/**
 *    Copyright (C) 2021-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.
 */


#include "mongo/db/query/query_utils.h"

#include "mongo/db/exec/sbe/match_path.h"

namespace mongo {

bool sortPatternHasPartsWithCommonPrefix(const SortPattern& sortPattern) {
    StringDataSet prefixSet;
    for (const auto& part : sortPattern) {
        // Ignore any $meta sorts that may be present.
        if (!part.fieldPath) {
            continue;
        }
        auto [_, inserted] = prefixSet.insert(part.fieldPath->getFieldName(0));
        if (!inserted) {
            return true;
        }
    }
    return false;
}

bool isIdHackEligibleQuery(const CollectionPtr& collection, const CanonicalQuery& query) {
    const auto& findCommand = query.getFindCommandRequest();
    return !findCommand.getShowRecordId() && findCommand.getHint().isEmpty() &&
        findCommand.getMin().isEmpty() && findCommand.getMax().isEmpty() &&
        !findCommand.getSkip() && CanonicalQuery::isSimpleIdQuery(findCommand.getFilter()) &&
        !findCommand.getTailable() &&
        CollatorInterface::collatorsMatch(query.getCollator(), collection->getDefaultCollator());
}

bool isQuerySbeCompatible(const CollectionPtr* collection, const CanonicalQuery* cq) {
    tassert(6071400,
            "Expected CanonicalQuery and Collection pointer to not be nullptr",
            cq && collection);
    auto expCtx = cq->getExpCtxRaw();

    // If we don't support all expressions used or the query is eligible for IDHack, don't use SBE.
    if (!expCtx || expCtx->sbeCompatibility == SbeCompatibility::notCompatible ||
        (*collection && isIdHackEligibleQuery(*collection, *cq))) {
        return false;
    }

    const auto* proj = cq->getProj();
    if (proj && (proj->requiresMatchDetails() || proj->containsElemMatch())) {
        return false;
    }

    // Queries against the oplog, a change collection, or a time-series collection are not
    // supported. Also queries on the inner side of a $lookup are not considered for SBE.
    const auto& nss = cq->nss();
    if (expCtx->inLookup || nss.isOplog() || nss.isChangeCollection() ||
        nss.isTimeseriesBucketsCollection() || !cq->metadataDeps().none()) {
        return false;
    }

    // TODO SERVER-75715: Remove this code block once SBE support for clustered collection scans is
    // fully implemented.
    // (Ignore FCV check): This is intentional because we always want to use this feature once the
    // feature flag is enabled.
    const bool sbeFull = feature_flags::gFeatureFlagSbeFull.isEnabledAndIgnoreFCVUnsafe();
    if (!sbeFull && (*collection && collection->get()->isClustered())) {
        // Queries against a clustered collection are not currently supported by SBE.
        return false;
    }

    const auto& sortPattern = cq->getSortPattern();
    // If the sort has meta or numeric path components, we cannot use SBE.
    return !sortPattern || std::all_of(sortPattern->begin(), sortPattern->end(), [](auto&& part) {
        return part.fieldPath &&
            !sbe::MatchPath(part.fieldPath->fullPath()).hasNumericPathComponents();
    });
}

bool isQueryPlanSbeCompatible(const QuerySolution* root) {
    tassert(7061701, "Expected QuerySolution pointer to not be nullptr", root);

    // TODO SERVER-52958: Add support in the SBE stage builders for the COUNT_SCAN stage.
    const bool isNotCountScan = !root->hasNode(StageType::STAGE_COUNT_SCAN);

    return isNotCountScan;
}

}  // namespace mongo