Enable bookmarks on topics page

feature/topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicScreen.kt

@@ -52,6 +52,7 @@ import com.google.samples.apps.nowinandroid.core.designsystem.component.NiaFilte
 import com.google.samples.apps.nowinandroid.core.designsystem.component.NiaLoadingWheel
 import com.google.samples.apps.nowinandroid.core.designsystem.theme.NiaTheme
 import com.google.samples.apps.nowinandroid.core.model.data.FollowableTopic
+import com.google.samples.apps.nowinandroid.core.model.data.SaveableNewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.previewNewsResources
 import com.google.samples.apps.nowinandroid.core.model.data.previewTopics
 import com.google.samples.apps.nowinandroid.core.ui.newsResourceCardItems
@@ -65,24 +66,27 @@ fun TopicRoute(
     modifier: Modifier = Modifier,
     viewModel: TopicViewModel = hiltViewModel(),
 ) {
-    val uiState: TopicScreenUiState by viewModel.uiState.collectAsStateWithLifecycle()
+    val topicUiState: TopicUiState by viewModel.topicUiState.collectAsStateWithLifecycle()
+    val newsUiState: NewsUiState by viewModel.newUiState.collectAsStateWithLifecycle()
 
     TopicScreen(
-        topicState = uiState.topicState,
+        topicState = topicUiState,
-        newsState = uiState.newsState,
+        newsUiState = newsUiState,
         modifier = modifier,
         onBackClick = onBackClick,
         onFollowClick = viewModel::followTopicToggle,
-    )
+        onBookmarkChanged = viewModel::bookmarkNews,
+        )
 }
 
 @VisibleForTesting
 @Composable
 internal fun TopicScreen(
     topicState: TopicUiState,
-    newsState: NewsUiState,
+    newsUiState: NewsUiState,
     onBackClick: () -> Unit,
     onFollowClick: (Boolean) -> Unit,
+    onBookmarkChanged: (String, Boolean) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     LazyColumn(
@@ -111,8 +115,9 @@ internal fun TopicScreen(
                 TopicBody(
                     name = topicState.followableTopic.topic.name,
                     description = topicState.followableTopic.topic.longDescription,
-                    news = newsState,
+                    news = newsUiState,
-                    imageUrl = topicState.followableTopic.topic.imageUrl
+                    imageUrl = topicState.followableTopic.topic.imageUrl,
+                    onBookmarkChanged = onBookmarkChanged
                 )
             }
         }
@@ -126,14 +131,15 @@ private fun LazyListScope.TopicBody(
     name: String,
     description: String,
     news: NewsUiState,
-    imageUrl: String
+    imageUrl: String,
+    onBookmarkChanged: (String, Boolean) -> Unit
 ) {
     // TODO: Show icon if available
     item {
         TopicHeader(name, description, imageUrl)
     }
 
-    TopicCards(news)
+    TopicCards(news, onBookmarkChanged)
 }
 
 @Composable
@@ -160,14 +166,17 @@ private fun TopicHeader(name: String, description: String, imageUrl: String) {
     }
 }
 
-private fun LazyListScope.TopicCards(news: NewsUiState) {
+private fun LazyListScope.TopicCards(
+    news: NewsUiState,
+    onBookmarkChanged: (String, Boolean) -> Unit
+) {
     when (news) {
         is NewsUiState.Success -> {
             newsResourceCardItems(
                 items = news.news,
-                newsResourceMapper = { it },
+                newsResourceMapper = { it.newsResource },
-                isBookmarkedMapper = { /* TODO */ false },
+                isBookmarkedMapper = { it.isSaved },
-                onToggleBookmark = { /* TODO */ },
+                onToggleBookmark = { onBookmarkChanged(it.newsResource.id, !it.isSaved) },
                 itemModifier = Modifier.padding(24.dp)
             )
         }
@@ -187,7 +196,7 @@ private fun TopicBodyPreview() {
         LazyColumn {
             TopicBody(
                 "Jetpack Compose", "Lorem ipsum maximum",
-                NewsUiState.Success(emptyList()), ""
+                NewsUiState.Success(emptyList()), "", { _, _ -> }
             )
         }
     }
@@ -238,9 +247,16 @@ fun TopicScreenPopulated() {
         NiaBackground {
             TopicScreen(
                 topicState = TopicUiState.Success(FollowableTopic(previewTopics[0], false)),
-                newsState = NewsUiState.Success(previewNewsResources),
+                newsUiState = NewsUiState.Success(
-                onBackClick = {},
+                    previewNewsResources.mapIndexed { index, newsResource ->
-                onFollowClick = {}
+                        SaveableNewsResource(
+                            newsResource = newsResource,
+                            isSaved = index % 2 == 0,
+                        )
+                    }
+                ), onBackClick = {},
+                onFollowClick = {},
+                onBookmarkChanged = { _, _ -> },
             )
         }
     }
@@ -256,9 +272,10 @@ fun TopicScreenLoading() {
         NiaBackground {
             TopicScreen(
                 topicState = TopicUiState.Loading,
-                newsState = NewsUiState.Loading,
+                newsUiState = NewsUiState.Loading,
                 onBackClick = {},
-                onFollowClick = {}
+                onFollowClick = {},
+                onBookmarkChanged = { _, _ -> },
             )
         }
     }

feature/topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt

@@ -19,11 +19,15 @@ package com.google.samples.apps.nowinandroid.feature.topic
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.google.samples.apps.nowinandroid.core.data.repository.AuthorsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.NewsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.TopicsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
+import com.google.samples.apps.nowinandroid.core.model.data.Author
+import com.google.samples.apps.nowinandroid.core.model.data.FollowableAuthor
 import com.google.samples.apps.nowinandroid.core.model.data.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
+import com.google.samples.apps.nowinandroid.core.model.data.SaveableNewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.result.Result
 import com.google.samples.apps.nowinandroid.core.result.asResult
@@ -48,63 +52,126 @@ class TopicViewModel @Inject constructor(
 
     private val topicId: String = checkNotNull(savedStateHandle[TopicDestination.topicIdArg])
 
+    val topicUiState: StateFlow<TopicUiState> = topicUiStateStream(
+        topicId = topicId,
+        userDataRepository = userDataRepository,
+        topicsRepository = topicsRepository
+    )
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000),
+            initialValue = TopicUiState.Loading
+        )
+
+    val newUiState: StateFlow<NewsUiState> = newsUiStateStream(
+        topicId = topicId,
+        userDataRepository = userDataRepository,
+        newsRepository = newsRepository
+    )
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000),
+            initialValue = NewsUiState.Loading
+        )
+
+    fun followTopicToggle(followed: Boolean) {
+        viewModelScope.launch {
+            userDataRepository.toggleFollowedTopicId(topicId, followed)
+        }
+    }
+
+    fun bookmarkNews(newsResourceId: String, bookmarked: Boolean) {
+        viewModelScope.launch {
+            userDataRepository.updateNewsResourceBookmark(newsResourceId, bookmarked)
+        }
+    }
+}
+
+private fun topicUiStateStream(
+    topicId: String,
+    userDataRepository: UserDataRepository,
+    topicsRepository: TopicsRepository,
+): Flow<TopicUiState> {
     // Observe the followed topics, as they could change over time.
-    private val followedTopicIdsStream: Flow<Result<Set<String>>> =
+    val followedTopicIdsStream: Flow<Set<String>> =
         userDataRepository.userDataStream
             .map { it.followedTopics }
-            .asResult()
 
     // Observe topic information
-    private val topic: Flow<Result<Topic>> = topicsRepository.getTopic(topicId).asResult()
+    val topicStream: Flow<Topic> = topicsRepository.getTopic(
-
+        id = topicId
-    // Observe the News for this topic
+    )
-    private val newsStream: Flow<Result<List<NewsResource>>> =
+
-        newsRepository.getNewsResourcesStream(
+    return combine(
-            filterTopicIds = setOf(element = topicId),
+        followedTopicIdsStream,
-        ).asResult()
+        topicStream,
-
+        ::Pair
-    val uiState: StateFlow<TopicScreenUiState> =
+    )
-        combine(
+        .asResult()
-            followedTopicIdsStream,
+        .map { followedTopicToTopicResult ->
-            topic,
+            when (followedTopicToTopicResult) {
-            newsStream
+                is Result.Success -> {
-        ) { followedTopicsResult, topicResult, newsResult ->
+                    val (followedTopics, topic) = followedTopicToTopicResult.data
-            val topic: TopicUiState =
+                    val followed = followedTopics.contains(topicId)
-                if (topicResult is Result.Success && followedTopicsResult is Result.Success) {
-                    val followed = followedTopicsResult.data.contains(topicId)
                     TopicUiState.Success(
                         followableTopic = FollowableTopic(
-                            topic = topicResult.data,
+                            topic = topic,
                             isFollowed = followed
                         )
                     )
-                } else if (
+                }
-                    topicResult is Result.Loading || followedTopicsResult is Result.Loading
+                is Result.Loading -> {
-                ) {
                     TopicUiState.Loading
-                } else {
+                }
+                is Result.Error -> {
                     TopicUiState.Error
                 }
-
-            val news: NewsUiState = when (newsResult) {
-                is Result.Success -> NewsUiState.Success(newsResult.data)
-                is Result.Loading -> NewsUiState.Loading
-                is Result.Error -> NewsUiState.Error
             }
-
-            TopicScreenUiState(topic, news)
         }
-            .stateIn(
+}
-                scope = viewModelScope,
-                started = SharingStarted.WhileSubscribed(5_000),
-                initialValue = TopicScreenUiState(TopicUiState.Loading, NewsUiState.Loading)
-            )
 
-    fun followTopicToggle(followed: Boolean) {
+private fun newsUiStateStream(
-        viewModelScope.launch {
+    topicId: String,
-            userDataRepository.toggleFollowedTopicId(topicId, followed)
+    newsRepository: NewsRepository,
+    userDataRepository: UserDataRepository,
+): Flow<NewsUiState> {
+    // Observe news
+    val newsStream: Flow<List<NewsResource>> = newsRepository.getNewsResourcesStream(
+        filterAuthorIds = emptySet(),
+        filterTopicIds = setOf(element = topicId),
+    )
+
+    // Observe bookmarks
+    val bookmarkStream: Flow<Set<String>> = userDataRepository.userDataStream
+        .map { it.bookmarkedNewsResources }
+
+    return combine(
+        newsStream,
+        bookmarkStream,
+        ::Pair
+    )
+        .asResult()
+        .map { newsToBookmarksResult ->
+            when (newsToBookmarksResult) {
+                is Result.Success -> {
+                    val (news, bookmarks) = newsToBookmarksResult.data
+                    NewsUiState.Success(
+                        news.map { newsResource ->
+                            SaveableNewsResource(
+                                newsResource,
+                                isSaved = bookmarks.contains(newsResource.id)
+                            )
+                        }
+                    )
+                }
+                is Result.Loading -> {
+                    NewsUiState.Loading
+                }
+                is Result.Error -> {
+                    NewsUiState.Error
+                }
+            }
         }
-    }
 }
 
 sealed interface TopicUiState {
@@ -114,12 +181,7 @@ sealed interface TopicUiState {
 }
 
 sealed interface NewsUiState {
-    data class Success(val news: List<NewsResource>) : NewsUiState
+    data class Success(val news: List<SaveableNewsResource>) : NewsUiState
     object Error : NewsUiState
     object Loading : NewsUiState
 }
-
-data class TopicScreenUiState(
-    val topicState: TopicUiState,
-    val newsState: NewsUiState
-)