Add Bun bundle docs and Telegram grammY support

src/telegram/download.ts

@@ -0,0 +1,50 @@
+import { detectMime, extensionForMime } from "../media/mime.js";
+import { saveMediaBuffer, type SavedMedia } from "../media/store.js";
+
+export type TelegramFileInfo = {
+  file_id: string;
+  file_unique_id?: string;
+  file_size?: number;
+  file_path?: string;
+};
+
+export async function getTelegramFile(
+  token: string,
+  fileId: string,
+): Promise<TelegramFileInfo> {
+  const res = await fetch(
+    `https://api.telegram.org/bot${token}/getFile?file_id=${encodeURIComponent(fileId)}`,
+  );
+  if (!res.ok) {
+    throw new Error(`getFile failed: ${res.status} ${res.statusText}`);
+  }
+  const json = (await res.json()) as { ok: boolean; result?: TelegramFileInfo };
+  if (!json.ok || !json.result?.file_path) {
+    throw new Error("getFile returned no file_path");
+  }
+  return json.result;
+}
+
+export async function downloadTelegramFile(
+  token: string,
+  info: TelegramFileInfo,
+  maxBytes?: number,
+): Promise<SavedMedia> {
+  if (!info.file_path) throw new Error("file_path missing");
+  const url = `https://api.telegram.org/file/bot${token}/${info.file_path}`;
+  const res = await fetch(url);
+  if (!res.ok || !res.body) {
+    throw new Error(`Failed to download telegram file: HTTP ${res.status}`);
+  }
+  const array = Buffer.from(await res.arrayBuffer());
+  const mime = detectMime({
+    buffer: array,
+    headerMime: res.headers.get("content-type"),
+    filePath: info.file_path,
+  });
+  // save with inbound subdir
+  const saved = await saveMediaBuffer(array, mime, "inbound", maxBytes);
+  // Ensure extension matches mime if possible
+  if (!saved.contentType && mime) saved.contentType = mime;
+  return saved;
+}