const http = require("http");

const jose = require("jose");

const LIB_ID = "panva";

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

async function importKey(keyMaterial, algs) {

  if (typeof keyMaterial === "string" && keyMaterial.includes("BEGIN")) {

    const asymAlgs = algs.filter((a) => /^(RS|PS|ES|Ed)/.test(a));

    const tryAlg = asymAlgs[0] || algs[0];

    return await jose

      .importSPKI(keyMaterial, tryAlg)

      .catch(async () => jose.importX509(keyMaterial, tryAlg));

  }

  if (typeof keyMaterial === "object" && keyMaterial !== null) {

    const alg = algs[0];

    return await jose.importJWK(keyMaterial, alg);

  }

  return new TextEncoder().encode(keyMaterial);

}

async function verdict(payload) {

  const { token, key, algs } = payload;

  try {

    const k = await importKey(key, algs);

    const { payload: claims } = await jose.jwtVerify(token, k, {

      algorithms: algs,

    });

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

  } catch (e) {

    return {

      valid: false,

      claims: null,

      error: `${e.code || 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", async () => {

    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 = await verdict(payload);

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

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

  });

});

server.listen(7004, "0.0.0.0", () => {

  console.error(`[${LIB_ID} ${LIB_VERSION}] listening :7004`);

});