//
   //  ========================================================================
   //  Copyright (c) 1995-2014 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.websocket.jsr356;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import javax.websocket.Decoder;
  import javax.websocket.EndpointConfig;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.websocket.jsr356.metadata.DecoderMetadata;
  import org.eclipse.jetty.websocket.jsr356.metadata.DecoderMetadataSet;
  
  /**
   * Factory for {@link DecoderMetadata}
   * <p>
   * Relies on search order of parent {@link DecoderFactory} instances as such.
   * <ul>
   * <li>From Static DecoderMetadataSet (based on data in annotations and static EndpointConfig)</li>
   * <li>From Composite DecoderMetadataSet (based static and instance specific EndpointConfig)</li>
   * <li>Container declared DecoderMetadataSet (primitives)</li>
   * </ul>
   */
  public class DecoderFactory implements Configurable
  {
      public static class Wrapper implements Configurable
      {
          private final Decoder decoder;
          private final DecoderMetadata metadata;
  
          private Wrapper(Decoder decoder, DecoderMetadata metadata)
          {
              this.decoder = decoder;
              this.metadata = metadata;
          }
  
          public Decoder getDecoder()
          {
              return decoder;
          }
  
          public DecoderMetadata getMetadata()
          {
              return metadata;
          }
  
          @Override
          public void init(EndpointConfig config)
          {
              this.decoder.init(config);
          }
      }
  
      private static final Logger LOG = Log.getLogger(DecoderFactory.class);
  
      private final DecoderMetadataSet metadatas;
      private DecoderFactory parentFactory;
      private Map<Class<?>, Wrapper> activeWrappers;
  
      public DecoderFactory(DecoderMetadataSet metadatas)
      {
          this.metadatas = metadatas;
          this.activeWrappers = new ConcurrentHashMap<>();
      }
  
      public DecoderFactory(DecoderMetadataSet metadatas, DecoderFactory parentFactory)
      {
          this(metadatas);
          this.parentFactory = parentFactory;
      }
  
      public Decoder getDecoderFor(Class<?> type)
      {
          Wrapper wrapper = getWrapperFor(type);
          if (wrapper == null)
          {
              return null;
          }
          return wrapper.decoder;
      }
  
      public DecoderMetadata getMetadataFor(Class<?> type)
     {
         if (LOG.isDebugEnabled())
         {
             LOG.debug("getMetadataFor({})",type);
         }
         DecoderMetadata metadata = metadatas.getMetadataByType(type);
 
         if (metadata != null)
         {
             return metadata;
         }
 
         if (parentFactory != null)
         {
             return parentFactory.getMetadataFor(type);
         }
 
         return null;
     }
 
     public Wrapper getWrapperFor(Class<?> type)
     {
         synchronized (activeWrappers)
         {
             Wrapper wrapper = activeWrappers.get(type);
 
             // Try parent (if needed)
             if ((wrapper == null) && (parentFactory != null))
             {
                 wrapper = parentFactory.getWrapperFor(type);
             }
 
             if (wrapper == null)
             {
                 // Attempt to create Wrapper on demand
                 DecoderMetadata metadata = metadatas.getMetadataByType(type);
                 if (metadata == null)
                 {
                     return null;
                 }
                 wrapper = newWrapper(metadata);
                 // track wrapper
                 activeWrappers.put(type,wrapper);
             }
 
             return wrapper;
         }
     }
 
     @Override
     public void init(EndpointConfig config)
     {
         if (LOG.isDebugEnabled())
         {
             LOG.debug("init({})",config);
         }
         // Instantiate all declared decoders
         for (DecoderMetadata metadata : metadatas)
         {
             Wrapper wrapper = newWrapper(metadata);
             activeWrappers.put(metadata.getObjectType(),wrapper);
         }
 
         // Initialize all decoders
         for (Wrapper wrapper : activeWrappers.values())
         {
             wrapper.decoder.init(config);
         }
     }
 
     public Wrapper newWrapper(DecoderMetadata metadata)
     {
         Class<? extends Decoder> decoderClass = metadata.getCoderClass();
         try
         {
             Decoder decoder = decoderClass.newInstance();
             return new Wrapper(decoder,metadata);
         }
         catch (InstantiationException | IllegalAccessException e)
         {
             throw new IllegalStateException("Unable to instantiate Decoder: " + decoderClass.getName());
         }
     }
 }