/*
    * Copyright 2017 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.ocsp;
  
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.handler.ssl.ReferenceCountedOpenSslContext;
  import io.netty.handler.ssl.ReferenceCountedOpenSslEngine;
  import io.netty.handler.ssl.SslHandshakeCompletionEvent;
  import io.netty.util.internal.ObjectUtil;
  import io.netty.util.internal.ThrowableUtil;
  import io.netty.util.internal.UnstableApi;
  
  import javax.net.ssl.SSLHandshakeException;
  
  /**
   * A handler for SSL clients to handle and act upon stapled OCSP responses.
   *
   * @see ReferenceCountedOpenSslContext#enableOcsp()
   * @see ReferenceCountedOpenSslEngine#getOcspResponse()
   */
  @UnstableApi
  public abstract class OcspClientHandler extends ChannelInboundHandlerAdapter {
  
      private static final SSLHandshakeException OCSP_VERIFICATION_EXCEPTION = ThrowableUtil.unknownStackTrace(
              new SSLHandshakeException("Bad OCSP response"), OcspClientHandler.class, "verify(...)");
  
      private final ReferenceCountedOpenSslEngine engine;
  
      protected OcspClientHandler(ReferenceCountedOpenSslEngine engine) {
          this.engine = ObjectUtil.checkNotNull(engine, "engine");
      }
  
      /**
       * @see ReferenceCountedOpenSslEngine#getOcspResponse()
       */
      protected abstract boolean verify(ChannelHandlerContext ctx, ReferenceCountedOpenSslEngine engine) throws Exception;
  
      @Override
      public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
          if (evt instanceof SslHandshakeCompletionEvent) {
              ctx.pipeline().remove(this);
  
              SslHandshakeCompletionEvent event = (SslHandshakeCompletionEvent) evt;
              if (event.isSuccess() && !verify(ctx, engine)) {
                  throw OCSP_VERIFICATION_EXCEPTION;
              }
          }
  
          ctx.fireUserEventTriggered(evt);
      }
  }