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.List;
  
  import org.apache.helix.HelixDataAccessor;
  import org.apache.helix.HelixException;
  import org.apache.helix.ZNRecord;
  import org.apache.helix.PropertyKey.Builder;
  import org.apache.helix.manager.zk.ZkClient;
  import org.apache.helix.model.LiveInstance;
  import org.apache.helix.tools.ClusterSetup;
  import org.apache.helix.webapp.RestAdminApplication;
  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 ClusterResource extends Resource
  {
    public ClusterResource(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 true;
    }
  
    @Override
    public Representation represent(Variant variant)
    {
      StringRepresentation presentation = null;
      try
      {
        String clusterName = (String) getRequest().getAttributes().get("clusterName");
        presentation = getClusterRepresentation(clusterName);
      }
  
      catch (Exception e)
      {
        String error = ClusterRepresentationUtil.getErrorAsJsonStringFromException(e);
        presentation = new StringRepresentation(error, MediaType.APPLICATION_JSON);
  
        e.printStackTrace();
      }
      return presentation;
    }
  
    StringRepresentation getClusterRepresentation(String clusterName) throws JsonGenerationException,
       JsonMappingException,
       IOException
   {
     ZkClient zkClient =
         (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
     ClusterSetup setupTool = new ClusterSetup(zkClient);
     List<String> instances =
         setupTool.getClusterManagementTool().getInstancesInCluster(clusterName);
 
     ZNRecord clusterSummayRecord = new ZNRecord("Cluster Summary");
     clusterSummayRecord.setListField("participants", instances);
 
     List<String> resources =
         setupTool.getClusterManagementTool().getResourcesInCluster(clusterName);
     clusterSummayRecord.setListField("resources", resources);
 
     List<String> models =
         setupTool.getClusterManagementTool().getStateModelDefs(clusterName);
     clusterSummayRecord.setListField("stateModelDefs", models);
 
     HelixDataAccessor accessor =
         ClusterRepresentationUtil.getClusterDataAccessor(zkClient, clusterName);
     Builder keyBuilder = accessor.keyBuilder();
 
     LiveInstance leader = accessor.getProperty(keyBuilder.controllerLeader());
     if (leader != null)
     {
       clusterSummayRecord.setSimpleField("LEADER", leader.getInstanceName());
     }
     else
     {
       clusterSummayRecord.setSimpleField("LEADER", "");
     }
     StringRepresentation representation =
         new StringRepresentation(ClusterRepresentationUtil.ZNRecordToJson(clusterSummayRecord),
                                  MediaType.APPLICATION_JSON);
 
     return representation;
   }
 
   @Override
   public void acceptRepresentation(Representation entity)
   {
     try
     {
       String clusterName = (String) getRequest().getAttributes().get("clusterName");
       ZkClient zkClient =
           (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
       ClusterSetup setupTool = new ClusterSetup(zkClient);
 
       JsonParameters jsonParameters = new JsonParameters(entity);
       String command = jsonParameters.getCommand();
 
       if (command == null)
       {
         throw new HelixException("Could NOT find 'command' in parameterMap: " + jsonParameters._parameterMap);
       }
       else if (command.equalsIgnoreCase(ClusterSetup.activateCluster)
           || JsonParameters.CLUSTERSETUP_COMMAND_ALIASES.get(ClusterSetup.activateCluster)
                                                         .contains(command))
       {
         jsonParameters.verifyCommand(ClusterSetup.activateCluster);
 
         boolean enabled = true;
         if (jsonParameters.getParameter(JsonParameters.ENABLED) != null)
         {
           enabled =
               Boolean.parseBoolean(jsonParameters.getParameter(JsonParameters.ENABLED));
         }
 
         String grandCluster = jsonParameters.getParameter(JsonParameters.GRAND_CLUSTER);
 
         setupTool.activateCluster(clusterName, grandCluster, enabled);
       }
       else if (command.equalsIgnoreCase(ClusterSetup.expandCluster))
       {
         setupTool.expandCluster(clusterName);
       }
       else
       {
         throw new HelixException("Unsupported command: " + command
             + ". Should be one of [" + ClusterSetup.activateCluster + ", "
             + ClusterSetup.expandCluster + "]");
       }
       getResponse().setEntity(getClusterRepresentation(clusterName));
       getResponse().setStatus(Status.SUCCESS_OK);
     }
     catch (Exception e)
     {
       getResponse().setEntity(ClusterRepresentationUtil.getErrorAsJsonStringFromException(e),
                               MediaType.APPLICATION_JSON);
       getResponse().setStatus(Status.SUCCESS_OK);
     }
   }
 
   @Override
   public void removeRepresentations()
   {
     try
     {
       String clusterName = (String) getRequest().getAttributes().get("clusterName");
       ZkClient zkClient =
           (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
       ClusterSetup setupTool = new ClusterSetup(zkClient);
       setupTool.deleteCluster(clusterName);
       getResponse().setStatus(Status.SUCCESS_OK);
     }
     catch (Exception e)
     {
       getResponse().setEntity(ClusterRepresentationUtil.getErrorAsJsonStringFromException(e),
                               MediaType.APPLICATION_JSON);
       getResponse().setStatus(Status.SUCCESS_OK);
     }
   }
 }