/// <reference lib="webworker" />
/**
 * Web Worker that owns a numbl instance. One run at a time; the host cancels
 * a run by terminating the worker, which is why nothing here needs to be
 * interruptible. The modes of stage 1 travel back to the host and return as
 * an input of stage 2, so a cancelled or crashed worker loses nothing kept.
 */
import { executeBundle, numblVersion } from "./execute";
import { collectBuffers } from "./plain";
import type { FromWorker, ToWorker } from "./protocol";
import type { BackendInfo } from "./types";

const backend: BackendInfo = {
  engine: "numbl",
  version: numblVersion(),
  optimization: "1",
  host: "web-worker",
};

const post = (msg: FromWorker, transfer: ArrayBuffer[] = []) => self.postMessage(msg, transfer);

self.onmessage = (e: MessageEvent<ToWorker>) => {
  const msg = e.data;
  if (msg.type === "info") {
    post({ type: "info", id: msg.id, backend });
    return;
  }
  const result = executeBundle({ bundle: msg.bundle, inputs: msg.inputs }, backend, (text) =>
    post({ type: "output", id: msg.id, text }),
  );
  const transfer = result.ok ? collectBuffers(result.value) : [];
  post({ type: "done", id: msg.id, result }, transfer);
};