RocketRepositoryImpl.kt

class RocketRepositoryImpl @Inject constructor(
    private val rocketApi: RocketApi,
    private val rocketDao: RocketDao
) : RocketRepository {

    override fun getRockets(): Flow<List<Rocket>> {
        return rocketDao
            .getRockets()
            .map { rocketsCached ->
                rocketsCached.map { it.toDomainModel() }
            }
            .onEach { rockets ->
                if (rockets.isEmpty()) {
                    refreshRockets()
                }
            }
    }

    override suspend fun refreshRockets() {
        rocketApi
            .getRockets()
            .map {
                it.toDomainModel().toEntityModel()
            }
            .also {
                rocketDao.saveRockets(it)
            }
    }
}