/**
 *    Copyright (C) 2022-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#pragma once

#include <map>
#include <memory>
#include <string>

#include "mongo/db/namespace_string.h"
#include "mongo/db/query/stats/ce_histogram.h"
#include "mongo/db/query/stats/collection_statistics.h"

namespace mongo::stats {

using Histograms = std::map<std::string, std::shared_ptr<const CEHistogram>>;

class CollectionStatisticsImpl : public CollectionStatistics {
public:
    CollectionStatisticsImpl(double cardinality, const NamespaceString& nss);

    /**
     * Returns the cardinality of the given collection.
     */
    double getCardinality() const override;

    /**
     * Returns the histogram for the given field path, or nullptr if none exists.
     */
    const CEHistogram* getHistogram(const std::string& path) const override;

    /**
     * Adds a histogram along the given path.
     */
    void addHistogram(const std::string& path,
                      std::shared_ptr<const CEHistogram> histogram) const override;

    ~CollectionStatisticsImpl() override = default;

private:
    double _cardinality;
    mutable Histograms _histograms;
    const NamespaceString _nss;
};

}  // namespace mongo::stats
