Save scroll offset of bottom navigation screens (#324)

* Save scroll offset of bottom navigation screens

* Save scroll offset of folder detail

feature/folder-detail/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/detail/FolderDetailFeature.kt

@@ -20,8 +20,14 @@ import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import br.alexandregpereira.hunter.domain.folder.model.MonsterPreviewFolder
 import br.alexandregpereira.hunter.folder.detail.di.FolderDetailStateRecoveryQualifier
 import br.alexandregpereira.hunter.folder.detail.ui.FolderDetailScreen
+import br.alexandregpereira.hunter.ui.compendium.monster.ColorState
+import br.alexandregpereira.hunter.ui.compendium.monster.MonsterCardState
+import br.alexandregpereira.hunter.ui.compendium.monster.MonsterImageState
+import br.alexandregpereira.hunter.ui.compendium.monster.MonsterTypeState
 import br.alexandregpereira.hunter.ui.compose.StateRecoveryLaunchedEffect
 import org.koin.compose.koinInject
 import org.koin.core.qualifier.named
@@ -38,10 +44,35 @@ fun FolderDetailFeature(
     val state by viewModel.state.collectAsState()
 
     FolderDetailScreen(
-        state = state,
+        isOpen = state.isOpen,
+        folderName = state.folderName,
+        monsters = remember(state.monsters) { state.monsters.asState() },
+        initialFirstVisibleItemIndex = remember { state.firstVisibleItemIndex },
+        initialFirstVisibleItemScrollOffset = remember { state.firstVisibleItemScrollOffset },
         contentPadding = contentPadding,
         onItemCLick = viewModel::onItemClick,
         onItemLongCLick = viewModel::onItemLongClick,
         onClose = viewModel::onClose,
+        onScrollChanges = viewModel::onScrollChanges,
     )
 }
+
+private fun List<MonsterPreviewFolder>.asState(): List<MonsterCardState> = map {
+    it.run {
+        MonsterCardState(
+            index = index,
+            name = name,
+            imageState = MonsterImageState(
+                url = imageUrl,
+                type = MonsterTypeState.valueOf(type.name),
+                backgroundColor = ColorState(
+                    light = backgroundColorLight,
+                    dark = backgroundColorDark
+                ),
+                challengeRating = challengeRating,
+                isHorizontal = isHorizontalImage,
+                contentDescription = name
+            )
+        )
+    }
+}

feature/folder-detail/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/detail/ui/FolderDetailScreen.kt

@@ -17,68 +17,68 @@
 package br.alexandregpereira.hunter.folder.detail.ui
 
 import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.lazy.grid.LazyGridState
+import androidx.compose.foundation.lazy.grid.rememberLazyGridState
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.remember
 import androidx.compose.ui.unit.dp
-import br.alexandregpereira.hunter.domain.folder.model.MonsterPreviewFolder
-import br.alexandregpereira.hunter.folder.detail.FolderDetailState
 import br.alexandregpereira.hunter.ui.compendium.CompendiumItemState.Item
 import br.alexandregpereira.hunter.ui.compendium.CompendiumItemState.Title
-import br.alexandregpereira.hunter.ui.compendium.monster.ColorState
 import br.alexandregpereira.hunter.ui.compendium.monster.MonsterCardState
 import br.alexandregpereira.hunter.ui.compendium.monster.MonsterCompendium
-import br.alexandregpereira.hunter.ui.compendium.monster.MonsterImageState
-import br.alexandregpereira.hunter.ui.compendium.monster.MonsterTypeState
 import br.alexandregpereira.hunter.ui.compose.AppFullScreen
 import br.alexandregpereira.hunter.ui.compose.plus
 
 @Composable
 internal fun FolderDetailScreen(
-    state: FolderDetailState,
+    isOpen: Boolean,
+    folderName: String,
+    monsters: List<MonsterCardState>,
+    initialFirstVisibleItemIndex: Int = 0,
+    initialFirstVisibleItemScrollOffset: Int = 0,
     contentPadding: PaddingValues = PaddingValues(),
     onItemCLick: (index: String) -> Unit = {},
     onItemLongCLick: (index: String) -> Unit = {},
-    onClose: () -> Unit = {}
+    onClose: () -> Unit = {},
+    onScrollChanges: (Int, Int) -> Unit = { _, _ -> },
 ) = AppFullScreen(
-    isOpen = state.isOpen,
+    isOpen = isOpen,
     contentPaddingValues = contentPadding,
     level = 0,
     onClose = onClose
 ) {
-    val monsters = remember(state.monsters) { state.monsters.asState() }
     val items = listOf(
         Title(
-            value = state.folderName,
+            value = folderName,
             isHeader = true
         ),
     ) + monsters.map {
         Item(value = it)
     }
+    val listState: LazyGridState = rememberLazyGridState(
+        initialFirstVisibleItemIndex = initialFirstVisibleItemIndex,
+        initialFirstVisibleItemScrollOffset = initialFirstVisibleItemScrollOffset
+    )
+    OnScrollChanges(
+        getScrollItemScrollValues = {
+            listState.firstVisibleItemIndex to listState.firstVisibleItemScrollOffset
+        },
+        onScrollChanges = onScrollChanges,
+    )
     MonsterCompendium(
         items = items,
+        listState = listState,
         animateItems = true,
         contentPadding = contentPadding + PaddingValues(top = 24.dp),
         onItemCLick = onItemCLick,
         onItemLongCLick = onItemLongCLick
     )
 }
 
-private fun List<MonsterPreviewFolder>.asState(): List<MonsterCardState> = map {
-    it.run {
-        MonsterCardState(
-            index = index,
-            name = name,
-            imageState = MonsterImageState(
-                url = imageUrl,
-                type = MonsterTypeState.valueOf(type.name),
-                backgroundColor = ColorState(
-                    light = backgroundColorLight,
-                    dark = backgroundColorDark
-                ),
-                challengeRating = challengeRating,
-                isHorizontal = isHorizontalImage,
-                contentDescription = name
-            )
-        )
-    }
+@Composable
+private fun OnScrollChanges(
+    getScrollItemScrollValues: () -> Pair<Int, Int>,
+    onScrollChanges: (Int, Int) -> Unit
+) {
+    val (firstVisibleItemIndex, firstVisibleItemScrollOffset) = getScrollItemScrollValues()
+    onScrollChanges(firstVisibleItemIndex, firstVisibleItemScrollOffset)
 }

feature/folder-detail/state-holder/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/detail/FolderDetailState.kt

@@ -21,5 +21,7 @@ import br.alexandregpereira.hunter.domain.folder.model.MonsterPreviewFolder
 data class FolderDetailState(
     val isOpen: Boolean = false,
     val folderName: String = "",
-    val monsters: List<MonsterPreviewFolder> = emptyList()
+    val monsters: List<MonsterPreviewFolder> = emptyList(),
+    val firstVisibleItemIndex: Int = 0,
+    val firstVisibleItemScrollOffset: Int = 0,
 )

feature/folder-detail/state-holder/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/detail/FolderDetailStateHolder.kt

@@ -75,6 +75,15 @@ class FolderDetailStateHolder internal constructor(
         folderDetailEventManager.dispatchResult(OnVisibilityChanges(isShowing = false))
     }
 
+    fun onScrollChanges(firstVisibleItemIndex: Int, firstVisibleItemScrollOffset: Int) {
+        setState {
+            copy(
+                firstVisibleItemIndex = firstVisibleItemIndex,
+                firstVisibleItemScrollOffset = firstVisibleItemScrollOffset
+            )
+        }
+    }
+
     private fun loadMonsters(folderName: String) {
         getMonstersByFolder(folderName)
             .flowOn(dispatcher)

feature/folder-list/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/list/FolderListFeature.kt

@@ -42,5 +42,6 @@ fun FolderListFeature(
         onItemSelectionClose = viewModel::onItemSelectionClose,
         onItemSelectionDeleteClick = viewModel::onItemSelectionDeleteClick,
         onItemSelectionAddToPreviewClick = viewModel::onItemSelectionAddToPreviewClick,
+        onScrollChanges = viewModel::onScrollChanges,
     )
 }

feature/folder-list/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/list/ui/FolderCardGrid.kt

@@ -24,6 +24,7 @@ import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.lazy.grid.rememberLazyGridState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
@@ -41,12 +42,24 @@ internal fun FolderCardGrid(
     folders: List<FolderCardState>,
     title: String,
     modifier: Modifier = Modifier,
+    initialFirstVisibleItemIndex: Int = 0,
+    initialFirstVisibleItemScrollOffset: Int = 0,
     contentPadding: PaddingValues = PaddingValues(),
     onCLick: (String) -> Unit = {},
     onLongCLick: (String) -> Unit = {},
+    onScrollChanges: (Int, Int) -> Unit = { _, _ -> },
 ) {
+    val lazyListState = rememberLazyGridState(
+        initialFirstVisibleItemIndex = initialFirstVisibleItemIndex,
+        initialFirstVisibleItemScrollOffset = initialFirstVisibleItemScrollOffset,
+    )
+    val getFirstVisibleItemValues = {
+        lazyListState.firstVisibleItemIndex to lazyListState.firstVisibleItemScrollOffset
+    }
+    OnScrollChanges(getFirstVisibleItemValues, onScrollChanges)
     LazyVerticalGrid(
         modifier = modifier,
+        state = lazyListState,
         columns = GridCells.Adaptive(minSize = 320.dp),
         verticalArrangement = Arrangement.spacedBy(24.dp),
         horizontalArrangement = Arrangement.spacedBy(32.dp),
@@ -85,6 +98,18 @@ internal fun FolderCardGrid(
     }
 }
 
+@Composable
+private fun OnScrollChanges(
+    getFirstVisibleItemValues: () -> Pair<Int, Int>,
+    onScrollChanges: (Int, Int) -> Unit
+) {
+    val (firstVisibleItemIndex, firstVisibleItemScrollOffset) = getFirstVisibleItemValues()
+    onScrollChanges(
+        firstVisibleItemIndex,
+        firstVisibleItemScrollOffset
+    )
+}
+
 @Preview
 @Composable
 private fun FolderCardGridPreview() = Window {

feature/folder-list/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/list/ui/FolderListScreen.kt

@@ -20,6 +20,7 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import br.alexandregpereira.hunter.folder.list.FolderListState
 
@@ -32,14 +33,18 @@ internal fun FolderListScreen(
     onItemSelectionClose: () -> Unit = {},
     onItemSelectionDeleteClick: () -> Unit = {},
     onItemSelectionAddToPreviewClick: () -> Unit = {},
+    onScrollChanges: (Int, Int) -> Unit = { _, _ -> },
 ) {
     Box(Modifier.fillMaxSize()) {
         FolderCardGrid(
             folders = state.folders,
             title = state.strings.title,
+            initialFirstVisibleItemIndex = remember { state.firstVisibleItemIndex },
+            initialFirstVisibleItemScrollOffset = remember { state.firstVisibleItemScrollOffset },
             contentPadding = contentPadding,
             onCLick = onCLick,
-            onLongCLick = onLongCLick
+            onLongCLick = onLongCLick,
+            onScrollChanges = onScrollChanges,
         )
 
         ItemSelection(

feature/folder-list/state-holder/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/list/FolderListState.kt

@@ -21,6 +21,8 @@ data class FolderListState(
     val strings: FolderListStrings = FolderListEmptyStrings(),
     val isItemSelectionOpen: Boolean = false,
     val itemSelectionCount: Int = 0,
+    val firstVisibleItemIndex: Int = 0,
+    val firstVisibleItemScrollOffset: Int = 0,
 ) {
 
     internal val itemSelection: Set<String> = folders

feature/folder-list/state-holder/src/commonMain/kotlin/br/alexandregpereira/hunter/folder/list/FolderListStateHolder.kt

@@ -117,6 +117,15 @@ class FolderListStateHolder internal constructor(
             .launchIn(scope)
     }
 
+    fun onScrollChanges(firstVisibleItemIndex: Int, firstVisibleItemScrollOffset: Int) {
+        setState {
+            copy(
+                firstVisibleItemIndex = firstVisibleItemIndex,
+                firstVisibleItemScrollOffset = firstVisibleItemScrollOffset,
+            )
+        }
+    }
+
     fun onItemSelect(folderName: String) {
         analytics.trackItemSelect(folderName)
         setState {

feature/monster-compendium/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/monster/compendium/ui/MonsterCompendiumScreen.kt

@@ -16,7 +16,6 @@
 
 package br.alexandregpereira.hunter.monster.compendium.ui
 
-import androidx.compose.animation.core.animateDpAsState
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding

feature/search/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/search/SearchScreenFeature.kt

@@ -19,22 +19,39 @@ package br.alexandregpereira.hunter.search
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import br.alexandregpereira.hunter.search.ui.SearchScreen
 import org.koin.compose.koinInject
 
 @Composable
 fun SearchScreenFeature(
     contentPadding: PaddingValues = PaddingValues(),
 ) {
-    val viewModel: SearchStateHolder = koinInject()
+    val stateHolder: SearchStateHolder = koinInject()
+    val state by stateHolder.state.collectAsState()
+
+    val initialFirstVisibleItemIndex = remember { state.firstVisibleItemIndex }
+    val initialFirstVisibleItemScrollOffset = remember { state.firstVisibleItemScrollOffset }
+    val initialSearchKeysScrollOffset = remember { state.searchKeysScrollOffset }
 
     SearchScreen(
-        state = viewModel.state.collectAsState().value,
+        searchValue = state.searchValue,
+        monsterRows = state.monsterRows,
+        searchLabel = state.searchLabel,
+        searchResults = state.searchResults,
+        isSearching = state.isSearching,
+        searchKeys = state.searchKeys,
+        initialFirstVisibleItemIndex = initialFirstVisibleItemIndex,
+        initialFirstVisibleItemScrollOffset = initialFirstVisibleItemScrollOffset,
+        initialSearchKeysScrollOffset = initialSearchKeysScrollOffset,
         contentPaddingValues = contentPadding,
-        onSearchValueChange = viewModel::onSearchValueChange,
-        onCardClick = viewModel::onItemClick,
-        onCardLongClick = viewModel::onItemLongClick,
-        onSearchKeyClick = viewModel::onSearchKeyClick,
-        onAddClick = viewModel::onAddClick,
+        onSearchValueChange = stateHolder::onSearchValueChange,
+        onCardClick = stateHolder::onItemClick,
+        onCardLongClick = stateHolder::onItemLongClick,
+        onSearchKeyClick = stateHolder::onSearchKeyClick,
+        onAddClick = stateHolder::onAddClick,
+        onScrollChanges = stateHolder::onScrollChanges,
+        onSearchKeysScrollChanges = stateHolder::onSearchKeysScrollChanges,
     )
 }

feature/search/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/search/SearchStateHolder.kt

@@ -149,4 +149,17 @@ internal class SearchStateHolder(
         val monsterIndexes = state.value.monsterRows.map { it.index }
         folderPreviewEventDispatcher.dispatchEvent(AddMonster(monsterIndexes))
     }
+
+    fun onScrollChanges(firstVisibleItemIndex: Int, firstVisibleItemScrollOffset: Int) {
+        setState {
+            copy(
+                firstVisibleItemIndex = firstVisibleItemIndex,
+                firstVisibleItemScrollOffset = firstVisibleItemScrollOffset
+            )
+        }
+    }
+
+    fun onSearchKeysScrollChanges(scrollOffset: Int) {
+        setState { copy(searchKeysScrollOffset = scrollOffset) }
+    }
 }

feature/search/compose/src/commonMain/kotlin/br/alexandregpereira/hunter/search/ui/SearchKeyButtons.kt

@@ -18,11 +18,17 @@ import br.alexandregpereira.hunter.ui.compose.AppButtonSize
 @Composable
 internal fun SearchKeyButtons(
     searchKeys: List<SearchKeyState>,
+    initialScrollOffset: Int,
     shouldShow: () -> Boolean,
     modifier: Modifier = Modifier,
     onClick: (Int) -> Unit,
+    onScrollChanges: (Int) -> Unit,
 ) {
-    val scrollState = rememberScrollState()
+    val scrollState = rememberScrollState(initial = initialScrollOffset)
+    onScrollChanges(
+        getScrollPosition = { scrollState.value },
+        onScrollChanges = onScrollChanges,
+    )
     AnimatedVisibility(
         visible = shouldShow(),
         enter = fadeIn(),
@@ -41,6 +47,14 @@ internal fun SearchKeyButtons(
     }
 }
 
+@Composable
+private fun onScrollChanges(
+    getScrollPosition: () -> Int,
+    onScrollChanges: (Int) -> Unit,
+) {
+    onScrollChanges(getScrollPosition())
+}
+
 @Composable
 internal fun SearchKeyButton(
     searchKey: SearchKeyState,