const http = require("http");
const { readFile, stat } = require("fs");
const { extname, join, normalize } = require("path");

const port = process.env.PORT || 3000;
const public_dir = join(__dirname, "public");
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",
  ".woff": "font/woff",
  ".woff2": "font/woff2",
  ".ttf": "font/ttf",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".ico": "image/x-icon"
};

const safe_path = (url_path) => {
  if (!url_path || url_path === "/") return join(public_dir, "index.html");
  const cleaned = normalize(url_path).replace(/^(\.\.([/\\]|$))+/, "");
  return join(public_dir, cleaned);
};

const send = (file_path, res) => {
  readFile(file_path, (err, data) => {
    if (err?.code === "ENOENT") {
      res.writeHead(404, { "Content-Type": "text/plain; charset=UTF-8" });
      res.end("404 not found");
      return;
    }
    if (err) {
      res.writeHead(500, { "Content-Type": "text/plain; charset=UTF-8" });
      res.end("500 internal server error");
      return;
    }
    const type = mime_types[extname(file_path).toLowerCase()] || "application/octet-stream";
    res.writeHead(200, { "Content-Type": type });
    res.end(data);
  });
};

http
  .createServer((req, res) => {
    const file_path = safe_path((req.url || "/").split("?")[0]);
    stat(file_path, (err, info) => send(!err && info.isDirectory() ? join(file_path, "index.html") : file_path, res));
  })
  .listen(port, () => {
    console.log(`web running at http://localhost:${port}`);
  });