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 readData() {
  try { return JSON.parse(fs.readFileSync(DATA, "utf8")); } catch (_) { return { products: [], orders: [] }; }
}
function writeData(data) {
  fs.writeFileSync(DATA, JSON.stringify(data, 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) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
  res.setHeader("Access-Control-Allow-Headers", "Content-Type");
  
  if (req.method === "OPTIONS") {
    res.writeHead(200);
    return res.end();
  }

  const url = req.url.split("?")[0];

  // API: получить товары
  if (req.method === "GET" && url === "/api/products") {
    const data = readData();
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify(data.products));
  }

  // API: добавить заказ
  if (req.method === "POST" && url === "/api/orders") {
    const order = await body(req);
    const data = readData();
    order.id = Date.now();
    order.createdAt = new Date().toISOString();
    order.status = "new";
    data.orders.push(order);
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true, orderId: order.id }));
  }

  // API: получить заказы
  if (req.method === "GET" && url === "/api/orders") {
    const data = readData();
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify(data.orders));
  }

  // Статика
  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);
    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 на порту " + PORT));