Implement search feature (#685)

Implement search feature

- Add a feature module named "search"
- Add a SearchScreen that is navigated by tapping the search icon at the top left corner
- Add a data layer that takes care of populating the *Fts tables and querying them by a search query
- Add a SearchViewModel that wires up the data layer of the Fts tables with the SearchScreen

The SearchScreen has following features:
- The user is able to type the search query in the TextField
- The search result is displayed as the user types
- When the search result is clicked, it navigates to:
  - The InterestsScreen when a topic is clicked
  - Chrome custom tab with the URL of the clicked news resource
- When the search result is clicked or the IME is explicitly closed by the user, the current search query in the TextField is saved as recent searches
- Latest recent searches are displayed in the SearchScreen

Author: thagikura

app/build.gradle.kts

@@ -83,6 +83,7 @@ dependencies {
     implementation(project(":feature:foryou"))
     implementation(project(":feature:bookmarks"))
     implementation(project(":feature:topic"))
+    implementation(project(":feature:search"))
     implementation(project(":feature:settings"))
 
     implementation(project(":core:common"))

app/src/main/java/com/google/samples/apps/nowinandroid/navigation/NiaNavHost.kt

@@ -18,14 +18,16 @@ package com.google.samples.apps.nowinandroid.navigation
 
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
-import androidx.navigation.NavHostController
 import androidx.navigation.compose.NavHost
 import com.google.samples.apps.nowinandroid.feature.bookmarks.navigation.bookmarksScreen
 import com.google.samples.apps.nowinandroid.feature.foryou.navigation.forYouNavigationRoute
 import com.google.samples.apps.nowinandroid.feature.foryou.navigation.forYouScreen
 import com.google.samples.apps.nowinandroid.feature.interests.navigation.interestsGraph
+import com.google.samples.apps.nowinandroid.feature.search.navigation.searchScreen
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.navigateToTopic
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.topicScreen
+import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.INTERESTS
+import com.google.samples.apps.nowinandroid.ui.NiaAppState
 
 /**
  * Top-level navigation graph. Navigation is organized as explained at
@@ -36,10 +38,11 @@ import com.google.samples.apps.nowinandroid.feature.topic.navigation.topicScreen
  */
 @Composable
 fun NiaNavHost(
-    navController: NavHostController,
+    appState: NiaAppState,
     modifier: Modifier = Modifier,
     startDestination: String = forYouNavigationRoute,
 ) {
+    val navController = appState.navController
     NavHost(
         navController = navController,
         startDestination = startDestination,
@@ -48,6 +51,11 @@ fun NiaNavHost(
         // TODO: handle topic clicks from each top level destination
         forYouScreen(onTopicClick = {})
         bookmarksScreen(onTopicClick = {})
+        searchScreen(
+            onBackClick = navController::popBackStack,
+            onInterestsClick = { appState.navigateToTopLevelDestination(INTERESTS) },
+            onTopicClick = navController::navigateToTopic,
+        )
         interestsGraph(
             onTopicClick = { topicId ->
                 navController.navigateToTopic(topicId)

app/src/main/java/com/google/samples/apps/nowinandroid/ui/NiaApp.kt

@@ -173,6 +173,10 @@ fun NiaApp(
                         if (destination != null) {
                             NiaTopAppBar(
                                 titleRes = destination.titleTextId,
+                                navigationIcon = NiaIcons.Search,
+                                navigationIconContentDescription = stringResource(
+                                    id = settingsR.string.top_app_bar_navigation_icon_description,
+                                ),
                                 actionIcon = NiaIcons.Settings,
                                 actionIconContentDescription = stringResource(
                                     id = settingsR.string.top_app_bar_action_icon_description,
@@ -181,10 +185,11 @@ fun NiaApp(
                                     containerColor = Color.Transparent,
                                 ),
                                 onActionClick = { appState.setShowSettingsDialog(true) },
+                                onNavigationClick = { appState.navigateToSearch() },
                             )
                         }
 
-                        NiaNavHost(appState.navController)
+                        NiaNavHost(appState)
                     }
 
                     // TODO: We may want to add padding or spacer when the snackbar is shown so that

app/src/main/java/com/google/samples/apps/nowinandroid/ui/NiaAppState.kt

@@ -42,6 +42,7 @@ import com.google.samples.apps.nowinandroid.feature.foryou.navigation.forYouNavi
 import com.google.samples.apps.nowinandroid.feature.foryou.navigation.navigateToForYou
 import com.google.samples.apps.nowinandroid.feature.interests.navigation.interestsRoute
 import com.google.samples.apps.nowinandroid.feature.interests.navigation.navigateToInterestsGraph
+import com.google.samples.apps.nowinandroid.feature.search.navigation.navigateToSearch
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.BOOKMARKS
 import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination.FOR_YOU
@@ -172,6 +173,10 @@ class NiaAppState(
     fun setShowSettingsDialog(shouldShow: Boolean) {
         shouldShowSettingsDialog = shouldShow
     }
+
+    fun navigateToSearch() {
+        navController.navigateToSearch()
+    }
 }
 
 /**

core/data-test/src/main/java/com/google/samples/apps/nowinandroid/core/data/test/TestDataModule.kt

@@ -18,9 +18,13 @@ package com.google.samples.apps.nowinandroid.core.data.test
 
 import com.google.samples.apps.nowinandroid.core.data.di.DataModule
 import com.google.samples.apps.nowinandroid.core.data.repository.NewsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.RecentSearchRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.SearchContentsRepository
 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.data.repository.fake.FakeNewsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeRecentSearchRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeSearchContentsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeTopicsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeUserDataRepository
 import com.google.samples.apps.nowinandroid.core.data.util.NetworkMonitor
@@ -50,6 +54,16 @@ interface TestDataModule {
         userDataRepository: FakeUserDataRepository,
     ): UserDataRepository
 
+    @Binds
+    fun bindsRecentSearchRepository(
+        recentSearchRepository: FakeRecentSearchRepository,
+    ): RecentSearchRepository
+
+    @Binds
+    fun bindsSearchContentsRepository(
+        searchContentsRepository: FakeSearchContentsRepository,
+    ): SearchContentsRepository
+
     @Binds
     fun bindsNetworkMonitor(
         networkMonitor: AlwaysOnlineNetworkMonitor,

core/data/src/main/java/com/google/samples/apps/nowinandroid/core/data/di/DataModule.kt

@@ -16,10 +16,14 @@
 
 package com.google.samples.apps.nowinandroid.core.data.di
 
+import com.google.samples.apps.nowinandroid.core.data.repository.DefaultRecentSearchRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.DefaultSearchContentsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.NewsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.OfflineFirstNewsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.OfflineFirstTopicsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.OfflineFirstUserDataRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.RecentSearchRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.SearchContentsRepository
 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.data.util.ConnectivityManagerNetworkMonitor
@@ -48,6 +52,16 @@ interface DataModule {
         userDataRepository: OfflineFirstUserDataRepository,
     ): UserDataRepository
 
+    @Binds
+    fun bindsRecentSearchRepository(
+        recentSearchRepository: DefaultRecentSearchRepository,
+    ): RecentSearchRepository
+
+    @Binds
+    fun bindsSearchContentsRepository(
+        searchContentsRepository: DefaultSearchContentsRepository,
+    ): SearchContentsRepository
+
     @Binds
     fun bindsNetworkMonitor(
         networkMonitor: ConnectivityManagerNetworkMonitor,

core/data/src/main/java/com/google/samples/apps/nowinandroid/core/data/model/RecentSearchQuery.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.data.model
+
+import com.google.samples.apps.nowinandroid.core.database.model.RecentSearchQueryEntity
+import kotlinx.datetime.Clock
+import kotlinx.datetime.Instant
+
+data class RecentSearchQuery(
+    val query: String,
+    val queriedDate: Instant = Clock.System.now(),
+)
+
+fun RecentSearchQueryEntity.asExternalModel() = RecentSearchQuery(
+    query = query,
+    queriedDate = queriedDate,
+)

core/data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/DefaultRecentSearchRepository.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.data.repository
+
+import com.google.samples.apps.nowinandroid.core.data.model.RecentSearchQuery
+import com.google.samples.apps.nowinandroid.core.data.model.asExternalModel
+import com.google.samples.apps.nowinandroid.core.database.dao.RecentSearchQueryDao
+import com.google.samples.apps.nowinandroid.core.database.model.RecentSearchQueryEntity
+import com.google.samples.apps.nowinandroid.core.network.Dispatcher
+import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.IO
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.withContext
+import kotlinx.datetime.Clock
+import javax.inject.Inject
+
+class DefaultRecentSearchRepository @Inject constructor(
+    private val recentSearchQueryDao: RecentSearchQueryDao,
+    @Dispatcher(IO) private val ioDispatcher: CoroutineDispatcher,
+) : RecentSearchRepository {
+    override suspend fun insertOrReplaceRecentSearch(searchQuery: String) {
+        withContext(ioDispatcher) {
+            recentSearchQueryDao.insertOrReplaceRecentSearchQuery(
+                RecentSearchQueryEntity(
+                    query = searchQuery,
+                    queriedDate = Clock.System.now(),
+                ),
+            )
+        }
+    }
+
+    override fun getRecentSearchQueries(limit: Int): Flow<List<RecentSearchQuery>> =
+        recentSearchQueryDao.getRecentSearchQueryEntities(limit).map { searchQueries ->
+            searchQueries.map {
+                it.asExternalModel()
+            }
+        }
+
+    override suspend fun clearRecentSearches() = recentSearchQueryDao.clearRecentSearchQueries()
+}

core/data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/DefaultSearchContentsRepository.kt

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.data.repository
+
+import com.google.samples.apps.nowinandroid.core.database.dao.NewsResourceDao
+import com.google.samples.apps.nowinandroid.core.database.dao.NewsResourceFtsDao
+import com.google.samples.apps.nowinandroid.core.database.dao.TopicDao
+import com.google.samples.apps.nowinandroid.core.database.dao.TopicFtsDao
+import com.google.samples.apps.nowinandroid.core.database.model.asExternalModel
+import com.google.samples.apps.nowinandroid.core.database.model.asFtsEntity
+import com.google.samples.apps.nowinandroid.core.model.data.SearchResult
+import com.google.samples.apps.nowinandroid.core.network.Dispatcher
+import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.IO
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.mapLatest
+import kotlinx.coroutines.withContext
+import javax.inject.Inject
+
+class DefaultSearchContentsRepository @Inject constructor(
+    private val newsResourceDao: NewsResourceDao,
+    private val newsResourceFtsDao: NewsResourceFtsDao,
+    private val topicDao: TopicDao,
+    private val topicFtsDao: TopicFtsDao,
+    @Dispatcher(IO) private val ioDispatcher: CoroutineDispatcher,
+) : SearchContentsRepository {
+
+    override suspend fun populateFtsData() {
+        withContext(ioDispatcher) {
+            newsResourceFtsDao.insertAll(
+                newsResourceDao.getOneOffNewsResources().map { it.asFtsEntity() },
+            )
+            topicFtsDao.insertAll(topicDao.getOneOffTopicEntities().map { it.asFtsEntity() })
+        }
+    }
+
+    override fun searchContents(searchQuery: String): Flow<SearchResult> {
+        // Surround the query by asterisks to match the query when it's in the middle of
+        // a word
+        val newsResourceIds = newsResourceFtsDao.searchAllNewsResources("*$searchQuery*")
+        val topicIds = topicFtsDao.searchAllTopics("*$searchQuery*")
+
+        val newsResourcesFlow = newsResourceIds
+            .mapLatest { it.toSet() }
+            .distinctUntilChanged()
+            .flatMapLatest {
+                newsResourceDao.getNewsResources(useFilterNewsIds = true, filterNewsIds = it)
+            }
+        val topicsFlow = topicIds
+            .mapLatest { it.toSet() }
+            .distinctUntilChanged()
+            .flatMapLatest(topicDao::getTopicEntities)
+        return combine(newsResourcesFlow, topicsFlow) { newsResources, topics ->
+            SearchResult(
+                topics = topics.map { it.asExternalModel() },
+                newsResources = newsResources.map { it.asExternalModel() },
+            )
+        }
+    }
+
+    override fun getSearchContentsCount(): Flow<Int> =
+        combine(
+            newsResourceFtsDao.getCount(),
+            topicFtsDao.getCount(),
+        ) { newsResourceCount, topicsCount ->
+            newsResourceCount + topicsCount
+        }
+}

core/data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/RecentSearchRepository.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.data.repository
+
+import com.google.samples.apps.nowinandroid.core.data.model.RecentSearchQuery
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Data layer interface for the recent searches.
+ */
+interface RecentSearchRepository {
+
+    /**
+     * Get the recent search queries up to the number of queries specified as [limit].
+     */
+    fun getRecentSearchQueries(limit: Int): Flow<List<RecentSearchQuery>>
+
+    /**
+     * Insert or replace the [searchQuery] as part of the recent searches.
+     */
+    suspend fun insertOrReplaceRecentSearch(searchQuery: String)
+
+    /**
+     * Clear the recent searches.
+     */
+    suspend fun clearRecentSearches()
+}