Add ESTABLISHED AppStage guard (#6791)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/488551667048375/task/1211343078555471?focus=true

### Description

- Guards the `AppStage` once `ESTABLISHED` has been reached
- Adds a kill switch to disable the guard

### Steps to test this PR

- [ ] Filter logcat for “UserStageStore"
- [ ] Fresh install, skip onboarding and add the widget
- [ ] Open the widget and send a query
- [ ] Verify "UserStageStore: User is already ESTABLISHED, returning
ESTABLISHED"
- [ ] In feature flag inventory, disable “establishedAppStageGuard"
- [ ] Open the widget and send a query
- [ ] Verify "UserStageStore: currentStage=ESTABLISHED,
newAppStage=DAX_ONBOARDING"

Author: joshliebe

app/src/main/java/com/duckduckgo/app/onboarding/store/UserStageStore.kt

@@ -16,11 +16,14 @@
 
 package com.duckduckgo.app.onboarding.store
 
+import com.duckduckgo.app.pixels.remoteconfig.AndroidBrowserConfigFeature
 import com.duckduckgo.common.utils.DispatcherProvider
 import javax.inject.Inject
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.withContext
+import logcat.LogPriority.DEBUG
+import logcat.logcat
 
 interface UserStageStore {
     fun userAppStageFlow(): Flow<AppStage>
@@ -33,6 +36,7 @@ interface UserStageStore {
 class AppUserStageStore @Inject constructor(
     private val userStageDao: UserStageDao,
     private val dispatcher: DispatcherProvider,
+    private val androidBrowserConfigFeature: AndroidBrowserConfigFeature,
 ) : UserStageStore {
 
     override fun userAppStageFlow(): Flow<AppStage> {
@@ -48,13 +52,22 @@ class AppUserStageStore @Inject constructor(
 
     override suspend fun stageCompleted(appStage: AppStage): AppStage {
         return withContext(dispatcher.io()) {
+            val currentStage = getUserAppStage()
+            if (currentStage == AppStage.ESTABLISHED &&
+                androidBrowserConfigFeature.establishedAppStageGuard().isEnabled()
+            ) {
+                logcat(DEBUG) { "UserStageStore: User is already ESTABLISHED, returning ESTABLISHED" }
+                return@withContext AppStage.ESTABLISHED
+            }
+
             val newAppStage = when (appStage) {
                 AppStage.NEW -> AppStage.DAX_ONBOARDING
                 AppStage.DAX_ONBOARDING -> AppStage.ESTABLISHED
                 AppStage.ESTABLISHED -> AppStage.ESTABLISHED
             }
 
             if (newAppStage != appStage) {
+                logcat(DEBUG) { "UserStageStore: currentStage=$currentStage, newAppStage=$newAppStage" }
                 userStageDao.updateUserStage(newAppStage)
             }
 

app/src/main/java/com/duckduckgo/app/pixels/remoteconfig/AndroidBrowserConfigFeature.kt

@@ -170,4 +170,13 @@ interface AndroidBrowserConfigFeature {
      */
     @Toggle.DefaultValue(DefaultFeatureValue.TRUE)
     fun validateIntentResolution(): Toggle
+
+    /**
+     * Kill switch to prevent changing the onboarding stage once AppStage.ESTABLISHED is reached
+     * @return `true` when the remote config has the global "establishedAppStageGuard" androidBrowserConfig
+     * sub-feature flag enabled
+     * If the remote feature is not present defaults to `true`
+     */
+    @Toggle.DefaultValue(DefaultFeatureValue.TRUE)
+    fun establishedAppStageGuard(): Toggle
 }

app/src/test/java/com/duckduckgo/app/onboarding/store/AppUserStageStoreTest.kt

@@ -17,7 +17,10 @@
 package com.duckduckgo.app.onboarding.store
 
 import app.cash.turbine.test
+import com.duckduckgo.app.pixels.remoteconfig.AndroidBrowserConfigFeature
 import com.duckduckgo.common.test.CoroutineTestRule
+import com.duckduckgo.feature.toggles.api.FakeFeatureToggleFactory
+import com.duckduckgo.feature.toggles.api.Toggle.State
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flowOf
@@ -35,7 +38,8 @@ class AppUserStageStoreTest {
     var coroutineRule = CoroutineTestRule()
 
     private val userStageDao: UserStageDao = mock()
-    private val testee = AppUserStageStore(userStageDao, coroutineRule.testDispatcherProvider)
+    private val androidBrowserConfigFeature: AndroidBrowserConfigFeature = FakeFeatureToggleFactory.create(AndroidBrowserConfigFeature::class.java)
+    private val testee = AppUserStageStore(userStageDao, coroutineRule.testDispatcherProvider, androidBrowserConfigFeature)
 
     @Test
     fun whenGetUserAppStageThenReturnCurrentStage() = runTest {
@@ -102,6 +106,48 @@ class AppUserStageStoreTest {
         }
     }
 
+    @Test
+    fun `when user is established and guard enabled then return established app stage without updating`() = runTest {
+        givenCurrentStage(AppStage.ESTABLISHED)
+
+        val result = testee.stageCompleted(AppStage.NEW)
+
+        assertEquals(AppStage.ESTABLISHED, result)
+        verify(userStageDao).currentUserAppStage()
+    }
+
+    @Test
+    fun `when user is established and guard disabled then update app stage`() = runTest {
+        givenCurrentStage(AppStage.ESTABLISHED)
+        androidBrowserConfigFeature.establishedAppStageGuard().setRawStoredState(State(false))
+
+        val result = testee.stageCompleted(AppStage.NEW)
+
+        assertEquals(AppStage.DAX_ONBOARDING, result)
+        verify(userStageDao).updateUserStage(AppStage.DAX_ONBOARDING)
+    }
+
+    @Test
+    fun `when user is not established and guard enabled then update app stage`() = runTest {
+        givenCurrentStage(AppStage.NEW)
+
+        val result = testee.stageCompleted(AppStage.NEW)
+
+        assertEquals(AppStage.DAX_ONBOARDING, result)
+        verify(userStageDao).updateUserStage(AppStage.DAX_ONBOARDING)
+    }
+
+    @Test
+    fun `when user is not established and guard disabled then update app stage`() = runTest {
+        givenCurrentStage(AppStage.NEW)
+        androidBrowserConfigFeature.establishedAppStageGuard().setRawStoredState(State(false))
+
+        val result = testee.stageCompleted(AppStage.NEW)
+
+        assertEquals(AppStage.DAX_ONBOARDING, result)
+        verify(userStageDao).updateUserStage(AppStage.DAX_ONBOARDING)
+    }
+
     private suspend fun givenCurrentStage(appStage: AppStage) {
         whenever(userStageDao.currentUserAppStage()).thenReturn(UserStage(appStage = appStage))
     }