Define PagingAction and PagingState

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

@@ -0,0 +1,71 @@
+package org.mobilenativefoundation.paging.core
+
+/**
+ * Defines the actions that can be dispatched to modify the paging state.
+ *
+ * @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.
+ */
+sealed interface PagingAction<Id : Comparable<Id>, out K : Any, out P : Any, out D : Any, out E : Any, out A : Any> {
+
+    /**
+     * Defines user-initiated actions.
+     */
+    sealed interface User<Id : Comparable<Id>, out K : Any, out P : Any, out D : Any, out E : Any, out A : Any> : PagingAction<Id, K, P, D, E, A> {
+
+        /**
+         * Represents a user-initiated action to load data for a specific page key.
+         *
+         * @param key The page key to load data for.
+         */
+        data class Load<Id : Comparable<Id>, out K : Any, out P : Any, out D : Any, out E : Any, out A : Any>(
+            val key: PagingKey<K, P>,
+        ) : User<Id, K, P, D, E, A>
+
+        /**
+         * Represents a custom user-initiated action.
+         *
+         * @param action The custom action payload.
+         */
+        data class Custom<Id : Comparable<Id>, out K : Any, out P : Any, out D : Any, out E : Any, out A : Any>(
+            val action: A
+        ) : User<Id, K, P, D, E, A>
+    }
+
+
+    /**
+     * Represents an app-initiated action to load data for a specific page key.
+     *
+     * @param key The page key to load data for.
+     */
+    data class Load<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+        val key: PagingKey<K, P>,
+    ) : PagingAction<Id, K, P, D, E, A>
+
+    /**
+     * Represents an app-initiated action to update the paging state with loaded data.
+     *
+     * @param params The parameters associated with the loaded data.
+     * @param data The loaded data.
+     */
+    data class UpdateData<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+        val params: PagingSource.LoadParams<K, P>,
+        val data: PagingSource.LoadResult.Data<Id, K, P, D>
+    ) : PagingAction<Id, K, P, D, E, A>
+
+    /**
+     * Represents an app-initiated action to update the paging state with an error.
+     *
+     * @param params The parameters associated with the error.
+     * @param error The error that occurred.
+     */
+    data class UpdateError<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, A : Any>(
+        val params: PagingSource.LoadParams<K, P>,
+        val error: PagingSource.LoadResult.Error<Id, K, P, D, E>
+    ) : PagingAction<Id, K, P, D, E, A>
+
+}

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

@@ -0,0 +1,79 @@
+package org.mobilenativefoundation.paging.core
+
+/**
+ * Represents the current state of the paging data.
+ *
+ * The paging state can be in different stages, such as [Initial], [Loading], [Error], or [Data].
+ * It can contain the current key, prefetch position, errors, and data, such as loaded items and the next key.
+ *
+ * @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.
+ */
+sealed interface PagingState<Id : Comparable<Id>, out K : Any, out P : Any, out D : Any, out E : Any> {
+    val currentKey: PagingKey<K, P>
+    val prefetchPosition: PagingKey<K, P>?
+
+    data class Initial<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+        override val currentKey: PagingKey<K, P>,
+        override val prefetchPosition: PagingKey<K, P>?
+    ) : PagingState<Id, K, P, D, E>
+
+    data class Loading<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+        override val currentKey: PagingKey<K, P>,
+        override val prefetchPosition: PagingKey<K, P>?
+    ) : PagingState<Id, K, P, D, E>
+
+    sealed interface Error<Id : Comparable<Id>, out K : Any, out P : Any, out D : Any, out E : Any, out RE : Any> : PagingState<Id, K, P, D, E> {
+        val error: RE
+
+        data class Exception<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+            override val error: Throwable,
+            override val currentKey: PagingKey<K, P>,
+            override val prefetchPosition: PagingKey<K, P>?
+        ) : Error<Id, K, P, D, E, Throwable>
+
+        data class Custom<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+            override val error: E,
+            override val currentKey: PagingKey<K, P>,
+            override val prefetchPosition: PagingKey<K, P>?
+        ) : Error<Id, K, P, D, E, E>
+    }
+
+    sealed interface Data<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any> : PagingState<Id, K, P, D, E> {
+        val data: List<PagingData.Single<Id, K, P, D>>
+        val itemsBefore: Int?
+        val itemsAfter: Int?
+        val nextKey: PagingKey<K, P>?
+
+        data class Idle<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+            override val data: List<PagingData.Single<Id, K, P, D>>,
+            override val itemsBefore: Int?,
+            override val itemsAfter: Int?,
+            override val nextKey: PagingKey<K, P>?,
+            override val currentKey: PagingKey<K, P>,
+            override val prefetchPosition: PagingKey<K, P>?
+        ) : Data<Id, K, P, D, E>
+
+        data class LoadingMore<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any>(
+            override val data: List<PagingData.Single<Id, K, P, D>>,
+            override val itemsBefore: Int?,
+            override val itemsAfter: Int?,
+            override val nextKey: PagingKey<K, P>?,
+            override val currentKey: PagingKey<K, P>,
+            override val prefetchPosition: PagingKey<K, P>?
+        ) : Data<Id, K, P, D, E>
+
+        data class ErrorLoadingMore<Id : Comparable<Id>, K : Any, P : Any, D : Any, E : Any, RE : Any>(
+            override val error: RE,
+            override val data: List<PagingData.Single<Id, K, P, D>>,
+            override val itemsBefore: Int?,
+            override val itemsAfter: Int?,
+            override val nextKey: PagingKey<K, P>?,
+            override val currentKey: PagingKey<K, P>,
+            override val prefetchPosition: PagingKey<K, P>?
+        ) : Data<Id, K, P, D, E>, Error<Id, K, P, D, E, RE>
+    }
+}