// Copyright (c) OpenMMLab. All rights reserved.

#ifndef MMDEPLOY_SRC_CORE_CPP_DETECTED_H_
#define MMDEPLOY_SRC_CORE_CPP_DETECTED_H_

#include <type_traits>

namespace mmdeploy::detail {

struct nonesuch {
  nonesuch() = delete;
  ~nonesuch() = delete;
  nonesuch(nonesuch const&) = delete;
  nonesuch(nonesuch const&&) = delete;
  void operator=(nonesuch const&) = delete;
  void operator=(nonesuch&&) = delete;
};

template <class Default, class AlwaysVoid, template <class...> class Op, class... Args>
struct detector {
  using value_t = std::false_type;
  using type = Default;
};

template <class Default, template <class...> class Op, class... Args>
struct detector<Default, std::void_t<Op<Args...>>, Op, Args...> {
  using value_t = std::true_type;
  using type = Op<Args...>;
};

template <template <class...> class Op, class... Args>
using is_detected = typename detector<nonesuch, void, Op, Args...>::value_t;

template <template <class...> class Op, class... Args>
using detected_t = typename detector<nonesuch, void, Op, Args...>::type;

template <template <class...> class Op, class... Args>
constexpr inline bool is_detected_v = is_detected<Op, Args...>::value;

template <class Default, template <class...> class Op, class... Args>
using detected_or = detector<Default, void, Op, Args...>;

template <class Default, template <class...> class Op, class... Args>
using detected_or_t = typename detected_or<Default, Op, Args...>::type;

template <class Expected, template <class...> class Op, class... Args>
using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;

template <class To, template <class...> class Op, class... Args>
using is_detected_convertible = std::is_convertible<detected_t<Op, Args...>, To>;

}  // namespace mmdeploy::detail

#endif  // MMDEPLOY_SRC_CORE_CPP_DETECTED_H_