/**
 *    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_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kQuery

#include "mongo/platform/basic.h"

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

#include <boost/optional.hpp>

#include "mongo/db/command_generic_argument.h"
#include "mongo/db/commands.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/repl/bson_extract_optime.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/str.h"

namespace mongo {

namespace {

const char kCollectionField[] = "collection";
const char kBatchSizeField[] = "batchSize";
const char kAwaitDataTimeoutField[] = "maxTimeMS";
const char kTermField[] = "term";
const char kLastKnownCommittedOpTimeField[] = "lastKnownCommittedOpTime";

}  // namespace

const char GetMoreRequest::kGetMoreCommandName[] = "getMore";

GetMoreRequest::GetMoreRequest() : cursorid(0), batchSize(0) {}

GetMoreRequest::GetMoreRequest(NamespaceString namespaceString,
                               CursorId id,
                               boost::optional<std::int64_t> sizeOfBatch,
                               boost::optional<Milliseconds> awaitDataTimeout,
                               boost::optional<long long> term,
                               boost::optional<repl::OpTime> lastKnownCommittedOpTime)
    : nss(std::move(namespaceString)),
      cursorid(id),
      batchSize(sizeOfBatch),
      awaitDataTimeout(awaitDataTimeout),
      term(term),
      lastKnownCommittedOpTime(lastKnownCommittedOpTime) {}

Status GetMoreRequest::isValid() const {
    if (!nss.isValid()) {
        return Status(ErrorCodes::InvalidNamespace,
                      str::stream() << "Invalid namespace for getMore: " << nss.ns());
    }

    if (cursorid == 0) {
        return Status(ErrorCodes::BadValue, "Cursor id for getMore must be non-zero");
    }

    if (batchSize && *batchSize <= 0) {
        return Status(ErrorCodes::BadValue,
                      str::stream() << "Batch size for getMore must be positive, "
                                    << "but received: "
                                    << *batchSize);
    }

    return Status::OK();
}

// static
StatusWith<GetMoreRequest> GetMoreRequest::parseFromBSON(const std::string& dbname,
                                                         const BSONObj& cmdObj) {
    // Required fields.
    boost::optional<CursorId> cursorid;
    boost::optional<NamespaceString> nss;

    // Optional fields.
    boost::optional<std::int64_t> batchSize;
    boost::optional<Milliseconds> awaitDataTimeout;
    boost::optional<long long> term;
    boost::optional<repl::OpTime> lastKnownCommittedOpTime;

    for (BSONElement el : cmdObj) {
        const auto fieldName = el.fieldNameStringData();
        if (fieldName == kGetMoreCommandName) {
            if (el.type() != BSONType::NumberLong) {
                return {ErrorCodes::TypeMismatch,
                        str::stream() << "Field 'getMore' must be of type long in: " << cmdObj};
            }

            cursorid = el.Long();
        } else if (fieldName == kCollectionField) {
            if (el.type() != BSONType::String) {
                return {ErrorCodes::TypeMismatch,
                        str::stream() << "Field 'collection' must be of type string in: "
                                      << cmdObj};
            }

            BSONElement collElt = cmdObj["collection"];
            const std::string coll = (collElt.type() == BSONType::String) ? collElt.String() : "";
            nss = NamespaceString(dbname, coll);
        } else if (fieldName == kBatchSizeField) {
            if (!el.isNumber()) {
                return {ErrorCodes::TypeMismatch,
                        str::stream() << "Field 'batchSize' must be a number in: " << cmdObj};
            }

            batchSize = el.numberLong();
        } else if (fieldName == kAwaitDataTimeoutField) {
            auto maxAwaitDataTime = QueryRequest::parseMaxTimeMS(el);
            if (!maxAwaitDataTime.isOK()) {
                return maxAwaitDataTime.getStatus();
            }

            if (maxAwaitDataTime.getValue()) {
                awaitDataTimeout = Milliseconds(maxAwaitDataTime.getValue());
            }
        } else if (fieldName == kTermField) {
            if (el.type() != BSONType::NumberLong) {
                return {ErrorCodes::TypeMismatch,
                        str::stream() << "Field 'term' must be of type NumberLong in: " << cmdObj};
            }
            term = el.Long();
        } else if (fieldName == kLastKnownCommittedOpTimeField) {
            repl::OpTime ot;
            Status status = bsonExtractOpTimeField(el.wrap(), kLastKnownCommittedOpTimeField, &ot);
            if (!status.isOK()) {
                return status;
            }
            lastKnownCommittedOpTime = ot;
        } else if (!isGenericArgument(fieldName)) {
            return {ErrorCodes::FailedToParse,
                    str::stream() << "Failed to parse: " << cmdObj << ". "
                                  << "Unrecognized field '"
                                  << fieldName
                                  << "'."};
        }
    }

    if (!cursorid) {
        return {ErrorCodes::FailedToParse,
                str::stream() << "Field 'getMore' missing in: " << cmdObj};
    }

    if (!nss) {
        return {ErrorCodes::FailedToParse,
                str::stream() << "Field 'collection' missing in: " << cmdObj};
    }

    GetMoreRequest request(
        std::move(*nss), *cursorid, batchSize, awaitDataTimeout, term, lastKnownCommittedOpTime);
    Status validStatus = request.isValid();
    if (!validStatus.isOK()) {
        return validStatus;
    }

    return request;
}

BSONObj GetMoreRequest::toBSON() const {
    BSONObjBuilder builder;

    builder.append(kGetMoreCommandName, cursorid);
    builder.append(kCollectionField, nss.coll());

    if (batchSize) {
        builder.append(kBatchSizeField, *batchSize);
    }

    if (awaitDataTimeout) {
        builder.append(kAwaitDataTimeoutField, durationCount<Milliseconds>(*awaitDataTimeout));
    }

    if (term) {
        builder.append(kTermField, *term);
    }

    if (lastKnownCommittedOpTime) {
        lastKnownCommittedOpTime->append(&builder, kLastKnownCommittedOpTimeField);
    }

    return builder.obj();
}

}  // namespace mongo