/* Local dev server: serves ./site and proxies /ws to the relay, so the pages
   run same-origin exactly like they do behind nginx in production.

   Usage:
     OBSERVER_TOKEN=test cargo run            # in relay/, terminal 1
     node devserver.mjs                       # terminal 2 -> http://localhost:8080
   Env: PORT (default 8080), RELAY (default 127.0.0.1:8770). */

import { createServer } from "node:http";
import { connect } from "node:net";
import { readFile } from "node:fs/promises";
import { extname, join, normalize } from "node:path";
import { fileURLToPath } from "node:url";

const PORT = Number(process.env.PORT || 8080);
const [RELAY_HOST, RELAY_PORT] = (process.env.RELAY || "127.0.0.1:8770").split(":");
const SITE = join(fileURLToPath(new URL(".", import.meta.url)), "site");

const MIME = {
  ".html": "text/html; charset=utf-8",
  ".css": "text/css; charset=utf-8",
  ".js": "text/javascript; charset=utf-8",
  ".mp3": "audio/mpeg",
  ".wav": "audio/wav",
};

const server = createServer(async (req, res) => {
  let path = decodeURIComponent(req.url.split("?")[0]);
  if (path === "/") path = "/clock.html";
  if (path === "/control") path = "/control.html";

  // keep it inside SITE
  const file = join(SITE, normalize(path));
  if (!file.startsWith(SITE)) {
    res.writeHead(403).end("forbidden");
    return;
  }
  try {
    const body = await readFile(file);
    res.writeHead(200, { "content-type": MIME[extname(file)] || "application/octet-stream" });
    res.end(body);
  } catch {
    res.writeHead(404).end("not found");
  }
});

// Proxy the WebSocket upgrade straight through to the relay.
server.on("upgrade", (req, socket, head) => {
  const upstream = connect(Number(RELAY_PORT), RELAY_HOST, () => {
    const lines = [`${req.method} ${req.url} HTTP/1.1`];
    for (let i = 0; i < req.rawHeaders.length; i += 2) {
      lines.push(`${req.rawHeaders[i]}: ${req.rawHeaders[i + 1]}`);
    }
    upstream.write(lines.join("\r\n") + "\r\n\r\n");
    if (head && head.length) upstream.write(head);
    socket.pipe(upstream);
    upstream.pipe(socket);
  });
  const bail = () => socket.destroy();
  upstream.on("error", bail);
  socket.on("error", () => upstream.destroy());
});

server.listen(PORT, () => {
  console.log(`observer-effect dev server: http://localhost:${PORT}/  (control: /control)`);
  console.log(`proxying /ws -> ${RELAY_HOST}:${RELAY_PORT}`);
});