/*
$info$
tags: thunklibs|fex_thunk_test
$end_info$
*/

#include <dlfcn.h>

#include <unordered_map>

#include "common/Host.h"

#include "api.h"

#include "thunkgen_host_libfex_thunk_test.inl"

static uint32_t fexfn_impl_libfex_thunk_test_QueryOffsetOf(guest_layout<ReorderingType*> data, int index) {
  if (index == 0) {
    return offsetof(guest_layout<ReorderingType>::type, a);
  } else {
    return offsetof(guest_layout<ReorderingType>::type, b);
  }
}

void fex_custom_repack_entry(host_layout<CustomRepackedType>& to, const guest_layout<CustomRepackedType>& from) {
  to.data.custom_repack_invoked = 1;
}

bool fex_custom_repack_exit(guest_layout<CustomRepackedType>& to, const host_layout<CustomRepackedType>& from) {
  return false;
}

template<StructType TypeIndex, typename Type>
static const TestBaseStruct* convert(const TestBaseStruct* source) {
  // Using malloc here since no easily available type information is available at the time of destruction.
  auto guest_next = reinterpret_cast<guest_layout<Type>*>((void*)source);
  auto child_mem = (char*)aligned_alloc(alignof(host_layout<Type>), sizeof(host_layout<Type>));
  auto child = new (child_mem) host_layout<Type> {*guest_next};

  fex_custom_repack_entry(*child, *reinterpret_cast<guest_layout<Type>*>((void*)(source)));

  return (const TestBaseStruct*)child;
}

template<StructType TypeIndex, typename Type>
static void convert_to_guest(void* into, const TestBaseStruct* from) {
  auto typed_into = (guest_layout<Type>*)into;
  auto oldNext = typed_into->data.Next;
  *typed_into = to_guest(to_host_layout(*(Type*)from));
  typed_into->data.Next = oldNext;

  fex_custom_repack_exit(*typed_into, to_host_layout(*(Type*)from));
}

template<StructType TypeIndex, typename Type>
inline constexpr std::pair<StructType, std::pair<const TestBaseStruct* (*)(const TestBaseStruct*), void (*)(void*, const TestBaseStruct*)>> converters = {
  TypeIndex,
  {convert<TypeIndex, Type>, convert_to_guest<TypeIndex, Type>}};

static std::unordered_map<StructType, std::pair<const TestBaseStruct* (*)(const TestBaseStruct*), void (*)(void*, const TestBaseStruct*)>> next_handlers {
  converters<StructType::Struct1, TestStruct1>,
  converters<StructType::Struct2, TestStruct2>,
};

static void default_fex_custom_repack_entry(TestBaseStruct& into, const guest_layout<TestBaseStruct>* from) {
  if (!from->data.Next.get_pointer()) {
    into.Next = nullptr;
    return;
  }
  auto typed_source = reinterpret_cast<const guest_layout<TestBaseStruct>*>(from->data.Next.get_pointer());

  auto next_handler = next_handlers.at(StructType {typed_source->data.Type.data});

  into.Next = (TestBaseStruct*)next_handler.first((const TestBaseStruct*)typed_source);
}

static void default_fex_custom_repack_reverse(guest_layout<TestBaseStruct>& into, const TestBaseStruct* from) {
  auto NextHost = from->Next;
  if (!NextHost) {
    return;
  }

  auto next_handler = next_handlers.at(static_cast<StructType>(into.data.Next.get_pointer()->data.Type.data));
  next_handler.second((void*)into.data.Next.get_pointer(), from->Next);

  free((void*)NextHost);
}

#define CREATE_INFO_DEFAULT_CUSTOM_REPACK(name)                                                                                  \
  void fex_custom_repack_entry(host_layout<name>& into, const guest_layout<name>& from) {                                        \
    default_fex_custom_repack_entry(*(TestBaseStruct*)&into.data, reinterpret_cast<const guest_layout<TestBaseStruct>*>(&from)); \
  }                                                                                                                              \
                                                                                                                                 \
  bool fex_custom_repack_exit(guest_layout<name>& into, const host_layout<name>& from) {                                         \
    auto prev_next = into.data.Next;                                                                                             \
    default_fex_custom_repack_reverse(*reinterpret_cast<guest_layout<TestBaseStruct>*>(&into),                                   \
                                      &reinterpret_cast<const TestBaseStruct&>(from.data));                                      \
    into = to_guest(from);                                                                                                       \
    into.data.Next = prev_next;                                                                                                  \
    return true;                                                                                                                 \
  }

CREATE_INFO_DEFAULT_CUSTOM_REPACK(TestStruct1)
CREATE_INFO_DEFAULT_CUSTOM_REPACK(TestStruct2)

void fex_custom_repack_entry(host_layout<TestBaseStruct>&, const guest_layout<TestBaseStruct>&) {
  std::abort();
}

bool fex_custom_repack_exit(guest_layout<TestBaseStruct>&, const host_layout<TestBaseStruct>&) {
  std::abort();
  return false;
}

EXPORTS(libfex_thunk_test)