draconisplusplus/include/rfl/internal/enums/Names.hpp

#ifndef RFL_INTERNAL_ENUMS_NAMES_HPP_
#define RFL_INTERNAL_ENUMS_NAMES_HPP_

#include <algorithm>
#include <array>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>

#include "../../Literal.hpp"
#include "../../define_literal.hpp"
#include "../../make_named_tuple.hpp"
#include "../StringLiteral.hpp"

namespace rfl {
  namespace internal {
    namespace enums {

      template <class EnumType, class LiteralType, size_t N, auto... _enums>
      struct Names {
        /// Contains a collection of enums as compile-time strings.
        using Literal = LiteralType;

        /// The number of possible values
        constexpr static size_t size = N;

        /// A list of all the possible enums
        constexpr static std::array<EnumType, N> enums_ =
            std::array<EnumType, N> {_enums...};

        static_assert(
            N == 0 || LiteralType::size() == N,
            "Size of literal and enum do not match."
        );

        template <class NewLiteral, auto _new_enum>
        using AddOneType = std::conditional_t<
            N == 0,
            Names<EnumType, NewLiteral, 1, _new_enum>,
            Names<
                EnumType,
                define_literal_t<LiteralType, NewLiteral>,
                N + 1,
                _enums...,
                _new_enum>>;
      };

      template <
          class EnumType,
          size_t N,
          StringLiteral... _names,
          auto... _enums>
      auto names_to_enumerator_named_tuple(Names<
                                           EnumType,
                                           Literal<_names...>,
                                           N,
                                           _enums...>) {
        return make_named_tuple(Field<_names, EnumType> {_enums}...);
      }

      template <
          class EnumType,
          size_t N,
          StringLiteral... _names,
          auto... _enums>
      auto names_to_underlying_enumerator_named_tuple(Names<
                                                      EnumType,
                                                      Literal<_names...>,
                                                      N,
                                                      _enums...>) {
        return make_named_tuple(
            Field<_names, std::underlying_type_t<EnumType>> {
                static_cast<std::underlying_type_t<EnumType>>(_enums)
            }...
        );
      }

      template <
          class EnumType,
          size_t N,
          StringLiteral... _names,
          auto... _enums>
      constexpr std::array<std::pair<std::string_view, EnumType>, N>
      names_to_enumerator_array(Names<
                                EnumType,
                                Literal<_names...>,
                                N,
                                _enums...>) {
        return {std::make_pair(
            LiteralHelper<_names>::field_.string_view(), _enums
        )...};
      }

      template <
          class EnumType,
          size_t N,
          StringLiteral... _names,
          auto... _enums>
      constexpr std::array<
          std::pair<std::string_view, std::underlying_type_t<EnumType>>,
          N>
      names_to_underlying_enumerator_array(Names<
                                           EnumType,
                                           Literal<_names...>,
                                           N,
                                           _enums...>) {
        return {std::make_pair(
            LiteralHelper<_names>::field_.string_view(),
            static_cast<std::underlying_type_t<EnumType>>(_enums)
        )...};
      }

    } // namespace enums
  } // namespace internal
} // namespace rfl

#endif