/*
 * Copyright 2019 by its authors. See AUTHORS.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef _EFL_ECORE_CXX_ECORE_MANUAL_HH
#define _EFL_ECORE_CXX_ECORE_MANUAL_HH

#include <Ecore.h>

#include <Eina.hh>

#include <utility>
#include <type_traits>
#include <memory>
#include <cstring>

namespace efl { namespace ecore {

template <typename T>
struct _identity
{
  typedef T type;
};

template <typename F>
void _ecore_main_loop_thread_safe_call_async_callback(void* data)
{
  std::unique_ptr<F> f (static_cast<F*>(data));
  try
    {
      (*f)();
    }
  catch(std::bad_alloc const& e)
    {
      eina_error_set(ENOMEM);
    }
  catch(std::system_error const& e)
    {
      efl::eina::set_error_code(e.code());
    }
  catch(...)
    {
      eina_error_set( efl::eina::unknown_error() );
    }
}

template <typename T>
struct _return_buffer
{
  typename std::aligned_storage<sizeof(T),std::alignment_of<T>::value>::type buffer;
};

template <>
struct _return_buffer<void>
{
};

template <typename F>
struct _data
{
  F& f;
  std::exception_ptr exception;
  typedef typename std::result_of<F()>::type result_type;
  _return_buffer<result_type> return_buffer;
};

template <typename F>
void* _ecore_main_loop_thread_safe_call_sync_callback_aux(_data<F>* d, _identity<void>)
{
  d->f();
  if(eina_error_get())
    d->exception = make_exception_ptr(std::system_error(efl::eina::get_error_code()));
  return 0;
}

template <typename F, typename R>
void* _ecore_main_loop_thread_safe_call_sync_callback_aux(_data<F>* d, _identity<R>)
{
  typedef R result_type;
  new (&d->return_buffer.buffer) result_type ( std::move(d->f()) );
  if(eina_error_get())
    {
      d->exception = make_exception_ptr(std::system_error(efl::eina::get_error_code()));
      eina_error_set(0);
      result_type* p = static_cast<result_type*>(static_cast<void*>(&d->return_buffer.buffer));
      p->~result_type();
    }
  return 0;
}

template <typename F>
void* _ecore_main_loop_thread_safe_call_sync_callback(void* data)
{
  _data<F>* d = static_cast<_data<F>*>(data);
  try
    {
      return _ecore_main_loop_thread_safe_call_sync_callback_aux
        (d, _identity<typename std::result_of<F()>::type>());
    }
  catch(std::bad_alloc const& e)
    {
      d->exception = std::current_exception();
    }
  catch(std::system_error const& e)
    {
      d->exception = std::current_exception();
    }
  catch(...)
    {
      d->exception = std::current_exception();
    }
  return 0;
}

template <typename F>
void main_loop_thread_safe_call_async(F&& f)
{
  ::ecore_main_loop_thread_safe_call_async( &ecore::_ecore_main_loop_thread_safe_call_async_callback<F>
                                            , new F(std::forward<F>(f)) );
}

template <typename F>
void _get_return_value(_data<F>& data, _identity<void>)
{
  if(data.exception)
    {
      std::rethrow_exception(data.exception);
    }
}

template <typename F, typename R>
R _get_return_value(_data<F>& data, _identity<R>)
{
  if(!data.exception)
    {
      R* b_ = static_cast<R*>(static_cast<void*>(&data.return_buffer.buffer));
      struct destroy
      {
        destroy(R* x_) : p_(x_)
        {}
        ~destroy()
        {
          p_->~R();
        }
        R* p_;
      } destroy_temp(b_);
      return std::move(*b_);
    }
  else
    {
      std::rethrow_exception(data.exception);
    }
}

template <typename F>
typename std::result_of<F()>::type
main_loop_thread_safe_call_sync(F&& f)
{
  typedef typename std::result_of<F()>::type result_type;
  _data<F> data {f, nullptr, {}};
  ::ecore_main_loop_thread_safe_call_sync
      (&ecore::_ecore_main_loop_thread_safe_call_sync_callback<F>, &data);
  return _get_return_value(data, _identity<result_type>());
}

struct ecore_init
{
  ecore_init()
  {
    ::ecore_init();
  }
  ~ecore_init()
  {
    ::ecore_shutdown();
  }
};

} }

#endif