AppScaffold removal.

app/src/main/java/org/thoughtcrime/securesms/chats/ConversationLoadingMask.kt

@@ -14,18 +14,22 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.State
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.GraphicsLayerScope
 import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.LayoutDirection
 import androidx.compose.ui.unit.dp
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.withTimeoutOrNull
-import org.thoughtcrime.securesms.window.AppScaffoldAnimationDefaults
-import org.thoughtcrime.securesms.window.AppScaffoldAnimationState
+import org.signal.core.ui.navigation.TransitionSpecs
 import kotlin.time.Duration.Companion.seconds
 
 /**
@@ -74,7 +78,7 @@ fun ConversationLoadingMask(
   }
 
   val chatModifier = Modifier.graphicsLayer {
-    with(chatAnimationState) { applyChildValues() }
+    with(chatAnimationState) { applyTo() }
   }
 
   Box(modifier = Modifier.fillMaxSize()) {
@@ -86,7 +90,7 @@ fun ConversationLoadingMask(
         contentDescription = null,
         modifier = Modifier
           .graphicsLayer {
-            with(fakeChatListAnimationState) { applyChildValues() }
+            with(fakeChatListAnimationState) { applyTo() }
           }
           .fillMaxSize()
       )
@@ -95,11 +99,12 @@ fun ConversationLoadingMask(
 }
 
 @Composable
-private fun Transition<Boolean>.fakeChatListAnimationState(): AppScaffoldAnimationState {
-  val alpha = animateFloat(transitionSpec = { AppScaffoldAnimationDefaults.tween() }) { if (it) 0f else 1f }
-  val offset = animateDp(transitionSpec = { AppScaffoldAnimationDefaults.tween() }) { if (it) (-48).dp else 0.dp }
+private fun Transition<Boolean>.fakeChatListAnimationState(): MaskAnimationState {
+  val shift = paneShiftOffset
+  val alpha = animateFloat(transitionSpec = { TransitionSpecs.paneShiftSpec() }) { if (it) 0f else 1f }
+  val offset = animateDp(transitionSpec = { TransitionSpecs.paneShiftSpec() }) { if (it) -shift else 0.dp }
   return remember {
-    AppScaffoldAnimationState(
+    MaskAnimationState(
       offset = offset,
       alpha = alpha
     )
@@ -107,22 +112,40 @@ private fun Transition<Boolean>.fakeChatListAnimationState(): AppScaffoldAnimati
 }
 
 @Composable
-private fun Transition<Boolean>.chatAnimationState(hasFake: Boolean): AppScaffoldAnimationState {
-  val alpha = animateFloat(transitionSpec = { AppScaffoldAnimationDefaults.tween() }) { if (it) 1f else 0f }
+private fun Transition<Boolean>.chatAnimationState(hasFake: Boolean): MaskAnimationState {
+  val shift = paneShiftOffset
+  val alpha = animateFloat(transitionSpec = { TransitionSpecs.paneShiftSpec() }) { if (it) 1f else 0f }
   return if (!hasFake) {
     remember {
-      AppScaffoldAnimationState(
+      MaskAnimationState(
         offset = mutableStateOf(0.dp),
         alpha = alpha
       )
     }
   } else {
-    val offset = animateDp(transitionSpec = { AppScaffoldAnimationDefaults.tween() }) { if (it) 0.dp else 48.dp }
+    val offset = animateDp(transitionSpec = { TransitionSpecs.paneShiftSpec() }) { if (it) 0.dp else shift }
     remember {
-      AppScaffoldAnimationState(
+      MaskAnimationState(
         offset = offset,
         alpha = alpha
       )
     }
   }
 }
+
+private val paneShiftOffset: Dp
+  @Composable get() = if (LocalLayoutDirection.current == LayoutDirection.Rtl) -TransitionSpecs.PANE_SHIFT_OFFSET else TransitionSpecs.PANE_SHIFT_OFFSET
+
+/**
+ * The alpha and horizontal offset a layer is drawn with.
+ */
+private class MaskAnimationState(
+  private val offset: State<Dp>,
+  private val alpha: State<Float>
+) {
+  fun GraphicsLayerScope.applyTo() {
+    this.alpha = this@MaskAnimationState.alpha.value
+    this.translationX = offset.value.toPx()
+    this.clip = true
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/InsetAwareConstraintLayout.kt

@@ -148,6 +148,20 @@ open class InsetAwareConstraintLayout @JvmOverloads constructor(
     windowInsetsListeners.remove(listener)
   }
 
+  /**
+   * A guideline's begin and end measure from the left and right edges in either direction, while the views constrained
+   * to these two use start and end. In RTL that inverts the span, collapsing every view sized by it.
+   */
+  private fun applyHorizontalGuidelines(isLtr: Boolean, parentStart: Int, parentEnd: Int) {
+    if (isLtr) {
+      parentStartGuideline?.setGuidelineBegin(parentStart)
+      parentEndGuideline?.setGuidelineEnd(parentEnd)
+    } else {
+      parentStartGuideline?.setGuidelineEnd(parentStart)
+      parentEndGuideline?.setGuidelineBegin(parentEnd)
+    }
+  }
+
   private fun applyInsets(windowInsets: Insets, keyboardInsets: Insets) {
     val isLtr = ViewUtil.isLtr(this)
 
@@ -166,8 +180,7 @@ open class InsetAwareConstraintLayout @JvmOverloads constructor(
     if (!statusBarShrinking) {
       statusBarGuideline?.setGuidelineBegin(statusBar)
       navigationBarGuideline?.setGuidelineEnd(navigationBar)
-      parentStartGuideline?.setGuidelineBegin(parentStart)
-      parentEndGuideline?.setGuidelineEnd(parentEnd)
+      applyHorizontalGuidelines(isLtr, parentStart, parentEnd)
 
       windowInsetsListeners.forEach {
         it.onApplyWindowInsets(statusBar, navigationBar, parentStart, parentEnd)

app/src/main/java/org/thoughtcrime/securesms/recipients/ui/RecipientPickerScaffold.kt

@@ -8,19 +8,25 @@ package org.thoughtcrime.securesms.recipients.ui
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxScope
+import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.isImeVisible
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.systemBars
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.widthIn
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
 import androidx.compose.material3.SnackbarHost
 import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
-import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
 import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
@@ -29,22 +35,22 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.LocalResources
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
+import androidx.window.core.layout.WindowSizeClass
 import org.signal.core.ui.compose.BreakpointPreviews
 import org.signal.core.ui.compose.Previews
 import org.signal.core.ui.compose.Scaffolds
 import org.signal.core.ui.compose.SignalIcons
 import org.signal.core.ui.detailPaneMaxContentWidth
-import org.signal.core.ui.isSplitPane
+import org.signal.core.ui.horizontalPartitionDefaultSpacerSize
+import org.signal.core.ui.listPaneDefaultPreferredWidth
 import org.signal.core.ui.rememberIsSplitPane
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.components.compose.ScreenTitlePane
-import org.thoughtcrime.securesms.window.AppScaffold
-import org.thoughtcrime.securesms.window.rememberAppScaffoldNavigator
 
 /**
  * Provides the common adaptive layout structure for recipient picker screens.
  */
-@OptIn(ExperimentalMaterial3Api::class, ExperimentalMaterial3AdaptiveApi::class, ExperimentalLayoutApi::class)
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun RecipientPickerScaffold(
   title: String,
@@ -57,8 +63,10 @@ fun RecipientPickerScaffold(
   val isSplitPane = LocalResources.current.rememberIsSplitPane()
   val windowSizeClass = currentWindowAdaptiveInfo().windowSizeClass
 
-  AppScaffold(
-    topBarContent = {
+  Scaffold(
+    containerColor = Color.Transparent,
+    contentWindowInsets = WindowInsets.systemBars,
+    topBar = {
       Scaffolds.DefaultTopAppBar(
         title = if (!isSplitPane) title else "",
         titleContent = { _, titleText -> Text(text = titleText, style = MaterialTheme.typography.titleLarge) },
@@ -68,41 +76,70 @@ fun RecipientPickerScaffold(
         actions = { topAppBarActions() }
       )
     },
-
-    secondaryContent = {
-      if (isSplitPane) {
-        ScreenTitlePane(
-          title = title,
-          modifier = Modifier.fillMaxSize()
-        )
-      } else {
-        Box {
-          primaryContent()
-          FloatingActionButtonContainer(floatingActionButton)
-        }
-      }
-    },
-
-    primaryContent = {
-      Box(
-        contentAlignment = Alignment.Center,
-        modifier = Modifier.fillMaxSize()
+    snackbarHost = {
+      SnackbarHost(snackbarHostState)
+    }
+  ) { paddingValues ->
+    if (isSplitPane) {
+      SplitPaneLayout(
+        title = title,
+        windowSizeClass = windowSizeClass,
+        modifier = Modifier.padding(paddingValues)
       ) {
         Box(modifier = Modifier.widthIn(max = windowSizeClass.detailPaneMaxContentWidth)) {
           primaryContent()
           FloatingActionButtonContainer(floatingActionButton)
         }
       }
-    },
+    } else {
+      Box(
+        modifier = Modifier
+          .fillMaxSize()
+          .padding(paddingValues)
+      ) {
+        primaryContent()
+        FloatingActionButtonContainer(floatingActionButton)
+      }
+    }
+  }
+}
 
-    snackbarHost = {
-      SnackbarHost(snackbarHostState)
-    },
+/**
+ * Places the screen title beside [content], capping the title pane at [listPaneDefaultPreferredWidth] and splitting
+ * the available width evenly below twice that.
+ */
+@Composable
+private fun SplitPaneLayout(
+  title: String,
+  windowSizeClass: WindowSizeClass,
+  modifier: Modifier = Modifier,
+  content: @Composable () -> Unit
+) {
+  val spacerWidth = windowSizeClass.horizontalPartitionDefaultSpacerSize
 
-    navigator = rememberAppScaffoldNavigator(
-      isSplitPane = isSplitPane
-    )
-  )
+  BoxWithConstraints(modifier = modifier.fillMaxSize()) {
+    val titlePaneWidth = ((maxWidth - spacerWidth) / 2).coerceAtMost(windowSizeClass.listPaneDefaultPreferredWidth)
+
+    Row(modifier = Modifier.fillMaxSize()) {
+      ScreenTitlePane(
+        title = title,
+        modifier = Modifier
+          .width(titlePaneWidth)
+          .fillMaxHeight()
+      )
+
+      Spacer(modifier = Modifier.width(spacerWidth))
+
+      Box(
+        contentAlignment = Alignment.Center,
+        modifier = Modifier
+          .weight(1f)
+          .fillMaxHeight()
+      ) {
+        content()
+      }
+    }
+  }
 }
 
 @OptIn(ExperimentalLayoutApi::class)

app/src/main/java/org/thoughtcrime/securesms/window/AppScaffold.kt

@@ -1,457 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.thoughtcrime.securesms.window
-
-import android.os.Build
-import androidx.activity.compose.BackHandler
-import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.EnterTransition
-import androidx.compose.animation.ExitTransition
-import androidx.compose.animation.SizeTransform
-import androidx.compose.animation.core.snap
-import androidx.compose.animation.slideInHorizontally
-import androidx.compose.animation.slideOutHorizontally
-import androidx.compose.animation.togetherWith
-import androidx.compose.foundation.background
-import androidx.compose.foundation.interaction.MutableInteractionSource
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.WindowInsets
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.layout.systemBars
-import androidx.compose.foundation.shape.RoundedCornerShape
-import androidx.compose.material3.LocalMinimumInteractiveComponentSize
-import androidx.compose.material3.Scaffold
-import androidx.compose.material3.Text
-import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
-import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
-import androidx.compose.material3.adaptive.layout.AnimatedPane
-import androidx.compose.material3.adaptive.layout.PaneAdaptedValue
-import androidx.compose.material3.adaptive.layout.PaneExpansionState
-import androidx.compose.material3.adaptive.layout.ThreePaneScaffoldScope
-import androidx.compose.material3.adaptive.layout.defaultDragHandleSemantics
-import androidx.compose.material3.adaptive.layout.rememberPaneExpansionState
-import androidx.compose.material3.adaptive.navigation.NavigableListDetailPaneScaffold
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.rememberCoroutineScope
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.clipToBounds
-import androidx.compose.ui.draw.drawWithContent
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.graphicsLayer
-import androidx.compose.ui.layout.layout
-import androidx.compose.ui.platform.LocalLayoutDirection
-import androidx.compose.ui.platform.LocalResources
-import androidx.compose.ui.text.style.TextAlign
-import androidx.compose.ui.unit.LayoutDirection
-import androidx.compose.ui.unit.dp
-import androidx.compose.ui.zIndex
-import kotlinx.coroutines.launch
-import org.signal.core.ui.NavigationType
-import org.signal.core.ui.compose.BreakpointPreviews
-import org.signal.core.ui.compose.Previews
-import org.signal.core.ui.rememberIsSplitPane
-import org.thoughtcrime.securesms.main.MainFloatingActionButtonsCallback
-import org.thoughtcrime.securesms.main.MainNavigationBar
-import org.thoughtcrime.securesms.main.MainNavigationBarState
-import org.thoughtcrime.securesms.main.MainNavigationRail
-import kotlin.math.max
-
-/**
- * A top-level scaffold that automatically adapts its layout based on the device's window size class. It is a generic container designed to handle the
- * arrangement of navigation rails, top/bottom bars, and list-detail pane management for both compact and large screens.
- *
- * On phone-class layouts (single horizontal partition) running on devices that predate predictive back (API < 33),
- * this dispatches to [SinglePaneAppScaffold], which skips [NavigableListDetailPaneScaffold] / [ThreePaneScaffold] and
- * its lookahead measurement pass. The scaffold's seek-driven predictive back animation never fires on those devices,
- * so we pay no UX cost for the simpler implementation.
- *
- * @param topBarContent An optional top bar that spans across all panes.
- *
- * @param primaryContent The main content, which is typically the detail view in a split-pane layout.
- * @param secondaryContent The secondary content, which is typically the list view in a split-pane layout.
- *
- * @param navRailContent The side navigation rail, shown on medium and larger screen sizes.
- * @param bottomNavContent The bottom navigation bar, shown on compact screen sizes.
- *
- * @param paneExpansionState Manages the position and expansion of the panes in a list-detail layout. Ignored by [SinglePaneAppScaffold].
- * @param paneExpansionDragHandle An optional drag handle used to resize panes in the list-detail layout. Ignored by [SinglePaneAppScaffold].
- *
- * @param animatorFactory Provides animations to control how panes enter and exit the screen during navigation. Ignored by [SinglePaneAppScaffold].
- */
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun AppScaffold(
-  navigator: AppScaffoldNavigator<Any>,
-  modifier: Modifier = Modifier,
-  topBarContent: @Composable () -> Unit = {},
-  primaryContent: @Composable () -> Unit = {},
-  secondaryContent: @Composable () -> Unit,
-  navRailContent: @Composable () -> Unit = {},
-  bottomNavContent: @Composable () -> Unit = {},
-  paneExpansionState: PaneExpansionState = rememberPaneExpansionState(),
-  paneExpansionDragHandle: (@Composable ThreePaneScaffoldScope.(PaneExpansionState) -> Unit)? = null,
-  snackbarHost: @Composable () -> Unit = {},
-  contentWindowInsets: WindowInsets = WindowInsets.systemBars,
-  animatorFactory: AppScaffoldAnimationStateFactory = AppScaffoldAnimationStateFactory.Default
-) {
-  val useSimpleScaffold = navigator.scaffoldDirective.maxHorizontalPartitions == 1 && Build.VERSION.SDK_INT < 33
-  if (useSimpleScaffold && LocalLayoutDirection.current != LayoutDirection.Rtl) {
-    SinglePaneAppScaffold(
-      navigator = navigator,
-      modifier = modifier,
-      topBarContent = topBarContent,
-      primaryContent = primaryContent,
-      secondaryContent = secondaryContent,
-      bottomNavContent = bottomNavContent,
-      snackbarHost = snackbarHost,
-      contentWindowInsets = contentWindowInsets,
-      animatorFactory = animatorFactory
-    )
-  } else {
-    AdaptiveAppScaffold(
-      navigator = navigator,
-      modifier = modifier,
-      topBarContent = topBarContent,
-      primaryContent = primaryContent,
-      secondaryContent = secondaryContent,
-      navRailContent = navRailContent,
-      bottomNavContent = bottomNavContent,
-      paneExpansionState = paneExpansionState,
-      paneExpansionDragHandle = paneExpansionDragHandle,
-      snackbarHost = snackbarHost,
-      contentWindowInsets = contentWindowInsets,
-      animatorFactory = animatorFactory
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-private fun AdaptiveAppScaffold(
-  navigator: AppScaffoldNavigator<Any>,
-  modifier: Modifier = Modifier,
-  topBarContent: @Composable () -> Unit = {},
-  primaryContent: @Composable () -> Unit = {},
-  secondaryContent: @Composable () -> Unit,
-  navRailContent: @Composable () -> Unit = {},
-  bottomNavContent: @Composable () -> Unit = {},
-  paneExpansionState: PaneExpansionState = rememberPaneExpansionState(),
-  paneExpansionDragHandle: (@Composable ThreePaneScaffoldScope.(PaneExpansionState) -> Unit)? = null,
-  snackbarHost: @Composable () -> Unit = {},
-  contentWindowInsets: WindowInsets = WindowInsets.systemBars,
-  animatorFactory: AppScaffoldAnimationStateFactory = AppScaffoldAnimationStateFactory.Default
-) {
-  val minPaneWidth = navigator.scaffoldDirective.defaultPanePreferredWidth
-  val navigationState = navigator.state
-
-  Scaffold(
-    containerColor = Color.Transparent,
-    contentWindowInsets = contentWindowInsets,
-    topBar = topBarContent,
-    snackbarHost = snackbarHost,
-    modifier = modifier
-  ) { paddingValues ->
-    NavigableListDetailPaneScaffold(
-      navigator = navigator,
-      listPane = {
-        val animationState = with(animatorFactory) {
-          this@NavigableListDetailPaneScaffold.getListAnimationState(navigationState)
-        }
-
-        AnimatedPane(
-          enterTransition = EnterTransition.None,
-          exitTransition = ExitTransition.None,
-          modifier = Modifier
-            .zIndex(0f)
-            .drawWithContent {
-              with(animationState) {
-                applyParentValues()
-              }
-            }
-        ) {
-          Box(
-            modifier = Modifier
-              .graphicsLayer {
-                with(animationState) {
-                  applyChildValues()
-                }
-              }
-              .clipToBounds()
-              .layout { measurable, constraints ->
-                val width = max(minPaneWidth.roundToPx(), constraints.maxWidth)
-                val placeable = measurable.measure(
-                  constraints.copy(
-                    minWidth = minPaneWidth.roundToPx(),
-                    maxWidth = width
-                  )
-                )
-                layout(constraints.maxWidth, placeable.height) {
-                  placeable.placeRelative(
-                    x = 0,
-                    y = 0
-                  )
-                }
-              }
-          ) {
-            ListAndNavigation(
-              topBarContent = { },
-              listContent = secondaryContent,
-              navRailContent = navRailContent,
-              bottomNavContent = bottomNavContent,
-              contentWindowInsets = WindowInsets() // parent scaffold already applies the necessary insets
-            )
-          }
-        }
-      },
-      detailPane = {
-        val animationState = with(animatorFactory) {
-          this@NavigableListDetailPaneScaffold.getDetailAnimationState(navigationState)
-        }
-
-        AnimatedPane(
-          enterTransition = EnterTransition.None,
-          exitTransition = ExitTransition.None,
-          modifier = Modifier
-            .zIndex(1f)
-            .drawWithContent {
-              with(animationState) {
-                applyParentValues()
-              }
-            }
-        ) {
-          Box(
-            modifier = Modifier
-              .graphicsLayer {
-                with(animationState) {
-                  applyChildValues()
-                }
-              }
-              .clipToBounds()
-              .layout { measurable, constraints ->
-                val width = max(minPaneWidth.roundToPx(), constraints.maxWidth)
-                val placeable = measurable.measure(
-                  constraints.copy(
-                    minWidth = minPaneWidth.roundToPx(),
-                    maxWidth = width
-                  )
-                )
-                layout(constraints.maxWidth, placeable.height) {
-                  placeable.placeRelative(
-                    x = 0,
-                    y = 0
-                  )
-                }
-              }
-          ) {
-            primaryContent()
-          }
-        }
-      },
-      paneExpansionDragHandle = paneExpansionDragHandle,
-      paneExpansionState = paneExpansionState,
-      modifier = Modifier.padding(paddingValues)
-    )
-  }
-}
-
-/**
- * Phone-only scaffold that swaps content between [secondaryContent] and [primaryContent] without using
- * [NavigableListDetailPaneScaffold]. Avoids the lookahead measurement pass and deep adaptive layout tree
- * that drives ANR on low-end devices.
- *
- */
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-private fun SinglePaneAppScaffold(
-  navigator: AppScaffoldNavigator<Any>,
-  modifier: Modifier = Modifier,
-  topBarContent: @Composable () -> Unit = {},
-  primaryContent: @Composable () -> Unit = {},
-  secondaryContent: @Composable () -> Unit,
-  bottomNavContent: @Composable () -> Unit = {},
-  snackbarHost: @Composable () -> Unit = {},
-  contentWindowInsets: WindowInsets = WindowInsets.systemBars,
-  animatorFactory: AppScaffoldAnimationStateFactory = AppScaffoldAnimationStateFactory.Default
-) {
-  val showDetail = navigator.scaffoldValue.primary == PaneAdaptedValue.Expanded
-  val coroutineScope = rememberCoroutineScope()
-  val isRtl = LocalLayoutDirection.current == LayoutDirection.Rtl
-  val directionMultiplier = if (isRtl) -1 else 1
-  val skipSlide = AppScaffoldNavigator.NavigationState.ENTER !in animatorFactory.enabledStates
-
-  BackHandler(enabled = navigator.canNavigateBack()) {
-    coroutineScope.launch { navigator.navigateBack() }
-  }
-
-  Scaffold(
-    containerColor = Color.Transparent,
-    contentWindowInsets = contentWindowInsets,
-    topBar = topBarContent,
-    snackbarHost = snackbarHost,
-    modifier = modifier
-  ) { paddingValues ->
-    AnimatedContent(
-      targetState = showDetail,
-      transitionSpec = {
-        val transform = when {
-          skipSlide -> EnterTransition.None togetherWith ExitTransition.None
-          targetState -> slideInHorizontally(animationSpec = AppScaffoldAnimationDefaults.tween()) { fullWidth -> fullWidth * directionMultiplier } togetherWith
-            slideOutHorizontally(animationSpec = AppScaffoldAnimationDefaults.tween()) { fullWidth -> -fullWidth * directionMultiplier }
-          else -> slideInHorizontally(animationSpec = AppScaffoldAnimationDefaults.tween()) { fullWidth -> -fullWidth * directionMultiplier } togetherWith
-            slideOutHorizontally(animationSpec = AppScaffoldAnimationDefaults.tween()) { fullWidth -> fullWidth * directionMultiplier }
-        }
-        transform using SizeTransform(clip = false) { _, _ -> snap() }
-      },
-      modifier = Modifier.padding(paddingValues),
-      label = "SimpleAppScaffold"
-    ) { isDetail ->
-      if (isDetail) {
-        primaryContent()
-      } else {
-        Column(modifier = Modifier.fillMaxSize()) {
-          Box(modifier = Modifier.weight(1f)) {
-            secondaryContent()
-          }
-          bottomNavContent()
-        }
-      }
-    }
-  }
-}
-
-@Composable
-private fun ListAndNavigation(
-  topBarContent: @Composable () -> Unit,
-  listContent: @Composable () -> Unit,
-  navRailContent: @Composable () -> Unit,
-  bottomNavContent: @Composable () -> Unit,
-  snackbarHost: @Composable () -> Unit = {},
-  contentWindowInsets: WindowInsets,
-  modifier: Modifier = Modifier
-) {
-  val navigationType = NavigationType.rememberNavigationType()
-
-  Scaffold(
-    containerColor = Color.Transparent,
-    topBar = topBarContent,
-    contentWindowInsets = contentWindowInsets,
-    snackbarHost = snackbarHost,
-    modifier = modifier
-  ) { paddingValues ->
-    Row(
-      modifier = Modifier
-        .padding(paddingValues)
-    ) {
-      if (navigationType == NavigationType.RAIL) {
-        navRailContent()
-      }
-
-      Column {
-        Box(modifier = Modifier.weight(1f)) {
-          listContent()
-        }
-
-        if (navigationType == NavigationType.BAR) {
-          bottomNavContent()
-        }
-      }
-    }
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@BreakpointPreviews
-@Composable
-private fun AppScaffoldPreview() {
-  Previews.Preview {
-    val windowSizeClass = currentWindowAdaptiveInfo().windowSizeClass
-    val isSplitPane = LocalResources.current.rememberIsSplitPane()
-
-    AppScaffold(
-      navigator = rememberAppScaffoldNavigator(
-        isSplitPane = isSplitPane,
-        defaultPanePreferredWidth = 416.dp,
-        horizontalPartitionSpacerSize = 16.dp
-      ),
-      secondaryContent = {
-        Box(
-          contentAlignment = Alignment.Center,
-          modifier = Modifier
-            .fillMaxSize()
-            .background(color = Color.Red)
-        ) {
-          Text(
-            text = "ListContent\n$windowSizeClass",
-            textAlign = TextAlign.Center
-          )
-        }
-      },
-      primaryContent = {
-        Box(
-          contentAlignment = Alignment.Center,
-          modifier = Modifier
-            .fillMaxSize()
-            .background(color = Color.Blue)
-        ) {
-          Text(
-            text = "DetailContent",
-            textAlign = TextAlign.Center
-          )
-        }
-      },
-      navRailContent = {
-        MainNavigationRail(
-          state = MainNavigationBarState(),
-          mainFloatingActionButtonsCallback = MainFloatingActionButtonsCallback.Empty,
-          onDestinationSelected = {}
-        )
-      },
-      bottomNavContent = {
-        MainNavigationBar(
-          state = MainNavigationBarState(),
-          onDestinationSelected = {}
-        )
-      },
-      paneExpansionState = rememberPaneExpansionState(),
-      paneExpansionDragHandle = {
-        AppPaneDragHandle(
-          paneExpansionState = it,
-          mutableInteractionSource = remember { MutableInteractionSource() }
-        )
-      }
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldScope.AppPaneDragHandle(
-  paneExpansionState: PaneExpansionState,
-  mutableInteractionSource: MutableInteractionSource
-) {
-  Box(
-    contentAlignment = Alignment.Center,
-    modifier = Modifier
-      .paneExpansionDraggable(
-        state = paneExpansionState,
-        minTouchTargetSize = LocalMinimumInteractiveComponentSize.current,
-        interactionSource = mutableInteractionSource,
-        semanticsProperties = paneExpansionState.defaultDragHandleSemantics()
-      )
-  ) {
-    Box(
-      modifier = Modifier
-        .size(4.dp, 48.dp)
-        .background(color = Color(0xFF605F5D), RoundedCornerShape(percent = 50))
-    )
-  }
-}

app/src/main/java/org/thoughtcrime/securesms/window/AppScaffoldAnimationState.kt

@@ -1,122 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.thoughtcrime.securesms.window
-
-import androidx.compose.animation.core.CubicBezierEasing
-import androidx.compose.animation.core.tween
-import androidx.compose.foundation.shape.RoundedCornerShape
-import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
-import androidx.compose.material3.adaptive.layout.ThreePaneScaffoldPaneScope
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.State
-import androidx.compose.runtime.derivedStateOf
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.GraphicsLayerScope
-import androidx.compose.ui.graphics.drawscope.ContentDrawScope
-import androidx.compose.ui.unit.Dp
-import androidx.compose.ui.unit.coerceAtMost
-import androidx.compose.ui.unit.dp
-
-/**
- * Default animation settings for app-scaffold animations.
- */
-object AppScaffoldAnimationDefaults {
-  val TweenEasing = CubicBezierEasing(0.4f, 0.0f, 0.2f, 1f)
-  val InitAnimationOffset = 48.dp
-
-  fun <T> tween() = tween<T>(durationMillis = 200, easing = TweenEasing)
-}
-
-data class AppScaffoldAnimationState(
-  private val alpha: State<Float> = mutableStateOf(1f),
-  private val scale: State<Float> = mutableStateOf(1f),
-  val scaleMinimum: Float = 0f,
-  private val offset: State<Dp> = mutableStateOf(0.dp),
-  private val corners: State<Dp> = mutableStateOf(0.dp),
-  val cornersMaximum: Dp = 1000.dp,
-  private val parentOverlayAlpha: State<Float> = mutableStateOf(0f)
-) {
-
-  private val unclampedScale by scale
-  private val unclampedCorners by corners
-
-  val contentAlpha by alpha
-  val contentScale by derivedStateOf { unclampedScale.coerceAtLeast(scaleMinimum) }
-  val contentOffset by offset
-  val contentCorners by derivedStateOf { unclampedCorners.coerceAtMost(cornersMaximum) }
-
-  fun ContentDrawScope.applyParentValues() {
-    drawContent()
-
-    drawRect(Color(0f, 0f, 0f, parentOverlayAlpha.value))
-  }
-
-  fun GraphicsLayerScope.applyChildValues() {
-    this.alpha = contentAlpha
-    this.scaleX = contentScale
-    this.scaleY = contentScale
-    this.translationX = contentOffset.toPx()
-    this.translationY = 0f
-    this.clip = true
-    this.shape = RoundedCornerShape(contentCorners)
-  }
-}
-
-/**
- * Allows for the customization of the AppScaffold Animators.
- */
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-class AppScaffoldAnimationStateFactory(
-  val enabledStates: Set<AppScaffoldNavigator.NavigationState> = AppScaffoldNavigator.NavigationState.entries.toSet()
-) {
-
-  companion object {
-    val Default = AppScaffoldAnimationStateFactory()
-
-    private val EMPTY_STATE = AppScaffoldAnimationState(
-      alpha = mutableStateOf(1f)
-    )
-  }
-
-  private var latestListSeekState: AppScaffoldAnimationState = EMPTY_STATE
-  private var latestDetailSeekState: AppScaffoldAnimationState = EMPTY_STATE
-
-  @Composable
-  fun ThreePaneScaffoldPaneScope.getListAnimationState(navigationState: AppScaffoldNavigator.NavigationState): AppScaffoldAnimationState {
-    if (navigationState !in enabledStates) {
-      return EMPTY_STATE
-    }
-
-    return when (navigationState) {
-      AppScaffoldNavigator.NavigationState.ENTER -> defaultListInitAnimationState()
-      AppScaffoldNavigator.NavigationState.EXIT -> defaultListInitAnimationState()
-      AppScaffoldNavigator.NavigationState.SEEK -> defaultListSeekAnimationState().also {
-        latestListSeekState = it
-      }
-
-      AppScaffoldNavigator.NavigationState.RELEASE -> defaultListReleaseAnimationState(latestListSeekState)
-    }
-  }
-
-  @Composable
-  fun ThreePaneScaffoldPaneScope.getDetailAnimationState(navigationState: AppScaffoldNavigator.NavigationState): AppScaffoldAnimationState {
-    if (navigationState !in enabledStates) {
-      return EMPTY_STATE
-    }
-
-    return when (navigationState) {
-      AppScaffoldNavigator.NavigationState.ENTER -> defaultDetailInitAnimationState()
-      AppScaffoldNavigator.NavigationState.EXIT -> defaultDetailInitAnimationState()
-      AppScaffoldNavigator.NavigationState.SEEK -> defaultDetailSeekAnimationState().also {
-        latestDetailSeekState = it
-      }
-
-      AppScaffoldNavigator.NavigationState.RELEASE -> defaultDetailReleaseAnimationState(latestDetailSeekState)
-    }
-  }
-}

app/src/main/java/org/thoughtcrime/securesms/window/AppScaffoldAnimators.kt

@@ -1,253 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.thoughtcrime.securesms.window
-
-import androidx.compose.animation.core.FiniteAnimationSpec
-import androidx.compose.animation.core.Spring
-import androidx.compose.animation.core.Transition
-import androidx.compose.animation.core.animateDp
-import androidx.compose.animation.core.animateFloat
-import androidx.compose.animation.core.spring
-import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
-import androidx.compose.material3.adaptive.layout.PaneAdaptedValue
-import androidx.compose.material3.adaptive.layout.ThreePaneScaffoldPaneScope
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.State
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.ui.platform.LocalLayoutDirection
-import androidx.compose.ui.unit.Dp
-import androidx.compose.ui.unit.LayoutDirection
-import androidx.compose.ui.unit.dp
-
-private const val SEEK_DAMPING_RATIO = Spring.DampingRatioNoBouncy
-private const val SEEK_STIFFNESS = Spring.StiffnessMedium
-
-/**
- * Default animation spec for back gesture seeking.
- */
-fun <T> appScaffoldSeekSpring(): FiniteAnimationSpec<T> = spring(
-  dampingRatio = SEEK_DAMPING_RATIO,
-  stiffness = SEEK_STIFFNESS
-)
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.animateDp(
-  transitionSpec: @Composable Transition.Segment<*>.() -> FiniteAnimationSpec<Dp> = { AppScaffoldAnimationDefaults.tween() },
-  targetWhenHiding: () -> Dp = { 0.dp },
-  targetWhenShowing: () -> Dp
-): State<Dp> {
-  return scaffoldStateTransition.animateDp(
-    transitionSpec = transitionSpec
-  ) {
-    val isHiding = it[paneRole] == PaneAdaptedValue.Hidden
-
-    if (isHiding) {
-      targetWhenHiding()
-    } else {
-      targetWhenShowing()
-    }
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.animateFloat(
-  transitionSpec: @Composable Transition.Segment<*>.() -> FiniteAnimationSpec<Float> = { AppScaffoldAnimationDefaults.tween() },
-  targetWhenHiding: () -> Float = { 0f },
-  targetWhenShowing: () -> Float
-): State<Float> {
-  return scaffoldStateTransition.animateFloat(
-    transitionSpec = transitionSpec
-  ) {
-    val isHiding = it[paneRole] == PaneAdaptedValue.Hidden
-
-    if (isHiding) {
-      targetWhenHiding()
-    } else {
-      targetWhenShowing()
-    }
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.defaultListInitAnimationState(): AppScaffoldAnimationState {
-  val directionMultiplier = if (LocalLayoutDirection.current == LayoutDirection.Rtl) -1 else 1
-
-  val offset = animateDp(
-    targetWhenHiding = {
-      -AppScaffoldAnimationDefaults.InitAnimationOffset * directionMultiplier
-    },
-    targetWhenShowing = {
-      0.dp
-    }
-  )
-
-  val alpha = animateFloat {
-    1f
-  }
-
-  return remember {
-    AppScaffoldAnimationState(
-      alpha = alpha,
-      offset = offset
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.defaultListSeekAnimationState(): AppScaffoldAnimationState {
-  val directionMultiplier = if (LocalLayoutDirection.current == LayoutDirection.Rtl) -1 else 1
-
-  val scale = animateFloat(
-    transitionSpec = {
-      appScaffoldSeekSpring()
-    },
-    targetWhenShowing = { 0.5f },
-    targetWhenHiding = { 1f }
-  )
-
-  val offset = animateDp(
-    transitionSpec = {
-      appScaffoldSeekSpring()
-    },
-    targetWhenHiding = { -(88.dp) * directionMultiplier },
-    targetWhenShowing = { 0.dp }
-  )
-
-  return remember {
-    AppScaffoldAnimationState(
-      offset = offset,
-      scale = scale,
-      scaleMinimum = 0.9f,
-      parentOverlayAlpha = mutableStateOf(0.2f)
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.defaultListReleaseAnimationState(from: AppScaffoldAnimationState): AppScaffoldAnimationState {
-  val initialScale = remember { from.contentScale }
-  val initialOffset = remember { from.contentOffset }
-
-  val scale = animateFloat(
-    targetWhenHiding = { initialScale },
-    targetWhenShowing = { 1f }
-  )
-
-  val offset = animateDp(
-    targetWhenHiding = { initialOffset },
-    targetWhenShowing = { 0.dp }
-  )
-
-  val alpha = animateFloat(
-    targetWhenHiding = { 0.2f },
-    targetWhenShowing = { 0f }
-  )
-
-  return remember {
-    AppScaffoldAnimationState(
-      scale = scale,
-      scaleMinimum = from.scaleMinimum,
-      offset = offset,
-      parentOverlayAlpha = alpha
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.defaultDetailInitAnimationState(): AppScaffoldAnimationState {
-  val directionMultiplier = if (LocalLayoutDirection.current == LayoutDirection.Rtl) -1 else 1
-
-  val offset = animateDp(
-    targetWhenHiding = {
-      AppScaffoldAnimationDefaults.InitAnimationOffset * directionMultiplier
-    },
-    targetWhenShowing = {
-      0.dp
-    }
-  )
-
-  val alpha = animateFloat {
-    1f
-  }
-
-  return remember {
-    AppScaffoldAnimationState(
-      alpha = alpha,
-      offset = offset
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.defaultDetailSeekAnimationState(): AppScaffoldAnimationState {
-  val directionMultiplier = if (LocalLayoutDirection.current == LayoutDirection.Rtl) -1 else 1
-
-  val scale = animateFloat(
-    transitionSpec = {
-      appScaffoldSeekSpring()
-    },
-    targetWhenShowing = { 1f },
-    targetWhenHiding = { 0.5f }
-  )
-
-  val offset = animateDp(
-    transitionSpec = {
-      appScaffoldSeekSpring()
-    },
-    targetWhenShowing = { 0.dp },
-    targetWhenHiding = { 88.dp * directionMultiplier }
-  )
-
-  val roundedCorners = animateDp(
-    transitionSpec = {
-      appScaffoldSeekSpring()
-    }
-  ) { 1000.dp }
-
-  return remember {
-    AppScaffoldAnimationState(
-      scale = scale,
-      scaleMinimum = 0.9f,
-      offset = offset,
-      corners = roundedCorners,
-      cornersMaximum = 42.dp
-    )
-  }
-}
-
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun ThreePaneScaffoldPaneScope.defaultDetailReleaseAnimationState(from: AppScaffoldAnimationState): AppScaffoldAnimationState {
-  val scale = remember { from.contentScale }
-  val offset = remember { from.contentOffset }
-  val corners = remember { from.contentCorners }
-
-  val scaleState = remember { mutableStateOf(scale) }
-  val offsetState = remember { mutableStateOf(offset) }
-  val cornersState = remember { mutableStateOf(corners) }
-
-  val alpha = animateFloat { 1f }
-
-  return remember {
-    AppScaffoldAnimationState(
-      scale = scaleState,
-      scaleMinimum = from.scaleMinimum,
-      offset = offsetState,
-      corners = cornersState,
-      cornersMaximum = from.cornersMaximum,
-      alpha = alpha
-    )
-  }
-}

app/src/main/java/org/thoughtcrime/securesms/window/AppScaffoldNavigator.kt

@@ -1,141 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.thoughtcrime.securesms.window
-
-import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
-import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
-import androidx.compose.material3.adaptive.layout.ThreePaneScaffoldRole
-import androidx.compose.material3.adaptive.layout.calculatePaneScaffoldDirective
-import androidx.compose.material3.adaptive.navigation.BackNavigationBehavior
-import androidx.compose.material3.adaptive.navigation.ThreePaneScaffoldNavigator
-import androidx.compose.material3.adaptive.navigation.rememberListDetailPaneScaffoldNavigator
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.Stable
-import androidx.compose.runtime.annotation.RememberInComposition
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
-import androidx.compose.ui.platform.LocalResources
-import androidx.compose.ui.unit.Dp
-import androidx.window.core.layout.WindowSizeClass
-import org.signal.core.ui.horizontalPartitionDefaultSpacerSize
-import org.signal.core.ui.isSplitPane
-import org.signal.core.ui.listPaneDefaultPreferredWidth
-import org.signal.core.ui.rememberIsSplitPane
-
-/**
- * AppScaffoldNavigator wraps a delegate navigator (such as the value returned by [rememberThreePaneScaffoldNavigatorDelegate]
- * and implements a state machine that will produce [NavigationState] to allow proper animation coordination.
- */
-@Stable
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-open class AppScaffoldNavigator<T> @RememberInComposition constructor(private val delegate: ThreePaneScaffoldNavigator<T>) : ThreePaneScaffoldNavigator<T> by delegate {
-
-  var state: NavigationState by mutableStateOf(NavigationState.ENTER)
-    private set
-
-  override suspend fun navigateTo(pane: ThreePaneScaffoldRole, contentKey: T?) {
-    state = NavigationState.ENTER
-    return delegate.navigateTo(pane, contentKey)
-  }
-
-  override suspend fun navigateBack(backNavigationBehavior: BackNavigationBehavior): Boolean {
-    if (state == NavigationState.SEEK) {
-      state = NavigationState.RELEASE
-    }
-
-    if (state == NavigationState.ENTER) {
-      state = NavigationState.EXIT
-    }
-
-    return delegate.navigateBack(backNavigationBehavior)
-  }
-
-  override suspend fun seekBack(backNavigationBehavior: BackNavigationBehavior, fraction: Float) {
-    if (fraction == 0f && state == NavigationState.SEEK) {
-      state = NavigationState.ENTER
-    }
-
-    if (fraction > 0f && state != NavigationState.SEEK) {
-      state = NavigationState.SEEK
-    }
-
-    return delegate.seekBack(backNavigationBehavior, fraction)
-  }
-
-  /**
-   * State machine which describes the current navigation state to help with animation coordination.
-   */
-  enum class NavigationState {
-    /**
-     * We've navigated to a new pane.
-     */
-    ENTER,
-
-    /**
-     * We've navigated back from a pane without using seek.
-     */
-    EXIT,
-
-    /**
-     * The user is performing a back gesture seek action.
-     */
-    SEEK,
-
-    /**
-     * The user has let go of a seek and will go back.
-     */
-    RELEASE
-  }
-}
-
-/**
- * Sane default navigator. If you want to provide your own implementation
- * of AppScaffoldNavigator, utilize the remember pattern here but use
- * [rememberThreePaneScaffoldNavigatorDelegate] to get a delegate and hand off
- * to your own subclass of [AppScaffoldNavigator]
- */
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun rememberAppScaffoldNavigator(
-  windowSizeClass: WindowSizeClass = currentWindowAdaptiveInfo().windowSizeClass,
-  isSplitPane: Boolean = LocalResources.current.rememberIsSplitPane(),
-  horizontalPartitionSpacerSize: Dp = windowSizeClass.horizontalPartitionDefaultSpacerSize,
-  defaultPanePreferredWidth: Dp = windowSizeClass.listPaneDefaultPreferredWidth
-): AppScaffoldNavigator<Any> {
-  val delegate = rememberThreePaneScaffoldNavigatorDelegate(
-    isSplitPane,
-    horizontalPartitionSpacerSize,
-    defaultPanePreferredWidth
-  )
-
-  return remember(delegate) { AppScaffoldNavigator(delegate) }
-}
-
-/**
- * Produces a ThreePaneScaffoldNavigatorDelegate. Since the developer can
- * further modify navigator behavior, this is best done using the delegate pattern.
- * Use this to grab the initial delegate, and then either subclass or create an
- * instance of [AppScaffoldNavigator] keyed to this delegate.
- */
-@OptIn(ExperimentalMaterial3AdaptiveApi::class)
-@Composable
-fun rememberThreePaneScaffoldNavigatorDelegate(
-  isSplitPane: Boolean,
-  horizontalPartitionSpacerSize: Dp,
-  defaultPanePreferredWidth: Dp
-): ThreePaneScaffoldNavigator<Any> {
-  return rememberListDetailPaneScaffoldNavigator<Any>(
-    scaffoldDirective = calculatePaneScaffoldDirective(
-      currentWindowAdaptiveInfo()
-    ).copy(
-      maxHorizontalPartitions = if (isSplitPane) 2 else 1,
-      horizontalPartitionSpacerSize = horizontalPartitionSpacerSize,
-      defaultPanePreferredWidth = defaultPanePreferredWidth
-    )
-  )
-}

app/src/main/java/org/thoughtcrime/securesms/window/AppScaffoldWithTopBar.kt

@@ -1,75 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.thoughtcrime.securesms.window
-
-import androidx.compose.foundation.background
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Text
-import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
-import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
-import androidx.compose.runtime.Composable
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.text.style.TextAlign
-import org.signal.core.ui.compose.BreakpointPreviews
-import org.signal.core.ui.compose.Previews
-import org.signal.core.ui.compose.Scaffolds
-import org.signal.core.ui.compose.SignalIcons
-
-@OptIn(ExperimentalMaterial3Api::class, ExperimentalMaterial3AdaptiveApi::class)
-@BreakpointPreviews
-@Composable
-private fun AppScaffoldWithTopBarPreview() {
-  Previews.Preview {
-    val windowSizeClass = currentWindowAdaptiveInfo().windowSizeClass
-
-    AppScaffold(
-      navigator = rememberAppScaffoldNavigator(),
-
-      topBarContent = {
-        Scaffolds.DefaultTopAppBar(
-          title = "Hello World!",
-          titleContent = { _, title -> Text(text = title, style = MaterialTheme.typography.titleLarge) },
-          navigationIcon = SignalIcons.ArrowStart.imageVector,
-          navigationContentDescription = "",
-          onNavigationClick = { }
-        )
-      },
-
-      secondaryContent = {
-        Box(
-          contentAlignment = Alignment.Center,
-          modifier = Modifier
-            .fillMaxSize()
-            .background(color = Color.Red)
-        ) {
-          Text(
-            text = "ListContent\n$windowSizeClass",
-            textAlign = TextAlign.Center
-          )
-        }
-      },
-
-      primaryContent = {
-        Box(
-          contentAlignment = Alignment.Center,
-          modifier = Modifier
-            .fillMaxSize()
-            .background(color = Color.Blue)
-        ) {
-          Text(
-            text = "DetailContent",
-            textAlign = TextAlign.Center
-          )
-        }
-      }
-    )
-  }
-}