/*
 *  Copyright (C) 2015 Naios <naios-dev@live.de>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _CALLBACK_H_
#define _CALLBACK_H_

#include <functional>
#include <utility>
#include <memory>

#include "functional_unwrap.hpp"

template<typename... Args>
using Callback = std::function<void(Args...)>;

template<typename... Args>
using SharedCallback = std::shared_ptr<Callback<Args...>>;

template<typename... Args>
using WeakCallback = std::weak_ptr<Callback<Args...>>;

namespace detail
{
    template<typename... Args>
    struct do_unwrap_callback;

    template<typename... Args>
    struct do_unwrap_callback<::fu::identity<Args...>>
    {
        typedef Callback<Args...> CallbackType;

        typedef SharedCallback<Args...> SharedCallbackType;

        typedef WeakCallback<Args...> WeakCallbackType;
    };

    template<typename _CTy>
    using unwrap_callback = do_unwrap_callback<::fu::argument_type_of_t<_CTy>>;

    /*
    template<typename... Args>
    struct WeakProxyFactory
    {
        static Callback<Args...> CreateProxyFromWeak(WeakCallback<Args...> const& weak_callback)
        {
            return [=](Args&&... args)
            {
                if (auto const callback = weak_callback.lock())
                    (*callback)(args...); // FIXME: use std::forward
            };
        }

        static Callback<Args...> CreateProxyFromShared(SharedCallback<Args...> const& shared_callback)
        {
            return CreateProxyFromWeak(WeakCallback<Args...>(shared_callback));
        }
    };
    */

} // detail

template<typename _CTy>
using callback_of_t = typename detail::unwrap_callback<_CTy>::CallbackType;

template<typename _CTy>
using shared_callback_of_t = typename detail::unwrap_callback<_CTy>::SharedCallbackType;

template<typename _CTy>
using weak_callback_of_t = typename detail::unwrap_callback<_CTy>::WeakCallbackType;

template<typename _CTy>
inline shared_callback_of_t<_CTy>
    make_shared_callback(_CTy&& callback)
{
    return std::make_shared<callback_of_t<_CTy>>
        (std::forward<callback_of_t<_CTy>>(callback));
}

/* Disabled due to clang errors
template<typename... Args>
inline auto make_weak_wrapped_callback(WeakCallback<Args...> const& weak_callback)
    -> Callback<Args...>
{
    // Some workarounds for clang...
    return detail::WeakProxyFactory<Args...>::CreateProxyFromWeak(weak_callback);
}

template<typename... Args>
inline auto make_weak_wrapped_callback(SharedCallback<Args...> const& shared_callback)
    -> Callback<Args...>
{
    // Some workarounds for clang...
    return detail::WeakProxyFactory<Args...>::CreateProxyFromShared(shared_callback);
}
*/

#endif /// _CALLBACK_H_