// front.ts: one public front door on port 8000 for the vals that ask for it.
// A val with PUBLIC=1 and a PORT in its .env is served at
//   https://<vm>.exe.xyz/<val>/...   (the prefix is removed), and at
//   https://<each host in its HOSTS>/...   (custom domains, comma-separated).
// Vals without PUBLIC=1 are never reachable here, only on their own,
// private port. WebSockets are not passed through.
const VALS = `${Deno.env.get("HOME")}/vals`;
type Route = { val: string; port: number; hosts: string[] };
let routes: Route[] = [], loaded = 0;

async function load() {
  if (Date.now() - loaded < 5000) return routes;
  const next: Route[] = [];
  for await (const d of Deno.readDir(VALS)) {
    if (!d.isDirectory || d.name.startsWith(".")) continue;
    let env = "";
    try {
      env = await Deno.readTextFile(`${VALS}/${d.name}/.env`);
    } catch { continue; }
    const get = (k: string) => env.match(new RegExp(`^${k}=(.*)$`, "m"))?.[1].trim();
    if (get("PUBLIC") !== "1" || !get("PORT")) continue;
    const hosts = (get("HOSTS") ?? "").split(",").map((h) => h.trim().toLowerCase()).filter(Boolean);
    next.push({ val: d.name, port: Number(get("PORT")), hosts });
  }
  routes = next;
  loaded = Date.now();
  return routes;
}

Deno.serve({ port: Number(Deno.env.get("PORT") ?? 8000) }, async (req) => {
  const url = new URL(req.url);
  const host = (req.headers.get("x-forwarded-host") ?? req.headers.get("host") ?? "")
    .replace(/:\d+$/, "").toLowerCase();
  const all = await load();
  let route = all.find((r) => r.hosts.includes(host));
  let path = url.pathname, prefix = "";
  if (!route) {
    const first = path.split("/")[1];
    route = all.find((r) => r.val === first);
    if (!route) return new Response("Not found\n", { status: 404 });
    prefix = `/${first}`;
    path = path.slice(prefix.length) || "/";
  }
  const headers = new Headers(req.headers);
  headers.set("accept-encoding", "identity");
  if (prefix) headers.set("x-forwarded-prefix", prefix);
  try {
    return await fetch(`http://127.0.0.1:${route.port}${path}${url.search}`, {
      method: req.method,
      headers,
      body: req.body,
      redirect: "manual",
    });
  } catch {
    return new Response(`${route.val} is not running\n`, { status: 502 });
  }
});