/**
 * Multi-request CSV sink that listens on 0.0.0.0:8765 and accepts
 * POST requests, writing each one to the configured path
 * (overwriting on each call). Stays up across multiple requests.
 *
 * Usage:
 *   node scripts/_csv-sink.ts <out-path> [port]
 */
import { createServer } from "node:http";
import { writeFileSync } from "node:fs";

const OUT_PATH = process.argv[2];
const PORT = Number(process.argv[3] ?? 8765);
if (!OUT_PATH) {
  console.error("Usage: tsx _csv-sink.ts <out-path> [port]");
  process.exit(1);
}

let count = 0;

const server = createServer((req, res) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Headers", "*");
  res.setHeader("Access-Control-Allow-Methods", "POST, OPTIONS");
  if (req.method === "OPTIONS") {
    res.writeHead(204);
    res.end();
    return;
  }
  if (req.method !== "POST") {
    res.writeHead(405);
    res.end("POST only");
    return;
  }
  const chunks: Buffer[] = [];
  req.on("data", (c: Buffer) => chunks.push(c));
  req.on("end", () => {
    const buf = Buffer.concat(chunks);
    writeFileSync(OUT_PATH, buf);
    count++;
    console.log(`#${count} wrote ${buf.length} bytes to ${OUT_PATH}`);
    res.writeHead(200, { "content-type": "text/plain" });
    res.end("ok");
    // Note: intentionally NOT closing the server — it stays up for
    // multiple requests.
  });
});

server.listen(PORT, "0.0.0.0", () => {
  console.log(`csv-sink (persistent) listening on 0.0.0.0:${PORT} → ${OUT_PATH}`);
});