// mkdir myproj
// cd myproj
// npm init
// npm install node-opcua
// => copy this file
// node --inspect-brk  test_server.js

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

const {
  OPCUAServer,
  OPCUAClient,
  OPCUACertificateManager,
  MessageSecurityMode,
  SecurityPolicy,
} = require("node-opcua");

const certificateFolder = path.join(__dirname, "certificates");
const PKIFolder = path.join(certificateFolder, "PKI");
const serverCertificate = path.join(certificateFolder, "server_certificate.pem");
const port = 4840;

const os = require('os');

function findMyIpAddresses() {

  const ipAddresses = [];
  const ifaces = os.networkInterfaces();
  for (let ifname of Object.keys(ifaces)) {
    const networkInterface = ifaces[ifname];
    for (let iface of networkInterface) {

      if ('IPv4' !== iface.family || iface.internal !== false) {
        // skip over internal (i.e. 127.0.0.1) and non-ipv4 addresses
        continue;
      }

      ipAddresses.push(iface.address);
    }
  }
  return ipAddresses;
}

const ipAddresses = findMyIpAddresses();

console.log(" My ipaddresses are ", ipAddresses.join(" "));

async function clientGetEndpoint(ipAddress) {
  const client = OPCUAClient.create({
    endpoint_must_exist: false,
  });
  client.on("backoff", () => {
    console.log("Cannot connect to ", ipAddress, "please check your settings");
  });

  await client.connect("opc.tcp://" + ipAddress + ":" + port);
  const e = await client.getEndpoints();

  console.log(e.toString());

  await client.disconnect();

}


async function fileExists(path) {
  return await new Promise((resolve, reject) =>
    fs.access(path, fs.constants.F_OK, (err) => resolve(!err))
  );
}
async function folderExists(path) {
  return await new Promise((resolve, reject) =>
    fs.access(path, fs.constants.F_OK, (err) => resolve(!err))
  );
}

async function exec(cmd) {
  console.log("Executing ", cmd);
  const promise = new Promise((resolve, reject) => {
    const child = child_process.exec(cmd, function(err) {
    });
    child.stdout.pipe(process.stdout);
    child.on("close", function(code) {
      console.log("done ... (" + code + ")");
      if (code == 0) {
        resolve();
      } else {
        reject(new Error("command ended with code " + code));
      }
    });
  });
  await promise;
}

const applicationUri = "urn:HelloWorldThisIsMyServer";

async function createSelfSignedCertificate(ipAddresses, serverCertificate) {


  const args = [
    "node", "node_modules/node-opcua-pki/bin/crypto_create_CA.js",
    // command
    "certificate",
    // arguments
    "-s", "-o", serverCertificate,
    "--ip", ipAddresses.join(","),
    "-a", applicationUri
  ];
  await exec(args.join(" "));
}
async function createServerCertificate() {

  const certificateFolderExists = await fileExists(certificateFolder);
  const serverCertificateExist = await fileExists(serverCertificate);
  if (!certificateFolderExists || !serverCertificateExist) {

    await createSelfSignedCertificate(ipAddresses, serverCertificate);
    console.log(" serverCertificate ", serverCertificate, "created");
  }
}

(async () => {

  try {

    await createServerCertificate();

    const serverCertificateManager = new OPCUACertificateManager({
      automaticallyAcceptUnknownCertificate: true,
      rootFolder: PKIFolder,
      name: "pki"
    });

    const server = new OPCUAServer({
      port,
      allowAnonymous: true,
      alternateHostname: ipAddresses,
      serverInfo: {
        applicationName: { text: "Mini NodeOPCUA Server", locale: "en" },
        applicationUri,
        productUri: "Mini NodeOPCUA-Server"
      },
      serverCertificateManager,
      certificateFile: serverCertificate,
      privateKeyFile: serverCertificateManager.privateKey,
      securityModes: [MessageSecurityMode.None],
      securityPolicies: [SecurityPolicy.None]

    });
    await server.initialize();
    await server.start();

    await clientGetEndpoint(ipAddresses[0]);

    console.log("server certificate = ", server.certificateFile);
    console.log("server key file    = ", server.privateKeyFile);


    const endpointUrl = server.endpoints[0].endpointDescriptions()[0].endpointUrl;
    console.log(" server is ready on ", endpointUrl);
    console.log("CTRL+C to stop");


    await exec(["openssl", "x509", "-in", serverCertificate, "-text"].join(" "));

    let stopped = false;
    process.on("SIGINT", async () => {
      if (stopped) return;
      console.log("shutting down ...")
      stopped = true;
      await server.shutdown();
      console.log("... done..");
    });
  }
  catch (err) {
    console.log("err = ", err.message);
    console.log(err);
    process.exit(-1);
  }
})();