refactor(navigation): hierarchical, route-dispatching CodeNavigator

apps/flipcash/core/src/main/kotlin/com/flipcash/app/core/extensions/CodeNavigator.kt

@@ -13,18 +13,23 @@ import com.getcode.navigation.core.NavOptions
  * open, the current sheet is animated closed before the new one opens.
  */
 fun CodeNavigator.openAsSheet(route: AppRoute, innerRoutes: List<AppRoute> = emptyList()) {
+    // Sheets are hosted by the parent-chain root navigator — the one whose NavDisplay runs the
+    // ModalBottomSheetSceneStrategy and observes pendingSheetDismiss/sheetGeneration. Route the
+    // operation there so it works even when called from a flow's inner navigator. For a caller
+    // that is already the root, `host` is `this`, so behavior is unchanged.
+    val host = rootNavigator
     val destination = AppRoute.Main.Sheet(route, innerRoutes)
-    val hasSheet = backStack.any { it is AppRoute.Main.Sheet }
+    val hasSheet = host.backStack.any { it is AppRoute.Main.Sheet }
 
     if (hasSheet) {
-        pendingSheetDismiss = {
+        host.pendingSheetDismiss = {
             Snapshot.withMutableSnapshot {
-                sheetGeneration++
-                navigate(destination)
+                host.sheetGeneration++
+                host.navigate(destination)
             }
         }
     } else {
-        navigate(destination)
+        host.navigate(destination)
     }
 }
 

apps/flipcash/features/deposit/src/main/kotlin/com/flipcash/app/deposit/DepositFlowScreen.kt

@@ -35,7 +35,6 @@ import com.getcode.navigation.flow.PreviewFlowNavigator
 import com.getcode.navigation.flow.deliverFlowResult
 import com.getcode.navigation.flow.rememberFlowNavigator
 import com.getcode.navigation.flow.rememberInitialStack
-import com.getcode.navigation.flowAnnotatedEntry
 import com.getcode.navigation.results.NavResultOrCanceled
 import com.getcode.navigation.results.NavResultStateRegistry
 import com.getcode.ui.components.AppBarWithTitle
@@ -86,7 +85,7 @@ fun DepositFlowScreen(
 private fun depositEntryProvider(
     showOtherOptions: Boolean,
 ): (NavKey) -> NavEntry<NavKey> = entryProvider {
-    flowAnnotatedEntry<DepositStep.UsdcInformational> {
+    annotatedEntry<DepositStep.UsdcInformational> {
         UsdcDepositInformationScreen(showOtherOptions)
     }
     annotatedEntry<DepositStep.SelectToken> {

apps/flipcash/features/direct-send/src/main/kotlin/com/flipcash/app/directsend/internal/screens/ContactListScreen.kt

@@ -30,7 +30,6 @@ import com.flipcash.app.permissions.ContactAccessResult
 import com.flipcash.app.permissions.rememberContactAccessHandle
 import com.flipcash.features.directsend.R
 import com.getcode.libs.analytics.LocalAnalytics
-import com.getcode.navigation.flow.LocalOuterCodeNavigator
 import com.getcode.navigation.flow.flowSharedViewModel
 import com.getcode.navigation.flow.rememberFlowNavigator
 import com.getcode.theme.CodeTheme
@@ -48,7 +47,6 @@ import kotlinx.coroutines.flow.filterIsInstance
 internal fun ContactListScreen() {
     val flowNavigator = rememberFlowNavigator<SendStep, SendResult>()
     val viewModel = flowSharedViewModel<SendFlowViewModel>()
-    val navigator = LocalOuterCodeNavigator.current
     val analytics = LocalAnalytics.current
 
     val state by viewModel.stateFlow.collectAsStateWithLifecycle()
@@ -57,7 +55,9 @@ internal fun ContactListScreen() {
         viewModel.eventFlow
             .filterIsInstance<SendFlowViewModel.Event.SendInvite>()
             .collect { event ->
-                navigator.show(AppRoute.Main.InviteContact(event.contact.e164))
+                // App route -> flowNavigator.navigate bubbles it to the app stack (identical to the
+                // old outerNavigator.show, since show(r) == navigate(r)).
+                flowNavigator.navigate(AppRoute.Main.InviteContact(event.contact.e164))
             }
     }
 

apps/flipcash/features/login/src/main/kotlin/com/flipcash/app/login/OnboardingFlowScreen.kt

@@ -54,7 +54,6 @@ import com.getcode.navigation.core.LocalCodeNavigator
 import com.getcode.navigation.core.NavOptions
 import com.getcode.navigation.flow.FlowExitReason
 import com.getcode.navigation.flow.FlowHost
-import com.getcode.navigation.flow.LocalOuterCodeNavigator
 import com.getcode.navigation.flow.rememberFlowNavigator
 import com.getcode.navigation.flow.rememberInitialStack
 import com.getcode.navigation.results.NavResultStateRegistry
@@ -282,7 +281,7 @@ private fun LoginStepContent(seed: String?) {
     val vm = hiltViewModel<LoginViewModel>()
     val state by vm.stateFlow.collectAsStateWithLifecycle()
     val flowNavigator = rememberFlowNavigator<OnboardingStep, OnboardingResult>()
-    val outerNavigator = LocalOuterCodeNavigator.current
+    val navigator = LocalCodeNavigator.current
     var visible by remember { mutableStateOf(false) }
     val activity = LocalActivity.current
 
@@ -354,7 +353,7 @@ private fun LoginStepContent(seed: String?) {
             login = { flowNavigator.navigateTo(OnboardingStep.SeedInput) },
             isLabsOpen = state.betaOptionsVisible,
             onLogoTapped = { vm.dispatchEvent(LoginViewModel.Event.OnLogoTapped) },
-            openBetaFlags = { outerNavigator.openAsSheet(AppRoute.Menu.Lab(onboarding = true)) },
+            openBetaFlags = { navigator.openAsSheet(AppRoute.Menu.Lab(onboarding = true)) },
         )
     }
 }

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/ChatFlowScreen.kt

@@ -2,7 +2,6 @@ package com.flipcash.app.messenger
 
 import android.os.Parcelable
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
@@ -19,17 +18,14 @@ import com.flipcash.app.messenger.internal.screens.MessengerScreen
 import com.getcode.navigation.annotatedEntry
 import com.getcode.navigation.core.LocalCodeNavigator
 import com.getcode.navigation.flow.FlowHost
-import com.getcode.navigation.flow.LocalOuterCodeNavigator
 import com.getcode.navigation.flow.flowSharedViewModel
-import com.getcode.navigation.flow.rememberFlowNavigator
 import com.getcode.navigation.flow.rememberInitialStack
 import com.getcode.navigation.results.NavResultOrCanceled
 import com.getcode.navigation.results.NavResultStateRegistry
 import com.getcode.navigation.results.navigateForResult
 import com.getcode.navigation.results.resultBackNavigator
 import com.getcode.navigation.scenes.LocalSheetNavigator
 import kotlinx.coroutines.flow.filterIsInstance
-import kotlinx.coroutines.flow.map
 
 @Composable
 fun ChatFlowScreen(
@@ -62,12 +58,10 @@ private fun chatEntryProvider(
 private fun FlowConversationScreen(identifier: ChatIdentifier) {
     val viewModel = flowSharedViewModel<ChatViewModel>()
     val navigator = LocalCodeNavigator.current
-    // The outer app/sheet nav host. Its entryProvider (appEntryProvider) registers
-    // full AppRoutes like Token.Swap/Info/Discovery; the inner [navigator] only knows
-    // this flow's ChatStep keys, so full routes must be pushed onto the outer navigator.
-    val outerNavigator = LocalOuterCodeNavigator.current
-    // The sheet-owning (root) navigator — the one whose back stack holds this chat's
-    // Main.Sheet and whose pendingSheetDismiss the dismiss animation observes.
+    // The sheet-owning (root) navigator — the one whose back stack holds this chat's Main.Sheet and
+    // whose pendingSheetDismiss the dismiss animation observes. openAsSheet is stack-local (it
+    // inspects/mutates this navigator's own back stack), so it can't ride the type dispatcher and
+    // must target the sheet navigator explicitly.
     val sheetNavigator = LocalSheetNavigator.current
 
     LaunchedEffect(viewModel, identifier) {
@@ -78,6 +72,8 @@ private fun FlowConversationScreen(identifier: ChatIdentifier) {
         viewModel.eventFlow
             .filterIsInstance<ChatViewModel.Event.NavigateToAmountEntry>()
             .collect {
+                // ChatStep.AmountEntry is a FlowStep -> the dispatcher keeps this push on the inner
+                // flow stack and registers the result callback on the inner store (intra-flow).
                 navigator.navigateForResult<ChatSendResult>(ChatStep.AmountEntry) { result ->
                     if (result is NavResultOrCanceled.ReturnValue) {
                         viewModel.dispatchEvent(ChatViewModel.Event.OnStartMessageInput)
@@ -91,14 +87,15 @@ private fun FlowConversationScreen(identifier: ChatIdentifier) {
             .filterIsInstance<ChatViewModel.Event.OpenScreen>()
             .collect { (route, asSheet) ->
                 if (asSheet) {
-                    // Dismiss this chat sheet and open [route] as a fresh sheet.
-                    // openAsSheet on the sheet-owning navigator animates the current
-                    // sheet closed (via pendingSheetDismiss) before opening the new one.
+                    // Dismiss this chat sheet and open [route] as a fresh sheet. openAsSheet on the
+                    // sheet-owning navigator animates the current sheet closed (via pendingSheetDismiss)
+                    // before opening the new one.
                     sheetNavigator?.openAsSheet(route)
                 } else {
-                    // Push onto the outer nav host (which registers full AppRoutes) rather
-                    // than the inner flow navigator, whose backstack only handles ChatSteps.
-                    outerNavigator.navigate(route)
+                    // A full AppRoute (never a ChatStep) -> the dispatcher bubbles it up the parent
+                    // chain to the outer app nav host, the same destination as the old
+                    // outerNavigator.navigate(route).
+                    navigator.navigate(route)
                 }
             }
     }
@@ -110,21 +107,19 @@ private fun FlowConversationScreen(identifier: ChatIdentifier) {
 private fun FlowAmountEntryScreen() {
     val viewModel = flowSharedViewModel<ChatViewModel>()
     val state by viewModel.stateFlow.collectAsStateWithLifecycle()
-    val flowNavigator = rememberFlowNavigator<ChatStep, Parcelable>()
+    val navigator = LocalCodeNavigator.current
     val resultBack = resultBackNavigator<ChatSendResult>()
 
-    // Re-provide the outer navigator so ChatAmountEntryContent can push
-    // app-level routes (RegionSelection, TokenSelection, etc.)
-    val outerNavigator = LocalOuterCodeNavigator.current
-    CompositionLocalProvider(LocalCodeNavigator provides outerNavigator) {
-        ChatAmountEntryContent(
-            amountDelegate = viewModel.amountDelegate,
-            resolveState = state.resolveState,
-            token = state.token,
-            eventFlow = viewModel.eventFlow,
-            onConfirm = { viewModel.dispatchEvent(ChatViewModel.Event.OnConfirmRequested) },
-            onSendComplete = { resultBack.returnValue(ChatSendResult) },
-            onExit = { flowNavigator.back() },
-        )
-    }
+    // No re-shadow: ChatAmountEntryContent reads the inner LocalCodeNavigator, and its
+    // navigator.push(AppRoute.Main.RegionSelection) / push(AppRoute.Sheets.TokenSelection)
+    // bubble to the app navigator through the dispatcher.
+    ChatAmountEntryContent(
+        amountDelegate = viewModel.amountDelegate,
+        resolveState = state.resolveState,
+        token = state.token,
+        eventFlow = viewModel.eventFlow,
+        onConfirm = { viewModel.dispatchEvent(ChatViewModel.Event.OnConfirmRequested) },
+        onSendComplete = { resultBack.returnValue(ChatSendResult) }, // intra-flow result -> Conversation
+        onExit = { navigator.navigateBack() },                       // pop the AmountEntry step
+    )
 }

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/ChatViewModel.kt

@@ -271,6 +271,17 @@ internal class ChatViewModel @Inject constructor(
                     is ChatIdentifier.ByChatId -> identifier.chatId
                 }
 
+                // Re-entering the same, already-open chat (e.g. returning from the amount-entry
+                // step) re-dispatches OnChatOpened. The chat is already resolved and its messages
+                // are cached in Room, so skip the re-resolve + network reload that would invalidate
+                // Paging and reflow the message list. Still keep the chat active and clear
+                // notifications.
+                if (chatId != null && stateFlow.value.chatId == chatId) {
+                    chatCoordinator.setActiveChatId(chatId)
+                    chatCoordinator.dismissNotifications(chatId)
+                    return@onEach
+                }
+
                 if (chatId != null) {
                     dispatchEvent(Event.ChatFound(chatId))
                     chatCoordinator.setActiveChatId(chatId)

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/MessengerScreen.kt

@@ -35,8 +35,7 @@ import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.TransformOrigin
-import androidx.compose.ui.layout.onSizeChanged
-import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.layout.SubcomposeLayout
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.style.TextAlign
@@ -348,30 +347,39 @@ private fun ChatInputScaffold(
     bottomBar: @Composable () -> Unit = {},
     content: @Composable (PaddingValues) -> Unit,
 ) {
-    val density = LocalDensity.current
-    var topBarHeight by remember { mutableStateOf(0.dp) }
-    var bottomBarHeight by remember { mutableStateOf(0.dp) }
+    // Overlay scaffold: the content fills the whole area (drawn behind the blurred bars) and is
+    // inset by the bar heights. SubcomposeLayout measures the bars BEFORE the content in the same
+    // layout pass, so the content receives correct padding on the very first frame. The previous
+    // onSizeChanged approach fed 0 padding on frame 1 and snapped to the real heights on frame 2,
+    // which made the message list visibly jump on every open and every pop-back.
+    SubcomposeLayout(
+        modifier = Modifier
+            .imePadding()
+            .testTag("chat_screen"),
+    ) { constraints ->
+        val looseConstraints = constraints.copy(minWidth = 0, minHeight = 0)
 
-    Box(modifier = Modifier.imePadding().testTag("chat_screen")) {
-        content(
-            PaddingValues(
-                top = topBarHeight,
-                bottom = bottomBarHeight,
-            )
+        val topPlaceables = subcompose(ChatScaffoldSlot.Top, topBar).map { it.measure(looseConstraints) }
+        val bottomPlaceables = subcompose(ChatScaffoldSlot.Bottom, bottomBar).map { it.measure(looseConstraints) }
+        val topHeight = topPlaceables.maxOfOrNull { it.height } ?: 0
+        val bottomHeight = bottomPlaceables.maxOfOrNull { it.height } ?: 0
+
+        val padding = PaddingValues(
+            top = topHeight.toDp(),
+            bottom = bottomHeight.toDp(),
         )
-        Box(
-            modifier = Modifier
-                .align(Alignment.TopCenter)
-                .onSizeChanged { topBarHeight = with(density) { it.height.toDp() } }
-        ) {
-            topBar()
-        }
-        Box(
-            modifier = Modifier
-                .align(Alignment.BottomCenter)
-                .onSizeChanged { bottomBarHeight = with(density) { it.height.toDp() } }
-        ) {
-            bottomBar()
+
+        val contentPlaceables = subcompose(ChatScaffoldSlot.Content) { content(padding) }
+            .map { it.measure(constraints) }
+
+        layout(constraints.maxWidth, constraints.maxHeight) {
+            contentPlaceables.forEach { it.place(0, 0) }
+            topPlaceables.forEach { it.place((constraints.maxWidth - it.width) / 2, 0) }
+            bottomPlaceables.forEach {
+                it.place((constraints.maxWidth - it.width) / 2, constraints.maxHeight - it.height)
+            }
         }
     }
 }
+
+private enum class ChatScaffoldSlot { Top, Bottom, Content }

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/components/MessageList.kt

@@ -21,6 +21,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableLongStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshotFlow
 import androidx.compose.runtime.snapshots.Snapshot
@@ -108,7 +109,10 @@ internal fun MessageList(
         // Track when the initial Paging refresh has truly completed (Loading → NotLoading).
         // This avoids showing the ContactInfoContainer before messages arrive,
         // which would cause the list to start scrolled to the wrong position.
-        var refreshSettled by remember { mutableStateOf(false) }
+        // rememberSaveable so it survives the screen being torn down and rebuilt when the
+        // amount-entry step is pushed over the conversation — otherwise the content gate
+        // re-arms on pop-back and the list re-settles (visible reflow).
+        var refreshSettled by rememberSaveable { mutableStateOf(false) }
         LaunchedEffect(Unit) {
             snapshotFlow { messages.loadState.refresh }
                 .dropWhile { it !is LoadState.Loading }

apps/flipcash/features/tokens/src/main/kotlin/com/flipcash/app/tokens/SwapFlowScreen.kt

@@ -13,7 +13,6 @@ import com.flipcash.app.core.tokens.SwapStep
 import com.getcode.opencode.model.financial.Fiat
 import com.getcode.navigation.annotatedEntry
 import com.getcode.navigation.core.LocalCodeNavigator
-import com.getcode.navigation.flowAnnotatedEntry
 import com.getcode.navigation.flow.rememberInitialStack
 import com.getcode.navigation.flow.FlowExitReason
 import com.getcode.navigation.flow.FlowHost
@@ -72,7 +71,9 @@ private fun swapEntryProvider(
     val depositFirstPurpose = (route.purpose as? SwapPurpose.Buy)
         ?.takeIf { it.fundingSource == FundingSource.Phantom }
 
-    flowAnnotatedEntry<SwapStep.Entry> { step ->
+    // SwapEntryScreen reads only the inner LocalCodeNavigator; its cross-boundary result nav
+    // resolves to the app navigator via the dispatcher, so a plain annotatedEntry is correct.
+    annotatedEntry<SwapStep.Entry> { step ->
         SwapEntryScreen(step.purpose, step.initialAmount)
     }
     annotatedEntry<SwapStep.SellReceipt> { SellReceiptScreen() }

apps/flipcash/features/withdrawal/src/main/kotlin/com/flipcash/app/withdrawal/WithdrawalFlowScreen.kt

@@ -37,7 +37,6 @@ import com.getcode.navigation.flow.PreviewFlowNavigator
 import com.getcode.navigation.flow.deliverFlowResult
 import com.getcode.navigation.flow.rememberFlowNavigator
 import com.getcode.navigation.flow.rememberInitialStack
-import com.getcode.navigation.flowAnnotatedEntry
 import com.getcode.navigation.results.NavResultOrCanceled
 import com.getcode.navigation.results.NavResultStateRegistry
 import com.getcode.ui.components.AppBarWithTitle
@@ -91,7 +90,7 @@ private fun withdrawalEntryProvider(
     annotatedEntry<WithdrawalStep.SelectToken> {
         WithdrawalSelectTokenScreen()
     }
-    flowAnnotatedEntry<WithdrawalStep.Amount> { step ->
+    annotatedEntry<WithdrawalStep.Amount> { step ->
         WithdrawalEntryScreen(step.mint)
     }
     annotatedEntry<WithdrawalStep.Destination> {

ui/navigation/build.gradle.kts

@@ -32,4 +32,7 @@ dependencies {
     api(libs.lifecycle.viewmodel.navigation3)
     api(libs.hilt.nav.compose)
     api(libs.rinku)
+
+    testImplementation(kotlin("test"))
+    testImplementation(libs.bundles.unit.testing)
 }

ui/navigation/src/main/kotlin/com/getcode/navigation/NavMetadata.kt

@@ -2,13 +2,10 @@ package com.getcode.navigation
 
 import android.os.Parcelable
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.CompositionLocalProvider
 import androidx.navigation3.runtime.EntryProviderScope
 import androidx.navigation3.runtime.NavKey
 import com.getcode.navigation.results.NavResultKey
 import com.getcode.navigation.results.NavigationRetVal
-import com.getcode.navigation.core.LocalCodeNavigator
-import com.getcode.navigation.flow.LocalOuterCodeNavigator
 import java.lang.reflect.ParameterizedType
 import kotlin.reflect.KClass
 
@@ -30,22 +27,6 @@ inline fun <reified T : NavKey> EntryProviderScope<NavKey>.annotatedEntry(
     entry(metadata = T::class.metadata(), content = content)
 }
 
-/**
- * Like [annotatedEntry] but re-provides the outer app-level [CodeNavigator][com.getcode.navigation.core.CodeNavigator]
- * as [LocalCodeNavigator] inside [content]. Use this for flow steps that need to push routes onto the
- * outer/app nav graph (e.g. region selection) while running inside a [FlowHost][com.getcode.navigation.flow.FlowHost].
- */
-inline fun <reified T : NavKey> EntryProviderScope<NavKey>.flowAnnotatedEntry(
-    noinline content: @Composable (T) -> Unit
-) {
-    entry(metadata = T::class.metadata()) { step: T ->
-        val outerNavigator = LocalOuterCodeNavigator.current
-        CompositionLocalProvider(LocalCodeNavigator provides outerNavigator) {
-            content(step)
-        }
-    }
-}
-
 /**
  * Compute metadata from a [KClass] by inspecting its marker interfaces.
  *