create DateTimeExtensions

[neozhu]

before

public LoggerAdvancedSpecification(LogsWithPaginationQuery filter)
{
    var timezoneOffset = filter.LocalTimezoneOffset;
    var utcNow = DateTime.UtcNow;
    // Corrected: Add the time zone offset to UTC time to get local time
    var localNow = utcNow.AddHours(timezoneOffset);

    // Calculate the start and end of today in local time
    var startOfTodayLocal = localNow.Date;
    var endOfTodayLocal = startOfTodayLocal.AddDays(1);
    var startOfLast30DaysLocal = startOfTodayLocal.AddDays(-30);

    // Convert local times back to UTC to match the TimeStamp's time zone
    var startOfTodayLocalAsUtc = startOfTodayLocal.AddHours(-timezoneOffset);
    var endOfTodayLocalAsUtc = endOfTodayLocal.AddHours(-timezoneOffset);
    var startOfLast30DaysLocalAsUtc = startOfLast30DaysLocal.AddHours(-timezoneOffset);

    // Build query conditions
    Query.Where(p => p.TimeStamp >= startOfTodayLocalAsUtc && p.TimeStamp < endOfTodayLocalAsUtc,
            filter.ListView == LogListView.CreatedToday)
        .Where(p => p.TimeStamp >= startOfLast30DaysLocalAsUtc, filter.ListView == LogListView.Last30days)
        .Where(p => p.Level == filter.Level.ToString(), filter.Level is not null)
        .Where(x =>x.Message.Contains(filter.Keyword),!string.IsNullOrEmpty(filter.Keyword));
}

after

public LoggerAdvancedSpecification(LogsWithPaginationQuery filter)
{
    DateTime today = DateTime.UtcNow;
    var todayrange = today.GetDateRange("TODAY", filter.LocalTimezoneOffset);
    var last30daysrange = today.GetDateRange("LAST_30_DAYS", filter.LocalTimezoneOffset);
    // Build query conditions
    Query.Where(p => p.TimeStamp >= todayrange.Start && p.TimeStamp < todayrange.End.AddDays(1),
            filter.ListView == LogListView.TODAY)
        .Where(p => p.TimeStamp >= last30daysrange.Start, filter.ListView == LogListView.LAST_30_DAYS)
        .Where(p => p.Level == filter.Level.ToString(), filter.Level is not null)
        .Where(x =>x.Message.Contains(filter.Keyword),!string.IsNullOrEmpty(filter.Keyword));
}