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 * 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
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package org.elasticsearch.search.aggregations;

import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
import org.elasticsearch.search.aggregations.metrics.max.InternalMax;
import org.elasticsearch.search.aggregations.metrics.min.InternalMin;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.test.InternalAggregationTestCase;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import static java.util.Collections.emptyList;
import static java.util.Collections.emptyMap;

public abstract class InternalSingleBucketAggregationTestCase<T extends InternalSingleBucketAggregation>
        extends InternalAggregationTestCase<T> {
    private final boolean hasInternalMax = randomBoolean();
    private final boolean hasInternalMin = randomBoolean();

    protected abstract T createTestInstance(String name, long docCount, InternalAggregations aggregations,
            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData);
    protected abstract void extraAssertReduced(T reduced, List<T> inputs);

    @Override
    protected final T createTestInstance(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
        List<InternalAggregation> internal = new ArrayList<>();
        if (hasInternalMax) {
            internal.add(new InternalMax("max", randomDouble(), randomNumericDocValueFormat(), emptyList(), emptyMap()));
        }
        if (hasInternalMin) {
            internal.add(new InternalMin("min", randomDouble(), randomNumericDocValueFormat(), emptyList(), emptyMap()));
        }
        // we shouldn't use the full long range here since we sum doc count on reduce, and don't want to overflow the long range there
        long docCount = between(0, Integer.MAX_VALUE);
        return createTestInstance(name, docCount, new InternalAggregations(internal), pipelineAggregators, metaData);
    }

    @Override
    protected final void assertReduced(T reduced, List<T> inputs) {
        assertEquals(inputs.stream().mapToLong(InternalSingleBucketAggregation::getDocCount).sum(), reduced.getDocCount());
        if (hasInternalMax) {
            double expected = inputs.stream().mapToDouble(i -> {
                        InternalMax max = i.getAggregations().get("max");
                        return max.getValue();
                    }).max().getAsDouble();
            InternalMax reducedMax = reduced.getAggregations().get("max");
            assertEquals(expected, reducedMax.getValue(), 0);
        }
        if (hasInternalMin) {
            double expected = inputs.stream().mapToDouble(i -> {
                        InternalMin min = i.getAggregations().get("min");
                        return min.getValue();
                    }).min().getAsDouble();
            InternalMin reducedMin = reduced.getAggregations().get("min");
            assertEquals(expected, reducedMin.getValue(), 0);
        }
        extraAssertReduced(reduced, inputs);
    }
}