/**
 *    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.
 */

#include "mongo/platform/basic.h"

#include <algorithm>

#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/commands.h"
#include "mongo/db/s/split_vector.h"

namespace mongo {

using std::string;
using std::stringstream;

namespace {

class SplitVector : public ErrmsgCommandDeprecated {
public:
    SplitVector() : ErrmsgCommandDeprecated("splitVector") {}

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

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

    std::string help() const override {
        return "Internal command.\n"
               "examples:\n"
               "  { splitVector : \"blog.post\" , keyPattern:{x:1} , min:{x:10} , max:{x:20}, "
               "maxChunkSize:200 }\n"
               "  maxChunkSize unit in MBs\n"
               "  May optionally specify 'maxSplitPoints' and 'maxChunkObjects' to avoid "
               "traversing the whole chunk\n"
               "  \n"
               "  { splitVector : \"blog.post\" , keyPattern:{x:1} , min:{x:10} , max:{x:20}, "
               "force: true }\n"
               "  'force' will produce one split point even if data is small; defaults to false\n"
               "NOTE: This command may take a while to run";
    }

    Status checkAuthForCommand(Client* client,
                               const std::string& dbname,
                               const BSONObj& cmdObj) const override {
        if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
                ResourcePattern::forExactNamespace(NamespaceString(parseNs(dbname, cmdObj))),
                ActionType::splitVector)) {
            return Status(ErrorCodes::Unauthorized, "Unauthorized");
        }
        return Status::OK();
    }

    std::string parseNs(const string& dbname, const BSONObj& cmdObj) const override {
        return CommandHelpers::CommandHelpers::parseNsFullyQualified(cmdObj);
    }

    bool errmsgRun(OperationContext* opCtx,
                   const string& dbname,
                   const BSONObj& jsobj,
                   string& errmsg,
                   BSONObjBuilder& result) override {

        const NamespaceString nss = NamespaceString(parseNs(dbname, jsobj));
        BSONObj keyPattern = jsobj.getObjectField("keyPattern");

        if (keyPattern.isEmpty()) {
            errmsg = "no key pattern found in splitVector";
            return false;
        }

        BSONObj min = jsobj.getObjectField("min");
        BSONObj max = jsobj.getObjectField("max");
        if (min.isEmpty() != max.isEmpty()) {
            errmsg = "either provide both min and max or leave both empty";
            return false;
        }

        bool force = false;
        BSONElement forceElem = jsobj["force"];
        if (forceElem.trueValue()) {
            force = true;
        }

        boost::optional<long long> maxSplitPoints;
        BSONElement maxSplitPointsElem = jsobj["maxSplitPoints"];
        if (maxSplitPointsElem.isNumber()) {
            maxSplitPoints = maxSplitPointsElem.safeNumberLong();
        }

        boost::optional<long long> maxChunkObjects;
        BSONElement maxChunkObjectsElem = jsobj["maxChunkObjects"];
        if (maxChunkObjectsElem.isNumber()) {
            maxChunkObjects = maxChunkObjectsElem.safeNumberLong();
            uassert(ErrorCodes::InvalidOptions,
                    "maxChunkObjects must be greater than 0",
                    *maxChunkObjects > 0);
        }

        const auto maxChunkSizeBytes = [&]() {
            BSONElement maxSizeElem = jsobj["maxChunkSize"];
            BSONElement maxSizeBytesElem = jsobj["maxChunkSizeBytes"];

            boost::optional<long long> ret = boost::none;
            // Use maxChunkSize if present otherwise maxChunkSizeBytes
            if (maxSizeElem.isNumber()) {
                long long maxChunkSizeMB = maxSizeElem.safeNumberLong();
                // Prevent maxChunkSizeBytes overflow. Check aimed to avoid fuzzer failures
                // since users are definitely not expected to specify maxChunkSize in exabytes.
                uassert(ErrorCodes::InvalidOptions,
                        str::stream()
                            << "The specified maxChunkSize in MB is too big: " << maxChunkSizeMB,
                        maxChunkSizeMB <= (LLONG_MAX >> 20));
                ret = maxChunkSizeMB << 20;
            } else if (maxSizeBytesElem.isNumber()) {
                ret = maxSizeBytesElem.safeNumberLong();
            }

            uassert(ErrorCodes::InvalidOptions,
                    "The specified max chunk size must be at least 1MB",
                    ret == boost::none || *ret >= 1024 * 1024);
            return ret;
        }();

        auto splitKeys = splitVector(opCtx,
                                     nss,
                                     keyPattern,
                                     min,
                                     max,
                                     force,
                                     maxSplitPoints,
                                     maxChunkObjects,
                                     maxChunkSizeBytes);

        result.append("splitKeys", splitKeys);
        return true;
    }

} cmdSplitVector;

}  // namespace
}  // namespace mongo