/**
 *    Copyright (C) 2023-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,
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 */

#include "mongo/db/query/query_stats/key.h"

#include "mongo/db/query/query_stats/query_stats_helpers.h"
#include "mongo/rpc/metadata/client_metadata.h"

namespace mongo::query_stats {

namespace {

BSONObj scrubHighCardinalityFields(const ClientMetadata* clientMetadata) {
    if (!clientMetadata) {
        return BSONObj();
    }
    return clientMetadata->documentWithoutMongosInfo();
}

BSONObj shapifyReadPreference(boost::optional<BSONObj> readPreference) {
    if (!readPreference) {
        return BSONObj();
    }

    BSONObjBuilder builder;
    for (const auto& elem : *readPreference) {
        if (elem.fieldNameStringData() != "tags"_sd) {
            builder.append(elem);
            continue;
        }

        // Sort the $readPreference tags so that different orderings still map to one query stats
        // store key.
        BSONObjSet sortedTags = SimpleBSONObjComparator::kInstance.makeBSONObjSet();
        for (const auto& tag : elem.Array()) {
            sortedTags.insert(tag.Obj());
        }

        BSONArrayBuilder arrBuilder(builder.subarrayStart("tags"_sd));
        for (const auto& tag : sortedTags) {
            arrBuilder.append(tag);
        }
    }
    return builder.obj();
}

}  // namespace

UniversalKeyComponents::UniversalKeyComponents(std::unique_ptr<query_shape::Shape> queryShape,
                                               const ClientMetadata* clientMetadata,
                                               boost::optional<BSONObj> commentObj,
                                               boost::optional<BSONObj> hint,
                                               boost::optional<BSONObj> readPreference,
                                               boost::optional<BSONObj> writeConcern,
                                               boost::optional<BSONObj> readConcern,
                                               std::unique_ptr<APIParameters> apiParams,
                                               query_shape::CollectionType collectionType,
                                               bool maxTimeMS)
    : _clientMetaData(scrubHighCardinalityFields(clientMetadata)),
      _commentObj(commentObj.value_or(BSONObj()).getOwned()),
      _hintObj(hint.value_or(BSONObj()).getOwned()),
      _writeConcern(writeConcern.value_or(BSONObj()).getOwned()),
      _shapifiedReadPreference(shapifyReadPreference(readPreference)),
      _shapifiedReadConcern(shapifyReadConcern(readConcern.value_or(BSONObj()))),
      _comment(commentObj ? _commentObj.firstElement() : BSONElement()),
      _queryShape(std::move(queryShape)),
      _apiParams(std::move(apiParams)),
      _clientMetaDataHash(clientMetadata ? clientMetadata->hashWithoutMongosInfo()
                                         : simpleHash(BSONObj())),
      _collectionType(collectionType),
      _hasField() {
    _hasField.clientMetaData = bool(clientMetadata);
    _hasField.comment = bool(commentObj);
    _hasField.hint = bool(hint);
    _hasField.readPreference = bool(readPreference);
    _hasField.writeConcern = bool(writeConcern);
    _hasField.readConcern = bool(readConcern);
    _hasField.maxTimeMS = maxTimeMS;
    tassert(7973600, "shape must not be null", _queryShape);
}

BSONObj UniversalKeyComponents::shapifyReadConcern(const BSONObj& readConcern,
                                                   const SerializationOptions& opts) {
    // Read concern should not be considered a literal.
    // afterClusterTime is distinct for every operation with causal consistency enabled. We
    // normalize it in order not to blow out the queryStats store cache.
    if (readConcern["afterClusterTime"].eoo() && readConcern["atClusterTime"].eoo()) {
        return readConcern.copy();
    } else {
        BSONObjBuilder bob;

        if (auto levelElem = readConcern["level"]) {
            bob.append(levelElem);
        }
        if (auto afterClusterTime = readConcern["afterClusterTime"]) {
            opts.appendLiteral(&bob, "afterClusterTime", afterClusterTime);
        }
        if (auto atClusterTime = readConcern["atClusterTime"]) {
            opts.appendLiteral(&bob, "atClusterTime", atClusterTime);
        }
        return bob.obj();
    }
}

size_t UniversalKeyComponents::size() const {
    return sizeof(*this) + _queryShape->size() +
        (_apiParams ? sizeof(*_apiParams) + shape_helpers::optionalSize(_apiParams->getAPIVersion())
                    : 0) +
        _hintObj.objsize() + (_hasField.clientMetaData ? _clientMetaData.objsize() : 0) +
        _commentObj.objsize() +
        (_hasField.readPreference ? _shapifiedReadPreference.objsize() : 0) +
        (_hasField.readConcern ? _shapifiedReadConcern.objsize() : 0) +
        (_hasField.writeConcern ? _writeConcern.objsize() : 0);
}

void UniversalKeyComponents::appendTo(BSONObjBuilder& bob, const SerializationOptions& opts) const {
    if (_hasField.comment) {
        opts.appendLiteral(&bob, "comment", _comment);
    }

    if (_hasField.readConcern) {
        auto readConcernToAppend = _shapifiedReadConcern;
        if (opts != SerializationOptions::kRepresentativeQueryShapeSerializeOptions) {
            // The options aren't the same as the first time we shapified, so re-computation is
            // necessary (e.g. use "?timestamp" instead of the representative Timestamp(0, 0)).
            readConcernToAppend = shapifyReadConcern(_shapifiedReadConcern, opts);
        }
        bob.append("readConcern", readConcernToAppend);
    }

    if (const auto& apiVersion = _apiParams->getAPIVersion()) {
        bob.append("apiVersion", apiVersion.value());
    }

    if (const auto& apiStrict = _apiParams->getAPIStrict()) {
        bob.append("apiStrict", apiStrict.value());
    }

    if (const auto& apiDeprecationErrors = _apiParams->getAPIDeprecationErrors()) {
        bob.append("apiDeprecationErrors", apiDeprecationErrors.value());
    }

    if (_hasField.readPreference) {
        bob.append("$readPreference", _shapifiedReadPreference);
    }

    if (_hasField.writeConcern) {
        bob.append("writeConcern", _writeConcern);
    }

    if (_hasField.clientMetaData) {
        bob.append("client", _clientMetaData);
    }
    if (_collectionType > query_shape::CollectionType::kUnknown) {
        bob.append("collectionType", toStringData(_collectionType));
    }
    if (!_hintObj.isEmpty()) {
        bob.append("hint", shape_helpers::extractHintShape(_hintObj, opts));
    }
    if (_hasField.maxTimeMS) {
        opts.appendLiteral(&bob, "maxTimeMS", 0ll);
    }
}
Key::Key(OperationContext* opCtx,
         std::unique_ptr<query_shape::Shape> queryShape,
         boost::optional<BSONObj> hint,
         boost::optional<BSONObj> readConcern,
         bool maxTimeMS,
         query_shape::CollectionType collectionType)
    : _universalComponents(
          std::move(queryShape),
          ClientMetadata::get(opCtx->getClient()),
          opCtx->getCommentOwnedCopy(),
          hint,
          ReadPreferenceSetting::get(opCtx).usedDefaultReadPrefValue()
              ? boost::none
              : boost::make_optional(ReadPreferenceSetting::get(opCtx).toInnerBSON()),
          opCtx->getWriteConcern().isImplicitDefaultWriteConcern()
              ? boost::none
              : boost::make_optional(opCtx->getWriteConcern().toBSON()),
          readConcern,
          std::make_unique<APIParameters>(APIParameters::get(opCtx)),
          collectionType,
          maxTimeMS) {}

BSONObj Key::toBson(OperationContext* opCtx, const SerializationOptions& opts) const {
    BSONObjBuilder bob;

    // We'll take care of appending this one outside of the appendTo() call below since it needs
    // an OperationContext in some re-parsing cases. The rest is simpler.
    bob.append("queryShape", _universalComponents._queryShape->toBson(opCtx, opts));

    _universalComponents.appendTo(bob, opts);
    appendCommandSpecificComponents(bob, opts);
    return bob.obj();
}
}  // namespace mongo::query_stats