/**
 *    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,
 *    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/change_collection_truncate_markers.h"
#include "mongo/db/change_stream_serverless_helpers.h"
#include "mongo/db/operation_context.h"

namespace mongo {
ChangeCollectionTruncateMarkers::ChangeCollectionTruncateMarkers(TenantId tenantId,
                                                                 std::deque<Marker> markers,
                                                                 int64_t leftoverRecordsCount,
                                                                 int64_t leftoverRecordsBytes,
                                                                 int64_t minBytesPerMarker)
    : CollectionTruncateMarkersWithPartialExpiration(
          std::move(markers), leftoverRecordsCount, leftoverRecordsBytes, minBytesPerMarker),
      _tenantId(std::move(tenantId)) {}

bool ChangeCollectionTruncateMarkers::_hasExcessMarkers(OperationContext* opCtx) const {
    const auto& markers = getMarkers();
    if (markers.empty()) {
        // If there's nothing in the markers queue then we don't have excess markers by definition.
        return false;
    }

    const Marker& oldestMarker = markers.front();
    const auto& [highestRecordIdInserted, _] = getPartialMarker();
    if (highestRecordIdInserted <= oldestMarker.lastRecord) {
        // We cannot expire the marker when the last entry is present there as it would break the
        // requirement of always having at least 1 entry present in the collection.
        return false;
    }

    auto now = opCtx->getServiceContext()->getFastClockSource()->now();
    auto expireAfterSeconds =
        Seconds{change_stream_serverless_helpers::getExpireAfterSeconds(_tenantId)};
    auto expirationTime = now - expireAfterSeconds;

    return oldestMarker.wallTime <= expirationTime;
}
}  // namespace mongo