src: fix is_saved logic

Signed-off-by: Aditya Wasan <adityawasan55@gmail.com>

app/src/main/java/dev/msfjarvis/lobsters/data/remote/LobstersPagingSource.kt

@@ -1,5 +1,6 @@
 package dev.msfjarvis.lobsters.data.remote
 
+import android.util.Log
 import androidx.paging.PagingSource
 import dev.msfjarvis.lobsters.data.api.LobstersApi
 import dev.msfjarvis.lobsters.data.local.LobstersPost
@@ -14,17 +15,9 @@ class LobstersPagingSource @Inject constructor(
   override suspend fun load(params: LoadParams<Int>): LoadResult<Int, LobstersPost> {
     return try {
       val page = params.key ?: 1
-      val posts = lobstersApi.getHottestPosts(page).map { post ->
-        // We can replace these two lines below with a getOrInsertPost repository method.
-        val dbPost = lobstersRepository.getPost(post.short_id)
-        return@map if (dbPost == null) {
-          // If db does not contain the post, add it and return the original post
-          lobstersRepository.addPostToDB(post)
-          post
-        } else {
-          // Otherwise return the db post
-          dbPost
-        }
+      val posts = lobstersApi.getHottestPosts(page).mapIndexed { index, post ->
+        val isSaved = lobstersRepository.isPostSaved(post.short_id)
+        return@mapIndexed post.copy(is_saved = isSaved)
       }
 
       LoadResult.Page(

app/src/main/java/dev/msfjarvis/lobsters/data/repo/LobstersRepository.kt

@@ -9,7 +9,6 @@ import javax.inject.Inject
 class LobstersRepository @Inject constructor(private val lobstersDatabase: LobstersDatabase) {
 
   fun isPostSaved(postId: String): Boolean {
-    // returns the post if it exists and its is_saved property is true
     val post = lobstersDatabase.postQueries.isPostSaved(postId).executeAsOneOrNull()
     return post != null
   }
@@ -27,9 +26,7 @@ class LobstersRepository @Inject constructor(private val lobstersDatabase: Lobst
   }
 
   suspend fun savePost(post: LobstersPost) = withContext(Dispatchers.IO) {
-    if (!isPostSaved(post.short_id)) {
-      lobstersDatabase.postQueries.savePost(post.short_id)
-    }
+      lobstersDatabase.postQueries.insertOrReplacePost(post.copy(is_saved = true))
   }
 
   suspend fun removeSavedPost(post: LobstersPost) = withContext(Dispatchers.IO) {

app/src/main/java/dev/msfjarvis/lobsters/ui/posts/LobstersItem.kt

@@ -14,10 +14,6 @@ import androidx.compose.material.Surface
 import androidx.compose.material.Text
 import androidx.compose.material.ripple.rememberRipple
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.stringResource
@@ -69,8 +65,6 @@ fun LobstersItem(
   onLongClick: () -> Unit,
   onSaveButtonClick: () -> Unit,
 ) {
-  var isSaved by remember { mutableStateOf(post.is_saved ?: false) }
-
   Surface(
     modifier = Modifier
       .fillMaxWidth()
@@ -127,14 +121,11 @@ fun LobstersItem(
           },
       )
       IconResource(
-        resourceId = if (isSaved) R.drawable.ic_favorite_24px else R.drawable.ic_favorite_border_24px,
+        resourceId = if (post.is_saved == true) R.drawable.ic_favorite_24px else R.drawable.ic_favorite_border_24px,
         modifier = Modifier
           .padding(8.dp)
           .clickable(
-            onClick = {
-              onSaveButtonClick()
-              isSaved = isSaved.not()
-            },
+            onClick = onSaveButtonClick,
             indication = rememberRipple(),
           )
           .constrainAs(saveButton) {

app/src/main/java/dev/msfjarvis/lobsters/ui/viewmodel/LobstersViewModel.kt

@@ -4,7 +4,9 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import androidx.paging.Pager
 import androidx.paging.PagingConfig
+import androidx.paging.cachedIn
 import dagger.hilt.android.lifecycle.HiltViewModel
+import dev.msfjarvis.lobsters.data.api.LobstersApi
 import dev.msfjarvis.lobsters.data.local.LobstersPost
 import dev.msfjarvis.lobsters.data.remote.LobstersPagingSource
 import dev.msfjarvis.lobsters.data.repo.LobstersRepository
@@ -17,17 +19,21 @@ import javax.inject.Inject
 class LobstersViewModel @Inject constructor(
   private val pagingSource: LobstersPagingSource,
   private val lobstersRepository: LobstersRepository,
+  private val lobstersApi: LobstersApi,
 ) : ViewModel() {
   private val _savedPosts = MutableStateFlow<List<LobstersPost>>(emptyList())
+  private var source: LobstersPagingSource? = null
   val savedPosts = _savedPosts.asStateFlow()
-  val posts = Pager(PagingConfig(5)) {
-    pagingSource
-  }.flow
+  val posts = Pager(PagingConfig(25)) {
+    source = LobstersPagingSource(lobstersApi, lobstersRepository)
+    source!!
+  }.flow.cachedIn(viewModelScope)
 
   fun toggleSave(post: LobstersPost) {
     viewModelScope.launch {
       val isSaved = lobstersRepository.isPostSaved(post.short_id)
       if (isSaved) removeSavedPost(post) else savePost(post)
+      invalidateSource()
     }
   }
 
@@ -39,6 +45,10 @@ class LobstersViewModel @Inject constructor(
     }
   }
 
+  fun invalidateSource() {
+    source?.invalidate()
+  }
+
   private fun savePost(post: LobstersPost) {
     viewModelScope.launch {
       lobstersRepository.savePost(post)