Implement Default Effects (#625)

Signed-off-by: mramotar <mramotar@dropbox.com>

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/PagingSourceCollector.kt

@@ -0,0 +1,30 @@
+package org.mobilenativefoundation.paging.core
+
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Represents a collector for [PagingSource.LoadResult] objects.
+ *
+ * @param Id The type of the unique identifier for each item in the paged data.
+ * @param K The type of the key used for paging.
+ * @param P The type of the parameters associated with each page of data.
+ * @param D The type of the data items.
+ * @param E The type of errors that can occur during the paging process.
+ * @param A The type of custom actions that can be dispatched.
+ */
+interface PagingSourceCollector<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any> {
+    /**
+     * Collects the load results from the [PagingSource] and dispatches appropriate [PagingAction] objects.
+     *
+     * @param params The [PagingSource.LoadParams] associated with the load operation.
+     * @param results The flow of [PagingSource.LoadResult] instances representing the load results.
+     * @param state The current [PagingState] when collecting the load results.
+     * @param dispatch The function to dispatch [PagingAction] instances based on the load results.
+     */
+    suspend operator fun invoke(
+        params: PagingSource.LoadParams<K, P>,
+        results: Flow<PagingSource.LoadResult<Id, K, P, D, E>>,
+        state: PagingState<Id, K, P, D, E>,
+        dispatch: (action: PagingAction<Id, K, P, D, E, A>) -> Unit
+    )
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/PagingSourceStreamProvider.kt

@@ -0,0 +1,22 @@
+package org.mobilenativefoundation.paging.core
+
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Represents a provider of [PagingSource.LoadResult] streams.
+ *
+ * @param Id The type of the unique identifier for each item in the paged data.
+ * @param K The type of the key used for paging.
+ * @param P The type of the parameters associated with each page of data.
+ * @param D The type of the data items.
+ * @param E The type of errors that can occur during the paging process.
+ */
+interface PagingSourceStreamProvider<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any> {
+    /**
+     * Provides a flow of [PagingSource.LoadResult] instances for the specified [PagingSource.LoadParams].
+     *
+     * @param params The [PagingSource.LoadParams] for which to provide the load result stream.
+     * @return A flow of [PagingSource.LoadResult] instances representing the load results.
+     */
+    fun provide(params: PagingSource.LoadParams<K, P>): Flow<PagingSource.LoadResult<Id, K, P, D, E>>
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/StorePagingSourceKeyFactory.kt

@@ -0,0 +1,5 @@
+package org.mobilenativefoundation.paging.core
+
+fun interface StorePagingSourceKeyFactory<Id : Comparable<Id>, K : Any, P : Any, D : Any> {
+    fun createKeyFor(single: PagingData.Single<Id, K, P, D>): PagingKey<K, P>
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/effects.kt

@@ -0,0 +1,49 @@
+package org.mobilenativefoundation.paging.core
+
+/**
+ * A type alias for an [Effect] that loads the next page of data when the paging state is [PagingState.Data.Idle].
+ *
+ * @param Id The type of the unique identifier for each item in the paged data.
+ * @param K The type of the key used for paging.
+ * @param P The type of the parameters associated with each page of data.
+ * @param D The type of the data items.
+ * @param E The type of errors that can occur during the paging process.
+ * @param A The type of custom actions that can be dispatched.
+ */
+typealias LoadNextEffect<Id, K, P, D, E, A> = Effect<Id, K, P, D, E, A, PagingAction.UpdateData<Id, K, P, D, E, A>, PagingState.Data.Idle<Id, K, P, D, E>>
+
+/**
+ * A type alias for an [Effect] that loads data when a [PagingAction.Load] action is dispatched and the paging state is [PagingState].
+ *
+ * @param Id The type of the unique identifier for each item in the paged data.
+ * @param K The type of the key used for paging.
+ * @param P The type of the parameters associated with each page of data.
+ * @param D The type of the data items.
+ * @param E The type of errors that can occur during the paging process.
+ * @param A The type of custom actions that can be dispatched to modify the paging state.
+ */
+typealias AppLoadEffect<Id, K, P, D, E, A> = Effect<Id, K, P, D, E, A, PagingAction.Load<Id, K, P, D, E, A>, PagingState<Id, K, P, D, E>>
+
+/**
+ * A type alias for an [Effect] that loads data when a [PagingAction.User.Load] action is dispatched and the paging state is [PagingState.Loading].
+ *
+ * @param Id The type of the unique identifier for each item in the paged data.
+ * @param K The type of the key used for paging.
+ * @param P The type of the parameters associated with each page of data.
+ * @param D The type of the data items.
+ * @param E The type of errors that can occur during the paging process.
+ * @param A The type of custom actions that can be dispatched to modify the paging state.
+ */
+typealias UserLoadEffect<Id, K, P, D, E, A> = Effect<Id, K, P, D, E, A, PagingAction.User.Load<Id, K, P, D, E, A>, PagingState.Loading<Id, K, P, D, E>>
+
+/**
+ * A type alias for an [Effect] that loads more data when a [PagingAction.User.Load] action is dispatched and the paging state is [PagingState.Data.LoadingMore].
+ *
+ * @param Id The type of the unique identifier for each item in the paged data.
+ * @param K The type of the key used for paging.
+ * @param P The type of the parameters associated with each page of data.
+ * @param D The type of the data items.
+ * @param E The type of errors that can occur during the paging process.
+ * @param A The type of custom actions that can be dispatched to modify the paging state.
+ */
+typealias UserLoadMoreEffect<Id, K, P, D, E, A> = Effect<Id, K, P, D, E, A, PagingAction.User.Load<Id, K, P, D, E, A>, PagingState.Data.LoadingMore<Id, K, P, D, E>>

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/impl/DefaultAppLoadEffect.kt

@@ -0,0 +1,43 @@
+package org.mobilenativefoundation.paging.core.impl
+
+import org.mobilenativefoundation.paging.core.AppLoadEffect
+import org.mobilenativefoundation.paging.core.Logger
+import org.mobilenativefoundation.paging.core.PagingAction
+import org.mobilenativefoundation.paging.core.PagingSource
+import org.mobilenativefoundation.paging.core.PagingSourceCollector
+import org.mobilenativefoundation.paging.core.PagingState
+
+class DefaultAppLoadEffect<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+    loggerInjector: OptionalInjector<Logger>,
+    dispatcherInjector: Injector<Dispatcher<Id, K, P, D, E, A>>,
+    pagingSourceCollectorInjector: Injector<PagingSourceCollector<Id, K, P, D, E, A>>,
+    pagingSourceInjector: Injector<PagingSource<Id, K, P, D, E>>,
+    private val jobCoordinator: JobCoordinator,
+    private val stateManager: StateManager<Id, K, P, D, E>,
+) : AppLoadEffect<Id, K, P, D, E, A> {
+    private val logger = lazy { loggerInjector.inject() }
+    private val dispatcher = lazy { dispatcherInjector.inject() }
+    private val pagingSourceCollector = lazy { pagingSourceCollectorInjector.inject() }
+    private val pagingSource = lazy { pagingSourceInjector.inject() }
+
+    override fun invoke(action: PagingAction.Load<Id, K, P, D, E, A>, state: PagingState<Id, K, P, D, E>, dispatch: (PagingAction<Id, K, P, D, E, A>) -> Unit) {
+        logger.value?.log(
+            """Running post reducer effect:
+                Effect: App load
+                State: $state
+                Action: $action
+            """.trimIndent(),
+        )
+
+        jobCoordinator.launchIfNotActive(action.key) {
+            val params = PagingSource.LoadParams(action.key, true)
+            pagingSourceCollector.value(
+                params,
+                pagingSource.value.stream(params),
+                stateManager.state.value,
+                dispatcher.value::dispatch
+            )
+        }
+    }
+
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/impl/DefaultLoadNextEffect.kt

@@ -0,0 +1,30 @@
+package org.mobilenativefoundation.paging.core.impl
+
+import org.mobilenativefoundation.paging.core.LoadNextEffect
+import org.mobilenativefoundation.paging.core.Logger
+import org.mobilenativefoundation.paging.core.PagingAction
+import org.mobilenativefoundation.paging.core.PagingState
+
+class DefaultLoadNextEffect<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+    loggerInjector: OptionalInjector<Logger>,
+    queueManagerInjector: Injector<QueueManager<K, P>>,
+) : LoadNextEffect<Id, K, P, D, E, A> {
+
+    private val logger = lazy { loggerInjector.inject() }
+    private val queueManager = lazy { queueManagerInjector.inject() }
+
+    override fun invoke(action: PagingAction.UpdateData<Id, K, P, D, E, A>, state: PagingState.Data.Idle<Id, K, P, D, E>, dispatch: (PagingAction<Id, K, P, D, E, A>) -> Unit) {
+        logger.value?.log(
+            """
+            Running post reducer effect:
+                Effect: Load next
+                State: $state
+                Action: $action
+            """.trimIndent(),
+        )
+
+        action.data.collection.nextKey?.key?.let {
+            queueManager.value.enqueue(action.data.collection.nextKey)
+        }
+    }
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/impl/DefaultPagingSourceCollector.kt

@@ -0,0 +1,23 @@
+package org.mobilenativefoundation.paging.core.impl
+
+import kotlinx.coroutines.flow.Flow
+import org.mobilenativefoundation.paging.core.PagingAction
+import org.mobilenativefoundation.paging.core.PagingSource
+import org.mobilenativefoundation.paging.core.PagingSourceCollector
+import org.mobilenativefoundation.paging.core.PagingState
+
+class DefaultPagingSourceCollector<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any> : PagingSourceCollector<Id, K, P, D, E, A> {
+    override suspend fun invoke(
+        params: PagingSource.LoadParams<K, P>,
+        results: Flow<PagingSource.LoadResult<Id, K, P, D, E>>,
+        state: PagingState<Id, K, P, D, E>,
+        dispatch: (action: PagingAction<Id, K, P, D, E, A>) -> Unit
+    ) {
+        results.collect { result ->
+            when (result) {
+                is PagingSource.LoadResult.Data -> dispatch(PagingAction.UpdateData(params, result))
+                is PagingSource.LoadResult.Error -> dispatch(PagingAction.UpdateError(params, result))
+            }
+        }
+    }
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/impl/DefaultUserLoadEffect.kt

@@ -0,0 +1,43 @@
+package org.mobilenativefoundation.paging.core.impl
+
+import org.mobilenativefoundation.paging.core.Logger
+import org.mobilenativefoundation.paging.core.PagingAction
+import org.mobilenativefoundation.paging.core.PagingSource
+import org.mobilenativefoundation.paging.core.PagingSourceCollector
+import org.mobilenativefoundation.paging.core.PagingState
+import org.mobilenativefoundation.paging.core.UserLoadEffect
+
+class DefaultUserLoadEffect<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+    loggerInjector: OptionalInjector<Logger>,
+    dispatcherInjector: Injector<Dispatcher<Id, K, P, D, E, A>>,
+    pagingSourceCollectorInjector: Injector<PagingSourceCollector<Id, K, P, D, E, A>>,
+    pagingSourceInjector: Injector<PagingSource<Id, K, P, D, E>>,
+    private val jobCoordinator: JobCoordinator,
+    private val stateManager: StateManager<Id, K, P, D, E>,
+) : UserLoadEffect<Id, K, P, D, E, A> {
+    private val logger = lazy { loggerInjector.inject() }
+    private val dispatcher = lazy { dispatcherInjector.inject() }
+    private val pagingSourceCollector = lazy { pagingSourceCollectorInjector.inject() }
+    private val pagingSource = lazy { pagingSourceInjector.inject() }
+
+    override fun invoke(action: PagingAction.User.Load<Id, K, P, D, E, A>, state: PagingState.Loading<Id, K, P, D, E>, dispatch: (PagingAction<Id, K, P, D, E, A>) -> Unit) {
+        logger.value?.log(
+            """Running post reducer effect:
+                Effect: User load
+                State: $state
+                Action: $action
+            """.trimIndent(),
+        )
+
+        jobCoordinator.launch(action.key) {
+            val params = PagingSource.LoadParams(action.key, true)
+            pagingSourceCollector.value(
+                params,
+                pagingSource.value.stream(params),
+                stateManager.state.value,
+                dispatcher.value::dispatch
+            )
+        }
+    }
+
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/impl/DefaultUserLoadMoreEffect.kt

@@ -0,0 +1,43 @@
+package org.mobilenativefoundation.paging.core.impl
+
+import org.mobilenativefoundation.paging.core.Logger
+import org.mobilenativefoundation.paging.core.PagingAction
+import org.mobilenativefoundation.paging.core.PagingSource
+import org.mobilenativefoundation.paging.core.PagingSourceCollector
+import org.mobilenativefoundation.paging.core.PagingState
+import org.mobilenativefoundation.paging.core.UserLoadMoreEffect
+
+class DefaultUserLoadMoreEffect<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+    loggerInjector: OptionalInjector<Logger>,
+    dispatcherInjector: Injector<Dispatcher<Id, K, P, D, E, A>>,
+    pagingSourceCollectorInjector: Injector<PagingSourceCollector<Id, K, P, D, E, A>>,
+    pagingSourceInjector: Injector<PagingSource<Id, K, P, D, E>>,
+    private val jobCoordinator: JobCoordinator,
+    private val stateManager: StateManager<Id, K, P, D, E>,
+) : UserLoadMoreEffect<Id, K, P, D, E, A> {
+    private val logger = lazy { loggerInjector.inject() }
+    private val dispatcher = lazy { dispatcherInjector.inject() }
+    private val pagingSourceCollector = lazy { pagingSourceCollectorInjector.inject() }
+    private val pagingSource = lazy { pagingSourceInjector.inject() }
+
+    override fun invoke(action: PagingAction.User.Load<Id, K, P, D, E, A>, state: PagingState.Data.LoadingMore<Id, K, P, D, E>, dispatch: (PagingAction<Id, K, P, D, E, A>) -> Unit) {
+        logger.value?.log(
+            """Running post reducer effect:
+                Effect: User load more
+                State: $state
+                Action: $action
+            """.trimIndent(),
+        )
+
+        jobCoordinator.launch(action.key) {
+            val params = PagingSource.LoadParams(action.key, true)
+            pagingSourceCollector.value(
+                params,
+                pagingSource.value.stream(params),
+                stateManager.state.value,
+                dispatcher.value::dispatch
+            )
+        }
+    }
+
+}

paging/core/src/commonMain/kotlin/org/mobilenativefoundation/paging/core/impl/StorePagingSourceStreamProvider.kt

@@ -0,0 +1,78 @@
+package org.mobilenativefoundation.paging.core.impl
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import org.mobilenativefoundation.paging.core.PagingData
+import org.mobilenativefoundation.paging.core.PagingKey
+import org.mobilenativefoundation.paging.core.PagingSource
+import org.mobilenativefoundation.paging.core.PagingSourceStreamProvider
+import org.mobilenativefoundation.paging.core.StorePagingSourceKeyFactory
+import org.mobilenativefoundation.store.store5.StoreReadResponse
+
+class StorePagingSourceStreamProvider<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+    private val createParentStream: (key: PagingKey<K, P>) -> Flow<PagingSource.LoadResult<Id, K, P, D, E>>,
+    private val createChildStream: (key: PagingKey<K, P>) -> Flow<StoreReadResponse<PagingData<Id, K, P, D>>>,
+    private val keyFactory: StorePagingSourceKeyFactory<Id, K, P, D>
+) : PagingSourceStreamProvider<Id, K, P, D, E> {
+    private val pages: MutableMap<PagingKey<K, P>, PagingSource.LoadResult.Data<Id, K, P, D>> = mutableMapOf()
+    private val mutexForPages = Mutex()
+
+    override fun provide(params: PagingSource.LoadParams<K, P>): Flow<PagingSource.LoadResult<Id, K, P, D, E>> =
+        createParentStream(params.key).map { result ->
+            when (result) {
+                is PagingSource.LoadResult.Data -> {
+                    mutexForPages.withLock {
+                        pages[params.key] = result
+                    }
+
+                    var data = result
+
+                    result.collection.items.forEach { child ->
+                        val childKey = keyFactory.createKeyFor(child)
+                        initAndCollectChildStream(child, childKey, params.key) { updatedData -> data = updatedData }
+                    }
+
+                    data
+                }
+
+                is PagingSource.LoadResult.Error -> result
+            }
+        }
+
+    private fun initAndCollectChildStream(
+        data: PagingData.Single<Id, K, P, D>,
+        key: PagingKey<K, P>,
+        parentKey: PagingKey<K, P>,
+        emit: (updatedData: PagingSource.LoadResult.Data<Id, K, P, D>) -> Unit
+    ) {
+        createChildStream(key).distinctUntilChanged().onEach { response ->
+
+            if (response is StoreReadResponse.Data) {
+                val updatedValue = response.value
+
+                if (updatedValue is PagingData.Single) {
+                    mutexForPages.withLock {
+                        pages[parentKey]!!.let { currentData ->
+                            val updatedItems = currentData.collection.items.toMutableList()
+                            val indexOfChild = updatedItems.indexOfFirst { it.id == data.id }
+                            val child = updatedItems[indexOfChild]
+                            if (child != updatedValue) {
+                                updatedItems[indexOfChild] = updatedValue
+
+                                val updatedPage = currentData.copy(collection = currentData.collection.copy(items = updatedItems))
+
+                                pages[parentKey] = updatedPage
+
+                                emit(updatedPage)
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}