import { workerData, parentPort } from "worker_threads";
import fetch from "node-fetch";
import fs from "fs-extra";
import path from "path";
import { fileURLToPath } from "url";
import { randomBytes } from "crypto";

const generateRandomFilename = () => randomBytes(8).toString("hex");

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const imgsDir = path.join(__dirname, "..", "..", "files");
fs.ensureDirSync(imgsDir);

const downloadFile = async (url: string) => {
  try {
    const response = await fetch(url);
    if (!response.ok) throw new Error(`Failed to fetch ${url}.`);
    const buffer = await response.buffer();
    const fileName = path.basename(url.split("?")[0]);
    const filePath = path.join(
      imgsDir,
      `${generateRandomFilename()}-${fileName}`
    );
    await fs.outputFile(filePath, buffer);
    parentPort?.postMessage(`Scraped ${url} to ${filePath}.`);
  } catch (error) {
    if (error instanceof Error) {
      parentPort?.postMessage(`Error scraping ${url}: ${error.message}.`);
    } else {
      parentPort?.postMessage(`Unknown error scraping ${url}.`);
    }
  }
};

const main = async () => {
  const { urlsChunk } = workerData as {
    urlsChunk: string[];
  };

  for (const url of urlsChunk) {
    await downloadFile(url);
  }
};

main();