simplified code across the app and consolidated duplicated helpers

lib/widget/downloads/download_tray.dart

@@ -5,7 +5,6 @@ import 'package:flutter/material.dart';
 import '../../routing/app_routes.dart';
 import '../../utils/downloads/download_job.dart';
 import '../../utils/downloads/download_manager.dart';
-import '../../utils/haptics.dart';
 import 'downloads_sheet.dart';
 import 'stale_download_guard.dart';
 
@@ -204,10 +203,7 @@ class _DownloadTrayHostState extends State<DownloadTrayHost>
       _manager.markOpened(job);
       return;
     }
-    if (!ensureDownloadStillExists(ctx, job)) return;
-    _manager.markOpened(job);
-    Haptics.success();
-    AppRoutes.openFileViewer(ctx, path, remoteFile: job.remoteFile);
+    openFinishedDownload(ctx, job, path);
   }
 
   /// Distance from the bottom to float the chip. Anchored bottom-LEFT (FABs are

lib/widget/downloads/downloads_sheet.dart

@@ -2,10 +2,8 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 
-import '../../routing/app_routes.dart';
 import '../../utils/downloads/download_job.dart';
 import '../../utils/downloads/download_manager.dart';
-import '../../utils/haptics.dart';
 import '../../view/pages/files/data/file_type_icon.dart';
 import '../centered_leading.dart';
 import '../details_bottom_sheet.dart';
@@ -90,14 +88,7 @@ class _DownloadsListState extends State<_DownloadsList> {
     // Pop the sheet first so a stale-file dialog lands on the underlying
     // screen instead of an emptied sheet.
     Navigator.of(widget.sheetContext).pop();
-    if (!ensureDownloadStillExists(widget.rootContext, job)) return;
-    Haptics.success();
-    DownloadManager.instance.markOpened(job);
-    AppRoutes.openFileViewer(
-      widget.rootContext,
-      path,
-      remoteFile: job.remoteFile,
-    );
+    openFinishedDownload(widget.rootContext, job, path);
   }
 }
 
@@ -140,8 +131,7 @@ class _DownloadRow extends StatelessWidget {
           DownloadInProgress() => IconButton(
             icon: const Icon(Icons.close),
             tooltip: 'Abbrechen',
-            onPressed: () =>
-                unawaited(DownloadManager.instance.cancel(job)),
+            onPressed: () => unawaited(DownloadManager.instance.cancel(job)),
           ),
           DownloadFailed() => IconButton(
             icon: const Icon(Icons.refresh),
@@ -167,7 +157,10 @@ class _DownloadRow extends StatelessWidget {
           alignment: Alignment.centerRight,
           padding: const EdgeInsets.only(right: 24),
           color: theme.colorScheme.errorContainer,
-          child: Icon(Icons.delete_outline, color: theme.colorScheme.onErrorContainer),
+          child: Icon(
+            Icons.delete_outline,
+            color: theme.colorScheme.onErrorContainer,
+          ),
         ),
         onDismissed: (_) => DownloadManager.instance.dismiss(job),
         child: tile,

lib/widget/downloads/stale_download_guard.dart

@@ -3,8 +3,10 @@ import 'dart:io';
 
 import 'package:flutter/material.dart';
 
+import '../../routing/app_routes.dart';
 import '../../utils/downloads/download_job.dart';
 import '../../utils/downloads/download_manager.dart';
+import '../../utils/haptics.dart';
 import '../confirm_dialog.dart';
 import '../info_dialog.dart';
 
@@ -21,20 +23,45 @@ bool ensureDownloadStillExists(BuildContext context, DownloadJob job) {
   if (path == null || File(path).existsSync()) return true;
 
   DownloadManager.instance.markOpened(job);
-  if (job.remotePath.isNotEmpty) {
-    ConfirmDialog(
-      title: 'Datei nicht mehr verfügbar',
-      content:
-          'Die heruntergeladene Datei wurde vom System aus dem Zwischenspeicher entfernt.\nErneut herunterladen?',
-      confirmButton: 'Herunterladen',
-      onConfirm: () => unawaited(DownloadManager.instance.retry(job)),
-    ).asDialog(context);
-  } else {
-    InfoDialog.show(
-      context,
-      'Die heruntergeladene Datei wurde vom System aus dem Zwischenspeicher entfernt. Bitte lade sie erneut herunter.',
-      title: 'Datei nicht mehr verfügbar',
-    );
-  }
+  showFileGoneDialog(
+    context,
+    subject: 'Die heruntergeladene Datei',
+    onRedownload: job.remotePath.isEmpty
+        ? null
+        : () => unawaited(DownloadManager.instance.retry(job)),
+  );
   return false;
 }
+
+/// Opens a finished download in the viewer, unless its file vanished.
+void openFinishedDownload(BuildContext context, DownloadJob job, String path) {
+  if (!ensureDownloadStillExists(context, job)) return;
+  DownloadManager.instance.markOpened(job);
+  Haptics.success();
+  AppRoutes.openFileViewer(context, path, remoteFile: job.remoteFile);
+}
+
+/// Tells the user that the system cleared a cached file ([subject], e.g.
+/// "Die Datei") and offers a re-download when [onRedownload] is given.
+void showFileGoneDialog(
+  BuildContext context, {
+  required String subject,
+  VoidCallback? onRedownload,
+}) {
+  const title = 'Datei nicht mehr verfügbar';
+  final gone = '$subject wurde vom System aus dem Zwischenspeicher entfernt.';
+  if (onRedownload == null) {
+    InfoDialog.show(
+      context,
+      '$gone Bitte lade sie erneut herunter.',
+      title: title,
+    );
+    return;
+  }
+  ConfirmDialog(
+    title: title,
+    content: '$gone\nErneut herunterladen?',
+    confirmButton: 'Herunterladen',
+    onConfirm: onRedownload,
+  ).asDialog(context);
+}