start add paged/loading component

pagination/compose/src/commonMain/kotlin/PagedComponent.kt

@@ -0,0 +1,108 @@
+package dev.inmo.micro_utils.pagination.compose
+
+import androidx.compose.runtime.*
+import dev.inmo.micro_utils.common.Optional
+import dev.inmo.micro_utils.common.dataOrThrow
+import dev.inmo.micro_utils.common.optional
+import dev.inmo.micro_utils.pagination.*
+
+class PagedComponentContext<T> internal constructor(
+    preset: PaginationResult<T>? = null,
+    initialPage: Int,
+    size: Int
+) {
+    internal val iterationState: MutableState<Pair<Int, Pagination>> = mutableStateOf(0 to SimplePagination(preset ?.page ?: initialPage, preset ?.size ?: size))
+
+    internal var dataOptional: PaginationResult<T>? = preset
+        private set
+    internal val dataState: MutableState<PaginationResult<T>?> = mutableStateOf(dataOptional)
+
+    fun loadNext() {
+        iterationState.value = iterationState.value.let {
+            if (dataState.value ?.isLastPage == true) return
+            (it.first + 1) to it.second.nextPage()
+        }
+    }
+    fun loadPrevious() {
+        iterationState.value = iterationState.value.let {
+            if (it.second.isFirstPage) return
+            (it.first - 1) to SimplePagination(
+                it.second.page - 1,
+                it.second.size
+            )
+        }
+    }
+    fun reload() {
+        iterationState.value = iterationState.value.let {
+            it.copy(it.first + 1)
+        }
+    }
+}
+
+@Composable
+internal fun <T> PagedComponent(
+    preload: PaginationResult<T>?,
+    initialPage: Int,
+    size: Int,
+    loader: suspend PagedComponentContext<T>.(Pagination) -> PaginationResult<T>,
+    block: @Composable PagedComponentContext<T>.(PaginationResult<T>) -> Unit
+) {
+    val context = remember { PagedComponentContext(preload, initialPage, size) }
+
+    LaunchedEffect(context.iterationState.value) {
+        context.dataState.value = loader(context, context.iterationState.value.second)
+    }
+
+    context.dataState.value ?.let {
+        context.block(it)
+    }
+}
+
+@Composable
+fun <T> PagedComponent(
+    preload: PaginationResult<T>,
+    loader: suspend PagedComponentContext<T>.(Pagination) -> PaginationResult<T>,
+    block: @Composable PagedComponentContext<T>.(PaginationResult<T>) -> Unit
+) {
+    PagedComponent(
+        preload,
+        preload.page,
+        preload.size,
+        loader,
+        block
+    )
+}
+
+@Composable
+fun <T> PagedComponent(
+    pageInfo: Pagination,
+    loader: suspend PagedComponentContext<T>.(Pagination) -> PaginationResult<T>,
+    block: @Composable PagedComponentContext<T>.(PaginationResult<T>) -> Unit
+) {
+    PagedComponent(
+        null,
+        pageInfo.page,
+        pageInfo.size,
+        loader,
+        block
+    )
+}
+
+@Composable
+fun <T> PagedComponent(
+    initialPage: Int,
+    size: Int,
+    loader: suspend PagedComponentContext<T>.(Pagination) -> PaginationResult<T>,
+    block: @Composable PagedComponentContext<T>.(PaginationResult<T>) -> Unit
+) {
+    PagedComponent(null, initialPage, size, loader, block)
+}
+
+@Composable
+fun <T> PagedComponent(
+    size: Int,
+    loader: suspend PagedComponentContext<T>.(Pagination) -> PaginationResult<T>,
+    block: @Composable PagedComponentContext<T>.(PaginationResult<T>) -> Unit
+) {
+    PagedComponent(0, size, loader, block)
+}