draconisplusplus/include/rfl/toml/Writer.hpp

#ifndef RFL_TOML_WRITER_HPP_
#define RFL_TOML_WRITER_HPP_

#include <exception>
#include <map>
#include <sstream>
#include <stdexcept>
#include <string>
#include <string_view>
#include <toml++/toml.hpp>
#include <type_traits>
#include <vector>

#include "../Ref.hpp"
#include "../Result.hpp"
#include "../always_false.hpp"

namespace rfl::toml {

  class Writer {
   public:
    struct TOMLArray {
      ::toml::array* val_;
    };

    struct TOMLObject {
      ::toml::table* val_;
    };

    struct TOMLVar {};

    using OutputArrayType  = TOMLArray;
    using OutputObjectType = TOMLObject;
    using OutputVarType    = TOMLVar;

    Writer(::toml::table* _root) : root_(_root) {}

    ~Writer() = default;

    template <class T>
    OutputArrayType array_as_root(const T _size) const noexcept {
      static_assert(rfl::always_false_v<T>, "TOML only allows tables as the root element.");
      return OutputArrayType { nullptr };
    }

    OutputObjectType object_as_root(const size_t _size) const noexcept {
      return OutputObjectType { root_ };
    }

    OutputVarType null_as_root() const noexcept { return OutputVarType {}; }

    template <class T>
    OutputVarType value_as_root(const T& _var) const noexcept {
      static_assert(rfl::always_false_v<T>, "TOML only allows tables as the root element.");
      return OutputVarType {};
    }

    OutputArrayType add_array_to_array(const size_t _size, OutputArrayType* _parent)
      const noexcept {
      const auto i = _parent->val_->size();
      _parent->val_->push_back(::toml::array());
      return OutputArrayType { _parent->val_->at(i).as_array() };
    }

    OutputArrayType add_array_to_object(
      const std::string_view& _name,
      const size_t            _size,
      OutputObjectType*       _parent
    ) const noexcept {
      _parent->val_->emplace(_name, ::toml::array());
      return OutputArrayType { _parent->val_->at_path(_name).as_array() };
    }

    OutputObjectType add_object_to_array(const size_t _size, OutputArrayType* _parent)
      const noexcept {
      const auto i = _parent->val_->size();
      _parent->val_->push_back(::toml::table());
      return OutputObjectType { _parent->val_->at(i).as_table() };
    }

    OutputObjectType add_object_to_object(
      const std::string_view& _name,
      const size_t            _size,
      OutputObjectType*       _parent
    ) const noexcept {
      _parent->val_->emplace(_name, ::toml::table());
      return OutputObjectType { _parent->val_->at_path(_name).as_table() };
    }

    template <class T>
    OutputVarType add_value_to_array(const T& _var, OutputArrayType* _parent) const noexcept {
      _parent->val_->push_back(::toml::value(_var));
      return OutputVarType {};
    }

    template <class T>
    OutputVarType add_value_to_object(
      const std::string_view& _name,
      const T&                _var,
      OutputObjectType*       _parent
    ) const noexcept {
      _parent->val_->emplace(_name, ::toml::value(_var));
      return OutputVarType {};
    }

    OutputVarType add_null_to_array(OutputArrayType* _parent) const noexcept {
      _parent->val_->push_back(std::string(""));
      return OutputVarType {};
    }

    OutputVarType add_null_to_object(const std::string_view& _name, OutputObjectType* _parent)
      const noexcept {
      _parent->val_->emplace(_name, ::toml::value(std::string("")));
      return OutputVarType {};
    }

    void end_array(OutputArrayType* _arr) const noexcept {}

    void end_object(OutputObjectType* _obj) const noexcept {}

   private:
    ::toml::table* root_;
  };

} // namespace rfl::toml

#endif // JSON_PARSER_HPP_