draconisplusplus/include/rfl/internal/transform_snake_case.hpp

#ifndef RFL_INTERNAL_TRANSFORMSNAKECASE_HPP_
#define RFL_INTERNAL_TRANSFORMSNAKECASE_HPP_

#include "StringLiteral.hpp"

namespace rfl::internal {

  /// Capitalizes a lower-case character.
  template <char c>
  consteval char to_upper() {
    if constexpr (c >= 'a' && c <= 'z') {
      return c + ('A' - 'a');
    } else {
      return c;
    }
  }

  /// Transforms the field name from snake case to camel case.
  template <internal::StringLiteral _name, bool _capitalize, size_t _i = 0, char... chars>
  consteval auto transform_snake_case() {
    if constexpr (_i == _name.arr_.size()) {
      return StringLiteral<sizeof...(chars) + 1>(chars...);
    } else if constexpr (_name.arr_[_i] == '_') {
      return transform_snake_case<_name, true, _i + 1, chars...>();
    } else if constexpr (_name.arr_[_i] == '\0') {
      return transform_snake_case<_name, false, _name.arr_.size(), chars...>();
    } else if constexpr (_capitalize) {
      return transform_snake_case<_name, false, _i + 1, chars..., to_upper<_name.arr_[_i]>()>();
    } else {
      return transform_snake_case<_name, false, _i + 1, chars..., _name.arr_[_i]>();
    }
  }
} // namespace rfl::internal

#endif