KI-AGENT: Kalender, Terminbearbeitung und Dateivorschau verbessern

mobile/src/lib/file-opening.ts

@@ -1,3 +1,7 @@
+import { File, Paths } from 'expo-file-system';
+import * as Sharing from 'expo-sharing';
+
+import type { ProjectFile } from '@/src/lib/api';
 import { getApiBaseUrlSync } from '@/src/lib/server-config';
 
 export function getOpenableFileUrl(rawUrl: string): string {
@@ -7,3 +11,28 @@ export function getOpenableFileUrl(rawUrl: string): string {
   const path = rawUrl.startsWith('/') ? rawUrl : `/${rawUrl}`;
   return `${apiBaseUrl}${path}`;
 }
+
+function safeFilename(file: ProjectFile): string {
+  const fallback = `dokument-${file.id}`;
+  const rawName = String(file.name || file.path?.split('/').pop() || fallback);
+  return rawName.replace(/[^a-zA-Z0-9äöüÄÖÜß._-]/g, '_');
+}
+
+export async function openAuthenticatedFile(file: ProjectFile, token: string): Promise<void> {
+  if (!file.url) throw new Error('Für dieses Dokument ist kein Download verfügbar.');
+
+  const target = new File(Paths.cache, `${file.id}-${safeFilename(file)}`);
+  const downloaded = await File.downloadFileAsync(getOpenableFileUrl(file.url), target, {
+    headers: { Authorization: `Bearer ${token}` },
+    idempotent: true,
+  });
+
+  if (!(await Sharing.isAvailableAsync())) {
+    throw new Error('Die Dokumentvorschau ist auf diesem Gerät nicht verfügbar.');
+  }
+
+  await Sharing.shareAsync(downloaded.uri, {
+    mimeType: file.mimeType || undefined,
+    dialogTitle: safeFilename(file),
+  });
+}