MultipleLayersSealedInterfaceErrorsExample.kt

class PostNewDeckUseCase(
    private val decksRepository: DecksRepository
) {

    suspend operator fun invoke(newDeck: Deck) : Result<Unit, PostNewDeckUseCaseError> {
        if (newDeck.cards.size != 60) {
            return Failure(InvalidDeckSizeError)
        }
        //...
        return decksRepository.createNewDeck(newDeck)
    }
}

class DecksRepository(
    private val someMagicTheGatheringApi : MagicTheGatheringApi
) {
    suspend fun createNewDeck(newDeck : Deck) : Result<Unit, CreateNewDeckError> = withContect(Dispatchers.IO) {
        someMagicTheGatheringApi.postNewDeck(newDeck.mapToDto())
        //catch api exceptions and map them to `MagicTheGatheringApiCallError`
    }
}

sealed interface PostNewDeckUseCaseError
object InvalidDeckSizeError: PostNewDeckUseCaseError

sealed interface CreateNewDeckError: PostNewDeckUseCaseError
object DeckAlreadyExistsError : CreateNewDeckError

sealed interface ApiCallError : GetSomethingUseCaseError, UpdateSomethingUseCaseError, CreateNewDeckError
//...