draconisplusplus/include/rfl/parsing/MapParser.hpp

#ifndef RFL_PARSING_MAPPARSER_HPP_
#define RFL_PARSING_MAPPARSER_HPP_

#include <map>
#include <stdexcept>
#include <string>
#include <type_traits>

#include "../Ref.hpp"
#include "../Result.hpp"
#include "../always_false.hpp"
#include "MapReader.hpp"
#include "Parent.hpp"
#include "Parser_base.hpp"
#include "schema/Type.hpp"
#include "to_single_error_message.hpp"

namespace rfl {
  namespace parsing {

    template <class R, class W, class MapType, class ProcessorsType>
      requires AreReaderAndWriter<R, W, MapType>
    struct MapParser {
     public:
      using InputObjectType = typename R::InputObjectType;
      using InputVarType    = typename R::InputVarType;

      using OutputObjectType = typename W::OutputObjectType;
      using OutputVarType    = typename W::OutputVarType;

      using KeyType   = std::remove_cvref_t<typename MapType::value_type::first_type>;
      using ValueType = std::remove_cvref_t<typename MapType::value_type::second_type>;

      using ParentType = Parent<W>;

      static Result<MapType> read(const R& _r, const InputVarType& _var) noexcept {
        const auto to_map = [&](auto obj) -> Result<MapType> { return make_map(_r, obj); };
        return _r.to_object(_var).and_then(to_map);
      }

      template <class P>
      static void write(const W& _w, const MapType& _m, const P& _parent) noexcept {
        auto obj = ParentType::add_object(_w, _m.size(), _parent);
        for (const auto& [k, v] : _m) {
          if constexpr (internal::has_reflection_type_v<KeyType>) {
            using ReflT = typename KeyType::ReflectionType;

            if constexpr (std::is_integral_v<ReflT> || std::is_floating_point_v<ReflT>) {
              const auto name       = std::to_string(k.reflection());
              const auto new_parent = typename ParentType::Object { name, &obj };
              Parser<R, W, std::remove_cvref_t<ValueType>, ProcessorsType>::write(
                _w, v, new_parent
              );
            } else {
              const auto name       = k.reflection();
              const auto new_parent = typename ParentType::Object { name, &obj };
              Parser<R, W, std::remove_cvref_t<ValueType>, ProcessorsType>::write(
                _w, v, new_parent
              );
            }

          } else if constexpr (std::is_integral_v<KeyType> || std::is_floating_point_v<KeyType>) {
            const auto name       = std::to_string(k);
            const auto new_parent = typename ParentType::Object { name, &obj };
            Parser<R, W, std::remove_cvref_t<ValueType>, ProcessorsType>::write(_w, v, new_parent);
          } else {
            const auto new_parent = typename ParentType::Object { k, &obj };
            Parser<R, W, std::remove_cvref_t<ValueType>, ProcessorsType>::write(_w, v, new_parent);
          }
        }
        _w.end_object(&obj);
      }

      static schema::Type to_schema(std::map<std::string, schema::Type>* _definitions) {
        return schema::Type { schema::Type::StringMap {
          Ref<schema::Type>::make(Parser<R, W, ValueType, ProcessorsType>::to_schema(_definitions)
          ) } };
      }

     private:
      static Result<MapType> make_map(const R& _r, const InputObjectType& _obj) {
        MapType            map;
        std::vector<Error> errors;
        const auto map_reader = MapReader<R, W, MapType, ProcessorsType>(&_r, &map, &errors);
        const auto err        = _r.read_object(map_reader, _obj);
        if (err) {
          return *err;
        }
        if (errors.size() != 0) {
          return to_single_error_message(errors);
        }
        return map;
      }
    };

  } // namespace parsing
} // namespace rfl

#endif