//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.spdy.generator;
  
  import java.nio.ByteBuffer;
  import java.security.cert.Certificate;
  import java.security.cert.CertificateEncodingException;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.eclipse.jetty.io.ByteBufferPool;
  import org.eclipse.jetty.spdy.SessionException;
  import org.eclipse.jetty.spdy.api.SessionStatus;
  import org.eclipse.jetty.spdy.frames.ControlFrame;
  import org.eclipse.jetty.spdy.frames.CredentialFrame;
  import org.eclipse.jetty.util.BufferUtil;
  
  public class CredentialGenerator extends ControlFrameGenerator
  {
      public CredentialGenerator(ByteBufferPool bufferPool)
      {
          super(bufferPool);
      }
  
      @Override
      public ByteBuffer generate(ControlFrame frame)
      {
          CredentialFrame credential = (CredentialFrame)frame;
  
          byte[] proof = credential.getProof();
  
          List<byte[]> certificates = serializeCertificates(credential.getCertificateChain());
          int certificatesLength = 0;
          for (byte[] certificate : certificates)
              certificatesLength += certificate.length;
  
          int frameBodyLength = 2 + 4 + proof.length + certificates.size() * 4 + certificatesLength;
  
          int totalLength = ControlFrame.HEADER_LENGTH + frameBodyLength;
          ByteBuffer buffer = getByteBufferPool().acquire(totalLength, Generator.useDirectBuffers);
          BufferUtil.clearToFill(buffer);
          generateControlFrameHeader(credential, frameBodyLength, buffer);
  
          buffer.putShort(credential.getSlot());
          buffer.putInt(proof.length);
          buffer.put(proof);
          for (byte[] certificate : certificates)
          {
              buffer.putInt(certificate.length);
              buffer.put(certificate);
          }
  
          buffer.flip();
          return buffer;
      }
  
      private List<byte[]> serializeCertificates(Certificate[] certificates)
      {
          try
          {
              List<byte[]> result = new ArrayList<>(certificates.length);
              for (Certificate certificate : certificates)
                  result.add(certificate.getEncoded());
              return result;
          }
          catch (CertificateEncodingException x)
          {
              throw new SessionException(SessionStatus.PROTOCOL_ERROR, x);
          }
      }
  }