content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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 org.apache.camel.component.cometd;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Set;
  
  import org.apache.camel.CamelContext;
  import org.apache.camel.Exchange;
  import org.apache.camel.Message;
  import org.apache.camel.spi.Metadata;
  import org.apache.camel.support.DefaultMessage;
  import org.cometd.bayeux.server.ServerChannel;
  import org.cometd.bayeux.server.ServerMessage;
  import org.cometd.bayeux.server.ServerSession;
  import org.cometd.server.BayeuxServerImpl;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A Strategy used to convert between a Camel {@link Exchange} and to and from a Cometd messages
   */
  public class CometdBinding {
  
      public static final String HEADERS_FIELD = "CamelHeaders";
      @Metadata(description = "The clientId of the session", javaType = "String")
      public static final String COMETD_CLIENT_ID_HEADER_NAME = "CometdClientId";
      @Metadata(description = "The subscription", javaType = "String")
      public static final String COMETD_SUBSCRIPTION_HEADER_NAME = "subscription";
      public static final String COMETD_SESSION_ATTR_HEADER_NAME = "CometdSessionAttr";
  
      private static final Logger LOG = LoggerFactory.getLogger(CometdBinding.class);
  
      private final BayeuxServerImpl bayeux;
      private boolean enableSessionHeader;
  
      public CometdBinding(BayeuxServerImpl bayeux) {
          this(bayeux, false);
      }
  
      public CometdBinding(BayeuxServerImpl bayeux, boolean enableSessionHeader) {
          this.bayeux = bayeux;
          this.enableSessionHeader = enableSessionHeader;
      }
  
      public ServerMessage.Mutable createCometdMessage(ServerChannel channel, ServerSession serverSession, Message camelMessage) {
          ServerMessage.Mutable mutable = bayeux.newMessage();
          mutable.setChannel(channel.getId());
  
          if (serverSession != null) {
              mutable.setClientId(serverSession.getId());
          }
          addHeadersToMessage(mutable, camelMessage);
          mutable.setData(camelMessage.getBody());
          return mutable;
      }
  
      public Message createCamelMessage(
              CamelContext camelContext, ServerSession remote, ServerMessage cometdMessage, Object data) {
          if (cometdMessage != null) {
              data = cometdMessage.getData();
          }
  
          Message message = new DefaultMessage(camelContext);
          message.setBody(data);
          Map<String, Object> headers = getHeadersFromMessage(cometdMessage);
          if (headers != null) {
              message.setHeaders(headers);
          }
          message.setHeader(COMETD_CLIENT_ID_HEADER_NAME, remote.getId());
  
          if (cometdMessage != null && cometdMessage.get(COMETD_SUBSCRIPTION_HEADER_NAME) != null) {
              message.setHeader(COMETD_SUBSCRIPTION_HEADER_NAME, cometdMessage.get(COMETD_SUBSCRIPTION_HEADER_NAME));
          }
  
          if (enableSessionHeader) {
              addSessionAttributesToMessageHeaders(remote, message);
          }
  
          return message;
      }
  
      private void addSessionAttributesToMessageHeaders(ServerSession remote, Message message) {
          Set<String> attributeNames = remote.getAttributeNames();
          for (String attributeName : attributeNames) {
              Object attribute = remote.getAttribute(attributeName);
  
              if (attribute instanceof Integer || attribute instanceof String || attribute instanceof Long
                      || attribute instanceof Double || attribute instanceof Boolean) {
                  message.setHeader(attributeName, attribute);
              } else {
                  // Do we need to support other type of session objects ?
                  LOG.info(
                          "Session attribute {} has a value of {} which cannot be included as at header because it is not an int, string, or long.",
                          attributeName, attribute);
              }
  
          }
      }
  
      public void addHeadersToMessage(ServerMessage.Mutable cometdMessage, Message camelMessage) {
          if (camelMessage.hasHeaders()) {
              Map<String, Object> ext = cometdMessage.getExt(true);
              ext.put(HEADERS_FIELD, filterHeaders(camelMessage.getHeaders()));
          }
      }
  
      //TODO: do something in the style of JMS where they have header Strategies?
      private Object filterHeaders(Map<String, Object> headers) {
          Map<String, Object> map = new HashMap<>();
          for (Entry<String, Object> entry : headers.entrySet()) {
              if (entry != null && entry.getKey() != null) {
                  map.put(entry.getKey(), entry.getValue());
              }
          }
          return map;
      }
  
      @SuppressWarnings("unchecked")
      private Map<String, Object> getHeadersFromMessage(ServerMessage message) {
          Map<String, Object> ext = message.getExt();
          if (ext != null && ext.containsKey(HEADERS_FIELD)) {
              return (Map<String, Object>) ext.get(HEADERS_FIELD);
          } else {
              return null;
          }
      }
  
  }
  