#include <thrust/functional.h>
#include <thrust/iterator/retag.h>
#include <thrust/set_operations.h>
#include <thrust/sort.h>

#include <unittest/unittest.h>

template <typename InputIterator1,
          typename InputIterator2,
          typename InputIterator3,
          typename InputIterator4,
          typename OutputIterator1,
          typename OutputIterator2>
cuda::std::pair<OutputIterator1, OutputIterator2> set_difference_by_key(
  my_system& system,
  InputIterator1,
  InputIterator1,
  InputIterator2,
  InputIterator2,
  InputIterator3,
  InputIterator4,
  OutputIterator1 keys_result,
  OutputIterator2 values_result)
{
  system.validate_dispatch();
  return cuda::std::make_pair(keys_result, values_result);
}

void TestSetDifferenceByKeyDispatchExplicit()
{
  thrust::device_vector<int> vec(1);

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

  ASSERT_EQUAL(true, sys.is_valid());
}
DECLARE_UNITTEST(TestSetDifferenceByKeyDispatchExplicit);

template <typename InputIterator1,
          typename InputIterator2,
          typename InputIterator3,
          typename InputIterator4,
          typename OutputIterator1,
          typename OutputIterator2>
cuda::std::pair<OutputIterator1, OutputIterator2> set_difference_by_key(
  my_tag,
  InputIterator1,
  InputIterator1,
  InputIterator2,
  InputIterator2,
  InputIterator3,
  InputIterator4,
  OutputIterator1 keys_result,
  OutputIterator2 values_result)
{
  *keys_result = 13;
  return cuda::std::make_pair(keys_result, values_result);
}

void TestSetDifferenceByKeyDispatchImplicit()
{
  thrust::device_vector<int> vec(1);

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

  ASSERT_EQUAL(13, vec.front());
}
DECLARE_UNITTEST(TestSetDifferenceByKeyDispatchImplicit);

template <typename Vector>
void TestSetDifferenceByKeySimple()
{
  using Iterator = typename Vector::iterator;

  Vector a_key{0, 2, 4, 5}, b_key{0, 3, 3, 4, 6};
  Vector a_val(4, 0), b_val(5, 1);

  Vector ref_key(2), ref_val(2);
  ref_key[0] = 2;
  ref_key[1] = 5;
  ref_val[0] = 0;
  ref_val[1] = 0;

  Vector result_key(2), result_val(2);

  cuda::std::pair<Iterator, Iterator> end = thrust::set_difference_by_key(
    a_key.begin(),
    a_key.end(),
    b_key.begin(),
    b_key.end(),
    a_val.begin(),
    b_val.begin(),
    result_key.begin(),
    result_val.begin());

  ASSERT_EQUAL_QUIET(result_key.end(), end.first);
  ASSERT_EQUAL_QUIET(result_val.end(), end.second);
  ASSERT_EQUAL(ref_key, result_key);
  ASSERT_EQUAL(ref_val, result_val);
}
DECLARE_VECTOR_UNITTEST(TestSetDifferenceByKeySimple);

template <typename T>
void TestSetDifferenceByKey(const size_t n)
{
  thrust::host_vector<T> random_keys = unittest::random_integers<unittest::int8_t>(n);
  thrust::host_vector<T> random_vals = unittest::random_integers<unittest::int8_t>(n);

  size_t denominators[]   = {1, 2, 3, 4, 5, 6, 7, 8, 9};
  size_t num_denominators = sizeof(denominators) / sizeof(size_t);

  for (size_t i = 0; i < num_denominators; ++i)
  {
    size_t size_a = n / denominators[i];

    thrust::host_vector<T> h_a_keys(random_keys.begin(), random_keys.begin() + size_a);
    thrust::host_vector<T> h_b_keys(random_keys.begin() + size_a, random_keys.end());

    thrust::host_vector<T> h_a_vals(random_vals.begin(), random_vals.begin() + size_a);
    thrust::host_vector<T> h_b_vals(random_vals.begin() + size_a, random_vals.end());

    thrust::stable_sort(h_a_keys.begin(), h_a_keys.end());
    thrust::stable_sort(h_b_keys.begin(), h_b_keys.end());

    thrust::device_vector<T> d_a_keys = h_a_keys;
    thrust::device_vector<T> d_b_keys = h_b_keys;

    thrust::device_vector<T> d_a_vals = h_a_vals;
    thrust::device_vector<T> d_b_vals = h_b_vals;

    thrust::host_vector<T> h_result_keys(n);
    thrust::host_vector<T> h_result_vals(n);

    thrust::device_vector<T> d_result_keys(n);
    thrust::device_vector<T> d_result_vals(n);

    cuda::std::pair<typename thrust::host_vector<T>::iterator, typename thrust::host_vector<T>::iterator> h_end;

    cuda::std::pair<typename thrust::device_vector<T>::iterator, typename thrust::device_vector<T>::iterator> d_end;

    h_end = thrust::set_difference_by_key(
      h_a_keys.begin(),
      h_a_keys.end(),
      h_b_keys.begin(),
      h_b_keys.end(),
      h_a_vals.begin(),
      h_b_vals.begin(),
      h_result_keys.begin(),
      h_result_vals.begin());
    h_result_keys.erase(h_end.first, h_result_keys.end());
    h_result_vals.erase(h_end.second, h_result_vals.end());

    d_end = thrust::set_difference_by_key(
      d_a_keys.begin(),
      d_a_keys.end(),
      d_b_keys.begin(),
      d_b_keys.end(),
      d_a_vals.begin(),
      d_b_vals.begin(),
      d_result_keys.begin(),
      d_result_vals.begin());
    d_result_keys.erase(d_end.first, d_result_keys.end());
    d_result_vals.erase(d_end.second, d_result_vals.end());

    ASSERT_EQUAL(h_result_keys, d_result_keys);
    ASSERT_EQUAL(h_result_vals, d_result_vals);
  }
}
DECLARE_VARIABLE_UNITTEST(TestSetDifferenceByKey);

template <typename T>
void TestSetDifferenceByKeyEquivalentRanges(const size_t n)
{
  thrust::host_vector<T> temp = unittest::random_integers<T>(n);

  thrust::host_vector<T> h_a_key = temp;
  thrust::sort(h_a_key.begin(), h_a_key.end());
  thrust::host_vector<T> h_b_key = h_a_key;

  thrust::host_vector<T> h_a_val = unittest::random_integers<T>(n);
  thrust::host_vector<T> h_b_val = unittest::random_integers<T>(n);

  thrust::device_vector<T> d_a_key = h_a_key;
  thrust::device_vector<T> d_b_key = h_b_key;

  thrust::device_vector<T> d_a_val = h_a_val;
  thrust::device_vector<T> d_b_val = h_b_val;

  thrust::host_vector<T> h_result_key(n), h_result_val(n);
  thrust::device_vector<T> d_result_key(n), d_result_val(n);

  cuda::std::pair<typename thrust::host_vector<T>::iterator, typename thrust::host_vector<T>::iterator> h_end;

  cuda::std::pair<typename thrust::device_vector<T>::iterator, typename thrust::device_vector<T>::iterator> d_end;

  h_end = thrust::set_difference_by_key(
    h_a_key.begin(),
    h_a_key.end(),
    h_b_key.begin(),
    h_b_key.end(),
    h_a_val.begin(),
    h_b_val.begin(),
    h_result_key.begin(),
    h_result_val.begin());
  h_result_key.erase(h_end.first, h_result_key.end());
  h_result_val.erase(h_end.second, h_result_val.end());

  d_end = thrust::set_difference_by_key(
    d_a_key.begin(),
    d_a_key.end(),
    d_b_key.begin(),
    d_b_key.end(),
    d_a_val.begin(),
    d_b_val.begin(),
    d_result_key.begin(),
    d_result_val.begin());
  d_result_key.erase(d_end.first, d_result_key.end());
  d_result_val.erase(d_end.second, d_result_val.end());

  ASSERT_EQUAL(h_result_key, d_result_key);
  ASSERT_EQUAL(h_result_val, d_result_val);
}
DECLARE_VARIABLE_UNITTEST(TestSetDifferenceByKeyEquivalentRanges);

template <typename T>
void TestSetDifferenceByKeyMultiset(const size_t n)
{
  thrust::host_vector<T> vec = unittest::random_integers<int>(2 * n);

  // restrict elements to [min,13)
  for (typename thrust::host_vector<T>::iterator i = vec.begin(); i != vec.end(); ++i)
  {
    int temp = static_cast<int>(*i);
    temp %= 13;
    *i = temp;
  }

  thrust::host_vector<T> h_a_key(vec.begin(), vec.begin() + n);
  thrust::host_vector<T> h_b_key(vec.begin() + n, vec.end());

  thrust::sort(h_a_key.begin(), h_a_key.end());
  thrust::sort(h_b_key.begin(), h_b_key.end());

  thrust::host_vector<T> h_a_val = unittest::random_integers<T>(n);
  thrust::host_vector<T> h_b_val = unittest::random_integers<T>(n);

  thrust::device_vector<T> d_a_key = h_a_key;
  thrust::device_vector<T> d_b_key = h_b_key;

  thrust::device_vector<T> d_a_val = h_a_val;
  thrust::device_vector<T> d_b_val = h_b_val;

  thrust::host_vector<T> h_result_key(n), h_result_val(n);
  thrust::device_vector<T> d_result_key(n), d_result_val(n);

  cuda::std::pair<typename thrust::host_vector<T>::iterator, typename thrust::host_vector<T>::iterator> h_end;

  cuda::std::pair<typename thrust::device_vector<T>::iterator, typename thrust::device_vector<T>::iterator> d_end;

  h_end = thrust::set_difference_by_key(
    h_a_key.begin(),
    h_a_key.end(),
    h_b_key.begin(),
    h_b_key.end(),
    h_a_val.begin(),
    h_b_val.begin(),
    h_result_key.begin(),
    h_result_val.begin());
  h_result_key.erase(h_end.first, h_result_key.end());
  h_result_val.erase(h_end.second, h_result_val.end());

  d_end = thrust::set_difference_by_key(
    d_a_key.begin(),
    d_a_key.end(),
    d_b_key.begin(),
    d_b_key.end(),
    d_a_val.begin(),
    d_b_val.begin(),
    d_result_key.begin(),
    d_result_val.begin());
  d_result_key.erase(d_end.first, d_result_key.end());
  d_result_val.erase(d_end.second, d_result_val.end());

  ASSERT_EQUAL(h_result_key, d_result_key);
  ASSERT_EQUAL(h_result_val, d_result_val);
}
DECLARE_VARIABLE_UNITTEST(TestSetDifferenceByKeyMultiset);