator<thrust::device_vector<int>::iterator> d_iter3(d_iter2);

  ASSERT_EQ(d_iter2, d_iter3);
  ASSERT_EQ(*d_iter2, *d_iter3);
}

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

  thrust::host_vector<int> h_v(4);
  thrust::sequence(h_v.begin(), h_v.end());

  thrust::reverse_iterator<thrust::host_vector<int>::iterator> h_iter(h_v.end());

  ASSERT_EQ(*h_iter, 3);

  h_iter++;
  ASSERT_EQ(*h_iter, 2);

  h_iter++;
  ASSERT_EQ(*h_iter, 1);

  h_iter++;
  ASSERT_EQ(*h_iter, 0);

  thrust::device_vector<int> d_v(4);
  thrust::sequence(d_v.begin(), d_v.end());

  thrust::reverse_iterator<thrust::device_vector<int>::iterator> d_iter(d_v.end());

  ASSERT_EQ(*d_iter, 3);

  d_iter++;
  ASSERT_EQ(*d_iter, 2);

  d_iter++;
  ASSERT_EQ(*d_iter, 1);

  d_iter++;
  ASSERT_EQ(*d_iter, 0);
}

TYPED_TEST(ReverseIteratorTests, ReverseIteratorCopy)
{
  using Vector = typename TestFixture::input_type;
  using Policy = typename TestFixture::execution_policy;
  using T      = typename Vector::value_type;

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

  Vector source(4);
  source[0] = (T) 10;
  source[1] = (T) 20;
  source[2] = (T) 30;
  source[3] = (T) 40;

  Vector destination(4, 0);

  thrust::copy(Policy{},
               thrust::make_reverse_iterator(source.end()),
               thrust::make_reverse_iterator(source.begin()),
               destination.begin());

  ASSERT_EQ(destination[0], (T) 40);
  ASSERT_EQ(destination[1], (T) 30);
  ASSERT_EQ(destination[2], (T) 20);
  ASSERT_EQ(destination[3], (T) 10);
}

TYPED_TEST(PrimitiveReverseIteratorTests, ReverseIteratorExclusiveScanSimple)
{
  using T = typename TestFixture::input_type;

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

  const size_t size = 10;

  T error_margin = (T) 0.01 * size;
  thrust::host_vector<T> h_data(size);
  thrust::sequence(h_data.begin(), h_data.end());

  thrust::device_vector<T> d_data = h_data;

  thrust::host_vector<T> h_result(h_data.size());
  thrust::device_vector<T> d_result(d_data.size());

  thrust::exclusive_scan(
    thrust::make_reverse_iterator(h_data.end()), thrust::make_reverse_iterator(h_data.begin()), h_result.begin());

  thrust::exclusive_scan(
    thrust::make_reverse_iterator(d_data.end()), thrust::make_reverse_iterator(d_data.begin()), d_result.begin());

  thrust::host_vector<T> h_result_d(d_result);
  for (size_t i = 0; i < size; i++)
  {
    ASSERT_NEAR(h_result[i], h_result_d[i], error_margin);
  }
}

TYPED_TEST(PrimitiveReverseIteratorTests, ReverseIteratorExclusiveScan)
{
  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);

    T error_margin = (T) 0.01 * size;

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

      thrust::host_vector<T> h_data = get_random_data<T>(size, 0, 10, seed);

      thrust::device_vector<T> d_data = h_data;

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

      thrust::exclusive_scan(
        thrust::make_reverse_iterator(h_data.end()), thrust::make_reverse_iterator(h_data.begin()), h_result.begin());

      thrust::exclusive_scan(
        thrust::make_reverse_iterator(d_data.end()), thrust::make_reverse_iterator(d_data.begin()), d_result.begin());

      thrust::host_vector<T> h_result_d(d_result);
      for (size_t i = 0; i < size; i++)
      {
        ASSERT_NEAR(h_result[i], h_result_d[i], error_margin);
      }
    }
  }
};
