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({}); } });
  });
}

http.createServer(async (req, res) => {
  const urlPath = req.url.split("?")[0];
  
  if (req.method === "GET" && urlPath === "/api/registrations") {
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify(readItems()));
  }
  
  if (req.method === "POST" && urlPath === "/api/registrations") {
    const item = await body(req);
    const items = readItems();
    const newItem = {
      id: Date.now(),
      firstName: item.firstName || "",
      lastName: item.lastName || "",
      phone: item.phone || "",
      telegram: item.telegram || "",
      registeredAt: new Date().toISOString()
    };
    items.push(newItem);
    writeItems(items);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true, data: newItem }));
  }
  
  if (req.method === "GET" && urlPath === "/api/stats") {
    const items = readItems();
    const today = new Date().toDateString();
    const todayCount = items.filter(p => new Date(p.registeredAt).toDateString() === today).length;
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ total: items.length, today: todayCount }));
  }
  
  let file = req.url === "/" ? "/index.html" : urlPath;
  const full = path.join(__dirname, file);
  if (full.startsWith(__dirname) && fs.existsSync(full) && fs.statSync(full).isFile()) {
    const ext = path.extname(full);
    const type = ext === ".css" ? "text/css" : ext === ".js" ? "application/javascript" : "text/html";
    res.writeHead(200, { "Content-Type": type + "; charset=utf-8" });
    return res.end(fs.readFileSync(full));
  }
  
  res.writeHead(404); res.end("Not found");
}).listen(PORT, () => console.log("Сервер запущен на порту " + PORT));