/*
    * 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;
  
  import io.netty.util.internal.ObjectUtil;
  import io.netty.internal.tcnative.SSL;
  import io.netty.internal.tcnative.SSLContext;
  import io.netty.internal.tcnative.SessionTicketKey;
  
  import javax.net.ssl.SSLSession;
  import javax.net.ssl.SSLSessionContext;
  import java.util.Arrays;
  import java.util.Enumeration;
  import java.util.NoSuchElementException;
  import java.util.concurrent.locks.Lock;
  
  /**
   * OpenSSL specific {@link SSLSessionContext} implementation.
   */
  public abstract class OpenSslSessionContext implements SSLSessionContext {
      private static final Enumeration<byte[]> EMPTY = new EmptyEnumeration();
  
      private final OpenSslSessionStats stats;
      final ReferenceCountedOpenSslContext context;
  
      // IMPORTANT: We take the OpenSslContext and not just the long (which points the native instance) to prevent
      //            the GC to collect OpenSslContext as this would also free the pointer and so could result in a
      //            segfault when the user calls any of the methods here that try to pass the pointer down to the native
      //            level.
      OpenSslSessionContext(ReferenceCountedOpenSslContext context) {
          this.context = context;
          stats = new OpenSslSessionStats(context);
      }
  
      @Override
      public SSLSession getSession(byte[] bytes) {
          if (bytes == null) {
              throw new NullPointerException("bytes");
          }
          return null;
      }
  
      @Override
      public Enumeration<byte[]> getIds() {
          return EMPTY;
      }
  
      /**
       * Sets the SSL session ticket keys of this context.
       * @deprecated use {@link #setTicketKeys(OpenSslSessionTicketKey...)}.
       */
      @Deprecated
      public void setTicketKeys(byte[] keys) {
          if (keys.length % SessionTicketKey.TICKET_KEY_SIZE != 0) {
              throw new IllegalArgumentException("keys.length % " + SessionTicketKey.TICKET_KEY_SIZE  + " != 0");
          }
          SessionTicketKey[] tickets = new SessionTicketKey[keys.length / SessionTicketKey.TICKET_KEY_SIZE];
          for (int i = 0, a = 0; i < tickets.length; i++) {
              byte[] name = Arrays.copyOfRange(keys, a, SessionTicketKey.NAME_SIZE);
              a += SessionTicketKey.NAME_SIZE;
              byte[] hmacKey = Arrays.copyOfRange(keys, a, SessionTicketKey.HMAC_KEY_SIZE);
              i += SessionTicketKey.HMAC_KEY_SIZE;
              byte[] aesKey = Arrays.copyOfRange(keys, a, SessionTicketKey.AES_KEY_SIZE);
              a += SessionTicketKey.AES_KEY_SIZE;
              tickets[i] = new SessionTicketKey(name, hmacKey, aesKey);
          }
          Lock writerLock = context.ctxLock.writeLock();
          writerLock.lock();
          try {
              SSLContext.clearOptions(context.ctx, SSL.SSL_OP_NO_TICKET);
              SSLContext.setSessionTicketKeys(context.ctx, tickets);
          } finally {
              writerLock.unlock();
          }
      }
  
      /**
       * Sets the SSL session ticket keys of this context.
       */
      public void setTicketKeys(OpenSslSessionTicketKey... keys) {
          ObjectUtil.checkNotNull(keys, "keys");
          SessionTicketKey[] ticketKeys = new SessionTicketKey[keys.length];
          for (int i = 0; i < ticketKeys.length; i++) {
              ticketKeys[i] = keys[i].key;
          }
          Lock writerLock = context.ctxLock.writeLock();
         writerLock.lock();
         try {
             SSLContext.clearOptions(context.ctx, SSL.SSL_OP_NO_TICKET);
             SSLContext.setSessionTicketKeys(context.ctx, ticketKeys);
         } finally {
             writerLock.unlock();
         }
     }
 
     /**
      * Enable or disable caching of SSL sessions.
      */
     public abstract void setSessionCacheEnabled(boolean enabled);
 
     /**
      * Return {@code true} if caching of SSL sessions is enabled, {@code false} otherwise.
      */
     public abstract boolean isSessionCacheEnabled();
 
     /**
      * Returns the stats of this context.
      */
     public OpenSslSessionStats stats() {
         return stats;
     }
 
     private static final class EmptyEnumeration implements Enumeration<byte[]> {
         @Override
         public boolean hasMoreElements() {
             return false;
         }
 
         @Override
         public byte[] nextElement() {
             throw new NoSuchElementException();
         }
     }
 }