Android: side chats and subagent viewer (android-next#06, port of upstream #899)

apps/android/app/src/main/java/sh/roboco/android/newsession/NewSessionCanvas.kt

@@ -145,6 +145,10 @@ internal fun NewSessionCanvas(
     state: NewSessionCanvasState = remember { NewSessionCanvasState() },
     insets: CanvasInsets? = null,
     wallpaper: @Composable (Modifier, () -> Rect?) -> Unit = { m, c -> WallpaperHero(m, cutout = c) },
+    /** android-next #06: a side chat's draft says "Ask on the side". */
+    headline: String = NewSessionHeadline,
+    /** android-next #06: false when the host draws its own bar (the side-chat draft's session header). */
+    navBar: Boolean = true,
 ) {
     ProvideHazeState {
         val haze = LocalHazeState.current!!
@@ -191,6 +195,7 @@ internal fun NewSessionCanvas(
                         Modifier
                             .hazeSource(haze, zIndex = 1f)
                             .testTag("new-session-hero"),
+                        headline = headline,
                     )
                 }
                 val composerSlot: @Composable () -> Unit = {
@@ -323,7 +328,7 @@ internal fun NewSessionCanvas(
                     },
                 )
             }
-            NewSessionNavBar(embedded, onClose, insets)
+            if (navBar) NewSessionNavBar(embedded, onClose, insets)
         }
     }
 }
@@ -337,7 +342,7 @@ internal fun NewSessionCanvas(
  * the column is 76.6 dp (1 line) or 105.2 dp (2 lines) at font scale 1.
  */
 @Composable
-internal fun NewSessionHero(harness: String, modifier: Modifier = Modifier) {
+internal fun NewSessionHero(harness: String, modifier: Modifier = Modifier, headline: String = NewSessionHeadline) {
     val palette = RobocoTheme.palette
     val typeScale = LocalTypeScale.current
     Column(
@@ -354,7 +359,7 @@ internal fun NewSessionHero(harness: String, modifier: Modifier = Modifier) {
                 .clearAndSetSemantics { },
         )
         BasicText(
-            "What are we building?",
+            headline,
             Modifier.testTag("new-session-headline"),
             style = uiStyle(Face.SansSemibold, typeScale.fixed(NewSessionLayout.HeadlineSize), palette.text)
                 .copy(textAlign = TextAlign.Center),
@@ -364,6 +369,12 @@ internal fun NewSessionHero(harness: String, modifier: Modifier = Modifier) {
     }
 }
 
+/** The New Session hero's headline (`:122`). */
+const val NewSessionHeadline = "What are we building?"
+
+/** A side chat's draft headline (upstream #899's `sideOf` hero). */
+const val SideChatHeadline = "Ask on the side"
+
 /**
  * The transparent nav bar (`:113-118`, `SplitRootController.swift:46-47`).
  *

apps/android/app/src/main/java/sh/roboco/android/newsession/NewSessionChips.kt

@@ -171,6 +171,9 @@ fun newSessionChips(
     return chips
 }
 
+/** The chips a side chat's draft keeps (iOS `refreshChips` with `sideOf`). */
+private val SideChatChipIds = setOf(NewSessionChipIds.Model, NewSessionChipIds.Effort)
+
 /**
  * Foundation's `String.capitalized` (`CFStringCapitalize`), which the effort
  * titles (here and in ticket 114's effort rows) use: a letter is
@@ -262,13 +265,16 @@ fun NewSessionChipsEffect(
 ) {
     val chips by remember(model, labels) {
         derivedStateOf {
-            newSessionChips(
+            val all = newSessionChips(
                 model.draft,
                 model.project,
                 model.currentOptions?.hosts.orEmpty(),
                 model.models,
                 labels,
             )
+            // android-next #06: a side chat runs in its parent's checkout
+            // on its parent's host — only the model and effort are picked.
+            if (model.side == null) all else all.filter { it.id in SideChatChipIds }
         }
     }
     // Seed synchronously so the first composition already has the chips.

apps/android/app/src/main/java/sh/roboco/android/newsession/NewSessionCreate.kt

@@ -77,7 +77,10 @@ internal object NewSessionRequests {
      * neither → `null`, and the caller fails **without** a core call (the
      * alert explains). Ids are the scoped ids the options carry.
      */
-    fun target(d: NewSessionDraft): SessionTarget? {
+    fun target(d: NewSessionDraft, side: SideChatParent? = null): SessionTarget? {
+        // android-next #06: ignored by the core for a side chat (the
+        // parent's host fills it), but the record needs one (iOS `sideOf`).
+        if (side != null) return SessionTarget.Projectless(deviceId = side.deviceId)
         val projectId = d.projectId
         if (projectId != null) return SessionTarget.Project(spaceId = projectId)
         val hostId = d.hostId
@@ -89,9 +92,11 @@ internal object NewSessionRequests {
      * `NewSession(target:config:branch:cwd:title:)` (`:629-630`):
      * `reasoning = effort` (nil ⇒ the engine chooses), `sandbox` is
      * always workspace-write on this canvas, `branch` only without a
-     * worktree (with one, the branch becomes the worktree's base).
+     * worktree (with one, the branch becomes the worktree's base). A side
+     * chat (android-next #06) names its parent and no branch: it runs in
+     * the parent's checkout (the core keeps the parent's sandbox too).
      */
-    fun newSession(d: NewSessionDraft, target: SessionTarget): NewSession = NewSession(
+    fun newSession(d: NewSessionDraft, target: SessionTarget, side: SideChatParent? = null): NewSession = NewSession(
         target = target,
         config = ChatConfig(
             harness = d.harness,
@@ -100,9 +105,10 @@ internal object NewSessionRequests {
             modelOptions = emptyMap(),
             sandbox = SandboxLevel.WORKSPACE_WRITE,
         ),
-        branch = if (d.worktree) null else d.branch,
+        branch = if (d.worktree || side != null) null else d.branch,
         cwd = null,
         title = null,
+        parentChatId = side?.chatId,
     )
 
     /**
@@ -117,6 +123,7 @@ internal object NewSessionRequests {
         text: String,
         images: List<StagedImage>,
         projects: List<ProjectOption>,
+        side: SideChatParent? = null,
     ): SendRequest = SendRequest(
         text = text,
         attachments = images.map { image ->
@@ -127,7 +134,8 @@ internal object NewSessionRequests {
                 data = image.bytes,
             )
         },
-        worktree = if (d.worktree) {
+        // A side chat never makes a worktree (iOS `draft.worktree && parentId == nil`).
+        worktree = if (d.worktree && side == null) {
             projects.firstOrNull { it.id == d.projectId }?.let { project ->
                 WorktreeSpec(
                     repoPath = project.path,
@@ -170,14 +178,15 @@ class NewSessionCreator(
         text: String,
         images: List<StagedImage>,
         projects: List<ProjectOption>,
+        side: SideChatParent? = null,
     ): String? {
         // No target: fail without a core call and without a log — the
         // alert explains it, and there is no error to log.
-        val target = NewSessionRequests.target(d) ?: return null
+        val target = NewSessionRequests.target(d, side) ?: return null
         return withContext(io) {
             try {
-                val chatId = core.createSession(NewSessionRequests.newSession(d, target))
-                core.sendFirst(chatId, NewSessionRequests.sendRequest(d, text, images, projects))
+                val chatId = core.createSession(NewSessionRequests.newSession(d, target, side))
+                core.sendFirst(chatId, NewSessionRequests.sendRequest(d, text, images, projects, side))
                 chatId
             } catch (cancelled: CancellationException) {
                 throw cancelled
@@ -201,6 +210,17 @@ val StartFailedAlert = RobocoAlert(
     buttons = listOf(AlertButton("OK", AlertButtonRole.Default)),
 )
 
+/**
+ * A side chat's failure alert (android-next #06, upstream #899's
+ * `create(sideOf:)` copy verbatim): the parent is gone or the create
+ * failed — the composer stays `Kept`.
+ */
+val SideChatStartFailedAlert = RobocoAlert(
+    title = "Couldn't start the side chat",
+    message = "Its session is no longer available.",
+    buttons = listOf(AlertButton("OK", AlertButtonRole.Default)),
+)
+
 /**
  * The canvas composer's offline gate (94's Roboco ADD, the parent
  * spec's "Send is disabled while the target engine is offline"): the