// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// SPDX-FileCopyrightText: Copyright Contributors to the Kokkos project

#ifndef KOKKOS_TEST_BITSET_HPP
#define KOKKOS_TEST_BITSET_HPP

#include <gtest/gtest.h>
#include <iostream>
#include <Kokkos_Macros.hpp>
#ifdef KOKKOS_ENABLE_EXPERIMENTAL_CXX20_MODULES
import kokkos.bitset;
import kokkos.core;
#else
#include <Kokkos_Bitset.hpp>
#include <Kokkos_Core.hpp>
#endif
#include <array>

#include <../../core/unit_test/tools/include/ToolTestingUtilities.hpp>

namespace Test {

namespace Impl {

template <typename Bitset, bool Set>
struct TestBitset {
  using bitset_type     = Bitset;
  using execution_space = typename bitset_type::execution_space;
  using value_type      = uint32_t;

  bitset_type m_bitset;

  TestBitset(bitset_type const& bitset) : m_bitset(bitset) {}

  unsigned testit(unsigned long long collisions) {
    execution_space().fence();

    unsigned count = 0;
    Kokkos::parallel_reduce(m_bitset.size() * collisions, *this, count);
    return count;
  }

  KOKKOS_INLINE_FUNCTION
  void init(value_type& v) const { v = 0; }

  KOKKOS_INLINE_FUNCTION
  void join(value_type& dst, const value_type& src) const { dst += src; }

  KOKKOS_INLINE_FUNCTION
  void operator()(uint32_t i, value_type& v) const {
    i = i % m_bitset.size();
    if (Set) {
      if (m_bitset.set(i)) {
        if (m_bitset.test(i)) ++v;
      }
    } else {
      if (m_bitset.reset(i)) {
        if (!m_bitset.test(i)) ++v;
      }
    }
  }
};

template <typename Bitset>
struct TestBitsetTest {
  using bitset_type     = Bitset;
  using execution_space = typename bitset_type::execution_space;
  using value_type      = uint32_t;

  bitset_type m_bitset;

  TestBitsetTest(bitset_type const& bitset) : m_bitset(bitset) {}

  unsigned testit() {
    execution_space().fence();

    unsigned count = 0;
    Kokkos::parallel_reduce(m_bitset.size(), *this, count);
    return count;
  }

  KOKKOS_INLINE_FUNCTION
  void init(value_type& v) const { v = 0; }

  KOKKOS_INLINE_FUNCTION
  void join(value_type& dst, const value_type& src) const { dst += src; }

  KOKKOS_INLINE_FUNCTION
  void operator()(uint32_t i, value_type& v) const {
    if (m_bitset.test(i)) ++v;
  }
};

template <typename Bitset, bool Set>
struct TestBitsetAny {
  using bitset_type     = Bitset;
  using execution_space = typename bitset_type::execution_space;
  using value_type      = uint32_t;

  bitset_type m_bitset;

  TestBitsetAny(bitset_type const& bitset) : m_bitset(bitset) {}

  unsigned testit() {
    execution_space().fence();

    unsigned count = 0;
    Kokkos::parallel_reduce(m_bitset.size(), *this, count);
    return count;
  }

  KOKKOS_INLINE_FUNCTION
  void init(value_type& v) const { v = 0; }

  KOKKOS_INLINE_FUNCTION
  void join(value_type& dst, const value_type& src) const { dst += src; }

  KOKKOS_INLINE_FUNCTION
  void operator()(uint32_t i, value_type& v) const {
    bool result       = false;
    unsigned attempts = 0;
    uint32_t hint     = (i >> 4) << 4;
    while (attempts < m_bitset.max_hint()) {
      if (Set) {
        Kokkos::tie(result, hint) = m_bitset.find_any_unset_near(hint, i);
        if (result && m_bitset.set(hint)) {
          ++v;
          break;
        } else if (!result) {
          ++attempts;
        }
      } else {
        Kokkos::tie(result, hint) = m_bitset.find_any_set_near(hint, i);
        if (result && m_bitset.reset(hint)) {
          ++v;
          break;
        } else if (!result) {
          ++attempts;
        }
      }
    }
  }
};
}  // namespace Impl

template <typename Device>
void test_bitset() {
  using bitset_type       = Kokkos::Bitset<Device>;
  using const_bitset_type = Kokkos::ConstBitset<Device>;

  {
    unsigned ts = 100u;
    bitset_type b1(Kokkos::view_alloc("MyBitset"), 0);
    ASSERT_TRUE(b1.is_allocated());

    b1 = bitset_type(ts);
    bitset_type b2(b1);
    bitset_type b3(ts);

    ASSERT_TRUE(b1.is_allocated());
    ASSERT_TRUE(b2.is_allocated());
    ASSERT_TRUE(b3.is_allocated());

    bitset_type b4;
    ASSERT_FALSE(b4.is_allocated());
  }

  std::array<unsigned, 7> test_sizes = {
      {0u, 10u, 100u, 1000u, 1u << 14, 1u << 16, 10000001}};

  for (const auto test_size : test_sizes) {
    // std::cout << "Bitset " << test_sizes[i] << std::endl;

    bitset_type bitset(test_size);

    // std::cout << "  Check initial count " << std::endl;
    // nothing should be set
    {
      Impl::TestBitsetTest<bitset_type> f(bitset);
      uint32_t count = f.testit();
      EXPECT_EQ(0u, count);
      EXPECT_EQ(count, bitset.count());
    }

    // std::cout << "  Check set() " << std::endl;
    bitset.set();
    // everything should be set
    {
      Impl::TestBitsetTest<const_bitset_type> f(bitset);
      uint32_t count = f.testit();
      EXPECT_EQ(bitset.size(), count);
      EXPECT_EQ(count, bitset.count());
    }

    // std::cout << "  Check reset() " << std::endl;
    bitset.reset();
    EXPECT_EQ(0u, bitset.count());

    // std::cout << "  Check set(i) " << std::endl;
    // test setting bits
    {
      Impl::TestBitset<bitset_type, true> f(bitset);
      uint32_t count = f.testit(10u);
      EXPECT_EQ(bitset.size(), bitset.count());
      EXPECT_EQ(bitset.size(), count);
    }

    // std::cout << "  Check reset(i) " << std::endl;
    // test resetting bits
    {
      Impl::TestBitset<bitset_type, false> f(bitset);
      uint32_t count = f.testit(10u);
      EXPECT_EQ(bitset.size(), count);
      EXPECT_EQ(0u, bitset.count());
    }

    // std::cout << "  Check find_any_set(i) " << std::endl;
    // test setting any bits
    {
      Impl::TestBitsetAny<bitset_type, true> f(bitset);
      uint32_t count = f.testit();
      EXPECT_EQ(bitset.size(), bitset.count());
      EXPECT_EQ(bitset.size(), count);
    }

    // std::cout << "  Check find_any_unset(i) " << std::endl;
    // test resetting any bits
    {
      Impl::TestBitsetAny<bitset_type, false> f(bitset);
      uint32_t count = f.testit();
      EXPECT_EQ(bitset.size(), count);
      EXPECT_EQ(0u, bitset.count());
    }
  }
}

TEST(TEST_CATEGORY, bitset) { test_bitset<TEST_EXECSPACE>(); }

TEST(TEST_CATEGORY, bitset_default_constructor_no_alloc) {
  using namespace Kokkos::Test::Tools;
  listen_tool_events(Config::DisableAll(), Config::EnableAllocs());

  auto success = validate_absence(
      [&]() {
        Kokkos::Bitset bs;
        EXPECT_FALSE(bs.is_allocated());
      },
      [&](AllocateDataEvent) {
        return MatchDiagnostic{true, {"Found alloc event"}};
      });
  ASSERT_TRUE(success);

  listen_tool_events(Config::DisableAll());
}

}  // namespace Test

#endif  // KOKKOS_TEST_BITSET_HPP