/**
 * 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.ambari.server.controller.internal;

import java.util.Collections;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.apache.ambari.server.controller.spi.NoSuchParentResourceException;
import org.apache.ambari.server.controller.spi.NoSuchResourceException;
import org.apache.ambari.server.controller.spi.Predicate;
import org.apache.ambari.server.controller.spi.Request;
import org.apache.ambari.server.controller.spi.RequestStatus;
import org.apache.ambari.server.controller.spi.Resource;
import org.apache.ambari.server.controller.spi.ResourceAlreadyExistsException;
import org.apache.ambari.server.controller.spi.SystemException;
import org.apache.ambari.server.controller.spi.UnsupportedPropertyException;
import org.apache.ambari.server.orm.entities.ViewEntity;
import org.apache.ambari.server.security.authorization.RoleAuthorization;
import org.apache.ambari.server.view.ViewRegistry;

/**
 * Resource provider for view instances.
 */
public class ViewResourceProvider extends AbstractAuthorizedResourceProvider {

  /**
   * View property id constants.
   */
  public static final String VIEW_NAME_PROPERTY_ID    = "ViewInfo/view_name";


  /**
   * The key property ids for a view resource.
   */
  private static Map<Resource.Type, String> keyPropertyIds = new HashMap<>();
  static {
    keyPropertyIds.put(Resource.Type.View, VIEW_NAME_PROPERTY_ID);
  }

  /**
   * The property ids for a view resource.
   */
  private static Set<String> propertyIds = new HashSet<>();
  static {
    propertyIds.add(VIEW_NAME_PROPERTY_ID);
  }


  // ----- Constructors ------------------------------------------------------

  /**
   * Construct a view resource provider.
   */
  public ViewResourceProvider() {
    super(propertyIds, keyPropertyIds);

    EnumSet<RoleAuthorization> requiredAuthorizations = EnumSet.of(RoleAuthorization.AMBARI_MANAGE_VIEWS);
    setRequiredCreateAuthorizations(requiredAuthorizations);
    setRequiredDeleteAuthorizations(requiredAuthorizations);
    setRequiredUpdateAuthorizations(requiredAuthorizations);
  }


  // ----- ResourceProvider --------------------------------------------------

  @Override
  protected RequestStatus createResourcesAuthorized(Request request)
      throws SystemException, UnsupportedPropertyException,
             ResourceAlreadyExistsException, NoSuchParentResourceException {
    throw new UnsupportedOperationException("Not yet supported.");
  }

  @Override
  public Set<Resource> getResources(Request request, Predicate predicate)
      throws SystemException, UnsupportedPropertyException, NoSuchResourceException, NoSuchParentResourceException {
    Set<Resource> resources    = new HashSet<>();
    ViewRegistry  viewRegistry = ViewRegistry.getInstance();
    Set<String>   requestedIds = getRequestPropertyIds(request, predicate);

    Set<Map<String, Object>> propertyMaps = getPropertyMaps(predicate);

    if (propertyMaps.isEmpty()) {
      propertyMaps.add(Collections.<String, Object>emptyMap());
    }

    for (Map<String, Object> propertyMap : propertyMaps) {

      String viewName    = (String) propertyMap.get(VIEW_NAME_PROPERTY_ID);

      for (ViewEntity viewDefinition : viewRegistry.getDefinitions()){
        if (viewName == null || viewName.equals(viewDefinition.getCommonName())) {
          if (viewRegistry.includeDefinition(viewDefinition)) {
            Resource resource = new ResourceImpl(Resource.Type.View);

            setResourceProperty(resource, VIEW_NAME_PROPERTY_ID, viewDefinition.getCommonName(), requestedIds);

            resources.add(resource);
          }
        }
      }
    }

    return resources;
  }

  @Override
  protected RequestStatus updateResourcesAuthorized(Request request, Predicate predicate)
      throws SystemException, UnsupportedPropertyException, NoSuchResourceException, NoSuchParentResourceException {
    throw new UnsupportedOperationException("Not yet supported.");
  }

  @Override
  protected RequestStatus deleteResourcesAuthorized(Request request, Predicate predicate)
      throws SystemException, UnsupportedPropertyException, NoSuchResourceException, NoSuchParentResourceException {
    throw new UnsupportedOperationException("Not yet supported.");
  }

  @Override
  public Map<Resource.Type, String> getKeyPropertyIds() {
    return keyPropertyIds;
  }


  // ----- AbstractResourceProvider ------------------------------------------

  @Override
  protected Set<String> getPKPropertyIds() {
    return new HashSet<>(keyPropertyIds.values());
  }
}