/*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  
  package io.netty.handler.ssl.util;
  
  import sun.security.x509.AlgorithmId;
  import sun.security.x509.CertificateAlgorithmId;
  import sun.security.x509.CertificateIssuerName;
  import sun.security.x509.CertificateSerialNumber;
  import sun.security.x509.CertificateSubjectName;
  import sun.security.x509.CertificateValidity;
  import sun.security.x509.CertificateVersion;
  import sun.security.x509.CertificateX509Key;
  import sun.security.x509.X500Name;
  import sun.security.x509.X509CertImpl;
  import sun.security.x509.X509CertInfo;
  
  import java.util.Date;
  import java.math.BigInteger;
  import java.security.KeyPair;
  import java.security.PrivateKey;
  import java.security.SecureRandom;
  import java.security.cert.CertificateException;
  
  import static io.netty.handler.ssl.util.SelfSignedCertificate.*;
  
  /**
   * Generates a self-signed certificate using {@code sun.security.x509} package provided by OpenJDK.
   */
  final class OpenJdkSelfSignedCertGenerator {
  
      static String[] generate(String fqdn, KeyPair keypair, SecureRandom random, Date notBefore, Date notAfter)
              throws Exception {
          PrivateKey key = keypair.getPrivate();
  
          // Prepare the information required for generating an X.509 certificate.
          X509CertInfo info = new X509CertInfo();
          X500Name owner = new X500Name("CN=" + fqdn);
          info.set(X509CertInfo.VERSION, new CertificateVersion(CertificateVersion.V3));
          info.set(X509CertInfo.SERIAL_NUMBER, new CertificateSerialNumber(new BigInteger(64, random)));
          try {
              info.set(X509CertInfo.SUBJECT, new CertificateSubjectName(owner));
          } catch (CertificateException ignore) {
              info.set(X509CertInfo.SUBJECT, owner);
          }
          try {
              info.set(X509CertInfo.ISSUER, new CertificateIssuerName(owner));
          } catch (CertificateException ignore) {
              info.set(X509CertInfo.ISSUER, owner);
          }
          info.set(X509CertInfo.VALIDITY, new CertificateValidity(notBefore, notAfter));
          info.set(X509CertInfo.KEY, new CertificateX509Key(keypair.getPublic()));
          info.set(X509CertInfo.ALGORITHM_ID,
                  new CertificateAlgorithmId(new AlgorithmId(AlgorithmId.sha256WithRSAEncryption_oid)));
  
          // Sign the cert to identify the algorithm that's used.
          X509CertImpl cert = new X509CertImpl(info);
          cert.sign(key, "SHA256withRSA");
  
          // Update the algorithm and sign again.
          info.set(CertificateAlgorithmId.NAME + '.' + CertificateAlgorithmId.ALGORITHM, cert.get(X509CertImpl.SIG_ALG));
          cert = new X509CertImpl(info);
          cert.sign(key, "SHA256withRSA");
          cert.verify(keypair.getPublic());
  
          return newSelfSignedCertificate(fqdn, key, cert);
      }
  
      private OpenJdkSelfSignedCertGenerator() { }
  }