import { Worker } from "node:worker_threads";
import { CoreError } from "./errors.ts";

function cancelled(): CoreError {
  return new CoreError("ARTIFACT_EXECUTION_FAILED", "执行已取消");
}

/** Runs trusted bundles with host permissions, outside the secure evaluator. */
export async function executeLocalWorker(
  javascript: string,
  inputJson: string,
  signal?: AbortSignal,
): Promise<unknown> {
  if (signal?.aborted) throw cancelled();
  const worker = new Worker(`
    (() => {
      const { parentPort } = require("node:worker_threads");
      globalThis.self = globalThis;
      globalThis.postMessage = (value) => parentPort.postMessage(value);
    })();
    ${javascript}
    ;
    if (typeof globalThis.onmessage !== "function") {
      throw new Error("Worker 未注册消息处理函数");
    }
    globalThis.onmessage({ data: require("node:worker_threads").workerData });
  `, { eval: true, workerData: inputJson });
  let onAbort: (() => void) | undefined;
  try {
    return await new Promise<unknown>((resolve, reject) => {
      worker.once("message", resolve);
      worker.once("error", (error) => reject(new CoreError(
        "ARTIFACT_EXECUTION_FAILED", error instanceof Error ? error.message : String(error),
      )));
      worker.once("exit", (exitCode) => reject(new CoreError(
        "ARTIFACT_EXECUTION_FAILED", "Worker 未返回响应便已退出", { exitCode },
      )));
      onAbort = () => reject(cancelled());
      signal?.addEventListener("abort", onAbort, { once: true });
      if (signal?.aborted) onAbort();
    });
  } finally {
    if (onAbort !== undefined) signal?.removeEventListener("abort", onAbort);
    // Terminate even after success: author timers must not outlive this request.
    await worker.terminate();
  }
}