/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.cluster;

import org.elasticsearch.cluster.routing.ShardRouting;

import java.util.Collections;
import java.util.Map;

/**
 * ClusterInfo is an object representing a map of nodes to {@link DiskUsage}
 * and a map of shard ids to shard sizes, see
 * <code>InternalClusterInfoService.shardIdentifierFromRouting(String)</code>
 * for the key used in the shardSizes map
 */
public class ClusterInfo {

    private final Map<String, DiskUsage> leastAvailableSpaceUsage;
    private final Map<String, DiskUsage> mostAvailableSpaceUsage;
    final Map<String, Long> shardSizes;
    public static final ClusterInfo EMPTY = new ClusterInfo();
    private final Map<ShardRouting, String> routingToDataPath;

    protected ClusterInfo() {
       this(Collections.EMPTY_MAP, Collections.EMPTY_MAP, Collections.EMPTY_MAP, Collections.EMPTY_MAP);
    }

    /**
     * Creates a new ClusterInfo instance.
     *
     * @param leastAvailableSpaceUsage a node id to disk usage mapping for the path that has the least available space on the node.
     * @param mostAvailableSpaceUsage  a node id to disk usage mapping for the path that has the most available space on the node.
     * @param shardSizes a shardkey to size in bytes mapping per shard.
     * @param routingToDataPath the shard routing to datapath mapping
     * @see #shardIdentifierFromRouting
     */
    public ClusterInfo(final Map<String, DiskUsage> leastAvailableSpaceUsage, final Map<String, DiskUsage> mostAvailableSpaceUsage, final Map<String, Long> shardSizes, Map<ShardRouting, String> routingToDataPath) {
        this.leastAvailableSpaceUsage = leastAvailableSpaceUsage;
        this.shardSizes = shardSizes;
        this.mostAvailableSpaceUsage = mostAvailableSpaceUsage;
        this.routingToDataPath = routingToDataPath;
    }

    /**
     * Returns a node id to disk usage mapping for the path that has the least available space on the node.
     */
    public Map<String, DiskUsage> getNodeLeastAvailableDiskUsages() {
        return this.leastAvailableSpaceUsage;
    }

    /**
     * Returns a node id to disk usage mapping for the path that has the most available space on the node.
     */
    public Map<String, DiskUsage> getNodeMostAvailableDiskUsages() {
        return this.mostAvailableSpaceUsage;
    }

    /**
     * Returns the shard size for the given shard routing or <code>null</code> it that metric is not available.
     */
    public Long getShardSize(ShardRouting shardRouting) {
        return shardSizes.get(shardIdentifierFromRouting(shardRouting));
    }

    /**
     * Returns the nodes absolute data-path the given shard is allocated on or <code>null</code> if the information is not available.
     */
    public String getDataPath(ShardRouting shardRouting) {
        return routingToDataPath.get(shardRouting);
    }

    /**
     * Returns the shard size for the given shard routing or <code>defaultValue</code> it that metric is not available.
     */
    public long getShardSize(ShardRouting shardRouting, long defaultValue) {
        Long shardSize = getShardSize(shardRouting);
        return shardSize == null ? defaultValue : shardSize;
    }

    /**
     * Method that incorporates the ShardId for the shard into a string that
     * includes a 'p' or 'r' depending on whether the shard is a primary.
     */
    static String shardIdentifierFromRouting(ShardRouting shardRouting) {
        return shardRouting.shardId().toString() + "[" + (shardRouting.primary() ? "p" : "r") + "]";
    }
}