/*
    * 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:
    *
    *   https://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;
  
  import io.netty.handler.ssl.JdkApplicationProtocolNegotiator.ProtocolSelectionListener;
  import io.netty.handler.ssl.JdkApplicationProtocolNegotiator.ProtocolSelector;
  import io.netty.util.internal.PlatformDependent;
  import org.eclipse.jetty.alpn.ALPN;
  
  import java.util.LinkedHashSet;
  import java.util.List;
  import javax.net.ssl.SSLEngine;
  import javax.net.ssl.SSLException;
  
  import static io.netty.handler.ssl.SslUtils.toSSLHandshakeException;
  import static io.netty.util.internal.ObjectUtil.checkNotNull;
  
  abstract class JettyAlpnSslEngine extends JdkSslEngine {
      private static final boolean available = initAvailable();
  
      static boolean isAvailable() {
          return available;
      }
  
      private static boolean initAvailable() {
          if (PlatformDependent.javaVersion() == 8) {
              try {
                  // Always use bootstrap class loader.
                  Class.forName("sun.security.ssl.ALPNExtension", true, null);
                  return true;
              } catch (Throwable ignore) {
                  // alpn-boot was not loaded.
              }
          }
          return false;
      }
  
      static JettyAlpnSslEngine newClientEngine(SSLEngine engine,
              JdkApplicationProtocolNegotiator applicationNegotiator) {
          return new ClientEngine(engine, applicationNegotiator);
      }
  
      static JettyAlpnSslEngine newServerEngine(SSLEngine engine,
              JdkApplicationProtocolNegotiator applicationNegotiator) {
          return new ServerEngine(engine, applicationNegotiator);
      }
  
      private JettyAlpnSslEngine(SSLEngine engine) {
          super(engine);
      }
  
      private static final class ClientEngine extends JettyAlpnSslEngine {
          ClientEngine(SSLEngine engine, final JdkApplicationProtocolNegotiator applicationNegotiator) {
              super(engine);
              checkNotNull(applicationNegotiator, "applicationNegotiator");
              final ProtocolSelectionListener protocolListener = checkNotNull(applicationNegotiator
                              .protocolListenerFactory().newListener(this, applicationNegotiator.protocols()),
                      "protocolListener");
              ALPN.put(engine, new ALPN.ClientProvider() {
                  @Override
                  public List<String> protocols() {
                      return applicationNegotiator.protocols();
                  }
  
                  @Override
                  public void selected(String protocol) throws SSLException {
                      try {
                          protocolListener.selected(protocol);
                      } catch (Throwable t) {
                          throw toSSLHandshakeException(t);
                      }
                  }
  
                  @Override
                  public void unsupported() {
                      protocolListener.unsupported();
                  }
              });
          }
  
          @Override
          public void closeInbound() throws SSLException {
              try {
                  ALPN.remove(getWrappedEngine());
              } finally {
                  super.closeInbound();
             }
         }
 
         @Override
         public void closeOutbound() {
             try {
                 ALPN.remove(getWrappedEngine());
             } finally {
                 super.closeOutbound();
             }
         }
     }
 
     private static final class ServerEngine extends JettyAlpnSslEngine {
         ServerEngine(SSLEngine engine, final JdkApplicationProtocolNegotiator applicationNegotiator) {
             super(engine);
             checkNotNull(applicationNegotiator, "applicationNegotiator");
             final ProtocolSelector protocolSelector = checkNotNull(applicationNegotiator.protocolSelectorFactory()
                             .newSelector(this, new LinkedHashSet<String>(applicationNegotiator.protocols())),
                     "protocolSelector");
             ALPN.put(engine, new ALPN.ServerProvider() {
                 @Override
                 public String select(List<String> protocols) throws SSLException {
                     try {
                         return protocolSelector.select(protocols);
                     } catch (Throwable t) {
                         throw toSSLHandshakeException(t);
                     }
                 }
 
                 @Override
                 public void unsupported() {
                     protocolSelector.unsupported();
                 }
             });
         }
 
         @Override
         public void closeInbound() throws SSLException {
             try {
                 ALPN.remove(getWrappedEngine());
             } finally {
                 super.closeInbound();
             }
         }
 
         @Override
         public void closeOutbound() {
             try {
                 ALPN.remove(getWrappedEngine());
             } finally {
                 super.closeOutbound();
             }
         }
     }
 }