Restore viewer window state and handle photo decoding errors

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/screens/PhotoViewerScreen.kt

@@ -2,9 +2,6 @@ package com.utun.chat.ui.screens
 
 import com.utun.chat.R
 import androidx.compose.ui.res.stringResource
-import android.app.Activity
-import android.content.Context
-import android.content.ContextWrapper
 import android.graphics.Bitmap
 import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.background
@@ -19,43 +16,33 @@ import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
-import androidx.core.view.WindowCompat
-import androidx.core.view.WindowInsetsCompat
-import androidx.core.view.WindowInsetsControllerCompat
 import com.utun.chat.data.LogManager
 import com.utun.chat.data.PhotoUtil
 import com.utun.chat.ui.components.ZoomableImage
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.withContext
 
 private const val MAX_DECODE_DIM = 4096
 
-private tailrec fun Context.findActivity(): Activity? = when (this) {
-    is Activity -> this
-    is ContextWrapper -> baseContext.findActivity()
-    else -> null
-}
-
+/** Локальное изображение с EXIF и Fit/zoom; декодирование в IO ограничено стороной 4096 пикселей.
+ * Экран владеет Bitmap через Compose; смена пути отменяет доставку старого результата. Ошибка оставляет доступным выход. */
 @Composable
 fun PhotoViewerScreen(filePath: String, onClose: () -> Unit) {
-    val context = LocalContext.current
     var bmp by remember(filePath) { mutableStateOf<Bitmap?>(null) }
     var loaded by remember(filePath) { mutableStateOf(false) }
     BackHandler(onBack = onClose)
 
-    /* ── immersive: hide system bars ── */
-    DisposableEffect(Unit) {
-        val act = context.findActivity()
-        val controller = act?.let { WindowCompat.getInsetsController(it.window, it.window.decorView) }
-        controller?.systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
-        controller?.hide(WindowInsetsCompat.Type.systemBars())
-        onDispose { controller?.show(WindowInsetsCompat.Type.systemBars()) }
-    }
+    ViewerFullscreenWindow("photo")
 
     LaunchedEffect(filePath) {
-        bmp = withContext(Dispatchers.IO) { PhotoUtil.decodeFitted(filePath, MAX_DECODE_DIM) }
+        bmp = try { withContext(Dispatchers.IO) { PhotoUtil.decodeFitted(filePath, MAX_DECODE_DIM) } }
+        catch (e: CancellationException) { throw e }
+        catch (e: Exception) {
+            LogManager.addLog("ERROR", "PhotoViewer", "decode exception path=$filePath: $e")
+            null
+        }
         loaded = true
         if (bmp == null) LogManager.addLog("ERROR", "PhotoViewer", "decode failed: $filePath")
         else LogManager.addLog("DEBUG", "PhotoViewer", "Opened image ${bmp?.width}x${bmp?.height} path=$filePath")

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/screens/ViewerFullscreenWindow.kt

@@ -0,0 +1,59 @@
+package com.utun.chat.ui.screens
+
+import android.app.Activity
+import android.content.ContextWrapper
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.remember
+import androidx.compose.ui.platform.LocalContext
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowCompat
+import androidx.core.view.WindowInsetsCompat
+import androidx.core.view.WindowInsetsControllerCompat
+import com.utun.chat.data.LogManager
+
+/** Immersive-режим viewer без смены ориентации; возвращает прежнюю видимость обеих панелей и поведение swipe.
+ * Вызывающий экран должен быть единственным владельцем fullscreen окна. identity — диагностическое имя без секретов. */
+@Composable
+internal fun ViewerFullscreenWindow(identity: String) {
+    val context = LocalContext.current
+    val activity = remember(context) {
+        generateSequence(context) { (it as? ContextWrapper)?.baseContext }.filterIsInstance<Activity>().firstOrNull()
+    }
+    DisposableEffect(activity, identity) {
+        val window = activity?.window
+        val controller = window?.let { WindowCompat.getInsetsController(it, it.decorView) }
+        val insets = window?.let { ViewCompat.getRootWindowInsets(it.decorView) }
+        val statusVisible = insets?.isVisible(WindowInsetsCompat.Type.statusBars()) ?: true
+        val navigationVisible = insets?.isVisible(WindowInsetsCompat.Type.navigationBars()) ?: true
+        val behavior = controller?.systemBarsBehavior
+        if (controller != null) try {
+            controller.systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
+            controller.hide(WindowInsetsCompat.Type.systemBars())
+            LogManager.addLog("INFO", "Viewer", "Fullscreen entered viewer=$identity")
+        } catch (e: Exception) {
+            LogManager.addLog("ERROR", "Viewer", "Cannot enter fullscreen viewer=$identity: $e")
+        }
+        onDispose {
+            if (controller != null && behavior != null) {
+                val restore: List<Pair<String, () -> Unit>> = listOf(
+                    "behavior" to { controller.systemBarsBehavior = behavior },
+                    "status" to {
+                        if (statusVisible) controller.show(WindowInsetsCompat.Type.statusBars())
+                        else controller.hide(WindowInsetsCompat.Type.statusBars())
+                    },
+                    "navigation" to {
+                        if (navigationVisible) controller.show(WindowInsetsCompat.Type.navigationBars())
+                        else controller.hide(WindowInsetsCompat.Type.navigationBars())
+                    }
+                )
+                var failures = 0
+                for ((part, action) in restore) try { action() } catch (e: Exception) {
+                    failures++
+                    LogManager.addLog("ERROR", "Viewer", "Window restore failed viewer=$identity part=$part: $e")
+                }
+                if (failures == 0) LogManager.addLog("INFO", "Viewer", "Window restored viewer=$identity")
+            }
+        }
+    }
+}