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 EMPTY; }
}
function writeData(data) {
  fs.writeFileSync(DATA, JSON.stringify(data, null, 2));
}

const EMPTY = {
  amal: {
    school: [
      { day: "Понедельник", items: ["Математика", "Русский язык", "Литература", "Физкультура"] },
      { day: "Вторник", items: ["Математика", "Казахский язык", "История", "Английский"] },
      { day: "Среда", items: ["Русский язык", "Литература", "Биология", "Физкультура"] },
      { day: "Четверг", items: ["Математика", "История", "География", "Труд"] },
      { day: "Пятница", items: ["Русский язык", "Английский", "ИЗО", "Классный час"] }
    ],
    clubs: [
      { day: "Понедельник", name: "Балет", time: "17:00" },
      { day: "Среда", name: "Балет", time: "17:00" },
      { day: "Пятница", name: "Домбра", time: "16:00" }
    ]
  },
  amre: {
    school: [
      { day: "Понедельник", items: ["Математика", "Русский язык", "Литература", "Физкультура"] },
      { day: "Вторник", items: ["Математика", "Казахский язык", "История", "Английский"] },
      { day: "Среда", items: ["Русский язык", "Литература", "Биология", "Физкультура"] },
      { day: "Четверг", items: ["Математика", "История", "География", "Труд"] },
      { day: "Пятница", items: ["Русский язык", "Английский", "ИЗО", "Классный час"] }
    ],
    clubs: [
      { day: "Вторник", name: "Шахматы", time: "17:00" },
      { day: "Четверг", name: "Шахматы", time: "17:00" },
      { day: "Пятница", name: "Домбра", time: "16:00" }
    ]
  },
  items: {
    school: ["Дневник", "Тетради", "Ручки", "Карандаши", "Линейка", "Ластик", "Пенал"],
    ballet: ["Купальник", "Колготки", "Чешки", "Пачка", "Заколки", "Вода"],
    chess: ["Шахматные часы", "Блокнот", "Ручка"],
    dombra: ["Домбра", "Ноты", "Медиатор"]
  }
};

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();
  }

  if (req.method === "GET" && req.url === "/api/data") {
    res.writeHead(200, { "Content-Type": "application/json; charset=utf-8" });
    return res.end(JSON.stringify(readData()));
  }
  
  if (req.method === "POST" && req.url === "/api/data") {
    const data = await body(req);
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json; charset=utf-8" });
    return res.end(JSON.stringify({ ok: true }));
  }

  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));