refactor(android): switch over to PagingData transformations

android/src/main/kotlin/dev/msfjarvis/claw/android/glance/SavedPostsWidget.kt

@@ -28,11 +28,11 @@ import androidx.glance.text.Text
 import androidx.glance.text.TextStyle
 import dev.msfjarvis.claw.common.theme.DarkThemeColors
 import dev.msfjarvis.claw.common.theme.LightThemeColors
-import dev.msfjarvis.claw.database.local.SavedPost
+import dev.msfjarvis.claw.model.UIPost
 import kotlinx.collections.immutable.ImmutableList
 import kotlinx.collections.immutable.toImmutableList
 
-class SavedPostsWidget(private val posts: List<SavedPost>) : GlanceAppWidget() {
+class SavedPostsWidget(private val posts: List<UIPost>) : GlanceAppWidget() {
   override suspend fun provideGlance(context: Context, id: GlanceId) {
     provideContent {
       GlanceTheme(
@@ -46,7 +46,7 @@ class SavedPostsWidget(private val posts: List<SavedPost>) : GlanceAppWidget() {
 }
 
 @Composable
-fun WidgetHost(posts: ImmutableList<SavedPost>, modifier: GlanceModifier = GlanceModifier) {
+fun WidgetHost(posts: ImmutableList<UIPost>, modifier: GlanceModifier = GlanceModifier) {
   LazyColumn(
     modifier =
       modifier.fillMaxSize().background(GlanceTheme.colors.background).appWidgetBackground(),

android/src/main/kotlin/dev/msfjarvis/claw/android/glance/WidgetListEntry.kt

@@ -33,13 +33,13 @@ import androidx.glance.text.TextStyle
 import dev.msfjarvis.claw.android.MainActivity
 import dev.msfjarvis.claw.android.MainActivity.Companion.NAVIGATION_KEY
 import dev.msfjarvis.claw.android.R
-import dev.msfjarvis.claw.database.local.SavedPost
+import dev.msfjarvis.claw.model.UIPost
 
 private val destinationKey = Key<String>(NAVIGATION_KEY)
 
 @Composable
 @GlanceComposable
-fun WidgetListEntry(post: SavedPost, modifier: GlanceModifier = GlanceModifier) {
+fun WidgetListEntry(post: UIPost, modifier: GlanceModifier = GlanceModifier) {
   val titleStyle = MaterialTheme.typography.titleMedium
   val commentsAction =
     actionStartActivity<MainActivity>(actionParametersOf(destinationKey to post.shortId))
@@ -68,7 +68,7 @@ fun WidgetListEntry(post: SavedPost, modifier: GlanceModifier = GlanceModifier)
       )
       Image(
         provider = ImageProvider(R.drawable.ic_comment),
-        contentDescription = "${post.commentCount ?: 0} comments",
+        contentDescription = "${post.commentCount} comments",
         modifier = GlanceModifier.padding(end = 4.dp).clickable(commentsAction),
       )
     }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/ext.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022-2023 Harsh Shandilya.
+ * Copyright © 2022-2024 Harsh Shandilya.
  * Use of this source code is governed by an MIT-style
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT.
@@ -16,9 +16,8 @@ import dev.msfjarvis.claw.android.ui.navigation.Destinations
 import dev.msfjarvis.claw.android.viewmodel.ClawViewModel
 import dev.msfjarvis.claw.common.posts.PostActions
 import dev.msfjarvis.claw.common.urllauncher.UrlLauncher
-import dev.msfjarvis.claw.database.local.SavedPost
 import dev.msfjarvis.claw.model.LinkMetadata
-import dev.msfjarvis.claw.model.LobstersPostDetails
+import dev.msfjarvis.claw.model.UIPost
 
 fun Context.getActivity(): ComponentActivity? {
   return when (this) {
@@ -59,11 +58,11 @@ fun rememberPostActions(
         urlLauncher.openUri(commentsUrl.replaceAfterLast('/', "r"))
       }
 
-      override fun toggleSave(post: SavedPost) {
+      override fun toggleSave(post: UIPost) {
         viewModel.toggleSave(post)
       }
 
-      override suspend fun getComments(postId: String): LobstersPostDetails {
+      override suspend fun getComments(postId: String): UIPost {
         return viewModel.getPostComments(postId)
       }
 

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/DatabasePosts.kt

@@ -27,13 +27,13 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import dev.msfjarvis.claw.common.posts.PostActions
 import dev.msfjarvis.claw.common.ui.decorations.MonthHeader
-import dev.msfjarvis.claw.database.local.SavedPost
+import dev.msfjarvis.claw.model.UIPost
 import kotlinx.collections.immutable.ImmutableMap
 
 @OptIn(ExperimentalFoundationApi::class)
 @Composable
 fun DatabasePosts(
-  items: ImmutableMap<String, List<SavedPost>>,
+  items: ImmutableMap<String, List<UIPost>>,
   listState: LazyListState,
   postActions: PostActions,
   modifier: Modifier = Modifier,
@@ -54,12 +54,7 @@ fun DatabasePosts(
         items.forEach { (month, posts) ->
           stickyHeader(contentType = "month-header") { MonthHeader(label = month) }
           items(items = posts, key = { it.shortId }, contentType = { "LobstersItem" }) { item ->
-            LobstersListItem(
-              item = item,
-              isSaved = { true },
-              isRead = { false },
-              postActions = postActions,
-            )
+            LobstersListItem(item = item, postActions = postActions)
             HorizontalDivider()
           }
         }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/LobstersListItem.kt

@@ -11,24 +11,16 @@ import androidx.compose.material.icons.automirrored.filled.Reply
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.produceState
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.vector.rememberVectorPainter
 import dev.msfjarvis.claw.common.posts.LobstersCard
 import dev.msfjarvis.claw.common.posts.PostActions
-import dev.msfjarvis.claw.database.local.SavedPost
+import dev.msfjarvis.claw.model.UIPost
 import me.saket.swipe.SwipeAction
 import me.saket.swipe.SwipeableActionsBox
 
 @Composable
-fun LobstersListItem(
-  item: SavedPost,
-  isSaved: (SavedPost) -> Boolean,
-  isRead: suspend (String) -> Boolean,
-  postActions: PostActions,
-  modifier: Modifier = Modifier,
-) {
-  val read by produceState(false, item.shortId) { value = isRead(item.shortId) }
+fun LobstersListItem(item: UIPost, postActions: PostActions, modifier: Modifier = Modifier) {
   val commentsAction =
     SwipeAction(
       icon = rememberVectorPainter(Icons.AutoMirrored.Filled.Reply),
@@ -36,12 +28,6 @@ fun LobstersListItem(
       onSwipe = { postActions.viewCommentsPage(item.commentsUrl) },
     )
   SwipeableActionsBox(endActions = listOf(commentsAction)) {
-    LobstersCard(
-      post = item,
-      isSaved = isSaved(item),
-      isRead = read,
-      postActions = postActions,
-      modifier = modifier,
-    )
+    LobstersCard(post = item, postActions = postActions, modifier = modifier)
   }
 }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/NetworkPosts.kt

@@ -27,9 +27,7 @@ import androidx.paging.compose.itemKey
 import dev.msfjarvis.claw.common.posts.PostActions
 import dev.msfjarvis.claw.common.ui.NetworkError
 import dev.msfjarvis.claw.common.ui.ProgressBar
-import dev.msfjarvis.claw.database.local.SavedPost
-import dev.msfjarvis.claw.model.LobstersPost
-import dev.msfjarvis.claw.model.toSavedPost
+import dev.msfjarvis.claw.model.UIPost
 import eu.bambooapps.material3.pullrefresh.PullRefreshIndicator
 import eu.bambooapps.material3.pullrefresh.pullRefresh
 import eu.bambooapps.material3.pullrefresh.rememberPullRefreshState
@@ -37,10 +35,8 @@ import eu.bambooapps.material3.pullrefresh.rememberPullRefreshState
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun NetworkPosts(
-  lazyPagingItems: LazyPagingItems<LobstersPost>,
+  lazyPagingItems: LazyPagingItems<UIPost>,
   listState: LazyListState,
-  isPostSaved: (SavedPost) -> Boolean,
-  isPostRead: suspend (String) -> Boolean,
   postActions: PostActions,
   modifier: Modifier = Modifier,
 ) {
@@ -64,13 +60,7 @@ fun NetworkPosts(
         ) { index ->
           val item = lazyPagingItems[index]
           if (item != null) {
-            val dbModel = item.toSavedPost()
-            LobstersListItem(
-              item = dbModel,
-              isSaved = isPostSaved,
-              isRead = isPostRead,
-              postActions = postActions,
-            )
+            LobstersListItem(item = item, postActions = postActions)
 
             HorizontalDivider()
           }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/SearchList.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2023 Harsh Shandilya.
+ * Copyright © 2023-2024 Harsh Shandilya.
  * Use of this source code is governed by an MIT-style
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT.
@@ -21,15 +21,13 @@ import androidx.paging.PagingData
 import androidx.paging.compose.collectAsLazyPagingItems
 import dev.msfjarvis.claw.common.posts.PostActions
 import dev.msfjarvis.claw.common.ui.SearchBar
-import dev.msfjarvis.claw.database.local.SavedPost
-import dev.msfjarvis.claw.model.LobstersPost
+import dev.msfjarvis.claw.model.UIPost
 import kotlinx.coroutines.flow.Flow
 
 @Composable
 fun SearchList(
-  items: Flow<PagingData<LobstersPost>>,
+  items: Flow<PagingData<UIPost>>,
   listState: LazyListState,
-  isPostSaved: (SavedPost) -> Boolean,
   postActions: PostActions,
   searchQuery: String,
   setSearchQuery: (String) -> Unit,
@@ -50,8 +48,6 @@ fun SearchList(
     NetworkPosts(
       lazyPagingItems = lazyPagingItems,
       listState = listState,
-      isPostSaved = isPostSaved,
-      isPostRead = { false },
       postActions = postActions,
     )
   }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/screens/LobstersPostsScreen.kt

@@ -228,8 +228,6 @@ fun LobstersPostsScreen(
           NetworkPosts(
             lazyPagingItems = hottestPosts,
             listState = hottestListState,
-            isPostSaved = viewModel::isPostSaved,
-            isPostRead = viewModel::isPostRead,
             postActions = postActions,
           )
         }
@@ -238,8 +236,6 @@ fun LobstersPostsScreen(
           NetworkPosts(
             lazyPagingItems = newestPosts,
             listState = newestListState,
-            isPostSaved = viewModel::isPostSaved,
-            isPostRead = viewModel::isPostRead,
             postActions = postActions,
           )
         }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/screens/SearchScreen.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2023 Harsh Shandilya.
+ * Copyright © 2023-2024 Harsh Shandilya.
  * Use of this source code is governed by an MIT-style
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT.
@@ -47,7 +47,6 @@ fun SearchScreen(
         SearchList(
           items = viewModel.searchResults,
           listState = listState,
-          isPostSaved = viewModel::isPostSaved,
           postActions = postActions,
           searchQuery = viewModel.searchQuery,
           setSearchQuery = { query -> viewModel.searchQuery = query },

android/src/main/kotlin/dev/msfjarvis/claw/android/viewmodel/ClawViewModel.kt

@@ -18,6 +18,9 @@ import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.viewModelScope
 import androidx.paging.Pager
 import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import androidx.paging.cachedIn
+import androidx.paging.map
 import com.deliveryhero.whetstone.app.ApplicationScope
 import com.deliveryhero.whetstone.viewmodel.ContributesViewModel
 import com.slack.eithernet.ApiResult.Failure
@@ -31,8 +34,12 @@ import dev.msfjarvis.claw.android.paging.SearchPagingSource
 import dev.msfjarvis.claw.api.LobstersApi
 import dev.msfjarvis.claw.core.injection.IODispatcher
 import dev.msfjarvis.claw.core.injection.MainDispatcher
-import dev.msfjarvis.claw.database.local.SavedPost
 import dev.msfjarvis.claw.model.Comment
+import dev.msfjarvis.claw.model.LobstersPost
+import dev.msfjarvis.claw.model.UIPost
+import dev.msfjarvis.claw.model.fromSavedPost
+import dev.msfjarvis.claw.model.toSavedPost
+import dev.msfjarvis.claw.model.toUIPost
 import java.io.IOException
 import java.io.InputStream
 import java.io.OutputStream
@@ -44,9 +51,11 @@ import javax.inject.Inject
 import kotlinx.collections.immutable.ImmutableMap
 import kotlinx.collections.immutable.toImmutableMap
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.shareIn
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
@@ -68,34 +77,43 @@ constructor(
   @MainDispatcher private val mainDispatcher: CoroutineDispatcher,
   @ForScope(ApplicationScope::class) context: Context,
 ) : AndroidViewModel(context as Application) {
-  private val hottestPostsPager =
-    Pager(PagingConfig(pageSize = PAGE_SIZE), initialKey = STARTING_PAGE_INDEX) {
-      pagingSourceFactory.create(api::getHottestPosts)
-    }
-  private val newestPostsPager =
-    Pager(PagingConfig(pageSize = PAGE_SIZE), initialKey = STARTING_PAGE_INDEX) {
-      pagingSourceFactory.create(api::getNewestPosts)
-    }
-  private val searchResultsPager =
-    Pager(PagingConfig(pageSize = PAGE_SIZE), initialKey = STARTING_PAGE_INDEX) {
-      searchPagingSourceFactory.create { searchQuery }
-    }
+  val hottestPosts =
+    Pager(
+        config = PagingConfig(pageSize = PAGE_SIZE),
+        initialKey = STARTING_PAGE_INDEX,
+        pagingSourceFactory = { pagingSourceFactory.create(api::getHottestPosts) },
+      )
+      .flow
+      .map(::mapUIPost)
+      .cachedIn(viewModelScope)
 
-  val hottestPosts
-    get() = hottestPostsPager.flow
-
-  val newestPosts
-    get() = newestPostsPager.flow
+  val newestPosts =
+    Pager(
+        config = PagingConfig(pageSize = PAGE_SIZE),
+        initialKey = STARTING_PAGE_INDEX,
+        pagingSourceFactory = { pagingSourceFactory.create(api::getNewestPosts) },
+      )
+      .flow
+      .map(::mapUIPost)
+      .cachedIn(viewModelScope)
+  val searchResults =
+    Pager(
+        PagingConfig(pageSize = PAGE_SIZE),
+        initialKey = STARTING_PAGE_INDEX,
+        pagingSourceFactory = { searchPagingSourceFactory.create { searchQuery } },
+      )
+      .flow
+      .map(::mapUIPost)
 
   val savedPosts
-    get() = savedPostsRepository.savedPosts
+    get() =
+      savedPostsRepository.savedPosts
+        .map { it.map(UIPost.Companion::fromSavedPost) }
+        .shareIn(viewModelScope, started = SharingStarted.Lazily, Int.MAX_VALUE)
 
   val savedPostsByMonth
     get() = savedPosts.map(::mapSavedPosts)
 
-  val searchResults
-    get() = searchResultsPager.flow
-
   var searchQuery by mutableStateOf("")
 
   private val _savedPostsMutex = Mutex()
@@ -104,12 +122,19 @@ constructor(
   init {
     viewModelScope.launch {
       savedPosts.collectLatest {
-        _savedPostsMutex.withLock { _savedPosts = it.map(SavedPost::shortId) }
+        _savedPostsMutex.withLock { _savedPosts = it.map(UIPost::shortId) }
       }
     }
   }
 
-  private fun mapSavedPosts(items: List<SavedPost>): ImmutableMap<String, List<SavedPost>> {
+  private fun mapUIPost(pagingData: PagingData<LobstersPost>): PagingData<UIPost> {
+    return pagingData.map { post ->
+      val uiPost = post.toUIPost()
+      uiPost.copy(isSaved = isPostSaved(uiPost), isRead = isPostRead(uiPost))
+    }
+  }
+
+  private fun mapSavedPosts(items: List<UIPost>): ImmutableMap<String, List<UIPost>> {
     val sorted =
       items.sortedWith { post1, post2 ->
         val post1Date = post1.createdAt.toLocalDateTime()
@@ -130,17 +155,19 @@ constructor(
       .toImmutableMap()
   }
 
-  fun isPostSaved(post: SavedPost): Boolean {
+  private fun isPostSaved(post: UIPost): Boolean {
     return _savedPosts.contains(post.shortId)
   }
 
-  fun toggleSave(post: SavedPost) {
+  private fun isPostRead(post: UIPost) = readPostsRepository.isRead(post.shortId)
+
+  fun toggleSave(post: UIPost) {
     viewModelScope.launch(ioDispatcher) {
       val saved = isPostSaved(post)
       if (saved) {
-        savedPostsRepository.removePost(post)
+        savedPostsRepository.removePost(post.toSavedPost())
       } else {
-        savedPostsRepository.savePost(post)
+        savedPostsRepository.savePost(post.toSavedPost())
       }
       val newPosts = savedPosts.first()
       withContext(mainDispatcher) {
@@ -152,7 +179,7 @@ constructor(
   suspend fun getPostComments(postId: String) =
     withContext(ioDispatcher) {
       when (val result = api.getPostDetails(postId)) {
-        is Success -> result.value
+        is Success -> result.value.toUIPost()
         is Failure.NetworkFailure -> throw result.error
         is Failure.UnknownFailure -> throw result.error
         is Failure.HttpFailure -> {
@@ -198,8 +225,6 @@ constructor(
     viewModelScope.launch { readPostsRepository.markRead(postId) }
   }
 
-  suspend fun isPostRead(postId: String) = readPostsRepository.isRead(postId)
-
   /**
    * Parses a given [String] into a [LocalDateTime]. This method is only intended to be used for
    * dates in the format returned by the Lobsters API, and is not a general purpose parsing

android/src/main/kotlin/dev/msfjarvis/claw/android/viewmodel/ReadPostsRepository.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2021-2023 Harsh Shandilya.
+ * Copyright © 2021-2024 Harsh Shandilya.
  * Use of this source code is governed by an MIT-style
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT.
@@ -23,6 +23,7 @@ constructor(
     withContext(dbDispatcher) { readPostsQueries.markRead(postId) }
   }
 
-  suspend fun isRead(postId: String): Boolean =
-    withContext(dbDispatcher) { readPostsQueries.isRead(postId).executeAsOneOrNull() != null }
+  fun isRead(postId: String): Boolean {
+    return readPostsQueries.isRead(postId).executeAsOneOrNull() != null
+  }
 }

android/src/main/kotlin/dev/msfjarvis/claw/android/work/SavedPostUpdaterWorker.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022-2023 Harsh Shandilya.
+ * Copyright © 2022-2024 Harsh Shandilya.
  * Use of this source code is governed by an MIT-style
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT.
@@ -18,6 +18,8 @@ import dev.msfjarvis.claw.android.glance.SavedPostsWidget
 import dev.msfjarvis.claw.android.viewmodel.SavedPostsRepository
 import dev.msfjarvis.claw.api.LobstersApi
 import dev.msfjarvis.claw.model.LobstersPostDetails
+import dev.msfjarvis.claw.model.UIPost
+import dev.msfjarvis.claw.model.fromSavedPost
 import dev.msfjarvis.claw.model.toSavedPost
 import javax.inject.Inject
 import kotlinx.coroutines.flow.first
@@ -44,7 +46,10 @@ constructor(
       .filterIsInstance<Success<LobstersPostDetails>>()
       .map { result -> result.value.toSavedPost() }
       .let { savedPostsRepository.savePosts(it) }
-    SavedPostsWidget(savedPostsRepository.savedPosts.first().take(50)).updateAll(applicationContext)
+    SavedPostsWidget(
+        savedPostsRepository.savedPosts.first().take(50).map(UIPost.Companion::fromSavedPost)
+      )
+      .updateAll(applicationContext)
     return Result.success()
   }
 }