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/*
 * Copyright (C) 2017-2017 DataStax Inc.
 *
 * Licensed 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 com.datastax.oss.simulacron.common.cluster;

import com.fasterxml.jackson.annotation.JsonIgnore;
import java.util.Collection;
import java.util.Optional;
import java.util.stream.Collectors;

/**
 * /** Defines some useful convenience methods for an object that exists at the 'Cluster' level of
 * Cluster (1 -> *) DataCenter (1 -> *) Node.
 *
 * @param  DataCenter type
 * @param  Node type
 */
public interface ClusterStructure, N extends NodeStructure>
    extends Identifiable {

  /** @return The {@link DataCenter}s belonging to this cluster. */
  Collection getDataCenters();

  /**
   * @return All nodes belonging to {@link DataCenter}s in this cluster. Note that this method
   *     builds a new collection on every invocation, so it is recommended to not call this
   *     repeatedly without a good reason.
   */
  @JsonIgnore
  default Collection getNodes() {
    return getDataCenters()
        .stream()
        .flatMap(dc -> dc.getNodes().stream())
        .collect(Collectors.toList());
  }

  /**
   * Convenience method to find the DataCenter with the given id.
   *
   * @param id id of the data center.
   * @return the data center if found or null.
   */
  default D dc(long id) {
    return getDataCenters().stream().filter(d -> d.getId() == id).findAny().orElse(null);
  }

  /**
   * Convenience method to find the Node in DataCenter 0 with the given id. This is a shortcut for
   * node(0, X) as it is common for clusters to only have 1 dc.
   *
   * @param id id of the node.
   * @return the node if found in dc 0 or null
   */
  default N node(long id) {
    return node(0, id);
  }

  /**
   * Convenience method to find the Node with the given DataCenter id and node id.
   *
   * @param dcId id of the data center.
   * @param nodeId id of the node.
   * @return the node if found or null
   */
  default N node(long dcId, long nodeId) {
    return Optional.ofNullable(dc(dcId)).map(d -> d.node(nodeId)).orElse(null);
  }
}