/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * 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.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.search.aggregations.metrics;

import org.opensearch.core.ParseField;
import org.opensearch.core.xcontent.ObjectParser;
import org.opensearch.core.xcontent.ObjectParser.ValueType;
import org.opensearch.core.xcontent.XContentBuilder;
import org.opensearch.core.xcontent.XContentParser;
import org.opensearch.search.aggregations.ParsedAggregation;
import org.opensearch.search.aggregations.metrics.InternalStats.Fields;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * A stats agg result parsed between nodes
 *
 * @opensearch.internal
 */
public class ParsedStats extends ParsedAggregation implements Stats {

    protected long count;
    protected double min;
    protected double max;
    protected double sum;
    protected double avg;

    protected final Map<String, String> valueAsString = new HashMap<>();

    @Override
    public long getCount() {
        return count;
    }

    @Override
    public double getMin() {
        return min;
    }

    @Override
    public double getMax() {
        return max;
    }

    @Override
    public double getAvg() {
        return avg;
    }

    @Override
    public double getSum() {
        return sum;
    }

    @Override
    public String getMinAsString() {
        return valueAsString.getOrDefault(Fields.MIN_AS_STRING, Double.toString(min));
    }

    @Override
    public String getMaxAsString() {
        return valueAsString.getOrDefault(Fields.MAX_AS_STRING, Double.toString(max));
    }

    @Override
    public String getAvgAsString() {
        return valueAsString.getOrDefault(Fields.AVG_AS_STRING, Double.toString(avg));
    }

    @Override
    public String getSumAsString() {
        return valueAsString.getOrDefault(Fields.SUM_AS_STRING, Double.toString(sum));
    }

    @Override
    public String getType() {
        return StatsAggregationBuilder.NAME;
    }

    @Override
    protected XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
        builder.field(Fields.COUNT, count);
        if (count != 0) {
            builder.field(Fields.MIN, min);
            builder.field(Fields.MAX, max);
            builder.field(Fields.AVG, avg);
            builder.field(Fields.SUM, sum);
            if (valueAsString.get(Fields.MIN_AS_STRING) != null) {
                builder.field(Fields.MIN_AS_STRING, getMinAsString());
                builder.field(Fields.MAX_AS_STRING, getMaxAsString());
                builder.field(Fields.AVG_AS_STRING, getAvgAsString());
                builder.field(Fields.SUM_AS_STRING, getSumAsString());
            }
        } else {
            builder.nullField(Fields.MIN);
            builder.nullField(Fields.MAX);
            builder.nullField(Fields.AVG);
            builder.field(Fields.SUM, 0.0d);
        }
        otherStatsToXContent(builder, params);
        return builder;
    }

    private static final ObjectParser<ParsedStats, Void> PARSER = new ObjectParser<>(
        ParsedStats.class.getSimpleName(),
        true,
        ParsedStats::new
    );

    static {
        declareStatsFields(PARSER);
    }

    protected static void declareStatsFields(ObjectParser<? extends ParsedStats, Void> objectParser) {
        declareAggregationFields(objectParser);
        objectParser.declareLong((agg, value) -> agg.count = value, new ParseField(Fields.COUNT));
        objectParser.declareField(
            (agg, value) -> agg.min = value,
            (parser, context) -> parseDouble(parser, Double.POSITIVE_INFINITY),
            new ParseField(Fields.MIN),
            ValueType.DOUBLE_OR_NULL
        );
        objectParser.declareField(
            (agg, value) -> agg.max = value,
            (parser, context) -> parseDouble(parser, Double.NEGATIVE_INFINITY),
            new ParseField(Fields.MAX),
            ValueType.DOUBLE_OR_NULL
        );
        objectParser.declareField(
            (agg, value) -> agg.avg = value,
            (parser, context) -> parseDouble(parser, 0),
            new ParseField(Fields.AVG),
            ValueType.DOUBLE_OR_NULL
        );
        objectParser.declareField(
            (agg, value) -> agg.sum = value,
            (parser, context) -> parseDouble(parser, 0),
            new ParseField(Fields.SUM),
            ValueType.DOUBLE_OR_NULL
        );
        objectParser.declareString(
            (agg, value) -> agg.valueAsString.put(Fields.MIN_AS_STRING, value),
            new ParseField(Fields.MIN_AS_STRING)
        );
        objectParser.declareString(
            (agg, value) -> agg.valueAsString.put(Fields.MAX_AS_STRING, value),
            new ParseField(Fields.MAX_AS_STRING)
        );
        objectParser.declareString(
            (agg, value) -> agg.valueAsString.put(Fields.AVG_AS_STRING, value),
            new ParseField(Fields.AVG_AS_STRING)
        );
        objectParser.declareString(
            (agg, value) -> agg.valueAsString.put(Fields.SUM_AS_STRING, value),
            new ParseField(Fields.SUM_AS_STRING)
        );
    }

    public static ParsedStats fromXContent(XContentParser parser, final String name) {
        ParsedStats parsedStats = PARSER.apply(parser, null);
        parsedStats.setName(name);
        return parsedStats;
    }

    protected XContentBuilder otherStatsToXContent(XContentBuilder builder, Params params) throws IOException {
        return builder;
    }
}