/**
 *    Copyright (C) 2018-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 "mongo/base/error_extra_info.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/record_id.h"
#include "mongo/stdx/variant.h"

namespace mongo {

enum class IncludeDuplicateRecordId { kOff, kOn };

/**
 * Represents an error returned from the storage engine when an attempt to insert a
 * key into a unique index fails because the same key already exists.
 */
class DuplicateKeyErrorInfo final : public ErrorExtraInfo {
public:
    using FoundValue = stdx::variant<stdx::monostate, RecordId, BSONObj>;

    static constexpr auto code = ErrorCodes::DuplicateKey;

    static std::shared_ptr<const ErrorExtraInfo> parse(const BSONObj&);

    explicit DuplicateKeyErrorInfo(const BSONObj& keyPattern,
                                   const BSONObj& keyValue,
                                   const BSONObj& collation,
                                   FoundValue&& foundValue,
                                   boost::optional<RecordId> duplicateRid);

    void serialize(BSONObjBuilder* bob) const override;

    BSONObj toBSON() const {
        BSONObjBuilder bob;
        serialize(&bob);
        return bob.obj();
    }

    const BSONObj& getKeyPattern() const {
        return _keyPattern;
    }

    const BSONObj& getDuplicatedKeyValue() const {
        return _keyValue;
    }

    const FoundValue& getFoundValue() const {
        return _foundValue;
    }

    boost::optional<RecordId> getDuplicateRid() const {
        return _duplicateRid;
    }

private:
    BSONObj _keyPattern;
    BSONObj _keyValue;

    // An empty object if the index which resulted in the duplicate key error has the simple
    // collation, otherwise gives the index's collation.
    BSONObj _collation;

    // Optionally, the value found at the cursor which produced the DuplicateKey error, for
    // diagnostic use. If the error came from an _id index, then the value will be the record id of
    // the duplicate document. If the error came from a clustered collection, then the value will be
    // the duplicate document itself.
    FoundValue _foundValue;

    // Optionally, the record id found at the cursor which produced the DuplicateKey error.
    boost::optional<RecordId> _duplicateRid;
};

}  // namespace mongo