//@HEADER
// ************************************************************************
//
//                        Kokkos v. 4.0
//       Copyright (2022) National Technology & Engineering
//               Solutions of Sandia, LLC (NTESS).
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
// See https://kokkos.org/LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//@HEADER

#ifndef KOKKOS_IMPL_PUBLIC_INCLUDE
#define KOKKOS_IMPL_PUBLIC_INCLUDE
#endif

#include <Kokkos_Macros.hpp>
#include <impl/Kokkos_DeviceManagement.hpp>

#if defined(KOKKOS_ENABLE_OPENMPTARGET) && defined(_OPENMP)

// FIXME_OPENMPTARGET - macro for workaround implementation in UniqueToken
// constructor. undef'ed at the end
#define KOKKOS_IMPL_OPENMPTARGET_WORKAROUND

#include <OpenMPTarget/Kokkos_OpenMPTarget.hpp>
#include <OpenMPTarget/Kokkos_OpenMPTarget_UniqueToken.hpp>
#include <OpenMPTarget/Kokkos_OpenMPTarget_Instance.hpp>
#include <impl/Kokkos_ExecSpaceManager.hpp>
#include <OpenMPTarget/Kokkos_OpenMPTarget_Parallel.hpp>

#include <sstream>

namespace Kokkos {
namespace Experimental {
namespace Impl {
uint32_t OpenMPTargetInternal::impl_get_instance_id() const noexcept {
  return m_instance_id;
}

void OpenMPTargetInternal::fence(openmp_fence_is_static is_static) {
  fence(
      "Kokkos::Experimental::Impl::OpenMPTargetInternal::fence: Unnamed "
      "Internal Fence",
      is_static);
}
void OpenMPTargetInternal::fence(const std::string& name,
                                 openmp_fence_is_static is_static) {
  if (is_static == openmp_fence_is_static::no) {
    Kokkos::Tools::Experimental::Impl::profile_fence_event<
        Kokkos::Experimental::OpenMPTarget>(
        name,
        Kokkos::Tools::Experimental::Impl::DirectFenceIDHandle{
            impl_get_instance_id()},
        [&]() {});
  } else {
    Kokkos::Tools::Experimental::Impl::profile_fence_event<
        Kokkos::Experimental::OpenMPTarget>(
        name,
        Kokkos::Tools::Experimental::SpecialSynchronizationCases::
            GlobalDeviceSynchronization,
        [&]() {});
  }
}
int OpenMPTargetInternal::concurrency() const {
  int max_threads = 2048 * 80;
#if defined(KOKKOS_IMPL_ARCH_NVIDIA_GPU)
  int max_threads_sm = 2048;
#if defined(KOKKOS_ARCH_AMPERE86)
  max_threads = max_threads_sm * 84;
#elif defined(KOKKOS_ARCH_AMPERE80)
  max_threads = max_threads_sm * 108;
#elif defined(KOKKOS_ARCH_VOLTA72)
  max_threads = max_threads_sm * 84;
#elif defined(KOKKOS_ARCH_VOLTA70)
  max_threads = max_threads_sm * 80;
#elif defined(KOKKOS_ARCH_PASCAL60) || defined(KOKKOS_ARCH_PASCAL61)
  max_threads = max_threads_sm * 60;
#endif
#elif defined(KOKKOS_ARCH_INTEL_GPU)
#pragma omp target map(max_threads)
  { max_threads = omp_get_num_procs(); }

  // Multiply the number of processors with the SIMD length.
  max_threads *= 32;
#endif

  return max_threads;
}
const char* OpenMPTargetInternal::name() { return "OpenMPTarget"; }
void OpenMPTargetInternal::print_configuration(std::ostream& os,
                                               bool /*verbose*/) const {
  // FIXME_OPENMPTARGET
  os << "Using OpenMPTarget\n";
#if defined(KOKKOS_IMPL_OPENMPTARGET_HIERARCHICAL_INTEL_GPU)
  os << "Defined KOKKOS_IMPL_OPENMPTARGET_HIERARCHICAL_INTEL_GPU: Workaround "
        "for "
        "hierarchical parallelism for Intel GPUs.";
#endif
}

void OpenMPTargetInternal::impl_finalize() {
  m_is_initialized = false;
  Kokkos::Impl::OpenMPTargetExec space;

  if (space.m_uniquetoken_ptr != nullptr)
    Kokkos::kokkos_free<Kokkos::Experimental::OpenMPTargetSpace>(
        space.m_uniquetoken_ptr);
}

void OpenMPTargetInternal::impl_initialize() {
  m_is_initialized = true;

  Kokkos::Impl::OpenMPTargetExec::MAX_ACTIVE_THREADS = concurrency();

  // FIXME_OPENMPTARGET:  Only fix the number of teams for NVIDIA architectures
  // from Pascal and upwards.
  // FIXME_OPENMPTARGTE: Cray compiler did not yet implement omp_set_num_teams.
#if !defined(KOKKOS_COMPILER_CRAY_LLVM)
#if defined(KOKKOS_IMPL_ARCH_NVIDIA_GPU) && defined(KOKKOS_COMPILER_CLANG) && \
    (KOKKOS_COMPILER_CLANG >= 1300)
  omp_set_num_teams(512);
#endif
#endif
}
int OpenMPTargetInternal::impl_is_initialized() {
  return m_is_initialized ? 1 : 0;
}

OpenMPTargetInternal* OpenMPTargetInternal::impl_singleton() {
  static OpenMPTargetInternal self;
  return &self;
}

}  // Namespace Impl

OpenMPTarget::OpenMPTarget()
    : m_space_instance(Impl::OpenMPTargetInternal::impl_singleton()) {}

const char* OpenMPTarget::name() {
  return Impl::OpenMPTargetInternal::impl_singleton()->name();
}
void OpenMPTarget::print_configuration(std::ostream& os, bool verbose) const {
  os << "OpenMPTarget Execution Space:\n";
  os << "  KOKKOS_ENABLE_OPENMPTARGET: yes\n";

  os << "\nOpenMPTarget Runtime Configuration:\n";

  m_space_instance->print_configuration(os, verbose);
}

uint32_t OpenMPTarget::impl_instance_id() const noexcept {
  return m_space_instance->impl_get_instance_id();
}

#ifdef KOKKOS_ENABLE_DEPRECATED_CODE_4
int OpenMPTarget::concurrency() {
  return Impl::OpenMPTargetInternal::impl_singleton()->concurrency();
}
#else
int OpenMPTarget::concurrency() const {
  return m_space_instance->concurrency();
}
#endif

void OpenMPTarget::fence(const std::string& name) {
  Impl::OpenMPTargetInternal::impl_singleton()->fence(name);
}

void OpenMPTarget::impl_static_fence(const std::string& name) {
  Impl::OpenMPTargetInternal::impl_singleton()->fence(
      name, Kokkos::Experimental::Impl::openmp_fence_is_static::yes);
}

void OpenMPTarget::impl_initialize(InitializationSettings const& settings) {
  using Kokkos::Impl::get_visible_devices;
  std::vector<int> const& visible_devices = get_visible_devices();
  using Kokkos::Impl::get_gpu;
  const int device_num = get_gpu(settings).value_or(visible_devices[0]);
  omp_set_default_device(device_num);

  Impl::OpenMPTargetInternal::impl_singleton()->impl_initialize();
}
void OpenMPTarget::impl_finalize() {
  Impl::OpenMPTargetInternal::impl_singleton()->impl_finalize();
}
int OpenMPTarget::impl_is_initialized() {
  return Impl::OpenMPTargetInternal::impl_singleton()->impl_is_initialized();
}
}  // Namespace Experimental

namespace Impl {
int g_openmptarget_space_factory_initialized =
    Kokkos::Impl::initialize_space_factory<Experimental::OpenMPTarget>(
        "160_OpenMPTarget");

}  // namespace Impl
}  // Namespace Kokkos

namespace Kokkos {
namespace Experimental {

UniqueToken<Kokkos::Experimental::OpenMPTarget,
            Kokkos::Experimental::UniqueTokenScope::Global>::
    UniqueToken(Kokkos::Experimental::OpenMPTarget const&) {
#ifdef KOKKOS_IMPL_OPENMPTARGET_WORKAROUND
  uint32_t* ptr = Kokkos::Impl::OpenMPTargetExec::m_uniquetoken_ptr;
  int count     = Kokkos::Experimental::OpenMPTarget().concurrency();
  if (ptr == nullptr) {
    int size = count * sizeof(uint32_t);
    ptr      = static_cast<uint32_t*>(
        Kokkos::kokkos_malloc<Kokkos::Experimental::OpenMPTargetSpace>(
            "Kokkos::OpenMPTarget::m_uniquetoken_ptr", size));
    std::vector<uint32_t> h_buf(count, 0);
    if (0 < size)
      KOKKOS_IMPL_OMPT_SAFE_CALL(omp_target_memcpy(ptr, h_buf.data(), size, 0,
                                                   0, omp_get_default_device(),
                                                   omp_get_initial_device()));

    Kokkos::Impl::OpenMPTargetExec::m_uniquetoken_ptr = ptr;
  }
#else
// FIXME_OPENMPTARGET - 2 versions of non-working implementations to fill `ptr`
// with 0's
// Version 1 - Creating a target region and filling the
// pointer Error - CUDA error: named symbol not found
#pragma omp target teams distribute parallel for is_device_ptr(ptr) \
    map(to                                                          \
        : size)
  for (int i = 0; i < count; ++i) ptr[i] = 0;

  // Version 2 : Allocating a view on the device and filling it with a scalar
  // value of 0.
  Kokkos::View<uint32_t*, Kokkos::Experimental::OpenMPTargetSpace> ptr_view(
      ptr, count);
  Kokkos::deep_copy(ptr_view, 0);
#endif
  m_buffer = ptr;
  m_count  = count;
}
}  // namespace Experimental
}  // namespace Kokkos

#undef KOKKOS_IMPL_OPENMPTARGET_WORKAROUND
#endif  // defined(KOKKOS_ENABLE_OPENMPTARGET) && defined(_OPENMP)
