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

const { repoRoot } = require("./lib/meals");

const DEFAULT_HOST = "127.0.0.1";
const DEFAULT_PORT = 4321;
const MIME_TYPES = {
  ".css": "text/css; charset=utf-8",
  ".gif": "image/gif",
  ".html": "text/html; charset=utf-8",
  ".ico": "image/x-icon",
  ".jpg": "image/jpeg",
  ".js": "application/javascript; charset=utf-8",
  ".json": "application/json; charset=utf-8",
  ".map": "application/json; charset=utf-8",
  ".mp3": "audio/mpeg",
  ".png": "image/png",
  ".svg": "image/svg+xml",
  ".ttf": "font/ttf",
  ".txt": "text/plain; charset=utf-8",
  ".webmanifest": "application/manifest+json; charset=utf-8",
  ".woff": "font/woff",
  ".woff2": "font/woff2",
};

function parseArgs(argv) {
  const options = {
    host: process.env.HOST || DEFAULT_HOST,
    port: Number.parseInt(process.env.PORT || String(DEFAULT_PORT), 10),
  };

  for (let index = 0; index < argv.length; index += 1) {
    const arg = argv[index];
    const value = argv[index + 1];

    if (arg === "--host" && value) {
      options.host = value;
      index += 1;
      continue;
    }

    if (arg === "--port" && value) {
      options.port = Number.parseInt(value, 10);
      index += 1;
    }
  }

  if (!Number.isInteger(options.port) || options.port <= 0 || options.port > 65535) {
    throw new Error("Port must be an integer between 1 and 65535");
  }

  return options;
}

function getContentType(filePath) {
  return MIME_TYPES[path.extname(filePath).toLowerCase()] || "application/octet-stream";
}

function resolveRequestPath(requestUrl) {
  const url = new URL(requestUrl, "http://localhost");
  const pathname = decodeURIComponent(url.pathname);
  const requestedPath = pathname === "/" ? "/index.html" : pathname;
  const absolutePath = path.resolve(repoRoot, `.${requestedPath}`);
  const withinRepo =
    absolutePath === repoRoot || absolutePath.startsWith(`${repoRoot}${path.sep}`);

  if (!withinRepo) {
    return null;
  }

  if (fs.existsSync(absolutePath) && fs.statSync(absolutePath).isDirectory()) {
    return path.join(absolutePath, "index.html");
  }

  return absolutePath;
}

function sendFile(response, filePath) {
  const stream = fs.createReadStream(filePath);

  response.writeHead(200, {
    "Content-Type": getContentType(filePath),
    "Cache-Control": "no-cache",
  });

  stream.pipe(response);
  stream.on("error", () => {
    response.writeHead(500, { "Content-Type": "text/plain; charset=utf-8" });
    response.end("Failed to read file");
  });
}

function createServer() {
  return http.createServer((request, response) => {
    const filePath = resolveRequestPath(request.url || "/");

    if (!filePath) {
      response.writeHead(403, { "Content-Type": "text/plain; charset=utf-8" });
      response.end("Forbidden");
      return;
    }

    if (!fs.existsSync(filePath) || !fs.statSync(filePath).isFile()) {
      response.writeHead(404, { "Content-Type": "text/plain; charset=utf-8" });
      response.end("Not found");
      return;
    }

    sendFile(response, filePath);
  });
}

function main() {
  const options = parseArgs(process.argv.slice(2));
  const server = createServer();

  server.listen(options.port, options.host, () => {
    console.log(`Serving ${repoRoot} at http://${options.host}:${options.port}`);
  });
}

if (require.main === module) {
  try {
    main();
  } catch (error) {
    console.error(error.message);
    process.exitCode = 1;
  }
}