/**
 *    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.
 */

#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kCommand

#include "mongo/platform/basic.h"

#include <vector>

#include "mongo/db/auth/action_set.h"
#include "mongo/db/auth/action_type.h"
#include "mongo/db/auth/privilege.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/database.h"
#include "mongo/db/catalog/index_catalog.h"
#include "mongo/db/commands.h"
#include "mongo/db/curop.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/index/expression_keys_private.h"
#include "mongo/db/index/haystack_access_method.h"
#include "mongo/db/index/haystack_access_method_internal.h"
#include "mongo/db/index/index_access_method.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/index_names.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/query/find_common.h"
#include "mongo/db/query/internal_plans.h"
#include "mongo/logv2/log.h"

/**
 * Examines all documents in a given radius of a given point.
 * Returns all documents that match a given search restriction.
 * See http://dochub.mongodb.org/core/haystackindexes
 *
 * Use when you want to look for restaurants within 25 miles with a certain name.
 * Don't use when you want to find the closest open restaurants.
 */
namespace mongo {
namespace {
Rarely geoSearchDeprecationSampler;  // Used to occasionally log deprecation messages.
bool loggedStartupWarning = false;
}  // namespace
using std::string;
using std::vector;

class GeoHaystackSearchCommand : public ErrmsgCommandDeprecated {
public:
    GeoHaystackSearchCommand() : ErrmsgCommandDeprecated("geoSearch") {}

    virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
        return false;
    }

    AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
        return AllowedOnSecondary::kAlways;
    }

    ReadConcernSupportResult supportsReadConcern(const BSONObj& cmdObj,
                                                 repl::ReadConcernLevel level) const final {
        // geoSearch must support read concerns in order to be run in transactions.
        return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
    }

    bool shouldAffectReadConcernCounter() const override {
        return true;
    }

    ReadWriteType getReadWriteType() const {
        return ReadWriteType::kRead;
    }

    std::size_t reserveBytesForReply() const override {
        return FindCommon::kInitReplyBufferSize;
    }

    virtual void addRequiredPrivileges(const std::string& dbname,
                                       const BSONObj& cmdObj,
                                       std::vector<Privilege>* out) const {
        ActionSet actions;
        actions.addAction(ActionType::find);
        out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
    }

    void searchHaystack(const HaystackAccessMethod* ham,
                        OperationContext* opCtx,
                        const Collection* collection,
                        const BSONObj& nearObj,
                        double maxDistance,
                        const BSONObj& search,
                        BSONObjBuilder* result,
                        unsigned limit) {
        Timer t;

        LOGV2_DEBUG(20680,
                    1,
                    "SEARCH near:{nearObj} maxDistance:{maxDistance} search: {search}",
                    "nearObj"_attr = redact(nearObj),
                    "maxDistance"_attr = maxDistance,
                    "search"_attr = redact(search));
        int x, y;
        {
            BSONObjIterator i(nearObj);
            x = ExpressionKeysPrivate::hashHaystackElement(i.next(), ham->_bucketSize);
            y = ExpressionKeysPrivate::hashHaystackElement(i.next(), ham->_bucketSize);
        }
        int scale = static_cast<int>(ceil(maxDistance / ham->_bucketSize));

        GeoHaystackSearchHopper hopper(
            opCtx, nearObj, maxDistance, limit, ham->_geoField, collection);

        long long btreeMatches = 0;

        for (int a = -scale; a <= scale && !hopper.limitReached(); ++a) {
            for (int b = -scale; b <= scale && !hopper.limitReached(); ++b) {
                BSONObjBuilder bb;
                bb.append("", ExpressionKeysPrivate::makeHaystackString(x + a, y + b));

                for (unsigned i = 0; i < ham->_otherFields.size(); i++) {
                    // See if the non-geo field we're indexing on is in the provided search term.
                    BSONElement e = dps::extractElementAtPath(search, ham->_otherFields[i]);
                    if (e.eoo())
                        bb.appendNull("");
                    else
                        bb.appendAs(e, "");
                }

                BSONObj key = bb.obj();

                stdx::unordered_set<RecordId, RecordId::Hasher> thisPass;


                auto exec = InternalPlanner::indexScan(opCtx,
                                                       collection,
                                                       ham->_descriptor,
                                                       key,
                                                       key,
                                                       BoundInclusion::kIncludeBothStartAndEndKeys,
                                                       PlanYieldPolicy::YieldPolicy::NO_YIELD);
                PlanExecutor::ExecState state;
                BSONObj obj;
                RecordId loc;
                while (PlanExecutor::ADVANCED == (state = exec->getNext(&obj, &loc))) {
                    if (hopper.limitReached()) {
                        break;
                    }
                    pair<stdx::unordered_set<RecordId, RecordId::Hasher>::iterator, bool> p =
                        thisPass.insert(loc);
                    // If a new element was inserted (haven't seen the RecordId before), p.second
                    // is true.
                    if (p.second) {
                        hopper.consider(loc);
                        btreeMatches++;
                    }
                }

                // Non-yielding collection scans from InternalPlanner will never error.
                invariant(PlanExecutor::ADVANCED == state || PlanExecutor::IS_EOF == state);
            }
        }

        BSONArrayBuilder arr(result->subarrayStart("results"));
        int num = hopper.appendResultsTo(&arr);
        arr.done();

        {
            BSONObjBuilder b(result->subobjStart("stats"));
            b.append("time", t.millis());
            b.appendNumber("btreeMatches", btreeMatches);
            b.append("n", num);
            b.done();
        }
    }

    bool errmsgRun(OperationContext* opCtx,
                   const string& dbname,
                   const BSONObj& cmdObj,
                   string& errmsg,
                   BSONObjBuilder& result) {
        if (!loggedStartupWarning) {
            LOGV2_OPTIONS(4670603,
                          {logv2::LogTag::kStartupWarnings},
                          "Support for geoSearch has been deprecated. Instead, create a 2d index "
                          "and use $geoNear or $geoWithin. See "
                          "https://dochub.mongodb.org/core/4.4-deprecate-geoHaystack");
            loggedStartupWarning = true;
            geoSearchDeprecationSampler.tick();
        } else if (geoSearchDeprecationSampler.tick()) {
            LOGV2_WARNING(4670604,
                          "Support for geoSearch has been deprecated. Instead, create a 2d index "
                          "and use $geoNear or $geoWithin. See "
                          "https://dochub.mongodb.org/core/4.4-deprecate-geoHaystack");
        }

        uassert(ErrorCodes::InvalidOptions,
                "read concern snapshot is not supported for geoSearch outside of transactions",
                repl::ReadConcernArgs::get(opCtx).getLevel() !=
                        repl::ReadConcernLevel::kSnapshotReadConcern ||
                    opCtx->inMultiDocumentTransaction());

        const NamespaceString nss = CommandHelpers::parseNsCollectionRequired(dbname, cmdObj);

        AutoGetCollectionForReadCommand ctx(opCtx, nss);

        // Check whether we are allowed to read from this node after acquiring our locks.
        auto replCoord = repl::ReplicationCoordinator::get(opCtx);
        uassertStatusOK(replCoord->checkCanServeReadsFor(
            opCtx, nss, ReadPreferenceSetting::get(opCtx).canRunOnSecondary()));

        const Collection* collection = ctx.getCollection();
        if (!collection) {
            errmsg = "can't find ns";
            return false;
        }

        vector<const IndexDescriptor*> idxs;
        collection->getIndexCatalog()->findIndexByType(opCtx, IndexNames::GEO_HAYSTACK, idxs);
        if (idxs.size() == 0) {
            errmsg = "no geoSearch index";
            return false;
        }
        if (idxs.size() > 1) {
            errmsg = "more than 1 geosearch index";
            return false;
        }

        BSONElement nearElt = cmdObj["near"];
        BSONElement maxDistance = cmdObj["maxDistance"];
        BSONElement search = cmdObj["search"];

        uassert(13318, "near needs to be an array", nearElt.isABSONObj());
        uassert(13319, "maxDistance needs a number", maxDistance.isNumber());
        uassert(13320, "search needs to be an object", search.type() == Object);

        unsigned limit = 50;
        if (cmdObj["limit"].isNumber())
            limit = static_cast<unsigned>(cmdObj["limit"].numberInt());

        const IndexDescriptor* desc = idxs[0];
        auto ham = static_cast<const HaystackAccessMethod*>(
            collection->getIndexCatalog()->getEntry(desc)->accessMethod());
        searchHaystack(ham,
                       opCtx,
                       collection,
                       nearElt.Obj(),
                       maxDistance.numberDouble(),
                       search.Obj(),
                       &result,
                       limit);
        return 1;
    }
} nameSearchCommand;

}  // namespace mongo