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

#ifndef KOKKOS_IMPL_KOKKOS_GRAPHIMPL_HPP
#define KOKKOS_IMPL_KOKKOS_GRAPHIMPL_HPP

#include <Kokkos_Macros.hpp>

#include <Kokkos_Core_fwd.hpp>
#include <Kokkos_Graph_fwd.hpp>

#include <Kokkos_Concepts.hpp>  // is_execution_policy
#include <impl/Kokkos_GraphImpl_fwd.hpp>

#include <concepts>
#include <memory>  // std::make_shared

namespace Kokkos {
namespace Impl {

template <Kokkos::ExecutionSpace Exec>
using root_impl_t =
    Kokkos::Impl::GraphNodeImpl<Exec, Kokkos::Experimental::GraphNodeRootTag,
                                Kokkos::Experimental::TypeErasedTag>;

template <typename T>
constexpr bool is_graph_root_v =
    std::same_as<T, Kokkos::Experimental::GraphNodeRootTag>;

template <typename T>
struct is_graph_capture<
    T, std::enable_if_t<
           Kokkos::Impl::is_specialization_of_v<T, GraphNodeCaptureImpl>>>
    : public std::true_type {};

template <typename T>
struct is_graph_then_host<
    T, std::enable_if_t<
           Kokkos::Impl::is_specialization_of_v<T, GraphNodeThenHostImpl>>>
    : public std::true_type {};

struct GraphAccess {
  template <class NodeType, class... Args>
  static auto make_node_shared_ptr(Args&&... args) {
    static_assert(
        Kokkos::Impl::is_specialization_of<NodeType, GraphNodeImpl>::value,
        "Kokkos Internal Error in graph interface");
    return std::make_shared<NodeType>((Args&&)args...);
  }

  template <class GraphImplWeakPtr, class ExecutionSpace, class Kernel,
            class Predecessor>
  static auto make_graph_node_ref(
      GraphImplWeakPtr graph_impl,
      std::shared_ptr<
          Kokkos::Impl::GraphNodeImpl<ExecutionSpace, Kernel, Predecessor>>
          pred_impl) {
    //----------------------------------------
    return Kokkos::Experimental::GraphNodeRef<ExecutionSpace, Kernel,
                                              Predecessor>{
        std::move(graph_impl), std::move(pred_impl)};
    //----------------------------------------
  }

  //----------------------------------------------------------------------------
  // <editor-fold desc="accessors for private members of public interface"> {{{2

  template <class NodeRef>
  static auto get_node_ptr(NodeRef&& node_ref) {
    static_assert(
        is_specialization_of<std::remove_cvref_t<NodeRef>,
                             Kokkos::Experimental::GraphNodeRef>::value,
        "Kokkos Internal Implementation error (bad argument to "
        "`GraphAccess::get_node_ptr()`)");
    return ((NodeRef&&)node_ref).get_node_ptr();
  }

  template <class NodeRef>
  static auto get_graph_weak_ptr(NodeRef&& node_ref) {
    static_assert(
        is_specialization_of<std::remove_cvref_t<NodeRef>,
                             Kokkos::Experimental::GraphNodeRef>::value,
        "Kokkos Internal Implementation error (bad argument to "
        "`GraphAccess::get_graph_weak_ptr()`)");
    return ((NodeRef&&)node_ref).get_graph_weak_ptr();
  }

  // </editor-fold> end accessors for private members of public interface }}}2
  //----------------------------------------------------------------------------
};

template <class Policy>
struct _add_graph_kernel_tag;

template <template <class...> class PolicyTemplate, class... PolicyTraits>
struct _add_graph_kernel_tag<PolicyTemplate<PolicyTraits...>> {
  using type = PolicyTemplate<PolicyTraits..., IsGraphKernelTag>;
};

}  // end namespace Impl

namespace Experimental {  // but not for users, so...

template <class Policy>
// requires ExecutionPolicy<Policy>
constexpr auto require(Policy const& policy,
                       Kokkos::Impl::KernelInGraphProperty) {
  static_assert(Kokkos::is_execution_policy<Policy>::value,
                "Internal implementation error!");
  return typename Kokkos::Impl::_add_graph_kernel_tag<Policy>::type{policy};
}

}  // end namespace Experimental

}  // end namespace Kokkos

#endif  // KOKKOS_IMPL_KOKKOS_GRAPHIMPL_HPP
