fix: fix theme switch

app/src/main/java/com/rosetta/messenger/MainActivity.kt

@@ -12,6 +12,7 @@ import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.animation.*
 import androidx.compose.animation.core.tween
 import androidx.compose.foundation.background
+import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.material3.Surface
@@ -129,7 +130,14 @@ class MainActivity : FragmentActivity() {
             }
 
             val scope = rememberCoroutineScope()
-            val isDarkTheme by preferencesManager.isDarkTheme.collectAsState(initial = true)
+            val themeMode by preferencesManager.themeMode.collectAsState(initial = "dark")
+            val systemInDarkTheme = isSystemInDarkTheme()
+            val isDarkTheme = when (themeMode) {
+                "light" -> false
+                "dark" -> true
+                "auto" -> systemInDarkTheme
+                else -> true
+            }
             val isLoggedIn by accountManager.isLoggedIn.collectAsState(initial = null)
             var showSplash by remember { mutableStateOf(true) }
             var showOnboarding by remember { mutableStateOf(true) }
@@ -296,11 +304,17 @@ class MainActivity : FragmentActivity() {
                                 MainScreen(
                                         account = currentAccount,
                                         isDarkTheme = isDarkTheme,
+                                        themeMode = themeMode,
                                         onToggleTheme = {
                                             scope.launch {
                                                 preferencesManager.setDarkTheme(!isDarkTheme)
                                             }
                                         },
+                                        onThemeModeChange = { mode ->
+                                            scope.launch {
+                                                preferencesManager.setThemeMode(mode)
+                                            }
+                                        },
                                         onLogout = {
                                             // Set currentAccount to null immediately to prevent UI
                                             // lag
@@ -461,7 +475,9 @@ class MainActivity : FragmentActivity() {
 fun MainScreen(
         account: DecryptedAccount? = null,
         isDarkTheme: Boolean = true,
+        themeMode: String = "dark",
         onToggleTheme: () -> Unit = {},
+        onThemeModeChange: (String) -> Unit = {},
         onLogout: () -> Unit = {},
         onAccountInfoUpdated: suspend () -> Unit = {}
 ) {
@@ -667,13 +683,12 @@ fun MainScreen(
             if (showThemeScreen) {
                 ThemeScreen(
                     isDarkTheme = isDarkTheme,
+                    currentThemeMode = themeMode,
                     onBack = {
                         showThemeScreen = false
                         showProfileScreen = true
                     },
-                    onThemeChange = { isDark ->
-                        onToggleTheme()
-                    }
+                    onThemeModeChange = onThemeModeChange
                 )
             }
         }

app/src/main/java/com/rosetta/messenger/data/PreferencesManager.kt

@@ -20,6 +20,7 @@ class PreferencesManager(private val context: Context) {
         // Onboarding & Theme
         val HAS_SEEN_ONBOARDING = booleanPreferencesKey("has_seen_onboarding")
         val IS_DARK_THEME = booleanPreferencesKey("is_dark_theme")
+        val THEME_MODE = stringPreferencesKey("theme_mode") // "light", "dark", "auto"
 
         // Notifications
         val NOTIFICATIONS_ENABLED = booleanPreferencesKey("notifications_enabled")
@@ -63,6 +64,15 @@ class PreferencesManager(private val context: Context) {
         context.dataStore.edit { preferences -> preferences[IS_DARK_THEME] = value }
     }
 
+    val themeMode: Flow<String> =
+            context.dataStore.data.map { preferences ->
+                preferences[THEME_MODE] ?: "dark" // Default to dark theme
+            }
+
+    suspend fun setThemeMode(value: String) {
+        context.dataStore.edit { preferences -> preferences[THEME_MODE] = value }
+    }
+
     // ═════════════════════════════════════════════════════════════
     // 🔔 NOTIFICATIONS
     // ═════════════════════════════════════════════════════════════

app/src/main/java/com/rosetta/messenger/ui/settings/ThemeScreen.kt

@@ -29,8 +29,9 @@ import com.rosetta.messenger.ui.components.AppleEmojiText
 @Composable
 fun ThemeScreen(
     isDarkTheme: Boolean,
+    currentThemeMode: String,
     onBack: () -> Unit,
-    onThemeChange: (Boolean) -> Unit
+    onThemeModeChange: (String) -> Unit
 ) {
     val backgroundColor = if (isDarkTheme) Color(0xFF1A1A1A) else Color(0xFFFFFFFF)
     val surfaceColor = if (isDarkTheme) Color(0xFF2C2C2E) else Color(0xFFF2F2F7)
@@ -38,7 +39,7 @@ fun ThemeScreen(
     val secondaryTextColor = if (isDarkTheme) Color(0xFF8E8E93) else Color(0xFF666666)
 
     // Theme mode: "light", "dark", "auto"
-    var themeMode by remember { mutableStateOf(if (isDarkTheme) "dark" else "light") }
+    var themeMode by remember { mutableStateOf(currentThemeMode) }
     
     // Handle back gesture
     BackHandler { onBack() }
@@ -105,7 +106,7 @@ fun ThemeScreen(
                     onClick = {
                         if (themeMode != "light") {
                             themeMode = "light"
-                            onThemeChange(false)
+                            onThemeModeChange("light")
                         }
                     },
                     textColor = textColor,
@@ -121,7 +122,7 @@ fun ThemeScreen(
                     onClick = {
                         if (themeMode != "dark") {
                             themeMode = "dark"
-                            onThemeChange(true)
+                            onThemeModeChange("dark")
                         }
                     },
                     textColor = textColor,
@@ -135,8 +136,10 @@ fun ThemeScreen(
                     title = "System",
                     isSelected = themeMode == "auto",
                     onClick = {
+                        if (themeMode != "auto") {
                             themeMode = "auto"
-                        // For now, we'll just keep the current theme
+                            onThemeModeChange("auto")
+                        }
                     },
                     textColor = textColor,
                     secondaryTextColor = secondaryTextColor,