const http = require("http");
const fs = require("fs");
const path = require("path");

const PORT = process.env.PORT || 3000;
const DATA = path.join(__dirname, "data.json");

function readItems() {
  try { return JSON.parse(fs.readFileSync(DATA, "utf8")); } catch (_) { return []; }
}
function writeItems(items) {
  fs.writeFileSync(DATA, JSON.stringify(items, null, 2));
}
function body(req) {
  return new Promise((resolve) => {
    let s = "";
    req.on("data", (c) => (s += c));
    req.on("end", () => { try { resolve(JSON.parse(s || "{}")); } catch (_) { resolve({}); } });
  });
}

const TYPES = {
  ".html": "text/html", ".css": "text/css", ".js": "application/javascript",
  ".json": "application/json", ".svg": "image/svg+xml", ".png": "image/png",
  ".ico": "image/x-icon", ".woff2": "font/woff2"
};

http.createServer(async (req, res) => {
  const url = req.url.split("?")[0];

  if (req.method === "GET" && url === "/api/registrations") {
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify(readItems()));
  }

  if (req.method === "POST" && url === "/api/register") {
    const item = await body(req);
    if (!item.fio || !item.email || !item.phone || !item.city || !item.track || !item.role || !item.experience) {
      res.writeHead(400, { "Content-Type": "application/json" });
      return res.end(JSON.stringify({ ok: false, error: "Заполнены не все обязательные поля" }));
    }
    const items = readItems();
    if (items.some(i => i.email.toLowerCase() === item.email.toLowerCase())) {
      res.writeHead(409, { "Content-Type": "application/json" });
      return res.end(JSON.stringify({ ok: false, error: "На этот email заявка уже отправлена" }));
    }
    items.push({
      id: Date.now(),
      fio: item.fio, email: item.email, phone: item.phone, city: item.city,
      track: item.track, role: item.role, team: item.team || "",
      experience: item.experience, createdAt: new Date().toISOString()
    });
    writeItems(items);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true }));
  }

  let file = url === "/" ? "/index.html" : url;
  const full = path.join(__dirname, file);
  if (full.startsWith(__dirname) && fs.existsSync(full) && fs.statSync(full).isFile()) {
    const ext = path.extname(full).toLowerCase();
    const type = TYPES[ext] || "application/octet-stream";
    res.writeHead(200, { "Content-Type": type + (ext === ".woff2" ? "" : "; charset=utf-8") });
    return res.end(fs.readFileSync(full));
  }
  res.writeHead(404); res.end("Not found");
}).listen(PORT, () => console.log("Сервер на порту " + PORT));