/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */

package org.elasticsearch.index.fielddata;

import com.carrotsearch.hppc.ObjectLongHashMap;
import org.apache.lucene.util.Accountable;
import org.elasticsearch.common.FieldMemoryStats;
import org.elasticsearch.common.metrics.CounterMetric;
import org.elasticsearch.common.regex.Regex;
import org.elasticsearch.common.util.CollectionUtils;
import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
import org.elasticsearch.index.shard.ShardId;

import java.util.Map;
import java.util.concurrent.ConcurrentMap;

public class ShardFieldData implements IndexFieldDataCache.Listener {

    private final CounterMetric evictionsMetric = new CounterMetric();
    private final CounterMetric totalMetric = new CounterMetric();
    private final ConcurrentMap<String, CounterMetric> perFieldTotals = ConcurrentCollections.newConcurrentMap();

    public FieldDataStats stats(String... fields) {
        ObjectLongHashMap<String> fieldTotals = null;
        if (CollectionUtils.isEmpty(fields) == false) {
            fieldTotals = new ObjectLongHashMap<>();
            for (Map.Entry<String, CounterMetric> entry : perFieldTotals.entrySet()) {
                if (Regex.simpleMatch(fields, entry.getKey())) {
                    fieldTotals.put(entry.getKey(), entry.getValue().count());
                }
            }
        }
        return new FieldDataStats(totalMetric.count(), evictionsMetric.count(), fieldTotals == null ? null :
            new FieldMemoryStats(fieldTotals));
    }

    @Override
    public void onCache(ShardId shardId, String fieldName, Accountable ramUsage) {
        totalMetric.inc(ramUsage.ramBytesUsed());
        CounterMetric total = perFieldTotals.get(fieldName);
        if (total != null) {
            total.inc(ramUsage.ramBytesUsed());
        } else {
            total = new CounterMetric();
            total.inc(ramUsage.ramBytesUsed());
            CounterMetric prev = perFieldTotals.putIfAbsent(fieldName, total);
            if (prev != null) {
                prev.inc(ramUsage.ramBytesUsed());
            }
        }
    }

    @Override
    public void onRemoval(ShardId shardId, String fieldName, boolean wasEvicted, long sizeInBytes) {
        if (wasEvicted) {
            evictionsMetric.inc();
        }
        if (sizeInBytes != -1) {
            totalMetric.dec(sizeInBytes);

            CounterMetric total = perFieldTotals.get(fieldName);
            if (total != null) {
                total.dec(sizeInBytes);
            }
        }
    }
}
