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.manager.zk.ZkClient;
  import org.apache.helix.model.StateModelDefinition;
  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 StateModelsResource extends Resource
  {
    private final static Logger LOG = Logger.getLogger(StateModelsResource.class);
  
    public StateModelsResource(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
      {
        presentation = getStateModelsRepresentation();
      }
      
      catch(Exception e)
      {
        String error = ClusterRepresentationUtil.getErrorAsJsonStringFromException(e);
        presentation = new StringRepresentation(error, MediaType.APPLICATION_JSON);
  
        LOG.error("", e);
      }
      return presentation;
   }
   
   StringRepresentation getStateModelsRepresentation() throws JsonGenerationException, JsonMappingException, IOException
   {
     String clusterName = (String)getRequest().getAttributes().get("clusterName");
     ZkClient zkClient = (ZkClient)getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
     ClusterSetup setupTool = new ClusterSetup(zkClient);
     
     List<String> models = setupTool.getClusterManagementTool().getStateModelDefs(clusterName);
     
     ZNRecord modelDefinitions = new ZNRecord("modelDefinitions");
     modelDefinitions.setListField("models", models);
     
     StringRepresentation representation = new StringRepresentation(ClusterRepresentationUtil.ZNRecordToJson(modelDefinitions), 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);;
       
       JsonParameters jsonParameters = new JsonParameters(entity);
       String command = jsonParameters.getCommand();
 
         
       if(command.equalsIgnoreCase(ClusterSetup.addStateModelDef))
       {
         ZNRecord newStateModel = jsonParameters.getExtraParameter(JsonParameters.NEW_STATE_MODEL_DEF);
         HelixDataAccessor accessor = ClusterRepresentationUtil.getClusterDataAccessor(zkClient, clusterName);
          
         accessor.setProperty(accessor.keyBuilder().stateModelDef(newStateModel.getId()), new StateModelDefinition(newStateModel) );
         getResponse().setEntity(getStateModelsRepresentation());
       }
       else
       {
           throw new HelixException("Unsupported command: " + command
                                    + ". Should be one of [" + ClusterSetup.addStateModelDef + "]");
       }
       
       getResponse().setStatus(Status.SUCCESS_OK);
     }
     catch(Exception e)
     {
       getResponse().setEntity(ClusterRepresentationUtil.getErrorAsJsonStringFromException(e),
           MediaType.APPLICATION_JSON);
       getResponse().setStatus(Status.SUCCESS_OK);
       LOG.error("Error in posting " + entity, e);
     }  
   }
 }