feat(nav): root swipe-back on chat with double-back exit and subpage hierarchy (#1001)

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/Navigation.kt

@@ -1,5 +1,7 @@
 package com.m57.hermescontrol
 
+import android.app.Activity
+import android.widget.Toast
 import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
@@ -31,10 +33,13 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableLongStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
@@ -191,7 +196,25 @@ fun MainNavigation(sessionId: String? = null) {
 
     val openDrawer: () -> Unit = { scope.launch { drawerState.open() } }
 
+    val context = LocalContext.current
+    var lastBackPressTime by remember { mutableLongStateOf(0L) }
+    val backToastText = stringResource(R.string.press_back_again_to_exit)
+
+    // Double-back to exit on root ChatScreen
     BackHandler(enabled = currentScreen == ChatScreen && backStack.size == 1) {
+        val now = System.currentTimeMillis()
+        if (now - lastBackPressTime < 2000L) {
+            (context as? Activity)?.finish()
+        } else {
+            lastBackPressTime = now
+            Toast.makeText(context, backToastText, Toast.LENGTH_SHORT).show()
+        }
+    }
+
+    // Safety fallback: if a non-chat screen somehow sits alone on stack, swipe back returns to ChatScreen
+    BackHandler(
+        enabled = currentScreen != ChatScreen && currentScreen != LandingScreen && backStack.size == 1,
+    ) {
         NavigationController.goBack()
     }
 

app/src/main/java/com/m57/hermescontrol/NavigationController.kt

@@ -31,30 +31,37 @@ object NavigationController {
 
     private var nextChatNavigationRequestId = 0L
 
-    // Top-level primary screens (Chat, Skills, Cron, System, Settings)
-    private val primaryScreens: MutableSet<NavKey> =
-        mutableSetOf(
-            ChatScreen,
-            SkillsScreen,
-            CronJobsScreen,
-            SystemScreen,
-            SettingsScreen,
-        )
-
-    /** Returns whether the given key is a primary top-level screen. */
-    fun isPrimaryScreen(key: NavKey): Boolean = key in primaryScreens
+    /**
+     * Top-level primary screens (all drawer-accessible screens).
+     * Navigating to any of these clears the stack to `[ChatScreen, key]` (or `[ChatScreen]` for Chat),
+     * ensuring swiping back returns to ChatScreen.
+     */
+    fun isPrimaryScreen(key: NavKey): Boolean = key == ChatScreen || ScreenRegistry.ALL_SCREENS.any { it.key == key }
 
     fun navigateTo(key: NavKey) {
         val stack = backStack ?: return
         if (stack.lastOrNull() == key) return
 
+        if (key == ChatScreen) {
+            stack.clear()
+            stack.add(ChatScreen)
+            return
+        }
+
+        if (key == LandingScreen) {
+            stack.clear()
+            stack.add(LandingScreen)
+            return
+        }
+
         if (isPrimaryScreen(key)) {
             stack.clear()
+            stack.add(ChatScreen)
+            stack.add(key)
+            return
         }
-        // Drawer dismissal is handled by DrawerGestureController (issue #619):
-        // when a non-gesture sub-page composes, its HermesScaffold reconciles
-        // drawerGesturesEnabled=false and the controller closes the drawer
-        // itself via SideEffect. No synchronous closeDrawer callback here.
+
+        // Subscreen / drill-down navigation: append to current stack
         stack.add(key)
     }
 
@@ -98,15 +105,13 @@ object NavigationController {
      */
     fun goBack(fallback: NavKey = ChatScreen) {
         val stack = backStack ?: return
-        if (stack.lastOrNull() == ChatScreen) {
-            resetTo(HistoryScreen)
-            return
-        }
         if (stack.size > 1) {
             stack.removeLastOrNull()
         } else if (stack.size == 1) {
-            stack.clear()
-            stack.add(fallback)
+            if (stack.lastOrNull() != fallback && stack.lastOrNull() != LandingScreen) {
+                stack.clear()
+                stack.add(fallback)
+            }
         }
     }
 }

app/src/main/res/values-ko/strings.xml

@@ -49,6 +49,7 @@
     <string name="billing_topup">충전</string>
 
     <!-- Navigation & Drawer -->
+    <string name="press_back_again_to_exit">종료하려면 뒤로가기를 한 번 더 누르세요</string>
     <string name="nav_drawer_title">헤르메스</string>
     <string name="nav_drawer_subtitle">AI 에이전트 제어</string>
     <string name="nav_drawer_section_converse">대화</string>

app/src/main/res/values-zh/strings.xml

@@ -55,6 +55,7 @@
     <string name="billing_credits_remaining">剩余额度：%1$s</string>
     <string name="billing_plan">套餐</string>
     <string name="billing_topup">充值</string>
+    <string name="press_back_again_to_exit">再次返回以退出应用</string>
     <string name="nav_drawer_title">Hermes</string>
     <string name="nav_drawer_subtitle">AI Agent 控制台</string>
     <string name="nav_drawer_section_converse">对话</string>

app/src/main/res/values/strings.xml

@@ -66,6 +66,7 @@
     <string name="billing_topup">Top-up</string>
 
     <!-- Navigation & Drawer -->
+    <string name="press_back_again_to_exit">Press back again to exit</string>
     <string name="nav_drawer_title">Hermes</string>
     <string name="nav_drawer_subtitle">AI Agent Control</string>
     <string name="nav_drawer_section_converse">Converse</string>

app/src/test/java/com/m57/hermescontrol/E2eIntegrationTest.kt

@@ -718,17 +718,19 @@ class E2eIntegrationTest {
 
         NavigationController.navigateTo(SkillsScreen)
         assertEquals(SkillsScreen, backStack.lastOrNull())
-        assertEquals(1, backStack.size)
+        assertEquals(2, backStack.size)
+        assertEquals(ChatScreen, backStack[0])
 
         NavigationController.navigateTo(CronJobsScreen)
         assertEquals(CronJobsScreen, backStack.lastOrNull())
-        assertEquals(1, backStack.size)
+        assertEquals(2, backStack.size)
+        assertEquals(ChatScreen, backStack[0])
 
-        // Non-clearing drawer screen adds to stack
+        // Drawer screen navigation always roots on ChatScreen
         NavigationController.navigateTo(ProfilesScreen)
         assertEquals(ProfilesScreen, backStack.lastOrNull())
         assertEquals(2, backStack.size)
-        assertEquals(CronJobsScreen, backStack[0])
+        assertEquals(ChatScreen, backStack[0])
     }
 
     // ── Tier 2: Boundary & Corner Cases (>=5 per feature) ────────────────

app/src/test/java/com/m57/hermescontrol/NavigationControllerTest.kt

@@ -12,15 +12,8 @@ import org.junit.Test
 
 /**
  * Unit tests for [NavigationController] — the central navigation guard that
- * prevents duplicate screen entries on the back stack.
- *
- * Issue #291 (Critical Test Coverage): Verifies the deduplication logic at
- * line 45 (`if (stack.lastOrNull() == key) return`) and the primary-screen
- * stack-clearing behavior at line 47-49.
- *
- * All tests are pure Kotlin with no Android dependencies — they only exercise
- * [NavigationController]'s companion object methods against a real
- * [NavBackStack] instance.
+ * prevents duplicate screen entries on the back stack and enforces
+ * swipe-back-to-chat hierarchy.
  */
 class NavigationControllerTest {
     @Before
@@ -47,7 +40,7 @@ class NavigationControllerTest {
 
     @Test
     fun `navigateTo on same primary screen is a no-op`() {
-        val backStack = NavBackStack<NavKey>(SkillsScreen)
+        val backStack = NavBackStack<NavKey>(ChatScreen, SkillsScreen)
         NavigationController.backStack = backStack
         val sizeBefore = backStack.size
 
@@ -58,69 +51,60 @@ class NavigationControllerTest {
     }
 
     @Test
-    fun `navigateTo on same non-primary screen is a no-op`() {
-        val backStack = NavBackStack<NavKey>(ProfilesScreen)
+    fun `navigateTo on same subscreen is a no-op`() {
+        val backStack = NavBackStack<NavKey>(ChatScreen, SettingsScreen, SettingsAppearance)
         NavigationController.backStack = backStack
 
-        // ProfilesScreen is NOT in the default primaryScreens so it stays on the stack
-        NavigationController.navigateTo(ProfilesScreen)
+        NavigationController.navigateTo(SettingsAppearance)
 
-        assertEquals(1, backStack.size)
+        assertEquals(3, backStack.size)
+        assertEquals(SettingsAppearance, backStack.lastOrNull())
+    }
+
+    // ── Primary-screen behaviour: resets stack to [ChatScreen, Target] ───────
+
+    @Test
+    fun `navigateTo on a different primary screen resets stack with ChatScreen as root`() {
+        val backStack = NavBackStack<NavKey>(ChatScreen)
+        NavigationController.backStack = backStack
+
+        NavigationController.navigateTo(SkillsScreen)
+        assertEquals(2, backStack.size)
+        assertEquals(ChatScreen, backStack.firstOrNull())
+        assertEquals(SkillsScreen, backStack.lastOrNull())
+
+        // Now navigate to another primary screen (e.g. ProfilesScreen)
+        NavigationController.navigateTo(ProfilesScreen)
+        assertEquals("primary screen navigation should reset stack to [ChatScreen, target]", 2, backStack.size)
+        assertEquals(ChatScreen, backStack.firstOrNull())
         assertEquals(ProfilesScreen, backStack.lastOrNull())
     }
 
-    // ── Primary-screen behaviour: stack clearing ──────────────────────────
-
     @Test
-    fun `navigateTo on a different primary screen clears the stack`() {
-        val backStack = NavBackStack<NavKey>(ChatScreen)
+    fun `navigateTo ChatScreen clears stack to single ChatScreen root`() {
+        val backStack = NavBackStack<NavKey>(ChatScreen, ProfilesScreen)
         NavigationController.backStack = backStack
 
-        // Navigate to a non-primary screen first (should add to stack)
-        NavigationController.navigateTo(LogsScreen)
-        assertEquals(2, backStack.size)
-
-        // Now navigate to a different primary screen — must clear
-        NavigationController.navigateTo(SkillsScreen)
-
-        assertEquals("primary screen navigation should clear the stack", 1, backStack.size)
-        assertEquals(SkillsScreen, backStack.lastOrNull())
-    }
-
-    @Test
-    fun `navigateTo on the current primary screen clears the stack`() {
-        val backStack = NavBackStack<NavKey>(ChatScreen)
-        NavigationController.backStack = backStack
-
-        // Add a non-primary screen
-        NavigationController.navigateTo(ProfilesScreen)
-        assertEquals(2, backStack.size)
-
-        // Navigate to ChatScreen — it's a primary screen, so the stack gets
-        // cleared before adding it. The dedup guard only fires when the key
-        // is already the LAST item (ChatScreen is at index 0, ProfilesScreen
-        // is last), not when it's merely present somewhere in the stack.
         NavigationController.navigateTo(ChatScreen)
 
-        // Primary screen navigation clears the stack
-        assertEquals("primary navigation clears stack", 1, backStack.size)
+        assertEquals("chat navigation should result in single root entry", 1, backStack.size)
         assertEquals(ChatScreen, backStack.lastOrNull())
     }
 
-    // ── Non-primary screen behaviour: stack appending ─────────────────────
+    // ── Subscreen behaviour: appends to stack ───────────────────────────────
 
     @Test
-    fun `navigateTo on a non-primary screen appends to the stack`() {
-        val backStack = NavBackStack<NavKey>(ChatScreen)
+    fun `navigateTo on a subscreen appends to the current stack`() {
+        val backStack = NavBackStack<NavKey>(ChatScreen, SettingsScreen)
         NavigationController.backStack = backStack
 
-        NavigationController.navigateTo(ProfilesScreen)
-        assertEquals(2, backStack.size)
-        assertEquals(ProfilesScreen, backStack.lastOrNull())
-
-        NavigationController.navigateTo(KeysScreen)
+        NavigationController.navigateTo(SettingsAppearance)
         assertEquals(3, backStack.size)
-        assertEquals(KeysScreen, backStack.lastOrNull())
+        assertEquals(SettingsAppearance, backStack.lastOrNull())
+
+        NavigationController.navigateTo(SettingsAbout)
+        assertEquals(4, backStack.size)
+        assertEquals(SettingsAbout, backStack.lastOrNull())
     }
 
     @Test
@@ -176,13 +160,9 @@ class NavigationControllerTest {
 
     @Test
     fun `resetTo clears the stack and sets the target screen`() {
-        val backStack = NavBackStack<NavKey>(ChatScreen)
+        val backStack = NavBackStack<NavKey>(ChatScreen, ProfilesScreen, KeysScreen)
         NavigationController.backStack = backStack
 
-        NavigationController.navigateTo(ProfilesScreen)
-        NavigationController.navigateTo(KeysScreen)
-        assertEquals(3, backStack.size)
-
         NavigationController.resetTo(SettingsScreen)
 
         assertEquals(1, backStack.size)
@@ -197,14 +177,17 @@ class NavigationControllerTest {
         assertNull(NavigationController.backStack)
     }
 
-    // ── goBack: never leave the stack empty ───────────────────────────────
+    // ── goBack: pops stack, preserves chat root ───────────────────────────
 
     @Test
     fun `goBack removes the top screen when stack has more than one`() {
-        val backStack = NavBackStack<NavKey>(ChatScreen)
+        val backStack = NavBackStack<NavKey>(ChatScreen, SettingsScreen, SettingsAppearance)
         NavigationController.backStack = backStack
-        NavigationController.navigateTo(ProfilesScreen)
+
+        NavigationController.goBack()
+
         assertEquals(2, backStack.size)
+        assertEquals(SettingsScreen, backStack.lastOrNull())
 
         NavigationController.goBack()
 
@@ -213,18 +196,18 @@ class NavigationControllerTest {
     }
 
     @Test
-    fun `goBack from chat opens history`() {
+    fun `goBack on root ChatScreen keeps ChatScreen`() {
         val backStack = NavBackStack<NavKey>(ChatScreen)
         NavigationController.backStack = backStack
 
         NavigationController.goBack()
 
         assertEquals(1, backStack.size)
-        assertEquals(HistoryScreen, backStack.lastOrNull())
+        assertEquals(ChatScreen, backStack.lastOrNull())
     }
 
     @Test
-    fun `goBack falls back to default screen when stack has one item`() {
+    fun `goBack falls back to default screen when non-root stack has one item`() {
         val backStack = NavBackStack<NavKey>(ProfilesScreen)
         NavigationController.backStack = backStack
 
@@ -256,18 +239,42 @@ class NavigationControllerTest {
     // ── primaryScreens ────────────────────────────────────────────────────
 
     @Test
-    fun `isPrimaryScreen returns true for default screens`() {
-        assertTrue("ChatScreen should be primary by default", NavigationController.isPrimaryScreen(ChatScreen))
-        assertTrue("SkillsScreen should be primary by default", NavigationController.isPrimaryScreen(SkillsScreen))
-        assertTrue("CronJobsScreen should be primary by default", NavigationController.isPrimaryScreen(CronJobsScreen))
-        assertTrue("SystemScreen should be primary by default", NavigationController.isPrimaryScreen(SystemScreen))
-        assertTrue("SettingsScreen should be primary by default", NavigationController.isPrimaryScreen(SettingsScreen))
+    fun `isPrimaryScreen returns true for all drawer screens`() {
+        assertTrue("ChatScreen should be primary", NavigationController.isPrimaryScreen(ChatScreen))
+        assertTrue("SkillsScreen should be primary", NavigationController.isPrimaryScreen(SkillsScreen))
+        assertTrue("CronJobsScreen should be primary", NavigationController.isPrimaryScreen(CronJobsScreen))
+        assertTrue("SystemScreen should be primary", NavigationController.isPrimaryScreen(SystemScreen))
+        assertTrue("SettingsScreen should be primary", NavigationController.isPrimaryScreen(SettingsScreen))
+        assertTrue("ProfilesScreen should be primary", NavigationController.isPrimaryScreen(ProfilesScreen))
+        assertTrue("LogsScreen should be primary", NavigationController.isPrimaryScreen(LogsScreen))
+        assertTrue("ConfigScreen should be primary", NavigationController.isPrimaryScreen(ConfigScreen))
+        assertTrue("BotsScreen should be primary", NavigationController.isPrimaryScreen(BotsScreen))
+        assertTrue("HistoryScreen should be primary", NavigationController.isPrimaryScreen(HistoryScreen))
     }
 
     @Test
-    fun `isPrimaryScreen returns false for non-default screens`() {
-        assertFalse("ProfilesScreen should NOT be primary", NavigationController.isPrimaryScreen(ProfilesScreen))
-        assertFalse("LogsScreen should NOT be primary", NavigationController.isPrimaryScreen(LogsScreen))
-        assertFalse("ConfigScreen should NOT be primary", NavigationController.isPrimaryScreen(ConfigScreen))
+    fun `isPrimaryScreen returns false for subscreen detail keys`() {
+        assertFalse(
+            "SettingsAppearance should NOT be primary",
+            NavigationController.isPrimaryScreen(SettingsAppearance),
+        )
+        assertFalse(
+            "SettingsConnection should NOT be primary",
+            NavigationController.isPrimaryScreen(SettingsConnection),
+        )
+        assertFalse("SettingsLanguage should NOT be primary", NavigationController.isPrimaryScreen(SettingsLanguage))
+        assertFalse("SettingsChat should NOT be primary", NavigationController.isPrimaryScreen(SettingsChat))
+        assertFalse("SettingsBehavior should NOT be primary", NavigationController.isPrimaryScreen(SettingsBehavior))
+        assertFalse("SettingsAbout should NOT be primary", NavigationController.isPrimaryScreen(SettingsAbout))
+        assertFalse(
+            "ToolsetDetailKey should NOT be primary",
+            NavigationController.isPrimaryScreen(ToolsetDetailKey("tool")),
+        )
+        assertFalse(
+            "MemoryProviderDetailKey should NOT be primary",
+            NavigationController.isPrimaryScreen(MemoryProviderDetailKey("mem")),
+        )
+        assertFalse("GroupChatKey should NOT be primary", NavigationController.isPrimaryScreen(GroupChatKey("room")))
+        assertFalse("AuthLoginScreen should NOT be primary", NavigationController.isPrimaryScreen(AuthLoginScreen))
     }
 }