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 { events: [] }; }
}
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, PUT, DELETE, OPTIONS");
  res.setHeader("Access-Control-Allow-Headers", "Content-Type");
  
  if (req.method === "OPTIONS") {
    res.writeHead(200);
    return res.end();
  }

  const urlPath = req.url.split("?")[0];
  const queryString = req.url.split("?")[1] || "";
  const query = new URLSearchParams(queryString);

  // API: GET /api/events
  if (req.method === "GET" && urlPath === "/api/events") {
    const tab = query.get("tab") || "biot";
    const data = readData();
    const events = data[tab + "Events"] || [];
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify(events));
  }

  // API: POST /api/events
  if (req.method === "POST" && urlPath === "/api/events") {
    const tab = query.get("tab") || "biot";
    console.log("POST /api/events tab:", tab);
    const data = readData();
    const event = await body(req);
    console.log("Event data:", event);
    event.id = Date.now();
    event.tab = tab;
    const arrayName = tab + "Events";
    if (!data[arrayName]) data[arrayName] = [];
    data[arrayName].push(event);
    console.log("Saving to:", arrayName, "Total:", data[arrayName].length);
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true, event }));
  }

  // API: PUT /api/events/:id
  if (req.method === "PUT" && urlPath.startsWith("/api/events/")) {
    const tab = query.get("tab") || "biot";
    const id = parseInt(urlPath.split("/")[3]);
    const data = readData();
    const events = data[tab + "Events"] || [];
    const idx = events.findIndex(e => e.id === id);
    if (idx !== -1) {
      events[idx] = { ...events[idx], ...await body(req) };
      data[tab + "Events"] = events;
      writeData(data);
      res.writeHead(200, { "Content-Type": "application/json" });
      return res.end(JSON.stringify({ ok: true }));
    }
    res.writeHead(404);
    return res.end(JSON.stringify({ error: "Не найдено" }));
  }

  // API: DELETE /api/events/:id
  if (req.method === "DELETE" && urlPath.startsWith("/api/events/")) {
    const tab = query.get("tab") || "biot";
    const id = parseInt(urlPath.split("/")[3]);
    const data = readData();
    data[tab + "Events"] = (data[tab + "Events"] || []).filter(e => e.id !== id);
    writeData(data);
    res.writeHead(200, { "Content-Type": "application/json" });
    return res.end(JSON.stringify({ ok: true }));
  }

  // Статика
  let file = urlPath === "/" ? "/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));