From 3a5e7b36db4321797fb22df941ff6b429d1b9f76 Mon Sep 17 00:00:00 2001
From: Adetunji Dahunsi <dahunsi@google.com>
Date: Tue, 31 May 2022 14:32:01 -0400
Subject: [PATCH] Add UserDataRepository

Change-Id: I96cd2e6d137ad1c26fe2a4fdd3ada733b5be06b0
---
 .idea/codeStyles/Project.xml                  | 19 +---
 .../core/data/test/TestDataModule.kt          |  7 ++
 .../nowinandroid/core/data/di/DataModule.kt   |  7 ++
 .../core/data/repository/AuthorsRepository.kt | 15 ---
 .../OfflineFirstAuthorsRepository.kt          | 10 --
 .../OfflineFirstTopicsRepository.kt           | 10 --
 .../OfflineFirstUserDataRepository.kt         | 42 ++++++++
 .../core/data/repository/TopicsRepository.kt  | 15 ---
 .../data/repository/UserDataRepository.kt     | 48 +++++++++
 .../repository/fake/FakeAuthorsRepository.kt  | 12 ---
 .../repository/fake/FakeTopicsRepository.kt   | 10 --
 .../repository/fake/FakeUserDataRepository.kt | 52 ++++++++++
 .../OfflineFirstAuthorsRepositoryTest.kt      |  1 -
 .../OfflineFirstTopicsRepositoryTest.kt       | 60 +----------
 .../OfflineFirstUserDataRepositoryTest.kt     | 99 +++++++++++++++++++
 core-datastore/build.gradle.kts               |  1 +
 .../datastore/NiaPreferencesDataSource.kt     | 10 ++
 .../nowinandroid/core/model/data/UserData.kt  | 26 +++++
 .../repository/TestAuthorsRepository.kt       | 26 -----
 .../repository/TestTopicsRepository.kt        | 26 -----
 .../repository/TestUserDataRepository.kt      | 79 +++++++++++++++
 .../feature/author/AuthorViewModel.kt         | 11 ++-
 .../feature/author/AuthorViewModelTest.kt     | 13 ++-
 .../feature/foryou/ForYouViewModel.kt         | 32 +++---
 .../feature/foryou/ForYouViewModelTest.kt     | 79 ++++++++-------
 .../feature/interests/InterestsViewModel.kt   | 19 ++--
 .../interests/InterestsViewModelTest.kt       | 32 +++---
 .../feature/topic/TopicViewModel.kt           | 11 ++-
 .../feature/topic/TopicViewModelTest.kt       | 13 ++-
 29 files changed, 492 insertions(+), 293 deletions(-)
 create mode 100644 core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepository.kt
 create mode 100644 core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/UserDataRepository.kt
 create mode 100644 core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeUserDataRepository.kt
 create mode 100644 core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepositoryTest.kt
 create mode 100644 core-model/src/main/java/com/google/samples/apps/nowinandroid/core/model/data/UserData.kt
 create mode 100644 core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestUserDataRepository.kt

diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index a24d14540..0a9e39c9d 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -34,14 +34,7 @@
       <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="99" />
       <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="99" />
       <option name="IMPORT_NESTED_CLASSES" value="true" />
-      <option name="CONTINUATION_INDENT_IN_PARAMETER_LISTS" value="false" />
-      <option name="CONTINUATION_INDENT_IN_ARGUMENT_LISTS" value="false" />
-      <option name="CONTINUATION_INDENT_FOR_EXPRESSION_BODIES" value="false" />
-      <option name="CONTINUATION_INDENT_FOR_CHAINED_CALLS" value="false" />
-      <option name="CONTINUATION_INDENT_IN_SUPERTYPE_LISTS" value="false" />
-      <option name="CONTINUATION_INDENT_IN_IF_CONDITIONS" value="false" />
-      <option name="WRAP_EXPRESSION_BODY_FUNCTIONS" value="1" />
-      <option name="IF_RPAREN_ON_NEW_LINE" value="true" />
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
     </JetCodeStyleSettings>
     <Properties>
       <option name="KEEP_BLANK_LINES" value="true" />
@@ -307,19 +300,11 @@
       </arrangement>
     </codeStyleSettings>
     <codeStyleSettings language="kotlin">
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
       <option name="KEEP_BLANK_LINES_IN_DECLARATIONS" value="1" />
       <option name="KEEP_BLANK_LINES_IN_CODE" value="1" />
       <option name="KEEP_BLANK_LINES_BEFORE_RBRACE" value="0" />
       <option name="ALIGN_MULTILINE_PARAMETERS" value="false" />
-      <option name="CALL_PARAMETERS_WRAP" value="1" />
-      <option name="CALL_PARAMETERS_LPAREN_ON_NEXT_LINE" value="true" />
-      <option name="CALL_PARAMETERS_RPAREN_ON_NEXT_LINE" value="true" />
-      <option name="METHOD_PARAMETERS_WRAP" value="5" />
-      <option name="METHOD_PARAMETERS_LPAREN_ON_NEXT_LINE" value="true" />
-      <option name="METHOD_PARAMETERS_RPAREN_ON_NEXT_LINE" value="true" />
-      <option name="EXTENDS_LIST_WRAP" value="1" />
-      <option name="METHOD_CALL_CHAIN_WRAP" value="1" />
-      <option name="ASSIGNMENT_WRAP" value="1" />
       <option name="FIELD_ANNOTATION_WRAP" value="1" />
       <option name="PARAMETER_ANNOTATION_WRAP" value="1" />
       <option name="VARIABLE_ANNOTATION_WRAP" value="1" />
diff --git a/core-data-test/src/main/java/com/google/samples/apps/nowinandroid/core/data/test/TestDataModule.kt b/core-data-test/src/main/java/com/google/samples/apps/nowinandroid/core/data/test/TestDataModule.kt
index 3966ead2e..fa31a37a5 100644
--- a/core-data-test/src/main/java/com/google/samples/apps/nowinandroid/core/data/test/TestDataModule.kt
+++ b/core-data-test/src/main/java/com/google/samples/apps/nowinandroid/core/data/test/TestDataModule.kt
@@ -20,9 +20,11 @@ import com.google.samples.apps.nowinandroid.core.data.di.DataModule
 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.data.repository.fake.FakeAuthorsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeNewsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeTopicsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.fake.FakeUserDataRepository
 import dagger.Binds
 import dagger.Module
 import dagger.hilt.components.SingletonComponent
@@ -48,4 +50,9 @@ interface TestDataModule {
     fun bindsNewsResourceRepository(
         fakeNewsRepository: FakeNewsRepository
     ): NewsRepository
+
+    @Binds
+    fun bindsUserDataRepository(
+        userDataRepository: FakeUserDataRepository
+    ): UserDataRepository
 }
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/di/DataModule.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/di/DataModule.kt
index f44ff986e..3e30e7e59 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/di/DataModule.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/di/DataModule.kt
@@ -21,7 +21,9 @@ import com.google.samples.apps.nowinandroid.core.data.repository.NewsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.OfflineFirstAuthorsRepository
 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.TopicsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
 import dagger.Binds
 import dagger.Module
 import dagger.hilt.InstallIn
@@ -45,4 +47,9 @@ interface DataModule {
     fun bindsNewsResourceRepository(
         newsRepository: OfflineFirstNewsRepository
     ): NewsRepository
+
+    @Binds
+    fun bindsUserDataRepository(
+        userDataRepository: OfflineFirstUserDataRepository
+    ): UserDataRepository
 }
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/AuthorsRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/AuthorsRepository.kt
index 6921b94b3..8a27d5704 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/AuthorsRepository.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/AuthorsRepository.kt
@@ -30,19 +30,4 @@ interface AuthorsRepository : Syncable {
      * Gets data for a specific author
      */
     fun getAuthorStream(id: String): Flow<Author>
-
-    /**
-     * Sets the user's currently followed authors
-     */
-    suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>)
-
-    /**
-     * Toggles the user's newly followed/unfollowed author
-     */
-    suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean)
-
-    /**
-     * Returns the users currently followed authors
-     */
-    fun getFollowedAuthorIdsStream(): Flow<Set<String>>
 }
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepository.kt
index 5344810f3..0773bdc59 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepository.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepository.kt
@@ -23,7 +23,6 @@ import com.google.samples.apps.nowinandroid.core.database.dao.AuthorDao
 import com.google.samples.apps.nowinandroid.core.database.model.AuthorEntity
 import com.google.samples.apps.nowinandroid.core.database.model.asExternalModel
 import com.google.samples.apps.nowinandroid.core.datastore.ChangeListVersions
-import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
 import com.google.samples.apps.nowinandroid.core.model.data.Author
 import com.google.samples.apps.nowinandroid.core.network.NiaNetworkDataSource
 import com.google.samples.apps.nowinandroid.core.network.model.NetworkAuthor
@@ -38,7 +37,6 @@ import kotlinx.coroutines.flow.map
 class OfflineFirstAuthorsRepository @Inject constructor(
     private val authorDao: AuthorDao,
     private val network: NiaNetworkDataSource,
-    private val niaPreferences: NiaPreferencesDataSource,
 ) : AuthorsRepository {
 
     override fun getAuthorStream(id: String): Flow<Author> =
@@ -50,14 +48,6 @@ class OfflineFirstAuthorsRepository @Inject constructor(
         authorDao.getAuthorEntitiesStream()
             .map { it.map(AuthorEntity::asExternalModel) }
 
-    override suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>) =
-        niaPreferences.setFollowedAuthorIds(followedAuthorIds)
-
-    override suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean) =
-        niaPreferences.toggleFollowedAuthorId(followedAuthorId, followed)
-
-    override fun getFollowedAuthorIdsStream(): Flow<Set<String>> = niaPreferences.followedAuthorIds
-
     override suspend fun syncWith(synchronizer: Synchronizer): Boolean =
         synchronizer.changeListSync(
             versionReader = ChangeListVersions::authorVersion,
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepository.kt
index 4e2c64c9d..04d800021 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepository.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepository.kt
@@ -23,7 +23,6 @@ import com.google.samples.apps.nowinandroid.core.database.dao.TopicDao
 import com.google.samples.apps.nowinandroid.core.database.model.TopicEntity
 import com.google.samples.apps.nowinandroid.core.database.model.asExternalModel
 import com.google.samples.apps.nowinandroid.core.datastore.ChangeListVersions
-import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.network.NiaNetworkDataSource
 import com.google.samples.apps.nowinandroid.core.network.model.NetworkTopic
@@ -38,7 +37,6 @@ import kotlinx.coroutines.flow.map
 class OfflineFirstTopicsRepository @Inject constructor(
     private val topicDao: TopicDao,
     private val network: NiaNetworkDataSource,
-    private val niaPreferences: NiaPreferencesDataSource,
 ) : TopicsRepository {
 
     override fun getTopicsStream(): Flow<List<Topic>> =
@@ -48,14 +46,6 @@ class OfflineFirstTopicsRepository @Inject constructor(
     override fun getTopic(id: String): Flow<Topic> =
         topicDao.getTopicEntity(id).map { it.asExternalModel() }
 
-    override suspend fun setFollowedTopicIds(followedTopicIds: Set<String>) =
-        niaPreferences.setFollowedTopicIds(followedTopicIds)
-
-    override suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean) =
-        niaPreferences.toggleFollowedTopicId(followedTopicId, followed)
-
-    override fun getFollowedTopicIdsStream() = niaPreferences.followedTopicIds
-
     override suspend fun syncWith(synchronizer: Synchronizer): Boolean =
         synchronizer.changeListSync(
             versionReader = ChangeListVersions::topicVersion,
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepository.kt
new file mode 100644
index 000000000..08bfa18b4
--- /dev/null
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepository.kt
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2022 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.datastore.NiaPreferencesDataSource
+import com.google.samples.apps.nowinandroid.core.model.data.UserData
+import javax.inject.Inject
+import kotlinx.coroutines.flow.Flow
+
+class OfflineFirstUserDataRepository @Inject constructor(
+    private val niaPreferencesDataSource: NiaPreferencesDataSource
+) : UserDataRepository {
+
+    override val userDataStream: Flow<UserData> =
+        niaPreferencesDataSource.userDataStream
+
+    override suspend fun setFollowedTopicIds(followedTopicIds: Set<String>) =
+        niaPreferencesDataSource.setFollowedTopicIds(followedTopicIds)
+
+    override suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean) =
+        niaPreferencesDataSource.toggleFollowedTopicId(followedTopicId, followed)
+
+    override suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>) =
+        niaPreferencesDataSource.setFollowedAuthorIds(followedAuthorIds)
+
+    override suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean) =
+        niaPreferencesDataSource.toggleFollowedAuthorId(followedAuthorId, followed)
+}
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/TopicsRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/TopicsRepository.kt
index a4d2185b1..2e48fb334 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/TopicsRepository.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/TopicsRepository.kt
@@ -30,19 +30,4 @@ interface TopicsRepository : Syncable {
      * Gets data for a specific topic
      */
     fun getTopic(id: String): Flow<Topic>
-
-    /**
-     * Sets the user's currently followed topics
-     */
-    suspend fun setFollowedTopicIds(followedTopicIds: Set<String>)
-
-    /**
-     * Toggles the user's newly followed/unfollowed topic
-     */
-    suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean)
-
-    /**
-     * Returns the users currently followed topics
-     */
-    fun getFollowedTopicIdsStream(): Flow<Set<String>>
 }
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/UserDataRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/UserDataRepository.kt
new file mode 100644
index 000000000..f07b4efbe
--- /dev/null
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/UserDataRepository.kt
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2022 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.model.data.UserData
+import kotlinx.coroutines.flow.Flow
+
+interface UserDataRepository {
+
+    /**
+     * Stream of [UserData]
+     */
+    val userDataStream: Flow<UserData>
+
+    /**
+     * Sets the user's currently followed topics
+     */
+    suspend fun setFollowedTopicIds(followedTopicIds: Set<String>)
+
+    /**
+     * Toggles the user's newly followed/unfollowed topic
+     */
+    suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean)
+
+    /**
+     * Sets the user's currently followed authors
+     */
+    suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>)
+
+    /**
+     * Toggles the user's newly followed/unfollowed author
+     */
+    suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean)
+}
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeAuthorsRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeAuthorsRepository.kt
index 4a0ebf0ba..a6e2f69d8 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeAuthorsRepository.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeAuthorsRepository.kt
@@ -18,7 +18,6 @@ package com.google.samples.apps.nowinandroid.core.data.repository.fake
 
 import com.google.samples.apps.nowinandroid.core.data.Synchronizer
 import com.google.samples.apps.nowinandroid.core.data.repository.AuthorsRepository
-import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
 import com.google.samples.apps.nowinandroid.core.model.data.Author
 import com.google.samples.apps.nowinandroid.core.network.Dispatcher
 import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.IO
@@ -41,7 +40,6 @@ import kotlinx.serialization.json.Json
  */
 class FakeAuthorsRepository @Inject constructor(
     @Dispatcher(IO) private val ioDispatcher: CoroutineDispatcher,
-    private val niaPreferences: NiaPreferencesDataSource,
     private val networkJson: Json,
 ) : AuthorsRepository {
 
@@ -65,15 +63,5 @@ class FakeAuthorsRepository @Inject constructor(
         return getAuthorsStream().map { it.first { author -> author.id == id } }
     }
 
-    override suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>) {
-        niaPreferences.setFollowedAuthorIds(followedAuthorIds)
-    }
-
-    override suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean) {
-        niaPreferences.toggleFollowedAuthorId(followedAuthorId, followed)
-    }
-
-    override fun getFollowedAuthorIdsStream(): Flow<Set<String>> = niaPreferences.followedAuthorIds
-
     override suspend fun syncWith(synchronizer: Synchronizer) = true
 }
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeTopicsRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeTopicsRepository.kt
index ec18600f0..7ee46fed6 100644
--- a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeTopicsRepository.kt
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeTopicsRepository.kt
@@ -18,7 +18,6 @@ package com.google.samples.apps.nowinandroid.core.data.repository.fake
 
 import com.google.samples.apps.nowinandroid.core.data.Synchronizer
 import com.google.samples.apps.nowinandroid.core.data.repository.TopicsRepository
-import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.network.Dispatcher
 import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.IO
@@ -43,7 +42,6 @@ import kotlinx.serialization.json.Json
 class FakeTopicsRepository @Inject constructor(
     @Dispatcher(IO) private val ioDispatcher: CoroutineDispatcher,
     private val networkJson: Json,
-    private val niaPreferences: NiaPreferencesDataSource
 ) : TopicsRepository {
     override fun getTopicsStream(): Flow<List<Topic>> = flow<List<Topic>> {
         emit(
@@ -65,13 +63,5 @@ class FakeTopicsRepository @Inject constructor(
         return getTopicsStream().map { it.first { topic -> topic.id == id } }
     }
 
-    override suspend fun setFollowedTopicIds(followedTopicIds: Set<String>) =
-        niaPreferences.setFollowedTopicIds(followedTopicIds)
-
-    override suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean) =
-        niaPreferences.toggleFollowedTopicId(followedTopicId, followed)
-
-    override fun getFollowedTopicIdsStream() = niaPreferences.followedTopicIds
-
     override suspend fun syncWith(synchronizer: Synchronizer) = true
 }
diff --git a/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeUserDataRepository.kt b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeUserDataRepository.kt
new file mode 100644
index 000000000..2e214333f
--- /dev/null
+++ b/core-data/src/main/java/com/google/samples/apps/nowinandroid/core/data/repository/fake/FakeUserDataRepository.kt
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2022 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.fake
+
+import com.google.samples.apps.nowinandroid.core.data.repository.AuthorsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
+import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
+import com.google.samples.apps.nowinandroid.core.model.data.UserData
+import javax.inject.Inject
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Fake implementation of the [AuthorsRepository] that returns hardcoded authors.
+ *
+ * This allows us to run the app with fake data, without needing an internet connection or working
+ * backend.
+ */
+class FakeUserDataRepository @Inject constructor(
+    private val niaPreferencesDataSource: NiaPreferencesDataSource,
+) : UserDataRepository {
+
+    override val userDataStream: Flow<UserData> =
+        niaPreferencesDataSource.userDataStream
+
+    override suspend fun setFollowedTopicIds(followedTopicIds: Set<String>) =
+        niaPreferencesDataSource.setFollowedTopicIds(followedTopicIds)
+
+    override suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean) =
+        niaPreferencesDataSource.toggleFollowedTopicId(followedTopicId, followed)
+
+    override suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>) {
+        niaPreferencesDataSource.setFollowedAuthorIds(followedAuthorIds)
+    }
+
+    override suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean) {
+        niaPreferencesDataSource.toggleFollowedAuthorId(followedAuthorId, followed)
+    }
+}
diff --git a/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepositoryTest.kt b/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepositoryTest.kt
index 1d7bc0407..61c5fb809 100644
--- a/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepositoryTest.kt
+++ b/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstAuthorsRepositoryTest.kt
@@ -62,7 +62,6 @@ class OfflineFirstAuthorsRepositoryTest {
         subject = OfflineFirstAuthorsRepository(
             authorDao = authorDao,
             network = network,
-            niaPreferences = niaPreferencesDataSource,
         )
     }
 
diff --git a/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepositoryTest.kt b/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepositoryTest.kt
index 9481af62f..48570d5f0 100644
--- a/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepositoryTest.kt
+++ b/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepositoryTest.kt
@@ -62,8 +62,7 @@ class OfflineFirstTopicsRepositoryTest {
 
         subject = OfflineFirstTopicsRepository(
             topicDao = topicDao,
-            network = network,
-            niaPreferences = niaPreferences
+            network = network
         )
     }
 
@@ -79,17 +78,6 @@ class OfflineFirstTopicsRepositoryTest {
             )
         }
 
-    @Test
-    fun offlineFirstTopicsRepository_news_resources_for_interests_is_backed_by_news_resource_dao() =
-        runTest {
-            Assert.assertEquals(
-                niaPreferences.followedTopicIds
-                    .first(),
-                subject.getFollowedTopicIdsStream()
-                    .first()
-            )
-        }
-
     @Test
     fun offlineFirstTopicsRepository_sync_pulls_from_network() =
         runTest {
@@ -183,50 +171,4 @@ class OfflineFirstTopicsRepositoryTest {
                 synchronizer.getChangeListVersions().topicVersion
             )
         }
-
-    @Test
-    fun offlineFirstTopicsRepository_toggle_followed_topics_logic_delegates_to_nia_preferences() =
-        runTest {
-            subject.toggleFollowedTopicId(followedTopicId = "0", followed = true)
-
-            Assert.assertEquals(
-                setOf("0"),
-                subject.getFollowedTopicIdsStream()
-                    .first()
-            )
-
-            subject.toggleFollowedTopicId(followedTopicId = "1", followed = true)
-
-            Assert.assertEquals(
-                setOf("0", "1"),
-                subject.getFollowedTopicIdsStream()
-                    .first()
-            )
-
-            Assert.assertEquals(
-                niaPreferences.followedTopicIds
-                    .first(),
-                subject.getFollowedTopicIdsStream()
-                    .first()
-            )
-        }
-
-    @Test
-    fun offlineFirstTopicsRepository_set_followed_topics_logic_delegates_to_nia_preferences() =
-        runTest {
-            subject.setFollowedTopicIds(followedTopicIds = setOf("1", "2"))
-
-            Assert.assertEquals(
-                setOf("1", "2"),
-                subject.getFollowedTopicIdsStream()
-                    .first()
-            )
-
-            Assert.assertEquals(
-                niaPreferences.followedTopicIds
-                    .first(),
-                subject.getFollowedTopicIdsStream()
-                    .first()
-            )
-        }
 }
diff --git a/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepositoryTest.kt b/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepositoryTest.kt
new file mode 100644
index 000000000..08e5294c6
--- /dev/null
+++ b/core-data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepositoryTest.kt
@@ -0,0 +1,99 @@
+/*
+ * Copyright 2022 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.datastore.NiaPreferencesDataSource
+import com.google.samples.apps.nowinandroid.core.datastore.test.testUserPreferencesDataStore
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+
+class OfflineFirstUserDataRepositoryTest {
+    private lateinit var subject: OfflineFirstUserDataRepository
+
+    private lateinit var niaPreferencesDataSource: NiaPreferencesDataSource
+
+    @get:Rule
+    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
+
+    @Before
+    fun setup() {
+        niaPreferencesDataSource = NiaPreferencesDataSource(
+            tmpFolder.testUserPreferencesDataStore()
+        )
+
+        subject = OfflineFirstUserDataRepository(
+            niaPreferencesDataSource = niaPreferencesDataSource
+        )
+    }
+
+    @Test
+    fun offlineFirstTopicsRepository_toggle_followed_topics_logic_delegates_to_nia_preferences() =
+        runTest {
+            subject.toggleFollowedTopicId(followedTopicId = "0", followed = true)
+
+            assertEquals(
+                setOf("0"),
+                subject.userDataStream
+                    .map { it.followedTopics }
+                    .first()
+            )
+
+            subject.toggleFollowedTopicId(followedTopicId = "1", followed = true)
+
+            assertEquals(
+                setOf("0", "1"),
+                subject.userDataStream
+                    .map { it.followedTopics }
+                    .first()
+            )
+
+            assertEquals(
+                niaPreferencesDataSource.followedTopicIds
+                    .first(),
+                subject.userDataStream
+                    .map { it.followedTopics }
+                    .first()
+            )
+        }
+
+    @Test
+    fun offlineFirstTopicsRepository_set_followed_topics_logic_delegates_to_nia_preferences() =
+        runTest {
+            subject.setFollowedTopicIds(followedTopicIds = setOf("1", "2"))
+
+            assertEquals(
+                setOf("1", "2"),
+                subject.userDataStream
+                    .map { it.followedTopics }
+                    .first()
+            )
+
+            assertEquals(
+                niaPreferencesDataSource.followedTopicIds
+                    .first(),
+                subject.userDataStream
+                    .map { it.followedTopics }
+                    .first()
+            )
+        }
+}
diff --git a/core-datastore/build.gradle.kts b/core-datastore/build.gradle.kts
index 52d7ebc7b..033005aa8 100644
--- a/core-datastore/build.gradle.kts
+++ b/core-datastore/build.gradle.kts
@@ -57,6 +57,7 @@ protobuf {
 
 dependencies {
     implementation(project(":core-common"))
+    implementation(project(":core-model"))
 
     testImplementation(project(":core-testing"))
 
diff --git a/core-datastore/src/main/java/com/google/samples/apps/nowinandroid/core/datastore/NiaPreferencesDataSource.kt b/core-datastore/src/main/java/com/google/samples/apps/nowinandroid/core/datastore/NiaPreferencesDataSource.kt
index 938e85af6..8ce1fb3ee 100644
--- a/core-datastore/src/main/java/com/google/samples/apps/nowinandroid/core/datastore/NiaPreferencesDataSource.kt
+++ b/core-datastore/src/main/java/com/google/samples/apps/nowinandroid/core/datastore/NiaPreferencesDataSource.kt
@@ -18,6 +18,7 @@ package com.google.samples.apps.nowinandroid.core.datastore
 
 import android.util.Log
 import androidx.datastore.core.DataStore
+import com.google.samples.apps.nowinandroid.core.model.data.UserData
 import java.io.IOException
 import javax.inject.Inject
 import kotlinx.coroutines.flow.Flow
@@ -143,4 +144,13 @@ class NiaPreferencesDataSource @Inject constructor(
             true
         }
         .map { it.followedAuthorIdsList.toSet() }
+
+    val userDataStream = userPreferences.data
+        .map {
+            UserData(
+                bookmarkedNewsResources = emptySet(),
+                followedTopics = it.followedTopicIdsList.toSet(),
+                followedAuthors = it.followedAuthorIdsList.toSet(),
+            )
+        }
 }
diff --git a/core-model/src/main/java/com/google/samples/apps/nowinandroid/core/model/data/UserData.kt b/core-model/src/main/java/com/google/samples/apps/nowinandroid/core/model/data/UserData.kt
new file mode 100644
index 000000000..4535a14b4
--- /dev/null
+++ b/core-model/src/main/java/com/google/samples/apps/nowinandroid/core/model/data/UserData.kt
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2022 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.model.data
+
+/**
+ * Class summarizing user interest data
+ */
+data class UserData(
+    val bookmarkedNewsResources: Set<String>,
+    val followedTopics: Set<String>,
+    val followedAuthors: Set<String>,
+)
diff --git a/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestAuthorsRepository.kt b/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestAuthorsRepository.kt
index c3f69d921..13d01e480 100644
--- a/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestAuthorsRepository.kt
+++ b/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestAuthorsRepository.kt
@@ -25,12 +25,6 @@ import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.map
 
 class TestAuthorsRepository : AuthorsRepository {
-    /**
-     * The backing hot flow for the list of followed author ids for testing.
-     */
-    private val _followedAuthorIds: MutableSharedFlow<Set<String>> =
-        MutableSharedFlow(replay = 1, onBufferOverflow = BufferOverflow.DROP_OLDEST)
-
     /**
      * The backing hot flow for the list of author ids for testing.
      */
@@ -43,21 +37,6 @@ class TestAuthorsRepository : AuthorsRepository {
         return authorsFlow.map { authors -> authors.find { it.id == id }!! }
     }
 
-    override fun getFollowedAuthorIdsStream(): Flow<Set<String>> = _followedAuthorIds
-
-    override suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>) {
-        _followedAuthorIds.tryEmit(followedAuthorIds)
-    }
-
-    override suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean) {
-        getCurrentFollowedAuthors()?.let { current ->
-            _followedAuthorIds.tryEmit(
-                if (followed) current.plus(followedAuthorId)
-                else current.minus(followedAuthorId)
-            )
-        }
-    }
-
     override suspend fun syncWith(synchronizer: Synchronizer) = true
 
     /**
@@ -66,9 +45,4 @@ class TestAuthorsRepository : AuthorsRepository {
     fun sendAuthors(authors: List<Author>) {
         authorsFlow.tryEmit(authors)
     }
-
-    /**
-     * A test-only API to allow querying the current followed authors.
-     */
-    fun getCurrentFollowedAuthors(): Set<String>? = _followedAuthorIds.replayCache.firstOrNull()
 }
diff --git a/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestTopicsRepository.kt b/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestTopicsRepository.kt
index 262c9687e..3aa064a2d 100644
--- a/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestTopicsRepository.kt
+++ b/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestTopicsRepository.kt
@@ -25,12 +25,6 @@ import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.map
 
 class TestTopicsRepository : TopicsRepository {
-    /**
-     * The backing hot flow for the list of followed topic ids for testing.
-     */
-    private val _followedTopicIds: MutableSharedFlow<Set<String>> =
-        MutableSharedFlow(replay = 1, onBufferOverflow = BufferOverflow.DROP_OLDEST)
-
     /**
      * The backing hot flow for the list of topics ids for testing.
      */
@@ -43,21 +37,6 @@ class TestTopicsRepository : TopicsRepository {
         return topicsFlow.map { topics -> topics.find { it.id == id }!! }
     }
 
-    override suspend fun setFollowedTopicIds(followedTopicIds: Set<String>) {
-        _followedTopicIds.tryEmit(followedTopicIds)
-    }
-
-    override suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean) {
-        getCurrentFollowedTopics()?.let { current ->
-            _followedTopicIds.tryEmit(
-                if (followed) current.plus(followedTopicId)
-                else current.minus(followedTopicId)
-            )
-        }
-    }
-
-    override fun getFollowedTopicIdsStream(): Flow<Set<String>> = _followedTopicIds
-
     /**
      * A test-only API to allow controlling the list of topics from tests.
      */
@@ -65,10 +44,5 @@ class TestTopicsRepository : TopicsRepository {
         topicsFlow.tryEmit(topics)
     }
 
-    /**
-     * A test-only API to allow querying the current followed topics.
-     */
-    fun getCurrentFollowedTopics(): Set<String>? = _followedTopicIds.replayCache.firstOrNull()
-
     override suspend fun syncWith(synchronizer: Synchronizer) = true
 }
diff --git a/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestUserDataRepository.kt b/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestUserDataRepository.kt
new file mode 100644
index 000000000..1cffbb369
--- /dev/null
+++ b/core-testing/src/main/java/com/google/samples/apps/nowinandroid/core/testing/repository/TestUserDataRepository.kt
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2022 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.testing.repository
+
+import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
+import com.google.samples.apps.nowinandroid.core.model.data.UserData
+import kotlinx.coroutines.channels.BufferOverflow.DROP_OLDEST
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.filterNotNull
+
+private val emptyUserData = UserData(
+    bookmarkedNewsResources = emptySet(),
+    followedTopics = emptySet(),
+    followedAuthors = emptySet()
+)
+
+class TestUserDataRepository : UserDataRepository {
+    /**
+     * The backing hot flow for the list of followed topic ids for testing.
+     */
+    private val _userData = MutableSharedFlow<UserData>(replay = 1, onBufferOverflow = DROP_OLDEST)
+
+    private val currentUserData get() = _userData.replayCache.firstOrNull() ?: emptyUserData
+
+    override val userDataStream: Flow<UserData> = _userData.filterNotNull()
+
+    override suspend fun setFollowedTopicIds(followedTopicIds: Set<String>) {
+        _userData.tryEmit(currentUserData.copy(followedTopics = followedTopicIds))
+    }
+
+    override suspend fun toggleFollowedTopicId(followedTopicId: String, followed: Boolean) {
+        currentUserData.let { current ->
+            val followedTopics = if (followed) current.followedTopics + followedTopicId
+            else current.followedTopics - followedTopicId
+
+            _userData.tryEmit(current.copy(followedTopics = followedTopics))
+        }
+    }
+
+    override suspend fun setFollowedAuthorIds(followedAuthorIds: Set<String>) {
+        _userData.tryEmit(currentUserData.copy(followedAuthors = followedAuthorIds))
+    }
+
+    override suspend fun toggleFollowedAuthorId(followedAuthorId: String, followed: Boolean) {
+        currentUserData.let { current ->
+            val followedAuthors = if (followed) current.followedAuthors + followedAuthorId
+            else current.followedAuthors - followedAuthorId
+
+            _userData.tryEmit(current.copy(followedAuthors = followedAuthors))
+        }
+    }
+
+    /**
+     * A test-only API to allow querying the current followed topics.
+     */
+    fun getCurrentFollowedTopics(): Set<String>? =
+        _userData.replayCache.firstOrNull()?.followedTopics
+
+    /**
+     * A test-only API to allow querying the current followed authors.
+     */
+    fun getCurrentFollowedAuthors(): Set<String>? =
+        _userData.replayCache.firstOrNull()?.followedAuthors
+}
diff --git a/feature-author/src/main/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModel.kt b/feature-author/src/main/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModel.kt
index 61329570c..3401c0529 100644
--- a/feature-author/src/main/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModel.kt
+++ b/feature-author/src/main/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModel.kt
@@ -21,6 +21,7 @@ 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.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.NewsResource
@@ -33,13 +34,15 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 
 @HiltViewModel
 class AuthorViewModel @Inject constructor(
     savedStateHandle: SavedStateHandle,
-    private val authorsRepository: AuthorsRepository,
+    private val userDataRepository: UserDataRepository,
+    authorsRepository: AuthorsRepository,
     newsRepository: NewsRepository
 ) : ViewModel() {
 
@@ -49,7 +52,9 @@ class AuthorViewModel @Inject constructor(
 
     // Observe the followed authors, as they could change over time.
     private val followedAuthorIdsStream: Flow<Result<Set<String>>> =
-        authorsRepository.getFollowedAuthorIdsStream().asResult()
+        userDataRepository.userDataStream
+            .map { it.followedAuthors }
+            .asResult()
 
     // Observe author information
     private val author: Flow<Result<Author>> = authorsRepository.getAuthorStream(
@@ -102,7 +107,7 @@ class AuthorViewModel @Inject constructor(
 
     fun followAuthorToggle(followed: Boolean) {
         viewModelScope.launch {
-            authorsRepository.toggleFollowedAuthorId(authorId, followed)
+            userDataRepository.toggleFollowedAuthorId(authorId, followed)
         }
     }
 }
diff --git a/feature-author/src/test/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModelTest.kt b/feature-author/src/test/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModelTest.kt
index b25dd979b..be2228cf5 100644
--- a/feature-author/src/test/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModelTest.kt
+++ b/feature-author/src/test/java/com/google/samples/apps/nowinandroid/feature/author/AuthorViewModelTest.kt
@@ -24,6 +24,7 @@ import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResourceType.Video
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestAuthorsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestNewsRepository
+import com.google.samples.apps.nowinandroid.core.testing.repository.TestUserDataRepository
 import com.google.samples.apps.nowinandroid.core.testing.util.TestDispatcherRule
 import com.google.samples.apps.nowinandroid.feature.author.navigation.AuthorDestination
 import kotlinx.coroutines.flow.first
@@ -40,6 +41,7 @@ class AuthorViewModelTest {
     @get:Rule
     val dispatcherRule = TestDispatcherRule()
 
+    private val userDataRepository = TestUserDataRepository()
     private val authorsRepository = TestAuthorsRepository()
     private val newsRepository = TestNewsRepository()
     private lateinit var viewModel: AuthorViewModel
@@ -52,6 +54,7 @@ class AuthorViewModelTest {
                     AuthorDestination.authorIdArg to testInputAuthors[0].author.id
                 )
             ),
+            userDataRepository = userDataRepository,
             authorsRepository = authorsRepository,
             newsRepository = newsRepository
         )
@@ -63,7 +66,7 @@ class AuthorViewModelTest {
             awaitItem()
             // To make sure AuthorUiState is success
             authorsRepository.sendAuthors(testInputAuthors.map(FollowableAuthor::author))
-            authorsRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
+            userDataRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
 
             val item = awaitItem()
             assertTrue(item.authorState is AuthorUiState.Success)
@@ -99,7 +102,7 @@ class AuthorViewModelTest {
     @Test
     fun uiStateAuthor_whenFollowedIdsSuccessAndAuthorLoading_thenShowLoading() = runTest {
         viewModel.uiState.test {
-            authorsRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
+            userDataRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
             assertEquals(AuthorUiState.Loading, awaitItem().authorState)
             cancel()
         }
@@ -111,7 +114,7 @@ class AuthorViewModelTest {
             viewModel.uiState.test {
                 awaitItem()
                 authorsRepository.sendAuthors(testInputAuthors.map { it.author })
-                authorsRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
+                userDataRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
                 val item = awaitItem()
                 assertTrue(item.authorState is AuthorUiState.Success)
                 assertTrue(item.newsState is NewsUiState.Loading)
@@ -125,7 +128,7 @@ class AuthorViewModelTest {
             viewModel.uiState.test {
                 awaitItem()
                 authorsRepository.sendAuthors(testInputAuthors.map { it.author })
-                authorsRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
+                userDataRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
                 newsRepository.sendNewsResources(sampleNewsResources)
                 val item = awaitItem()
                 assertTrue(item.authorState is AuthorUiState.Success)
@@ -141,7 +144,7 @@ class AuthorViewModelTest {
                 awaitItem()
                 authorsRepository.sendAuthors(testInputAuthors.map { it.author })
                 // Set which author IDs are followed, not including 0.
-                authorsRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
+                userDataRepository.setFollowedAuthorIds(setOf(testInputAuthors[1].author.id))
 
                 viewModel.followAuthorToggle(true)
 
diff --git a/feature-foryou/src/main/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModel.kt b/feature-foryou/src/main/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModel.kt
index f7e36c430..8f7a424f2 100644
--- a/feature-foryou/src/main/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModel.kt
+++ b/feature-foryou/src/main/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModel.kt
@@ -27,6 +27,7 @@ import androidx.lifecycle.viewmodel.compose.saveable
 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.FollowableAuthor
 import com.google.samples.apps.nowinandroid.core.model.data.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
@@ -51,26 +52,25 @@ import kotlinx.coroutines.launch
 @OptIn(SavedStateHandleSaveableApi::class)
 @HiltViewModel
 class ForYouViewModel @Inject constructor(
-    private val authorsRepository: AuthorsRepository,
-    private val topicsRepository: TopicsRepository,
+    authorsRepository: AuthorsRepository,
+    topicsRepository: TopicsRepository,
     private val newsRepository: NewsRepository,
+    private val userDataRepository: UserDataRepository,
     savedStateHandle: SavedStateHandle
 ) : ViewModel() {
 
     private val followedInterestsState: StateFlow<FollowedInterestsState> =
-        combine(
-            authorsRepository.getFollowedAuthorIdsStream(),
-            topicsRepository.getFollowedTopicIdsStream(),
-        ) { followedAuthors, followedTopics ->
-            if (followedAuthors.isEmpty() && followedTopics.isEmpty()) {
-                None
-            } else {
-                FollowedInterests(
-                    authorIds = followedAuthors,
-                    topicIds = followedTopics
-                )
+        userDataRepository.userDataStream
+            .map { userData ->
+                if (userData.followedAuthors.isEmpty() && userData.followedTopics.isEmpty()) {
+                    None
+                } else {
+                    FollowedInterests(
+                        authorIds = userData.followedAuthors,
+                        topicIds = userData.followedTopics
+                    )
+                }
             }
-        }
             .stateIn(
                 scope = viewModelScope,
                 started = SharingStarted.WhileSubscribed(5_000),
@@ -232,8 +232,8 @@ class ForYouViewModel @Inject constructor(
         }
 
         viewModelScope.launch {
-            topicsRepository.setFollowedTopicIds(inProgressTopicSelection)
-            authorsRepository.setFollowedAuthorIds(inProgressAuthorSelection)
+            userDataRepository.setFollowedTopicIds(inProgressTopicSelection)
+            userDataRepository.setFollowedAuthorIds(inProgressAuthorSelection)
             // Clear out the old selection, in case we return to onboarding
             withMutableSnapshot {
                 inProgressTopicSelection = emptySet()
diff --git a/feature-foryou/src/test/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModelTest.kt b/feature-foryou/src/test/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModelTest.kt
index dffe9c40b..e39f10f3b 100644
--- a/feature-foryou/src/test/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModelTest.kt
+++ b/feature-foryou/src/test/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModelTest.kt
@@ -28,6 +28,7 @@ import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestAuthorsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestNewsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestTopicsRepository
+import com.google.samples.apps.nowinandroid.core.testing.repository.TestUserDataRepository
 import com.google.samples.apps.nowinandroid.core.testing.util.TestDispatcherRule
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.test.advanceUntilIdle
@@ -42,6 +43,7 @@ class ForYouViewModelTest {
     @get:Rule
     val dispatcherRule = TestDispatcherRule()
 
+    private val userDataRepository = TestUserDataRepository()
     private val authorsRepository = TestAuthorsRepository()
     private val topicsRepository = TestTopicsRepository()
     private val newsRepository = TestNewsRepository()
@@ -50,6 +52,7 @@ class ForYouViewModelTest {
     @Before
     fun setup() {
         viewModel = ForYouViewModel(
+            userDataRepository = userDataRepository,
             authorsRepository = authorsRepository,
             topicsRepository = topicsRepository,
             newsRepository = newsRepository,
@@ -130,7 +133,7 @@ class ForYouViewModelTest {
                 ),
                 awaitItem()
             )
-            topicsRepository.setFollowedTopicIds(emptySet())
+            userDataRepository.setFollowedTopicIds(emptySet())
 
             cancel()
         }
@@ -146,7 +149,7 @@ class ForYouViewModelTest {
                 ),
                 awaitItem()
             )
-            authorsRepository.setFollowedAuthorIds(emptySet())
+            userDataRepository.setFollowedAuthorIds(emptySet())
 
             cancel()
         }
@@ -158,9 +161,9 @@ class ForYouViewModelTest {
             advanceUntilIdle()
             expectMostRecentItem()
             topicsRepository.sendTopics(sampleTopics)
-            topicsRepository.setFollowedTopicIds(emptySet())
+            userDataRepository.setFollowedTopicIds(emptySet())
             authorsRepository.sendAuthors(sampleAuthors)
-            authorsRepository.setFollowedAuthorIds(emptySet())
+            userDataRepository.setFollowedAuthorIds(emptySet())
 
             advanceUntilIdle()
             assertEquals(
@@ -255,8 +258,8 @@ class ForYouViewModelTest {
             .test {
                 topicsRepository.sendTopics(sampleTopics)
                 authorsRepository.sendAuthors(sampleAuthors)
-                topicsRepository.setFollowedTopicIds(emptySet())
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
 
                 advanceUntilIdle()
@@ -352,9 +355,9 @@ class ForYouViewModelTest {
                 advanceUntilIdle()
                 expectMostRecentItem()
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(setOf("0", "1"))
+                userDataRepository.setFollowedTopicIds(setOf("0", "1"))
 
                 assertEquals(
                     ForYouUiState(
@@ -393,9 +396,9 @@ class ForYouViewModelTest {
                 advanceUntilIdle()
                 expectMostRecentItem()
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(setOf("0", "1"))
+                userDataRepository.setFollowedAuthorIds(setOf("0", "1"))
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
 
                 assertEquals(
                     ForYouUiState(
@@ -432,9 +435,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
 
                 advanceUntilIdle()
@@ -701,9 +704,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
 
                 advanceUntilIdle()
@@ -970,9 +973,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateTopicSelection("1", isChecked = true)
                 viewModel.updateTopicSelection("1", isChecked = false)
@@ -1068,9 +1071,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateAuthorSelection("1", isChecked = true)
                 viewModel.updateAuthorSelection("1", isChecked = false)
@@ -1166,9 +1169,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateTopicSelection("1", isChecked = true)
 
@@ -1197,8 +1200,8 @@ class ForYouViewModelTest {
                     ),
                     expectMostRecentItem()
                 )
-                assertEquals(setOf("1"), topicsRepository.getCurrentFollowedTopics())
-                assertEquals(emptySet<Int>(), authorsRepository.getCurrentFollowedAuthors())
+                assertEquals(setOf("1"), userDataRepository.getCurrentFollowedTopics())
+                assertEquals(emptySet<Int>(), userDataRepository.getCurrentFollowedAuthors())
                 cancel()
             }
     }
@@ -1208,9 +1211,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateAuthorSelection("0", isChecked = true)
 
@@ -1235,8 +1238,8 @@ class ForYouViewModelTest {
                     ),
                     expectMostRecentItem()
                 )
-                assertEquals(emptySet<Int>(), topicsRepository.getCurrentFollowedTopics())
-                assertEquals(setOf("0"), authorsRepository.getCurrentFollowedAuthors())
+                assertEquals(emptySet<Int>(), userDataRepository.getCurrentFollowedTopics())
+                assertEquals(setOf("0"), userDataRepository.getCurrentFollowedAuthors())
                 cancel()
             }
     }
@@ -1246,9 +1249,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateAuthorSelection("1", isChecked = true)
                 viewModel.updateTopicSelection("1", isChecked = true)
@@ -1278,8 +1281,8 @@ class ForYouViewModelTest {
                     ),
                     expectMostRecentItem()
                 )
-                assertEquals(setOf("1"), topicsRepository.getCurrentFollowedTopics())
-                assertEquals(setOf("1"), authorsRepository.getCurrentFollowedAuthors())
+                assertEquals(setOf("1"), userDataRepository.getCurrentFollowedTopics())
+                assertEquals(setOf("1"), userDataRepository.getCurrentFollowedAuthors())
                 cancel()
             }
     }
@@ -1289,9 +1292,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateTopicSelection("1", isChecked = true)
                 viewModel.saveFollowedInterests()
@@ -1299,7 +1302,7 @@ class ForYouViewModelTest {
                 advanceUntilIdle()
                 expectMostRecentItem()
 
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
 
                 advanceUntilIdle()
                 assertEquals(
@@ -1393,9 +1396,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(emptySet())
+                userDataRepository.setFollowedTopicIds(emptySet())
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateAuthorSelection("1", isChecked = true)
                 viewModel.saveFollowedInterests()
@@ -1403,7 +1406,7 @@ class ForYouViewModelTest {
                 advanceUntilIdle()
                 expectMostRecentItem()
 
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
 
                 advanceUntilIdle()
                 assertEquals(
@@ -1496,9 +1499,9 @@ class ForYouViewModelTest {
         viewModel.uiState
             .test {
                 topicsRepository.sendTopics(sampleTopics)
-                topicsRepository.setFollowedTopicIds(setOf("1"))
+                userDataRepository.setFollowedTopicIds(setOf("1"))
                 authorsRepository.sendAuthors(sampleAuthors)
-                authorsRepository.setFollowedAuthorIds(setOf("1"))
+                userDataRepository.setFollowedAuthorIds(setOf("1"))
                 newsRepository.sendNewsResources(sampleNewsResources)
                 viewModel.updateNewsResourceSaved("2", true)
 
diff --git a/feature-interests/src/main/java/com/google/samples/apps/nowinandroid/feature/interests/InterestsViewModel.kt b/feature-interests/src/main/java/com/google/samples/apps/nowinandroid/feature/interests/InterestsViewModel.kt
index f2e419d53..c6c01c3ca 100644
--- a/feature-interests/src/main/java/com/google/samples/apps/nowinandroid/feature/interests/InterestsViewModel.kt
+++ b/feature-interests/src/main/java/com/google/samples/apps/nowinandroid/feature/interests/InterestsViewModel.kt
@@ -20,6 +20,7 @@ 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.TopicsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
 import com.google.samples.apps.nowinandroid.core.model.data.FollowableAuthor
 import com.google.samples.apps.nowinandroid.core.model.data.FollowableTopic
 import dagger.hilt.android.lifecycle.HiltViewModel
@@ -35,8 +36,9 @@ import kotlinx.coroutines.launch
 
 @HiltViewModel
 class InterestsViewModel @Inject constructor(
-    private val authorsRepository: AuthorsRepository,
-    private val topicsRepository: TopicsRepository
+    private val userDataRepository: UserDataRepository,
+    authorsRepository: AuthorsRepository,
+    topicsRepository: TopicsRepository
 ) : ViewModel() {
 
     private val _tabState = MutableStateFlow(
@@ -48,18 +50,17 @@ class InterestsViewModel @Inject constructor(
     val tabState: StateFlow<InterestsTabState> = _tabState.asStateFlow()
 
     val uiState: StateFlow<InterestsUiState> = combine(
+        userDataRepository.userDataStream,
         authorsRepository.getAuthorsStream(),
-        authorsRepository.getFollowedAuthorIdsStream(),
         topicsRepository.getTopicsStream(),
-        topicsRepository.getFollowedTopicIdsStream(),
-    ) { availableAuthors, followedAuthorIdsState, availableTopics, followedTopicIdsState ->
+    ) { userData, availableAuthors, availableTopics ->
 
         InterestsUiState.Interests(
             authors = availableAuthors
                 .map { author ->
                     FollowableAuthor(
                         author = author,
-                        isFollowed = author.id in followedAuthorIdsState
+                        isFollowed = author.id in userData.followedAuthors
                     )
                 }
                 .sortedBy { it.author.name },
@@ -67,7 +68,7 @@ class InterestsViewModel @Inject constructor(
                 .map { topic ->
                     FollowableTopic(
                         topic = topic,
-                        isFollowed = topic.id in followedTopicIdsState
+                        isFollowed = topic.id in userData.followedTopics
                     )
                 }
                 .sortedBy { it.topic.name }
@@ -81,13 +82,13 @@ class InterestsViewModel @Inject constructor(
 
     fun followTopic(followedTopicId: String, followed: Boolean) {
         viewModelScope.launch {
-            topicsRepository.toggleFollowedTopicId(followedTopicId, followed)
+            userDataRepository.toggleFollowedTopicId(followedTopicId, followed)
         }
     }
 
     fun followAuthor(followedAuthorId: String, followed: Boolean) {
         viewModelScope.launch {
-            authorsRepository.toggleFollowedAuthorId(followedAuthorId, followed)
+            userDataRepository.toggleFollowedAuthorId(followedAuthorId, followed)
         }
     }
 
diff --git a/feature-interests/src/test/java/com/google/samples/apps/nowinandroid/interests/InterestsViewModelTest.kt b/feature-interests/src/test/java/com/google/samples/apps/nowinandroid/interests/InterestsViewModelTest.kt
index 248fe926d..249b3329c 100644
--- a/feature-interests/src/test/java/com/google/samples/apps/nowinandroid/interests/InterestsViewModelTest.kt
+++ b/feature-interests/src/test/java/com/google/samples/apps/nowinandroid/interests/InterestsViewModelTest.kt
@@ -23,6 +23,7 @@ import com.google.samples.apps.nowinandroid.core.model.data.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestAuthorsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestTopicsRepository
+import com.google.samples.apps.nowinandroid.core.testing.repository.TestUserDataRepository
 import com.google.samples.apps.nowinandroid.core.testing.util.TestDispatcherRule
 import com.google.samples.apps.nowinandroid.feature.interests.InterestsUiState
 import com.google.samples.apps.nowinandroid.feature.interests.InterestsViewModel
@@ -37,13 +38,18 @@ class InterestsViewModelTest {
     @get:Rule
     val dispatcherRule = TestDispatcherRule()
 
+    private val userDataRepository = TestUserDataRepository()
     private val authorsRepository = TestAuthorsRepository()
     private val topicsRepository = TestTopicsRepository()
     private lateinit var viewModel: InterestsViewModel
 
     @Before
     fun setup() {
-        viewModel = InterestsViewModel(authorsRepository, topicsRepository)
+        viewModel = InterestsViewModel(
+            userDataRepository = userDataRepository,
+            authorsRepository = authorsRepository,
+            topicsRepository = topicsRepository,
+        )
     }
 
     @Test
@@ -58,8 +64,8 @@ class InterestsViewModelTest {
     fun uiState_whenFollowedTopicsAreLoading_thenShowLoading() = runTest {
         viewModel.uiState.test {
             assertEquals(InterestsUiState.Loading, awaitItem())
-            authorsRepository.setFollowedAuthorIds(setOf("1"))
-            topicsRepository.setFollowedTopicIds(emptySet())
+            userDataRepository.setFollowedAuthorIds(setOf("1"))
+            userDataRepository.setFollowedTopicIds(emptySet())
             cancel()
         }
     }
@@ -68,8 +74,8 @@ class InterestsViewModelTest {
     fun uiState_whenFollowedAuthorsAreLoading_thenShowLoading() = runTest {
         viewModel.uiState.test {
             assertEquals(InterestsUiState.Loading, awaitItem())
-            authorsRepository.setFollowedAuthorIds(emptySet())
-            topicsRepository.setFollowedTopicIds(setOf("1"))
+            userDataRepository.setFollowedAuthorIds(emptySet())
+            userDataRepository.setFollowedTopicIds(setOf("1"))
             cancel()
         }
     }
@@ -81,9 +87,9 @@ class InterestsViewModelTest {
             .test {
                 awaitItem()
                 authorsRepository.sendAuthors(emptyList())
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 topicsRepository.sendTopics(testInputTopics.map { it.topic })
-                topicsRepository.setFollowedTopicIds(setOf(testInputTopics[0].topic.id))
+                userDataRepository.setFollowedTopicIds(setOf(testInputTopics[0].topic.id))
 
                 assertEquals(
                     false,
@@ -110,9 +116,9 @@ class InterestsViewModelTest {
             .test {
                 awaitItem()
                 authorsRepository.sendAuthors(testInputAuthors.map { it.author })
-                authorsRepository.setFollowedAuthorIds(setOf(testInputAuthors[0].author.id))
+                userDataRepository.setFollowedAuthorIds(setOf(testInputAuthors[0].author.id))
                 topicsRepository.sendTopics(listOf())
-                topicsRepository.setFollowedTopicIds(setOf())
+                userDataRepository.setFollowedTopicIds(setOf())
 
                 awaitItem()
                 viewModel.followAuthor(
@@ -135,9 +141,9 @@ class InterestsViewModelTest {
             .test {
                 awaitItem()
                 authorsRepository.sendAuthors(emptyList())
-                authorsRepository.setFollowedAuthorIds(emptySet())
+                userDataRepository.setFollowedAuthorIds(emptySet())
                 topicsRepository.sendTopics(testOutputTopics.map { it.topic })
-                topicsRepository.setFollowedTopicIds(
+                userDataRepository.setFollowedTopicIds(
                     setOf(testOutputTopics[0].topic.id, testOutputTopics[1].topic.id)
                 )
 
@@ -166,11 +172,11 @@ class InterestsViewModelTest {
             .test {
                 awaitItem()
                 authorsRepository.sendAuthors(testOutputAuthors.map { it.author })
-                authorsRepository.setFollowedAuthorIds(
+                userDataRepository.setFollowedAuthorIds(
                     setOf(testOutputAuthors[0].author.id, testOutputAuthors[1].author.id)
                 )
                 topicsRepository.sendTopics(listOf())
-                topicsRepository.setFollowedTopicIds(setOf())
+                userDataRepository.setFollowedTopicIds(setOf())
 
                 awaitItem()
                 viewModel.followAuthor(
diff --git a/feature-topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt b/feature-topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt
index 9e1bba01b..d647e4bf7 100644
--- a/feature-topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt
+++ b/feature-topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt
@@ -21,6 +21,7 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 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.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
@@ -33,13 +34,15 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 
 @HiltViewModel
 class TopicViewModel @Inject constructor(
     savedStateHandle: SavedStateHandle,
-    private val topicsRepository: TopicsRepository,
+    private val userDataRepository: UserDataRepository,
+    topicsRepository: TopicsRepository,
     newsRepository: NewsRepository
 ) : ViewModel() {
 
@@ -47,7 +50,9 @@ class TopicViewModel @Inject constructor(
 
     // Observe the followed topics, as they could change over time.
     private val followedTopicIdsStream: Flow<Result<Set<String>>> =
-        topicsRepository.getFollowedTopicIdsStream().asResult()
+        userDataRepository.userDataStream
+            .map { it.followedTopics }
+            .asResult()
 
     // Observe topic information
     private val topic: Flow<Result<Topic>> = topicsRepository.getTopic(topicId).asResult()
@@ -97,7 +102,7 @@ class TopicViewModel @Inject constructor(
 
     fun followTopicToggle(followed: Boolean) {
         viewModelScope.launch {
-            topicsRepository.toggleFollowedTopicId(topicId, followed)
+            userDataRepository.toggleFollowedTopicId(topicId, followed)
         }
     }
 }
diff --git a/feature-topic/src/test/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModelTest.kt b/feature-topic/src/test/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModelTest.kt
index 46d32ea80..a5e37a4ae 100644
--- a/feature-topic/src/test/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModelTest.kt
+++ b/feature-topic/src/test/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModelTest.kt
@@ -24,6 +24,7 @@ import com.google.samples.apps.nowinandroid.core.model.data.NewsResourceType.Vid
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestNewsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestTopicsRepository
+import com.google.samples.apps.nowinandroid.core.testing.repository.TestUserDataRepository
 import com.google.samples.apps.nowinandroid.core.testing.util.TestDispatcherRule
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.TopicDestination
 import kotlinx.coroutines.flow.first
@@ -40,6 +41,7 @@ class TopicViewModelTest {
     @get:Rule
     val dispatcherRule = TestDispatcherRule()
 
+    private val userDataRepository = TestUserDataRepository()
     private val topicsRepository = TestTopicsRepository()
     private val newsRepository = TestNewsRepository()
     private lateinit var viewModel: TopicViewModel
@@ -49,6 +51,7 @@ class TopicViewModelTest {
         viewModel = TopicViewModel(
             savedStateHandle =
             SavedStateHandle(mapOf(TopicDestination.topicIdArg to testInputTopics[0].topic.id)),
+            userDataRepository = userDataRepository,
             topicsRepository = topicsRepository,
             newsRepository = newsRepository
         )
@@ -59,7 +62,7 @@ class TopicViewModelTest {
         viewModel.uiState.test {
             awaitItem()
             topicsRepository.sendTopics(testInputTopics.map(FollowableTopic::topic))
-            topicsRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
+            userDataRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
             val item = awaitItem()
             assertTrue(item.topicState is TopicUiState.Success)
 
@@ -92,7 +95,7 @@ class TopicViewModelTest {
     @Test
     fun uiStateTopic_whenFollowedIdsSuccessAndTopicLoading_thenShowLoading() = runTest {
         viewModel.uiState.test {
-            topicsRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
+            userDataRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
             assertEquals(TopicUiState.Loading, awaitItem().topicState)
             cancel()
         }
@@ -104,7 +107,7 @@ class TopicViewModelTest {
             viewModel.uiState.test {
                 awaitItem()
                 topicsRepository.sendTopics(testInputTopics.map { it.topic })
-                topicsRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
+                userDataRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
                 val item = awaitItem()
                 assertTrue(item.topicState is TopicUiState.Success)
                 assertTrue(item.newsState is NewsUiState.Loading)
@@ -118,7 +121,7 @@ class TopicViewModelTest {
             viewModel.uiState.test {
                 awaitItem()
                 topicsRepository.sendTopics(testInputTopics.map { it.topic })
-                topicsRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
+                userDataRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
                 newsRepository.sendNewsResources(sampleNewsResources)
                 val item = awaitItem()
                 assertTrue(item.topicState is TopicUiState.Success)
@@ -134,7 +137,7 @@ class TopicViewModelTest {
                 awaitItem()
                 topicsRepository.sendTopics(testInputTopics.map { it.topic })
                 // Set which topic IDs are followed, not including 0.
-                topicsRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
+                userDataRepository.setFollowedTopicIds(setOf(testInputTopics[1].topic.id))
 
                 viewModel.followTopicToggle(true)