from dataclasses import dataclass

from litestar import Litestar, get
from litestar.dto import DataclassDTO


@dataclass(frozen=True)
class UserId:
    value: int


@dataclass(frozen=True)
class UserResponse:
    user_id: UserId


class UserResponseDTO(DataclassDTO[UserResponse]):
    pass


@get("/user", return_dto=UserResponseDTO)
async def get_user() -> UserResponse:
    return UserResponse(user_id=UserId(42))


app = Litestar(
    route_handlers=[get_user],
    type_encoders={UserId: lambda uid: uid.value},
)