import { requireApiContext } from "@/server/api/context";
import { ApiError, json, readFormData, withApi } from "@/server/api/respond";
import { CHAT_AUDIO_MAX_BYTES, transcribeChatAudio } from "@/server/services/lotse/chat/transcribe";

/**
 * POST /api/v1/lotse/transcribe — multipart `file` (audio, max. 10 MB) → `{ text }` (lane L16).
 * Microphone key of the Lotse chat: the transcript is put into the input field and can be edited
 * before sending. The audio is not stored.
 */
export const POST = withApi(async (req: Request) => {
  const ctx = await requireApiContext("lotse", "lotse:use", "field:execute");
  const declared = Number(req.headers.get("content-length") ?? "0");
  if (declared > CHAT_AUDIO_MAX_BYTES + 1024 * 1024) throw new ApiError("payload_too_large", "audio too large");
  const form = await readFormData(req);
  const file = form.get("file");
  if (!(file instanceof File)) throw new ApiError("invalid", "file missing");
  if (file.size > CHAT_AUDIO_MAX_BYTES) throw new ApiError("payload_too_large", "audio too large");
  const result = await transcribeChatAudio(ctx, Buffer.from(await file.arrayBuffer()));
  return json(result);
});