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

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

let cachedData = null;

function loadData() {
  if (cachedData) return cachedData;
  try {
    const content = fs.readFileSync(DATA_FILE, "utf8");
    cachedData = JSON.parse(content);
    return cachedData;
  } catch (e) {
    console.error("Ошибка загрузки данных:", e.message);
    return [];
  }
}

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) => {
  if (req.method === "GET" && req.url === "/api/data") {
    const data = loadData();
    res.writeHead(200, { 
      "Content-Type": "application/json; charset=utf-8",
      "Access-Control-Allow-Origin": "*"
    });
    return res.end(JSON.stringify(data));
  }
  
  let file = req.url === "/" ? "/index.html" : req.url.split("?")[0];
  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" : ext === ".json" ? "application/json" : "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));