const { Worker, isMainThread, parentPort, workerData } = require("worker_threads");
const os = require("os");

console.time("Node Loop Benchmark");

const numThreads = os.cpus().length;
const total = 1_000_000_000;
const chunk = Math.floor(total / numThreads);
let completed = 0;
let sum = 0;

const sumTo = (n) => (n * (n - 1)) / 2;

if (isMainThread) {
  return new Promise((resolve) => {
    function handleMessage(partialSum) {
      sum += partialSum;
      completed++;
      if (completed === numThreads) {
        resolve();
      }
    }
    for (let i = 0; i < numThreads; i++) {
      const start = i * chunk;
      const end = i === numThreads - 1 ? total : start + chunk;
      const worker = new Worker(__filename, { workerData: { start, end } });
      worker.on("message", handleMessage);
    }
  }).then(() => {
    console.timeEnd("Node Loop Benchmark");
    console.log("Sum:", sum);
  });
} else {
  const { start, end } = workerData;
  const partialSum = sumTo(end) - sumTo(start);
  parentPort.postMessage(partialSum);
}