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.data.MediaType;
import org.restlet.data.Status;
import org.restlet.representation.Representation;
import org.restlet.representation.StringRepresentation;
import org.restlet.representation.Variant;
import org.restlet.resource.ServerResource;

public class StateModelsResource extends ServerResource {
  private final static Logger LOG = Logger.getLogger(StateModelsResource.class);

  public StateModelsResource() {
    getVariants().add(new Variant(MediaType.TEXT_PLAIN));
    getVariants().add(new Variant(MediaType.APPLICATION_JSON));
    setNegotiated(false);
  }

  @Override
  public Representation get() {
    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 Representation post(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);
    }
    return null;
  }
}