Refactor regV5 navigation to remove some unnecessary layers.

2026-02-15 07:28:30 +00:00 · 2025-12-12 12:51:26 -05:00
parent 2ca4748e00
commit c25f6d0bc4
7 changed files with 155 additions and 142 deletions
--- a/gradle/verification-metadata.xml
+++ b/gradle/verification-metadata.xml
@@ -4618,6 +4618,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="0a940e79e256cc7fbec69d8eb35362ac79599ab4b21ab4846aba64ba4960a192" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-livedata-ktx" version="2.10.0">
+         <artifact name="lifecycle-livedata-ktx-2.10.0.aar">
+            <sha256 value="3b42f425ab72b1d142ada7e075d78d9ab1500703729c1a342148eff4c0c23dcf" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-livedata-ktx-2.10.0.module">
+            <sha256 value="4d37fcd30801b06d5c508914b01154ee397071b0d5fcd634a48a45ded2dee09e" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-livedata-ktx" version="2.8.7">
         <artifact name="lifecycle-livedata-ktx-2.8.7.aar">
            <sha256 value="80af6960fb8b5d5b26bc04086613435e78a7c214be8b68b461bb79dedc431f76" origin="Generated by Gradle"/>
@@ -4749,6 +4757,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="f7cd5051bacb3f4b8ec7dc40ac6342a61eea1147592dda9f364a24cf882c7ddb" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-reactivestreams" version="2.10.0">
+         <artifact name="lifecycle-reactivestreams-2.10.0.aar">
+            <sha256 value="a68df4b53f0cc9c063691b2658cd059ec9e7f0d84439f0b458d95efc6cbe605c" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-reactivestreams-2.10.0.module">
+            <sha256 value="bc873cdd0c60ed59878fcdd122aeb571171158465454c0e674686d410dcf4f6c" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-reactivestreams" version="2.8.7">
         <artifact name="lifecycle-reactivestreams-2.8.7.aar">
            <sha256 value="305da124ecc7108bb8ff28b4140a75ce034e81e0ac6e4d51cddb476e2607e92e" origin="Generated by Gradle"/>
@@ -4791,6 +4807,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="28b7d48306489ebba7b9e1d65563377f994be708e7a9757e47ddc5c0421ad1a4" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-reactivestreams-ktx" version="2.10.0">
+         <artifact name="lifecycle-reactivestreams-ktx-2.10.0.aar">
+            <sha256 value="a46076ff7cb61666d60ea516236d50886bc06152411277e900c1ff4d9d8b812d" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-reactivestreams-ktx-2.10.0.module">
+            <sha256 value="74cf3d5d8d148203b471b8e749153bb8d8c2ba1118f8f794f7b329d6a6b5341a" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-reactivestreams-ktx" version="2.8.7">
         <artifact name="lifecycle-reactivestreams-ktx-2.8.7.aar">
            <sha256 value="e7d818e836f21895d65afd982b6a89ce5c7826c696bd273613445429c3da0d7c" origin="Generated by Gradle"/>
@@ -5114,6 +5138,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="b6803f906a89fd85c77df343dd4aeeb349125ca79e12d55d68d4cf42f42231f6" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-runtime-compose-desktop" version="2.10.0">
+         <artifact name="lifecycle-runtime-compose-desktop-2.10.0.jar">
+            <sha256 value="4d233eeecc6e2769a76442830c5fd1884057c36d0ce2745167193a10cc8976f8" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-runtime-compose-desktop-2.10.0.module">
+            <sha256 value="257b0bc6df73ad860e6b378b94890867964c7430da9c884a65f667cfe5cbdc10" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-runtime-compose-desktop" version="2.9.4">
         <artifact name="lifecycle-runtime-compose-desktop-2.9.4.jar">
            <md5 value="8f8fe81afd5c0e7c0f3e8a38142f8aa2" origin="Generated by Gradle"/>
@@ -5141,6 +5173,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="aaadee69ebaa3bae99ba7b5eb46aa7d38bd0be636d63f418cb43ec307a8f31da" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-runtime-desktop" version="2.10.0">
+         <artifact name="lifecycle-runtime-desktop-2.10.0.jar">
+            <sha256 value="6f70b76fb7a262f47b99317c23271c28a89ad18400547b4bfefbd2ef04500f90" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-runtime-desktop-2.10.0.module">
+            <sha256 value="2eeef8084cf67129e199227a3fabacf8506f57faeecb0aab0f765d5c4e59040a" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-runtime-desktop" version="2.8.7">
         <artifact name="lifecycle-runtime-desktop-2.8.7.module">
            <md5 value="edc88458a7e5ff7fe2314aea7f42d7f5" origin="Generated by Gradle"/>
@@ -5374,6 +5414,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="87ae364cb972aa5db8f80a97dde1b8dc5533841c43bfa798abdad82cf2515fe1" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-service" version="2.10.0">
+         <artifact name="lifecycle-service-2.10.0.aar">
+            <sha256 value="60bea13bbea42b6aa007e5a48c0b432c9b3dd05887482a43baa8f5a9042dc2e2" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-service-2.10.0.module">
+            <sha256 value="4f13973559bff5ea98e056556488c526a705df7776559d6551bfefaecf15a79a" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-service" version="2.6.1">
         <artifact name="lifecycle-service-2.6.1.module">
            <md5 value="10b87bd8171b0293794b99ed3b9f9d27" origin="Generated by Gradle"/>
@@ -5749,6 +5797,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="84450bb22ee6ce369c3ff52042e1d308cac63991782dacd95b8e5e357a97a221" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.lifecycle" name="lifecycle-viewmodel-compose-jvmstubs" version="2.10.0">
+         <artifact name="lifecycle-viewmodel-compose-jvmstubs-2.10.0.jar">
+            <sha256 value="e7a2558fe359d92d5ad455540589b25b2b5a9d77e4a3df7df26a139c08664c89" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="lifecycle-viewmodel-compose-jvmstubs-2.10.0.module">
+            <sha256 value="9dfac7b9733b7aa0c334571548c74b0cf675daeb31125c4e5131a5e249c4c3e8" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.lifecycle" name="lifecycle-viewmodel-compose-jvmstubs" version="2.9.0">
         <artifact name="lifecycle-viewmodel-compose-jvmstubs-2.9.0.jar">
            <sha256 value="02d761721139eb2d175b0efb44e318408c6a3e38bfa923dde886eaa506069d44" origin="Generated by Gradle"/>
@@ -5770,6 +5826,9 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
         </artifact>
      </component>
      <component group="androidx.lifecycle" name="lifecycle-viewmodel-desktop" version="2.10.0">
+         <artifact name="lifecycle-viewmodel-desktop-2.10.0.jar">
+            <sha256 value="e7c86a5e5c66fd41fd3cc9c9ad31a2997110b1a6380c441ba3f7b6b0b070e32b" origin="Generated by Gradle"/>
+         </artifact>
         <artifact name="lifecycle-viewmodel-desktop-2.10.0.module">
            <sha256 value="cda319d7c9e32602859a72be81c0026e56d1797ef9ba67e9173e905d3f74774f" origin="Generated by Gradle"/>
         </artifact>
@@ -6067,6 +6126,9 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
         </artifact>
      </component>
      <component group="androidx.lifecycle" name="lifecycle-viewmodel-savedstate-desktop" version="2.10.0">
+         <artifact name="lifecycle-viewmodel-savedstate-desktop-2.10.0.jar">
+            <sha256 value="92944597842a697623d0746d719d8af3acb9f4c780da611062fa60d993944d2c" origin="Generated by Gradle"/>
+         </artifact>
         <artifact name="lifecycle-viewmodel-savedstate-desktop-2.10.0.module">
            <sha256 value="59b7367fbd82b74a6053291a12743cac0c2cf1fe96929378c51d82bf8fe9a95d" origin="Generated by Gradle"/>
         </artifact>
@@ -6410,6 +6472,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="ec5f820c5856ab72029dc58acd54cee1e1952ec7e6233848dd10e9071f0eedbc" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.navigation3" name="navigation3-runtime-desktop" version="1.0.0">
+         <artifact name="navigation3-runtime-desktop-1.0.0.jar">
+            <sha256 value="db659bc9be9528a8af3ac65f218f632b7bbc1978b039522ae5d51210f4e0ee68" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="navigation3-runtime-desktop-1.0.0.module">
+            <sha256 value="eeab8a14560ab88ff0c96fcc10a142b8beea4cc93704add5627667921a9312e2" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.navigation3" name="navigation3-ui" version="1.0.0">
         <artifact name="navigation3-ui-1.0.0.module">
            <md5 value="3777271d1686b054e2464aadb712b084" origin="Generated by Gradle"/>
@@ -6851,6 +6921,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="06a0201247847e59303e4ffb468c9419c614708f568787e0abd5a92c6dadad40" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.savedstate" name="savedstate-compose-desktop" version="1.4.0">
+         <artifact name="savedstate-compose-desktop-1.4.0.jar">
+            <sha256 value="c02a98b0c2b35cdde245c0bfe6e7ff453c7b6d06a5eb8681d25b7f54b874ea48" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="savedstate-compose-desktop-1.4.0.module">
+            <sha256 value="808ff723a153acce160489a5bc4b58ca1d7033fe84a9060f52d17db227eaa4cd" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.savedstate" name="savedstate-compose-jvmstubs" version="1.3.0">
         <artifact name="savedstate-compose-jvmstubs-1.3.0.jar">
            <sha256 value="4a94787a6e5bcfe143390a4f2737d4425d2ea867f2b34a847de6cda3c6ccc58a" origin="Generated by Gradle"/>
@@ -6879,6 +6957,14 @@ https://docs.gradle.org/current/userguide/dependency_verification.html
            <sha256 value="945f3c713ab1f3896db216d199f924441453961ee2bbd74bb47ae8919dbaf759" origin="Generated by Gradle"/>
         </artifact>
      </component>
+      <component group="androidx.savedstate" name="savedstate-desktop" version="1.4.0">
+         <artifact name="savedstate-desktop-1.4.0.jar">
+            <sha256 value="e965ed7a011be83a271ac7d82249a776368479ee3a2b07948c3445b51d640856" origin="Generated by Gradle"/>
+         </artifact>
+         <artifact name="savedstate-desktop-1.4.0.module">
+            <sha256 value="e73f2cf8818ece347d8b5dff990d0db639a7dfb8fcc85eeecb2618383f7ecef7" origin="Generated by Gradle"/>
+         </artifact>
+      </component>
      <component group="androidx.savedstate" name="savedstate-ktx" version="1.2.1">
         <artifact name="savedstate-ktx-1.2.1.aar">
            <md5 value="232e75b56e6fea8591d591f98b2ecff2" origin="Generated by Gradle"/>
--- a/registration/app/build.gradle.kts
+++ b/registration/app/build.gradle.kts
@@ -82,6 +82,9 @@ dependencies {
  implementation(libs.androidx.navigation3.runtime)
  implementation(libs.androidx.navigation3.ui)

+  // Permissions
+  implementation(libs.accompanist.permissions)
+
  // Compose BOM
  platform(libs.androidx.compose.bom).let { composeBom ->
    implementation(composeBom)
--- a/registration/app/src/main/java/org/signal/registration/sample/AppViewModel.kt
+++ b/registration/app/src/main/java/org/signal/registration/sample/AppViewModel.kt
@@ -1,13 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.sample
-
-import androidx.lifecycle.ViewModel
-import org.signal.core.ui.navigation.ResultEventBus
-
-class AppViewModel : ViewModel() {
-  val resultEventBus = ResultEventBus()
-}
--- a/registration/app/src/main/java/org/signal/registration/sample/MainActivity.kt
+++ b/registration/app/src/main/java/org/signal/registration/sample/MainActivity.kt
@@ -3,13 +3,13 @@
 * SPDX-License-Identifier: AGPL-3.0-only
 */

+@file:OptIn(ExperimentalPermissionsApi::class)
+
 package org.signal.registration.sample

 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
-import androidx.activity.result.ActivityResultLauncher
-import androidx.activity.viewModels
 import androidx.compose.animation.EnterTransition
 import androidx.compose.animation.ExitTransition
 import androidx.compose.animation.core.tween
@@ -39,15 +39,12 @@ import androidx.navigation3.runtime.rememberDecoratedNavEntries
 import androidx.navigation3.runtime.rememberNavBackStack
 import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
 import androidx.navigation3.ui.NavDisplay
+import com.google.accompanist.permissions.ExperimentalPermissionsApi
 import kotlinx.serialization.Serializable
 import org.signal.core.ui.compose.theme.SignalTheme
-import org.signal.core.ui.navigation.ResultEffect
-import org.signal.core.ui.navigation.ResultEventBus
-import org.signal.registration.NetworkController
-import org.signal.registration.RegistrationActivity
 import org.signal.registration.RegistrationDependencies
-import org.signal.registration.StorageController
-import org.signal.registration.sample.MainActivity.Companion.REGISTRATION_RESULT
+import org.signal.registration.RegistrationNavHost
+import org.signal.registration.RegistrationRepository
 import org.signal.registration.sample.screens.RegistrationCompleteScreen
 import org.signal.registration.sample.screens.main.MainScreen
 import org.signal.registration.sample.screens.main.MainScreenViewModel
@@ -89,6 +86,9 @@ sealed interface SampleRoute : NavKey {
  @Serializable
  data object Main : SampleRoute

+  @Serializable
+  data object Registration : SampleRoute
+
  @Serializable
  data object RegistrationComplete : SampleRoute

@@ -104,15 +104,14 @@ class MainActivity : ComponentActivity() {
    const val REGISTRATION_RESULT = "registration_result"
  }

-  private val viewModel: AppViewModel by viewModels()
-
-  private val registrationLauncher: ActivityResultLauncher<Unit> = registerForActivityResult(RegistrationActivity.RegistrationContract()) { success ->
-    viewModel.resultEventBus.sendResult(REGISTRATION_RESULT, success)
-  }
-
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

+    val registrationRepository = RegistrationRepository(
+      networkController = RegistrationDependencies.get().networkController,
+      storageController = RegistrationDependencies.get().storageController
+    )
+
    setContent {
      SignalTheme {
        Surface(
@@ -122,11 +121,9 @@ class MainActivity : ComponentActivity() {
          val backStack = rememberNavBackStack(SampleRoute.Main)

          SampleNavHost(
-            onLaunchRegistration = { registrationLauncher.launch(Unit) },
            backStack = backStack,
-            resultEventBus = viewModel.resultEventBus,
-            storageController = RegistrationDependencies.get().storageController,
-            networkController = RegistrationDependencies.get().networkController,
+            registrationRepository = registrationRepository,
+            registrationDependencies = RegistrationDependencies.get(),
            onStartOver = {
              backStack.clear()
              backStack.add(SampleRoute.Main)
@@ -140,20 +137,18 @@ class MainActivity : ComponentActivity() {

@Composable
 private fun SampleNavHost(
-  onLaunchRegistration: () -> Unit,
  onStartOver: () -> Unit,
+  registrationRepository: RegistrationRepository,
+  registrationDependencies: RegistrationDependencies,
  backStack: NavBackStack<NavKey>,
-  resultEventBus: ResultEventBus,
-  storageController: StorageController,
-  networkController: NetworkController,
  modifier: Modifier = Modifier
 ) {
  val entryProvider: (NavKey) -> NavEntry<NavKey> = entryProvider {
    entry<SampleRoute.Main> {
      val viewModel: MainScreenViewModel = viewModel(
        factory = MainScreenViewModel.Factory(
-          storageController = storageController,
-          onLaunchRegistration = onLaunchRegistration,
+          storageController = registrationDependencies.storageController,
+          onLaunchRegistration = { backStack.add(SampleRoute.Registration) },
          onOpenPinSettings = { backStack.add(SampleRoute.PinSettings) }
        )
      )
@@ -164,19 +159,22 @@ private fun SampleNavHost(
        onPauseOrDispose { }
      }

-      ResultEffect<Boolean>(resultEventBus, REGISTRATION_RESULT) { success ->
-        if (success) {
-          viewModel.refreshData()
-          backStack.add(SampleRoute.RegistrationComplete)
-        }
-      }
-
      MainScreen(
        state = state,
        onEvent = { viewModel.onEvent(it) }
      )
    }

+    entry<SampleRoute.Registration> {
+      RegistrationNavHost(
+        registrationRepository,
+        modifier = Modifier.fillMaxSize(),
+        onRegistrationComplete = {
+          backStack.add(SampleRoute.RegistrationComplete)
+        }
+      )
+    }
+
    entry<SampleRoute.RegistrationComplete> {
      RegistrationCompleteScreen(onStartOver = onStartOver)
    }
@@ -186,7 +184,7 @@ private fun SampleNavHost(
    ) {
      val viewModel: PinSettingsViewModel = viewModel(
        factory = PinSettingsViewModel.Factory(
-          networkController = networkController,
+          networkController = registrationDependencies.networkController,
          onBack = { backStack.removeLastOrNull() }
        )
      )
--- a/registration/lib/src/main/java/org/signal/registration/RegistrationActivity.kt
+++ b/registration/lib/src/main/java/org/signal/registration/RegistrationActivity.kt
@@ -7,11 +7,11 @@ import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.result.contract.ActivityResultContract
 import androidx.activity.viewModels
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.material3.Surface
+import androidx.compose.ui.Modifier
 import com.google.accompanist.permissions.ExperimentalPermissionsApi
-import com.google.accompanist.permissions.rememberMultiplePermissionsState
 import org.signal.core.ui.compose.theme.SignalTheme
-import org.signal.registration.screens.RegistrationHostScreen

 /**
 * Activity entry point for the registration flow.
@@ -39,16 +39,11 @@ class RegistrationActivity : ComponentActivity() {
    super.onCreate(savedInstanceState)

    setContent {
-      val permissionsState = rememberMultiplePermissionsState(
-        permissions = viewModel.getRequiredPermissions()
-      )
-
      SignalTheme(incognitoKeyboardEnabled = false) {
        Surface {
-          RegistrationHostScreen(
+          RegistrationNavHost(
            registrationRepository = repository,
-            viewModel = viewModel,
-            permissionsState = permissionsState,
+            modifier = Modifier.fillMaxSize(),
            onRegistrationComplete = {
              setResult(RESULT_OK)
              finish()
--- a/registration/lib/src/main/java/org/signal/registration/RegistrationNavigation.kt
+++ b/registration/lib/src/main/java/org/signal/registration/RegistrationNavigation.kt
@@ -3,6 +3,8 @@
 * SPDX-License-Identifier: AGPL-3.0-only
 */

+@file:OptIn(ExperimentalPermissionsApi::class)
+
 package org.signal.registration

 import android.os.Parcelable
@@ -15,7 +17,6 @@ import androidx.compose.animation.togetherWith
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
@@ -27,6 +28,7 @@ import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
 import androidx.navigation3.ui.NavDisplay
 import com.google.accompanist.permissions.ExperimentalPermissionsApi
 import com.google.accompanist.permissions.MultiplePermissionsState
+import com.google.accompanist.permissions.rememberMultiplePermissionsState
 import kotlinx.parcelize.Parcelize
 import kotlinx.serialization.Serializable
 import org.signal.core.ui.navigation.ResultEffect
@@ -48,6 +50,8 @@ import org.signal.registration.screens.pinentry.PinEntryScreen
 import org.signal.registration.screens.restore.RestoreViaQrScreen
 import org.signal.registration.screens.restore.RestoreViaQrScreenEvents
 import org.signal.registration.screens.restore.RestoreViaQrState
+import org.signal.registration.screens.util.navigateBack
+import org.signal.registration.screens.util.navigateTo
 import org.signal.registration.screens.verificationcode.VerificationCodeScreen
 import org.signal.registration.screens.verificationcode.VerificationCodeViewModel
 import org.signal.registration.screens.welcome.WelcomeScreen
@@ -113,8 +117,9 @@ private const val CAPTCHA_RESULT = "captcha_token"
 /**
 * Sets up the navigation graph for the registration flow using Navigation 3.
 *
- * @param registrationViewModel The shared ViewModel for the registration flow.
- * @param permissionsState The permissions state managed at the activity level.
+ * @param registrationRepository The repository for registration data.
+ * @param registrationViewModel Optional ViewModel for testing. If null, creates one internally.
+ * @param permissionsState Optional permissions state for testing. If null, creates one internally.
 * @param modifier Modifier to be applied to the NavDisplay.
 * @param onRegistrationComplete Callback invoked when registration is successfully completed.
 */
@@ -122,20 +127,23 @@ private const val CAPTCHA_RESULT = "captcha_token"
@Composable
 fun RegistrationNavHost(
  registrationRepository: RegistrationRepository,
-  registrationViewModel: RegistrationViewModel,
-  permissionsState: MultiplePermissionsState,
+  registrationViewModel: RegistrationViewModel? = null,
+  permissionsState: MultiplePermissionsState? = null,
  modifier: Modifier = Modifier,
  onRegistrationComplete: () -> Unit = {}
 ) {
-  val registrationState by registrationViewModel.state.collectAsStateWithLifecycle()
-  val navigator = remember { RegistrationNavigator(eventEmitter = registrationViewModel::onEvent) }
+  val viewModel: RegistrationViewModel = registrationViewModel ?: viewModel(
+    factory = RegistrationViewModel.Factory(registrationRepository)
+  )
+
+  val registrationState by viewModel.state.collectAsStateWithLifecycle()
+  val permissions: MultiplePermissionsState = permissionsState ?: rememberMultiplePermissionsState(viewModel.getRequiredPermissions())

  val entryProvider = entryProvider {
-    registrationEntries(
+    navigationEntries(
      registrationRepository = registrationRepository,
-      registrationViewModel = registrationViewModel,
-      permissionsState = permissionsState,
-      navigator = navigator,
+      registrationViewModel = viewModel,
+      permissionsState = permissions,
      onRegistrationComplete = onRegistrationComplete
    )
  }
@@ -152,7 +160,7 @@ fun RegistrationNavHost(

  NavDisplay(
    entries = entries,
-    onBack = { registrationViewModel.onEvent(RegistrationFlowEvent.NavigateBack) },
+    onBack = { viewModel.onEvent(RegistrationFlowEvent.NavigateBack) },
    modifier = modifier,
    transitionSpec = {
      // Slide in from right and fade in when navigating forward
@@ -204,25 +212,22 @@ fun RegistrationNavHost(
  )
 }

-/**
- * Defines all navigation entries for the registration flow.
- */
-@OptIn(ExperimentalPermissionsApi::class)
-private fun EntryProviderScope<NavKey>.registrationEntries(
+private fun EntryProviderScope<NavKey>.navigationEntries(
  registrationRepository: RegistrationRepository,
  registrationViewModel: RegistrationViewModel,
  permissionsState: MultiplePermissionsState,
-  navigator: RegistrationNavigator,
  onRegistrationComplete: () -> Unit
 ) {
+  val parentEventEmitter: (RegistrationFlowEvent) -> Unit = registrationViewModel::onEvent
+
  // --- Welcome Screen
  entry<RegistrationRoute.Welcome> {
    WelcomeScreen(
      onEvent = { event ->
        when (event) {
-          WelcomeScreenEvents.Continue -> navigator.navigate(RegistrationRoute.Permissions(forRestore = false))
-          WelcomeScreenEvents.DoesNotHaveOldPhone -> navigator.navigate(RegistrationRoute.Restore)
-          WelcomeScreenEvents.HasOldPhone -> navigator.navigate(RegistrationRoute.Permissions(forRestore = true))
+          WelcomeScreenEvents.Continue -> parentEventEmitter.navigateTo(RegistrationRoute.Permissions(forRestore = false))
+          WelcomeScreenEvents.DoesNotHaveOldPhone -> parentEventEmitter.navigateTo(RegistrationRoute.Restore)
+          WelcomeScreenEvents.HasOldPhone -> parentEventEmitter.navigateTo(RegistrationRoute.Permissions(forRestore = true))
        }
      }
    )
@@ -234,9 +239,9 @@ private fun EntryProviderScope<NavKey>.registrationEntries(
      permissionsState = permissionsState,
      onProceed = {
        if (key.forRestore) {
-          navigator.navigate(RegistrationRoute.RestoreViaQr)
+          parentEventEmitter.navigateTo(RegistrationRoute.RestoreViaQr)
        } else {
-          navigator.navigate(RegistrationRoute.PhoneNumberEntry)
+          parentEventEmitter.navigateTo(RegistrationRoute.PhoneNumberEntry)
        }
      }
    )
@@ -281,10 +286,10 @@ private fun EntryProviderScope<NavKey>.registrationEntries(
        when (event) {
          is CaptchaScreenEvents.CaptchaCompleted -> {
            registrationViewModel.resultBus.sendResult(CAPTCHA_RESULT, event.token)
-            navigator.goBack()
+            parentEventEmitter.navigateBack()
          }
          CaptchaScreenEvents.Cancel -> {
-            navigator.goBack()
+            parentEventEmitter.navigateBack()
          }
        }
      }
@@ -370,7 +375,7 @@ private fun EntryProviderScope<NavKey>.registrationEntries(
        when (event) {
          AccountLockedScreenEvents.Next -> {
            // TODO: Navigate to appropriate next screen (likely back to welcome or phone entry)
-            navigator.navigate(RegistrationRoute.Welcome)
+            parentEventEmitter.navigateTo(RegistrationRoute.Welcome)
          }
          AccountLockedScreenEvents.LearnMore -> {
            // TODO: Open learn more URL
@@ -393,7 +398,7 @@ private fun EntryProviderScope<NavKey>.registrationEntries(
            // TODO: Retry QR code generation
          }
          RestoreViaQrScreenEvents.Cancel -> {
-            navigator.goBack()
+            parentEventEmitter.navigateBack()
          }
          RestoreViaQrScreenEvents.UseProxy -> {
            // TODO: Navigate to proxy settings
@@ -420,20 +425,3 @@ private fun EntryProviderScope<NavKey>.registrationEntries(
    }
  }
 }
-
-/**
- * Navigator for the registration flow.
- * Handles navigation events by updating the back stack.
- */
-private class RegistrationNavigator(
-  private val eventEmitter: (RegistrationFlowEvent) -> Unit
-) {
-
-  fun navigate(route: RegistrationRoute) {
-    eventEmitter(RegistrationFlowEvent.NavigateToScreen(route))
-  }
-
-  fun goBack() {
-    eventEmitter(RegistrationFlowEvent.NavigateBack)
-  }
-}
--- a/registration/lib/src/main/java/org/signal/registration/screens/RegistrationHostScreen.kt
+++ b/registration/lib/src/main/java/org/signal/registration/screens/RegistrationHostScreen.kt
@@ -1,44 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens
-
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.runtime.Composable
-import androidx.compose.ui.Modifier
-import com.google.accompanist.permissions.ExperimentalPermissionsApi
-import com.google.accompanist.permissions.MultiplePermissionsState
-import org.signal.registration.RegistrationNavHost
-import org.signal.registration.RegistrationRepository
-import org.signal.registration.RegistrationViewModel
-
-/**
- * Entry point for the registration flow.
- *
- * This composable sets up the entire registration navigation flow and can be
- * embedded into the main app's navigation or launched as a standalone flow.
- *
- * @param viewModel The shared ViewModel for the registration flow.
- * @param permissionsState The permissions state managed at the activity level.
- * @param modifier Modifier to be applied to the root container.
- * @param onRegistrationComplete Callback invoked when the registration process is successfully completed.
- */
-@OptIn(ExperimentalPermissionsApi::class)
-@Composable
-fun RegistrationHostScreen(
-  registrationRepository: RegistrationRepository,
-  viewModel: RegistrationViewModel,
-  permissionsState: MultiplePermissionsState,
-  modifier: Modifier = Modifier,
-  onRegistrationComplete: () -> Unit = {}
-) {
-  RegistrationNavHost(
-    registrationRepository = registrationRepository,
-    registrationViewModel = viewModel,
-    permissionsState = permissionsState,
-    modifier = modifier.fillMaxSize(),
-    onRegistrationComplete = onRegistrationComplete
-  )
-}