fix: msteams attachments + plugin prompt hints

Co-authored-by: Christof <10854026+Evizero@users.noreply.github.com>

src/media/mime.ts

@@ -32,9 +32,11 @@ const EXT_BY_MIME: Record<string, string> = {
   "text/markdown": ".md",
 };
 
-const MIME_BY_EXT: Record<string, string> = Object.fromEntries(
-  Object.entries(EXT_BY_MIME).map(([mime, ext]) => [ext, mime]),
-);
+const MIME_BY_EXT: Record<string, string> = {
+  ...Object.fromEntries(Object.entries(EXT_BY_MIME).map(([mime, ext]) => [ext, mime])),
+  // Additional extension aliases
+  ".jpeg": "image/jpeg",
+};
 
 const AUDIO_FILE_EXTENSIONS = new Set([
   ".aac",

src/media/store.test.ts

@@ -161,4 +161,114 @@ describe("media store", () => {
       expect(path.extname(saved.path)).toBe(".xlsx");
     });
   });
+
+  describe("extractOriginalFilename", () => {
+    it("extracts original filename from embedded pattern", async () => {
+      await withTempStore(async (store) => {
+        // Pattern: {original}---{uuid}.{ext}
+        const filename = "report---a1b2c3d4-e5f6-7890-abcd-ef1234567890.pdf";
+        const result = store.extractOriginalFilename(`/path/to/${filename}`);
+        expect(result).toBe("report.pdf");
+      });
+    });
+
+    it("handles uppercase UUID pattern", async () => {
+      await withTempStore(async (store) => {
+        const filename = "Document---A1B2C3D4-E5F6-7890-ABCD-EF1234567890.docx";
+        const result = store.extractOriginalFilename(`/media/inbound/${filename}`);
+        expect(result).toBe("Document.docx");
+      });
+    });
+
+    it("falls back to basename for non-matching patterns", async () => {
+      await withTempStore(async (store) => {
+        // UUID-only filename (legacy format)
+        const uuidOnly = "a1b2c3d4-e5f6-7890-abcd-ef1234567890.pdf";
+        expect(store.extractOriginalFilename(`/path/${uuidOnly}`)).toBe(uuidOnly);
+
+        // Regular filename without embedded pattern
+        expect(store.extractOriginalFilename("/path/to/regular.txt")).toBe("regular.txt");
+
+        // Filename with --- but invalid UUID part
+        expect(store.extractOriginalFilename("/path/to/foo---bar.txt")).toBe("foo---bar.txt");
+      });
+    });
+
+    it("preserves original name with special characters", async () => {
+      await withTempStore(async (store) => {
+        const filename = "报告_2024---a1b2c3d4-e5f6-7890-abcd-ef1234567890.pdf";
+        const result = store.extractOriginalFilename(`/media/${filename}`);
+        expect(result).toBe("报告_2024.pdf");
+      });
+    });
+  });
+
+  describe("saveMediaBuffer with originalFilename", () => {
+    it("embeds original filename in stored path when provided", async () => {
+      await withTempStore(async (store) => {
+        const buf = Buffer.from("test content");
+        const saved = await store.saveMediaBuffer(
+          buf,
+          "text/plain",
+          "inbound",
+          5 * 1024 * 1024,
+          "report.txt",
+        );
+
+        // Should contain the original name and a UUID pattern
+        expect(saved.id).toMatch(/^report---[a-f0-9-]{36}\.txt$/);
+        expect(saved.path).toContain("report---");
+
+        // Should be able to extract original name
+        const extracted = store.extractOriginalFilename(saved.path);
+        expect(extracted).toBe("report.txt");
+      });
+    });
+
+    it("sanitizes unsafe characters in original filename", async () => {
+      await withTempStore(async (store) => {
+        const buf = Buffer.from("test");
+        // Filename with unsafe chars: < > : " / \ | ? *
+        const saved = await store.saveMediaBuffer(
+          buf,
+          "text/plain",
+          "inbound",
+          5 * 1024 * 1024,
+          "my<file>:test.txt",
+        );
+
+        // Unsafe chars should be replaced with underscores
+        expect(saved.id).toMatch(/^my_file_test---[a-f0-9-]{36}\.txt$/);
+      });
+    });
+
+    it("truncates long original filenames", async () => {
+      await withTempStore(async (store) => {
+        const buf = Buffer.from("test");
+        const longName = "a".repeat(100) + ".txt";
+        const saved = await store.saveMediaBuffer(
+          buf,
+          "text/plain",
+          "inbound",
+          5 * 1024 * 1024,
+          longName,
+        );
+
+        // Original name should be truncated to 60 chars
+        const baseName = path.parse(saved.id).name.split("---")[0];
+        expect(baseName.length).toBeLessThanOrEqual(60);
+      });
+    });
+
+    it("falls back to UUID-only when originalFilename not provided", async () => {
+      await withTempStore(async (store) => {
+        const buf = Buffer.from("test");
+        const saved = await store.saveMediaBuffer(buf, "text/plain", "inbound");
+
+        // Should be UUID-only pattern (legacy behavior)
+        expect(saved.id).toMatch(/^[a-f0-9-]{36}\.txt$/);
+        expect(saved.id).not.toContain("---");
+      });
+    });
+  });
 });

src/media/store.ts

@@ -11,6 +11,43 @@ const resolveMediaDir = () => path.join(resolveConfigDir(), "media");
 const MAX_BYTES = 5 * 1024 * 1024; // 5MB default
 const DEFAULT_TTL_MS = 2 * 60 * 1000; // 2 minutes
 
+/**
+ * Sanitize a filename for cross-platform safety.
+ * Removes chars unsafe on Windows/SharePoint/all platforms.
+ * Keeps: alphanumeric, dots, hyphens, underscores, Unicode letters/numbers.
+ */
+function sanitizeFilename(name: string): string {
+  // Remove: < > : " / \ | ? * and control chars (U+0000-U+001F)
+  // oxlint-disable-next-line no-control-regex -- Intentionally matching control chars
+  const unsafe = /[<>:"/\\|?*\x00-\x1f]/g;
+  const sanitized = name.trim().replace(unsafe, "_").replace(/\s+/g, "_"); // Replace whitespace runs with underscore
+  // Collapse multiple underscores, trim leading/trailing, limit length
+  return sanitized.replace(/_+/g, "_").replace(/^_|_$/g, "").slice(0, 60);
+}
+
+/**
+ * Extract original filename from path if it matches the embedded format.
+ * Pattern: {original}---{uuid}.{ext} → returns "{original}.{ext}"
+ * Falls back to basename if no pattern match, or "file.bin" if empty.
+ */
+export function extractOriginalFilename(filePath: string): string {
+  const basename = path.basename(filePath);
+  if (!basename) return "file.bin"; // Fallback for empty input
+
+  const ext = path.extname(basename);
+  const nameWithoutExt = path.basename(basename, ext);
+
+  // Check for ---{uuid} pattern (36 chars: 8-4-4-4-12 with hyphens)
+  const match = nameWithoutExt.match(
+    /^(.+)---[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i,
+  );
+  if (match?.[1]) {
+    return `${match[1]}${ext}`;
+  }
+
+  return basename; // Fallback: use as-is
+}
+
 export function getMediaDir() {
   return resolveMediaDir();
 }
@@ -152,17 +189,29 @@ export async function saveMediaBuffer(
   contentType?: string,
   subdir = "inbound",
   maxBytes = MAX_BYTES,
+  originalFilename?: string,
 ): Promise<SavedMedia> {
   if (buffer.byteLength > maxBytes) {
     throw new Error(`Media exceeds ${(maxBytes / (1024 * 1024)).toFixed(0)}MB limit`);
   }
   const dir = path.join(resolveMediaDir(), subdir);
   await fs.mkdir(dir, { recursive: true });
-  const baseId = crypto.randomUUID();
+  const uuid = crypto.randomUUID();
   const headerExt = extensionForMime(contentType?.split(";")[0]?.trim() ?? undefined);
   const mime = await detectMime({ buffer, headerMime: contentType });
-  const ext = headerExt ?? extensionForMime(mime);
-  const id = ext ? `${baseId}${ext}` : baseId;
+  const ext = headerExt ?? extensionForMime(mime) ?? "";
+
+  let id: string;
+  if (originalFilename) {
+    // Embed original name: {sanitized}---{uuid}.ext
+    const base = path.parse(originalFilename).name;
+    const sanitized = sanitizeFilename(base);
+    id = sanitized ? `${sanitized}---${uuid}${ext}` : `${uuid}${ext}`;
+  } else {
+    // Legacy: just UUID
+    id = ext ? `${uuid}${ext}` : uuid;
+  }
+
   const dest = path.join(dir, id);
   await fs.writeFile(dest, buffer);
   return { id, path: dest, size: buffer.byteLength, contentType: mime };