package org.apache.helix.webapp.resources;
   
   /*
    * 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.
   */
  
  import java.io.IOException;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  import org.apache.helix.HelixDataAccessor;
  import org.apache.helix.HelixException;
  import org.apache.helix.manager.zk.ZkClient;
  import org.apache.helix.model.InstanceConfig;
  import org.apache.helix.model.LiveInstance;
  import org.apache.helix.tools.ClusterSetup;
  import org.apache.helix.webapp.RestAdminApplication;
  import org.apache.log4j.Logger;
  import org.codehaus.jackson.JsonGenerationException;
  import org.codehaus.jackson.map.JsonMappingException;
  import org.restlet.Context;
  import org.restlet.data.MediaType;
  import org.restlet.data.Request;
  import org.restlet.data.Response;
  import org.restlet.data.Status;
  import org.restlet.resource.Representation;
  import org.restlet.resource.Resource;
  import org.restlet.resource.StringRepresentation;
  import org.restlet.resource.Variant;
  
  
  public class InstancesResource extends Resource
  {
    private final static Logger LOG = Logger.getLogger(InstancesResource.class);
  
    public InstancesResource(Context context, Request request, Response response)
    {
      super(context, request, response);
      getVariants().add(new Variant(MediaType.TEXT_PLAIN));
      getVariants().add(new Variant(MediaType.APPLICATION_JSON));
    }
  
    @Override
    public boolean allowGet()
    {
      return true;
    }
  
    @Override
    public boolean allowPost()
    {
      return true;
    }
  
    @Override
    public boolean allowPut()
    {
      return false;
    }
  
    @Override
    public boolean allowDelete()
    {
      return false;
    }
  
    @Override
    public Representation represent(Variant variant)
    {
      StringRepresentation presentation = null;
      try
      {
        String clusterName = (String) getRequest().getAttributes().get("clusterName");
        presentation = getInstancesRepresentation(clusterName);
      }
  
      catch (Exception e)
      {
        String error = ClusterRepresentationUtil.getErrorAsJsonStringFromException(e);
        presentation = new StringRepresentation(error, MediaType.APPLICATION_JSON);
  
        LOG.error("", e);
     }
     return presentation;
   }
 
   StringRepresentation getInstancesRepresentation(String clusterName) throws JsonGenerationException,
       JsonMappingException,
       IOException
   {
     ZkClient zkClient =
         (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
 
     HelixDataAccessor accessor =
         ClusterRepresentationUtil.getClusterDataAccessor(zkClient, clusterName);
     Map<String, LiveInstance> liveInstancesMap =
         accessor.getChildValuesMap(accessor.keyBuilder().liveInstances());
     Map<String, InstanceConfig> instanceConfigsMap =
         accessor.getChildValuesMap(accessor.keyBuilder().instanceConfigs());
     
     Map<String, List<String>> tagInstanceLists = new TreeMap<String, List<String>>();
     
     for (String instanceName : instanceConfigsMap.keySet())
     {
       boolean isAlive = liveInstancesMap.containsKey(instanceName);
       instanceConfigsMap.get(instanceName)
                         .getRecord()
                         .setSimpleField("Alive", isAlive + "");
       InstanceConfig config = instanceConfigsMap.get(instanceName);
       for(String tag : config.getTags())
       {
         if(!tagInstanceLists.containsKey(tag))
         {
           tagInstanceLists.put(tag, new LinkedList<String>());
         }
         if(!tagInstanceLists.get(tag).contains(instanceName))
         {
           tagInstanceLists.get(tag).add(instanceName);
         }
       }
     }
 
     StringRepresentation representation =
         new StringRepresentation(ClusterRepresentationUtil.ObjectToJson(instanceConfigsMap.values()) + ClusterRepresentationUtil.ObjectToJson(tagInstanceLists),
                                  MediaType.APPLICATION_JSON);
 
     return representation;
   }
 
   @Override
   public void acceptRepresentation(Representation entity)
   {
     try
     {
       String clusterName = (String) getRequest().getAttributes().get("clusterName");
       JsonParameters jsonParameters = new JsonParameters(entity);
       String command = jsonParameters.getCommand();
 
       ZkClient zkClient =
           (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
       ClusterSetup setupTool = new ClusterSetup(zkClient);
 
       if (command.equalsIgnoreCase(ClusterSetup.addInstance)
           || JsonParameters.CLUSTERSETUP_COMMAND_ALIASES.get(ClusterSetup.addInstance)
                                                         .contains(command))
       {
         if (jsonParameters.getParameter(JsonParameters.INSTANCE_NAME) != null)
         {
           setupTool.addInstanceToCluster(clusterName,
                                          jsonParameters.getParameter(JsonParameters.INSTANCE_NAME));
         }
         else if (jsonParameters.getParameter(JsonParameters.INSTANCE_NAMES) != null)
         {
           setupTool.addInstancesToCluster(clusterName,
                                           jsonParameters.getParameter(JsonParameters.INSTANCE_NAMES)
                                                         .split(";"));
         }
         else
         {
           throw new HelixException("Missing Json paramaters: '"
               + JsonParameters.INSTANCE_NAME + "' or '" + JsonParameters.INSTANCE_NAMES
               + "' ");
         }
       }
       else if (command.equalsIgnoreCase(ClusterSetup.swapInstance))
       {
         if (jsonParameters.getParameter(JsonParameters.NEW_INSTANCE) == null
             || jsonParameters.getParameter(JsonParameters.OLD_INSTANCE) == null)
         {
           throw new HelixException("Missing Json paramaters: '"
               + JsonParameters.NEW_INSTANCE + "' or '" + JsonParameters.OLD_INSTANCE
               + "' ");
         }
         setupTool.swapInstance(clusterName,
                                jsonParameters.getParameter(JsonParameters.OLD_INSTANCE),
                                jsonParameters.getParameter(JsonParameters.NEW_INSTANCE));
       }
       else
       {
         throw new HelixException("Unsupported command: " + command
             + ". Should be one of [" + ClusterSetup.addInstance + ", "
             + ClusterSetup.swapInstance + "]");
       }
 
       getResponse().setEntity(getInstancesRepresentation(clusterName));
       getResponse().setStatus(Status.SUCCESS_OK);
     }
     catch (Exception e)
     {
       getResponse().setEntity(ClusterRepresentationUtil.getErrorAsJsonStringFromException(e),
                               MediaType.APPLICATION_JSON);
       getResponse().setStatus(Status.SUCCESS_OK);
       LOG.error("", e);
     }
   }
 }