Repository resource

Resource.kt

class Resource<in Input, out Output>(
    private val remoteFetch: suspend (Input) -> Output?,
    private val localFetch: suspend (Input) -> Output?,
    private val localStore: suspend (Output) -> Unit,
    private val localDelete: suspend () -> Unit,
    private val refreshControl: RefreshControl = RefreshControl()
) : RefreshControl.Listener, ITimeLimitedResource by refreshControl {

    init { refreshControl.addListener(this) }

    // Public API
    suspend fun query(args: Input, force: Boolean = false): Flow<Output?> = flow {
        if (!force) {
            fetchFromLocal(args)?.run { emit(this) }
        }
        if (refreshControl.isExpired() || force) {
            fetchFromRemote(args).run { emit(this) }
        }
    }

    override suspend fun cleanup() {
        deleteLocal()
    }

    // Private API
    private suspend fun deleteLocal() = kotlin.runCatching {
        localDelete()
    }.getOrNull()


    private suspend fun fetchFromLocal(args: Input) = kotlin.runCatching {
        localFetch(args)
    }.getOrNull()

    private suspend fun fetchFromRemote(args: Input) = kotlin.runCatching {
        remoteFetch(args)
    }.getOrThrow()?.also {
        kotlin.runCatching {
            localStore(it)
            refreshControl.refresh()
        }
    }
}