server.js

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

const PORT = Number(process.env.PORT || 4173);
const HOST = process.env.HOST || "127.0.0.1";
const ROOT = __dirname;
const PUBLIC_DIR = path.join(ROOT, "public");
const LAYOUT_FILE = "uiAccessoriesLayout.json";
const LAYOUT_PATH = path.join(ROOT, LAYOUT_FILE);

const MIME_TYPES = {
  ".html": "text/html; charset=utf-8",
  ".css": "text/css; charset=utf-8",
  ".js": "application/javascript; charset=utf-8",
  ".json": "application/json; charset=utf-8",
  ".svg": "image/svg+xml"
};

function send(res, status, body, contentType = "text/plain; charset=utf-8") {
  res.writeHead(status, { "Content-Type": contentType });
  res.end(body);
}

async function readBody(req) {
  const chunks = [];
  for await (const chunk of req) {
    chunks.push(chunk);
  }
  return Buffer.concat(chunks).toString("utf8");
}

async function serveStatic(req, res) {
  const url = new URL(req.url, `http://${req.headers.host}`);
  const pathname = url.pathname === "/" ? "/index.html" : url.pathname;
  const decodedPath = decodeURIComponent(pathname);
  const filePath = path.normalize(path.join(PUBLIC_DIR, decodedPath));

  if (!filePath.startsWith(PUBLIC_DIR)) {
    send(res, 403, "Forbidden");
    return;
  }

  try {
    const file = await fs.readFile(filePath);
    send(res, 200, file, MIME_TYPES[path.extname(filePath)] || "application/octet-stream");
  } catch (error) {
    if (error.code === "ENOENT") {
      send(res, 404, "Not found");
      return;
    }
    send(res, 500, "Server error");
  }
}

async function handleApi(req, res) {
  if (req.url === "/api/layout" && req.method === "GET") {
    try {
      const layout = await fs.readFile(LAYOUT_PATH, "utf8");
      send(res, 200, layout, "application/json; charset=utf-8");
    } catch {
      send(res, 500, JSON.stringify({ error: `Could not read ${LAYOUT_FILE}` }), "application/json; charset=utf-8");
    }
    return;
  }

  if (req.url === "/api/layout" && req.method === "POST") {
    try {
      const body = await readBody(req);
      const parsed = JSON.parse(body);
      const users = Object.keys(parsed);

      if (users.length === 0 || !users.every((user) => Array.isArray(parsed[user]))) {
        send(res, 400, JSON.stringify({ error: "Invalid layout format" }), "application/json; charset=utf-8");
        return;
      }

      const stamp = new Date().toISOString().replace(/[:.]/g, "-");
      await fs.copyFile(LAYOUT_PATH, path.join(ROOT, `uiAccessoriesLayout.backup-${stamp}.json`));
      await fs.writeFile(LAYOUT_PATH, `${JSON.stringify(parsed, null, 4)}\n`, "utf8");
      send(res, 200, JSON.stringify({ ok: true }), "application/json; charset=utf-8");
    } catch (error) {
      const status = error instanceof SyntaxError ? 400 : 500;
      send(res, status, JSON.stringify({ error: `Could not save ${LAYOUT_FILE}` }), "application/json; charset=utf-8");
    }
    return;
  }

  send(res, 404, JSON.stringify({ error: "Not found" }), "application/json; charset=utf-8");
}

const server = http.createServer((req, res) => {
  if (req.url.startsWith("/api/")) {
    handleApi(req, res);
    return;
  }
  serveStatic(req, res);
});

server.on("error", (error) => {
  if (error.code === "EADDRINUSE") {
    console.error(`Port ${PORT} is already in use. Open http://${HOST}:${PORT} or start with another port:`);
    console.error("PORT=4174 npm start");
    process.exit(1);
  }

  console.error(error);
  process.exit(1);
});

server.listen(PORT, HOST, () => {
  console.log(`Homebridge layout editor: http://${HOST}:${PORT}`);
});