// Copyright 2016-2018 AJ ONeal. All rights reserved
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
'use strict';

var oldver = false;

module.exports = function (bitlen, exp) {
  bitlen = parseInt(bitlen, 10) || 2048;
  exp = parseInt(exp, 10) || 65537;

  try {
    return require('./generate-privkey-node.js')(bitlen, exp);
  } catch(e) {
    if (!/generateKeyPairSync is not a function/.test(e.message)) {
      throw e;
    }
    try {
      return require('./generate-privkey-ursa.js')(bitlen, exp);
    } catch(e) {
      if (e.code !== 'MODULE_NOT_FOUND') {
        console.error("[rsa-compat] Unexpected error when using 'ursa':");
        console.error(e);
      }
      if (!oldver) {
        oldver = true;
        console.warn("[WARN] rsa-compat: Your version of node does not have crypto.generateKeyPair()");
        console.warn("[WARN] rsa-compat: Please update to node >= v10.12 or 'npm install --save ursa node-forge'");
        console.warn("[WARN] rsa-compat: Using node-forge as a fallback may be unacceptably slow.");
        if (/arm|mips/i.test(require('os').arch)) {
          console.warn("================================================================");
          console.warn("                         WARNING");
          console.warn("================================================================");
          console.warn("");
          console.warn("WARNING: You are generating an RSA key using pure JavaScript on");
          console.warn("         a VERY SLOW cpu. This could take DOZENS of minutes!");
          console.warn("");
          console.warn("         We recommend installing node >= v10.12, or 'gcc' and 'ursa'");
          console.warn("");
          console.warn("EXAMPLE:");
          console.warn("");
          console.warn("        sudo apt-get install build-essential && npm install ursa");
          console.warn("");
          console.warn("================================================================");
        }
      }
      try {
        return require('./generate-privkey-forge.js')(bitlen, exp);
      } catch(e) {
        if (e.code !== 'MODULE_NOT_FOUND') {
          throw e;
        }
        console.error("[ERROR] rsa-compat: could not generate a private key.");
        console.error("None of crypto.generateKeyPair, ursa, nor node-forge are present");
      }
    }
  }
};

if (require.main === module) {
  var keypair = module.exports(2048, 0x10001);
  console.info(keypair.privateKeyPem);
}