/**
 * earth-now.co
 * Author:  Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * File:    infra/proxy.mjs
 * Purpose: Zero-dependency reverse proxy (nginx.conf equivalent) — routes /api,/v1,/sse,/badge to the API, the rest to web; SSE-safe (no buffering)
 */

import http from "node:http";

const PORT = Number(process.env.PROXY_PORT ?? 8080);
const API = { host: "127.0.0.1", port: Number(process.env.API_PORT ?? 4000) };
const WEB = { host: "127.0.0.1", port: Number(process.env.WEB_PORT ?? 4100) };

const API_PREFIXES = ["/api", "/v1", "/sse", "/badge"];

function targetFor(url) {
  return API_PREFIXES.some((p) => url === p || url.startsWith(`${p}/`) || url.startsWith(`${p}?`))
    ? API
    : WEB;
}

const server = http.createServer((req, res) => {
  const target = targetFor(req.url ?? "/");
  const upstream = http.request(
    {
      host: target.host,
      port: target.port,
      path: req.url,
      method: req.method,
      headers: { ...req.headers, host: req.headers.host ?? "www.earth-now.co" },
    },
    (up) => {
      res.writeHead(up.statusCode ?? 502, up.headers);
      // pipe() flushes chunks as they arrive — SSE streams pass through unbuffered.
      up.pipe(res);
    },
  );
  upstream.on("error", () => {
    if (!res.headersSent) res.writeHead(502, { "content-type": "application/json" });
    res.end(JSON.stringify({ error: "upstream unavailable" }));
  });
  req.pipe(upstream);
  // If the client disconnects (closed SSE tab), tear down the upstream leg too.
  res.on("close", () => upstream.destroy());
});

// Long-lived SSE connections: disable the default 5-minute socket timeout.
server.requestTimeout = 0;
server.headersTimeout = 60_000;

server.listen(PORT, "127.0.0.1", () => {
  console.log(`earth-now proxy on 127.0.0.1:${PORT} → api :${API.port}, web :${WEB.port}`);
});