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 { producers: [], products: [] }; }
}
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) => {
  // API: получить все данные
  if (req.method === "GET" && req.url === "/api/data") {
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify(readData()));
  }
  // API: добавить производителя
  if (req.method === "POST" && req.url === "/api/producers") {
    const p = await body(req);
    const data = readData();
    data.producers.push({ id: Date.now(), ...p });
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true }));
  }
  // API: добавить товар с ценой
  if (req.method === "POST" && req.url === "/api/products") {
    const prod = await body(req);
    const data = readData();
    data.products.push({ id: Date.now(), ...prod });
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true }));
  }
  // API: удалить производителя
  if (req.method === "DELETE" && req.url.startsWith("/api/producers/")) {
    const id = parseInt(req.url.split("/")[3]);
    const data = readData();
    data.producers = data.producers.filter(p => p.id !== id);
    data.products = data.products.filter(pr => pr.producerId !== id);
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true }));
  }
  // API: удалить товар
  if (req.method === "DELETE" && req.url.startsWith("/api/products/")) {
    const id = parseInt(req.url.split("/")[3]);
    const data = readData();
    data.products = data.products.filter(p => p.id !== id);
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true }));
  }
  // Статика
  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" : "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));