const http = require("http");

const jwt = require("jsonwebtoken");

const LIB_ID = "nodejwt";

const LIB_VERSION = require("jsonwebtoken/package.json").version;

function verdict(payload) {

  const { token, key, algs } = payload;

  try {

    const claims = jwt.verify(token, key, { algorithms: algs });

    return { valid: true, claims, error: null, lib: LIB_ID, version: LIB_VERSION };

  } catch (e) {

    return {

      valid: false,

      claims: null,

      error: `${e.name}: ${e.message}`,

      lib: LIB_ID,

      version: LIB_VERSION,

    };

  }

}

const server = http.createServer((req, res) => {

  if (req.method !== "POST" || req.url !== "/verify") {

    res.writeHead(404);

    return res.end();

  }

  let body = "";

  req.on("data", (c) => (body += c));

  req.on("end", () => {

    let payload;

    try {

      payload = JSON.parse(body);

    } catch {

      res.writeHead(400, { "Content-Type": "application/json" });

      return res.end(JSON.stringify({ error: "bad json" }));

    }

    const out = verdict(payload);

    res.writeHead(200, { "Content-Type": "application/json" });

    res.end(JSON.stringify(out));

  });

});

server.listen(7001, "0.0.0.0", () => {

  console.error(`[${LIB_ID} ${LIB_VERSION}] listening :7001`);

});