app: remove existing post loading

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

app/src/main/java/dev/msfjarvis/lobsters/ui/main/MainActivity.kt

@@ -24,6 +24,7 @@ import androidx.navigation.compose.currentBackStackEntryAsState
 import androidx.navigation.compose.navigate
 import androidx.navigation.compose.rememberNavController
 import dagger.hilt.android.AndroidEntryPoint
+import dev.msfjarvis.lobsters.model.LobstersPost
 import dev.msfjarvis.lobsters.util.IconResource
 import dev.msfjarvis.lobsters.ui.viewmodel.LobstersViewModel
 import dev.msfjarvis.lobsters.ui.navigation.Destination
@@ -54,7 +55,7 @@ class MainActivity : AppCompatActivity() {
 fun LobstersApp() {
   val viewModel: LobstersViewModel = viewModel()
   val navController = rememberNavController()
-  val hottestPosts by viewModel.posts.collectAsState()
+  val hottestPosts = emptyList<LobstersPost>()
   val savedPosts by viewModel.savedPosts.collectAsState()
 
   Scaffold(
@@ -68,7 +69,6 @@ fun LobstersApp() {
         HottestPosts(
           posts = hottestPosts,
           listState = hottestPostsListState,
-          overscrollAction = viewModel::getMorePosts,
           saveAction = viewModel::savePost,
           modifier = Modifier.padding(bottom = innerPadding.bottom),
         )

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

@@ -1,7 +1,7 @@
 package dev.msfjarvis.lobsters.ui.posts
 
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.lazy.LazyColumnForIndexed
+import androidx.compose.foundation.lazy.LazyColumnFor
 import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
@@ -14,7 +14,6 @@ fun HottestPosts(
   posts: List<LobstersPost>,
   listState: LazyListState,
   modifier: Modifier = Modifier,
-  overscrollAction: () -> Unit,
   saveAction: (LobstersPost) -> Unit,
 ) {
   val urlLauncher = UrlLauncherAmbient.current
@@ -22,14 +21,11 @@ fun HottestPosts(
   if (posts.isEmpty()) {
     EmptyList(saved = false)
   } else {
-    LazyColumnForIndexed(
+    LazyColumnFor(
       items = posts,
       state = listState,
       modifier = Modifier.padding(horizontal = 8.dp).then(modifier)
-    ) { index, item ->
-      if (posts.lastIndex == index) {
-        overscrollAction.invoke()
-      }
+    ) { item ->
       LobstersItem(
         post = item,
         onClick = { urlLauncher.launch(item.url.ifEmpty { item.commentsUrl }) },

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

@@ -3,44 +3,21 @@ package dev.msfjarvis.lobsters.ui.viewmodel
 import androidx.hilt.lifecycle.ViewModelInject
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import dev.msfjarvis.lobsters.data.api.LobstersApi
 import dev.msfjarvis.lobsters.data.source.PostsDatabase
 import dev.msfjarvis.lobsters.model.LobstersPost
-import kotlinx.coroutines.CoroutineExceptionHandler
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
-import java.net.SocketTimeoutException
-import java.net.UnknownHostException
 
 class LobstersViewModel @ViewModelInject constructor(
-  private val lobstersApi: LobstersApi,
   database: PostsDatabase,
 ) : ViewModel() {
-  private var apiPage = 1
-  private val _posts = MutableStateFlow<List<LobstersPost>>(emptyList())
   private val _savedPosts = MutableStateFlow<List<LobstersPost>>(emptyList())
-  private val postsDao = database.postsDao()
   private val savedPostsDao = database.savedPostsDao()
-  private val coroutineExceptionHandler = CoroutineExceptionHandler { _, throwable ->
-    when (throwable) {
-      // Swallow known network errors that can be recovered from.
-      is UnknownHostException, is SocketTimeoutException -> {
-        if (_posts.value.isEmpty()) {
-          viewModelScope.launch {
-            postsDao.loadPosts().collectLatest { _posts.value = it }
-          }
-        }
-      }
-      else -> throw throwable
-    }
-  }
-  val posts: StateFlow<List<LobstersPost>> get() = _posts
   val savedPosts: StateFlow<List<LobstersPost>> get() = _savedPosts
 
   init {
-    getMorePostsInternal(true)
     getSavedPosts()
   }
 
@@ -50,24 +27,6 @@ class LobstersViewModel @ViewModelInject constructor(
     }
   }
 
-  fun getMorePosts() {
-    getMorePostsInternal(false)
-  }
-
-  private fun getMorePostsInternal(firstLoad: Boolean) {
-    viewModelScope.launch(coroutineExceptionHandler) {
-      val newPosts = lobstersApi.getHottestPosts(apiPage)
-      if (firstLoad) {
-        _posts.value = newPosts
-        postsDao.deleteAllPosts()
-      } else {
-        _posts.value += newPosts
-      }
-      apiPage += 1
-      postsDao.insertPosts(*_posts.value.toTypedArray())
-    }
-  }
-
   fun savePost(post: LobstersPost) {
     viewModelScope.launch {
       savedPostsDao.insertPosts(post)