refactor(android): boost page load performance

This is kinda embarassing tbh.

android/src/main/kotlin/dev/msfjarvis/claw/android/paging/LobstersPagingSource.kt

@@ -16,11 +16,13 @@ import dagger.assisted.AssistedInject
 import dev.msfjarvis.claw.android.viewmodel.ReadPostsRepository
 import dev.msfjarvis.claw.android.viewmodel.SavedPostsRepository
 import dev.msfjarvis.claw.core.injection.IODispatcher
+import dev.msfjarvis.claw.database.local.SavedPost
 import dev.msfjarvis.claw.model.LobstersPost
 import dev.msfjarvis.claw.model.UIPost
 import dev.msfjarvis.claw.model.toUIPost
 import java.io.IOException
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.withContext
 
 class LobstersPagingSource
@@ -31,8 +33,16 @@ constructor(
   private val savedPostsRepository: SavedPostsRepository,
   private val readPostsRepository: ReadPostsRepository,
 ) : PagingSource<Int, UIPost>() {
+  private lateinit var savedPosts: List<String>
+  private lateinit var readPosts: List<String>
 
   override suspend fun load(params: LoadParams<Int>): LoadResult<Int, UIPost> {
+    if (!::savedPosts.isInitialized) {
+      savedPosts = savedPostsRepository.savedPosts.first().map(SavedPost::shortId)
+    }
+    if (!::readPosts.isInitialized) {
+      readPosts = readPostsRepository.readPosts.first()
+    }
     val page = params.key ?: STARTING_PAGE_INDEX
     return when (val result = withContext(ioDispatcher) { remoteFetcher.getItemsAtPage(page) }) {
       is Success ->
@@ -43,8 +53,8 @@ constructor(
               it
                 .toUIPost()
                 .copy(
-                  isSaved = savedPostsRepository.isPostSaved(it.shortId),
+                  isSaved = savedPosts.contains(it.shortId),
-                  isRead = readPostsRepository.isPostRead(it.shortId),
+                  isRead = readPosts.contains(it.shortId),
                 )
             },
           prevKey = if (page == STARTING_PAGE_INDEX) null else page - 1,

android/src/main/kotlin/dev/msfjarvis/claw/android/paging/SearchPagingSource.kt

@@ -18,10 +18,12 @@ import dev.msfjarvis.claw.android.viewmodel.ReadPostsRepository
 import dev.msfjarvis.claw.android.viewmodel.SavedPostsRepository
 import dev.msfjarvis.claw.api.LobstersSearchApi
 import dev.msfjarvis.claw.core.injection.IODispatcher
+import dev.msfjarvis.claw.database.local.SavedPost
 import dev.msfjarvis.claw.model.UIPost
 import dev.msfjarvis.claw.model.toUIPost
 import java.io.IOException
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.withContext
 
 /**
@@ -39,8 +41,16 @@ constructor(
   private val savedPostsRepository: SavedPostsRepository,
   private val readPostsRepository: ReadPostsRepository,
 ) : PagingSource<Int, UIPost>() {
+  private lateinit var savedPosts: List<String>
+  private lateinit var readPosts: List<String>
 
   override suspend fun load(params: LoadParams<Int>): LoadResult<Int, UIPost> {
+    if (!::savedPosts.isInitialized) {
+      savedPosts = savedPostsRepository.savedPosts.first().map(SavedPost::shortId)
+    }
+    if (!::readPosts.isInitialized) {
+      readPosts = readPostsRepository.readPosts.first()
+    }
     val searchQuery = queryProvider()
     // If there is no query, we don't need to call the API at all.
     if (searchQuery.isEmpty()) {
@@ -60,8 +70,8 @@ constructor(
               it
                 .toUIPost()
                 .copy(
-                  isSaved = savedPostsRepository.isPostSaved(it.shortId),
+                  isSaved = savedPosts.contains(it.shortId),
-                  isRead = readPostsRepository.isPostRead(it.shortId),
+                  isRead = readPosts.contains(it.shortId),
                 )
             },
           prevKey = if (page == STARTING_PAGE_INDEX) null else page - 1,

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

@@ -25,8 +25,4 @@ constructor(
   suspend fun markRead(postId: String) {
     withContext(dbDispatcher) { readPostsQueries.markRead(postId) }
   }
-
-  suspend fun isPostRead(shortId: String): Boolean {
-    return withContext(dbDispatcher) { readPostsQueries.isPostRead(shortId).executeAsOne() }
-  }
 }

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

@@ -45,10 +45,6 @@ constructor(
     }
   }
 
-  suspend fun isPostSaved(postId: String): Boolean {
-    return withContext(dbDispatcher) { savedPostQueries.isPostSaved(postId).executeAsOne() }
-  }
-
   private companion object {
     private const val TAG = "SavedPostsRepository"
   }

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

@@ -2,13 +2,6 @@ CREATE TABLE IF NOT EXISTS ReadPosts(
   id TEXT NOT NULL PRIMARY KEY
 );
 
-isPostRead:
-SELECT EXISTS(
-  SELECT 1
-  FROM ReadPosts
-  WHERE id = ?
-) AS isRead;
-
 selectAllPosts:
 SELECT *
 FROM ReadPosts;

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

@@ -14,13 +14,6 @@ CREATE TABLE IF NOT EXISTS SavedPost(
   description TEXT NOT NULL DEFAULT ""
 );
 
-isPostSaved:
-SELECT EXISTS(
-  SELECT 1
-  FROM SavedPost
-  WHERE shortId = ?
-) AS isSaved;
-
 insertOrReplacePost:
 INSERT OR REPLACE
 INTO SavedPost