private async Task <List <BranchHoliday> > GetBranchesHolidays(long chatId)
{
if (branchHolidays != null)
{
return(branchHolidays);
}
var allTimeZones = TimeZoneInfo.GetSystemTimeZones();
// get "current" days for all possible time zones
var earliestTimeZoneDiff = allTimeZones.Min(tz => tz.BaseUtcOffset);
var latestTimeZoneDiff = allTimeZones.Max(tz => tz.BaseUtcOffset);
var earliestNowDay = DateTime.UtcNow.Add(earliestTimeZoneDiff).Date;
var latestNowDay = DateTime.UtcNow.Add(latestTimeZoneDiff).Date;
branchHolidays = await crmService.GetBranchHolidays(chatId, earliestNowDay, latestNowDay);
return(branchHolidays);
}