refactor: improve read posts search performance

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

@@ -57,8 +57,6 @@ 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
 import kotlinx.coroutines.withContext
 
 @ContributesViewModel
@@ -84,7 +82,7 @@ constructor(
         pagingSourceFactory = { pagingSourceFactory.create(api::getHottestPosts) },
       )
       .flow
-      .map(::mapUIPost)
+      .map(::mapToUIPost)
       .cachedIn(viewModelScope)
 
   val newestPosts =
@@ -94,7 +92,7 @@ constructor(
         pagingSourceFactory = { pagingSourceFactory.create(api::getNewestPosts) },
       )
       .flow
-      .map(::mapUIPost)
+      .map(::mapToUIPost)
       .cachedIn(viewModelScope)
   val searchResults =
     Pager(
@@ -103,38 +101,33 @@ constructor(
         pagingSourceFactory = { searchPagingSourceFactory.create { searchQuery } },
       )
       .flow
-      .map(::mapUIPost)
+      .map(::mapToUIPost)
 
-  val savedPosts
+  val savedPosts =
-    get() =
+    savedPostsRepository.savedPosts
-      savedPostsRepository.savedPosts
+      .map { it.map(UIPost.Companion::fromSavedPost) }
-        .map { it.map(UIPost.Companion::fromSavedPost) }
+      .shareIn(viewModelScope, started = SharingStarted.Lazily, Int.MAX_VALUE)
-        .shareIn(viewModelScope, started = SharingStarted.Lazily, Int.MAX_VALUE)
 
-  val savedPostsByMonth
+  val savedPostsByMonth = savedPosts.map(::groupSavedPosts)
-    get() = savedPosts.map(::mapSavedPosts)
 
   var searchQuery by mutableStateOf("")
 
-  private val _savedPostsMutex = Mutex()
+  private var _readPosts = emptyList<String>()
   private var _savedPosts = emptyList<String>()
 
   init {
-    viewModelScope.launch {
+    viewModelScope.launch { savedPosts.collectLatest { _savedPosts = it.map(UIPost::shortId) } }
-      savedPosts.collectLatest {
+    viewModelScope.launch { readPostsRepository.readPosts.collectLatest { _readPosts = it } }
-        _savedPostsMutex.withLock { _savedPosts = it.map(UIPost::shortId) }
-      }
-    }
   }
 
-  private fun mapUIPost(pagingData: PagingData<LobstersPost>): PagingData<UIPost> {
+  private fun mapToUIPost(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>> {
+  private fun groupSavedPosts(items: List<UIPost>): ImmutableMap<String, List<UIPost>> {
     val sorted =
       items.sortedWith { post1, post2 ->
         val post1Date = post1.createdAt.toLocalDateTime()
@@ -159,7 +152,9 @@ constructor(
     return _savedPosts.contains(post.shortId)
   }
 
-  private fun isPostRead(post: UIPost) = readPostsRepository.isRead(post.shortId)
+  private fun isPostRead(post: UIPost): Boolean {
+    return _readPosts.contains(post.shortId)
+  }
 
   fun toggleSave(post: UIPost) {
     viewModelScope.launch(ioDispatcher) {

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

@@ -6,6 +6,8 @@
  */
 package dev.msfjarvis.claw.android.viewmodel
 
+import app.cash.sqldelight.coroutines.asFlow
+import app.cash.sqldelight.coroutines.mapToList
 import dev.msfjarvis.claw.core.injection.DatabaseDispatcher
 import dev.msfjarvis.claw.database.local.ReadPostsQueries
 import javax.inject.Inject
@@ -18,12 +20,9 @@ constructor(
   private val readPostsQueries: ReadPostsQueries,
   @DatabaseDispatcher private val dbDispatcher: CoroutineDispatcher,
 ) {
+  val readPosts = readPostsQueries.selectAllPosts().asFlow().mapToList(dbDispatcher)
 
   suspend fun markRead(postId: String) {
     withContext(dbDispatcher) { readPostsQueries.markRead(postId) }
   }
-
-  fun isRead(postId: String): Boolean {
-    return readPostsQueries.isRead(postId).executeAsOneOrNull() != null
-  }
 }

database/core/src/main/sqldelight/dev/msfjarvis/claw/database/local/ReadPosts.sq

@@ -2,16 +2,15 @@ CREATE TABLE ReadPosts(
   id TEXT NOT NULL PRIMARY KEY
 );
 
+selectAllPosts:
+SELECT *
+FROM ReadPosts;
+
 markRead:
-INSERT OR REPLACE
+INSERT OR IGNORE
 INTO ReadPosts(id)
 VALUES (?);
 
 markUnread:
 DELETE FROM ReadPosts
 WHERE id = ?;
-
-isRead:
-SELECT *
-FROM ReadPosts
-WHERE id = ?;

database/core/src/main/sqldelight/dev/msfjarvis/claw/database/local/SavedPost.sq

@@ -36,8 +36,3 @@ deletePost:
 DELETE
 FROM SavedPost
 WHERE shortId = ?;
-
-selectPost:
-SELECT *
-FROM SavedPost
-WHERE shortId = ?;

database/impl/src/test/kotlin/dev/msfjarvis/claw/database/local/ReadPostsQueriesTest.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.
@@ -23,8 +23,8 @@ class ReadPostsQueriesTest {
   fun `mark post as read`() {
     val id = UUID.randomUUID().toString()
     postQueries.markRead(id)
-    assertThat(postQueries.isRead(id).executeAsOne()).isNotNull()
+    assertThat(postQueries.selectAllPosts().executeAsList()).contains(id)
     postQueries.markUnread(id)
-    assertThat(postQueries.isRead(id).executeAsOneOrNull()).isNull()
+    assertThat(postQueries.selectAllPosts().executeAsList()).doesNotContain(id)
   }
 }

database/impl/src/test/kotlin/dev/msfjarvis/claw/database/local/SavedPostQueriesTest.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.
@@ -32,7 +32,7 @@ class SavedPostQueriesTest {
   @Test
   fun `update post in database`() {
     // Get 1 post
-    val post = createTestData(1)[0]
+    val post = createTestData(1).first()
 
     // Insert post into DB
     postQueries.insertOrReplacePost(post)
@@ -46,15 +46,14 @@ class SavedPostQueriesTest {
     assertThat(postsCount).isEqualTo(1)
 
     // Check if post is updated
-    val postFromDb = postQueries.selectPost(post.shortId).executeAsOne()
+    val postFromDb = postQueries.selectAllPosts().executeAsOne()
-
     assertThat(postFromDb.submitterName).isEqualTo("Fake name")
   }
 
   @Test
   fun `get post from db`() {
     // Get 1 post
-    val post = createTestData(1)[0]
+    val post = createTestData(1).first()
 
     // Insert post into DB
     postQueries.insertOrReplacePost(post)