#pragma once

#include <boost/signals2.hpp>
#include <boost/signals2/variadic_signal.hpp>
#include <type_traits>

using namespace boost::signals2;

// Base adapter interface exposing a typed callback signal and name.
template <typename InType, typename CallbackRetTypeTag, typename... CbkAargs> class AdapterBase {
  using cbk_ret_type_t_ = typename CallbackRetTypeTag::type;

  // If return type is not void we combine all callback invocation results.
  class CollectAllCombiner_ {
  public:
    using result_type = std::conditional_t<!std::is_void_v<cbk_ret_type_t_>, std::vector<cbk_ret_type_t_>, std::false_type>;

    template <typename InputIterator> result_type operator()(InputIterator first, InputIterator last) const {
      result_type results;
      if constexpr (!std::is_same_v<result_type, std::false_type>) {
        for (; first != last; ++first) {
          results.push_back(*first);
        }
      }

      return results;
    }
  };

public:
  // Use combiner if return type is not void
  using signature_t = std::conditional_t<std::is_void_v<cbk_ret_type_t_>, void(const InType &, CbkAargs &&...), cbk_ret_type_t_(const InType &, CbkAargs &&...)>;
  using callback_type_t = std::conditional_t<!std::is_void_v<cbk_ret_type_t_>, signal<signature_t, CollectAllCombiner_>, signal<signature_t>>;

  AdapterBase(const std::string &name) : mc_name_(name) {}

  virtual callback_type_t &callback() const = 0;
  inline const auto &name() const { return mc_name_; }

private:
  const std::string mc_name_;
};