public async Task <List <Order> > PickOrderAsync(int count, DateTime at)
{
await BeginTransactionAsync();
var orders = await _context.Orders.ToArrayAsync();
var pickedCount = _context.Orders.Count(o => o.PickedAt > DateTime.MinValue);
if (pickedCount > 0)
{
throw new BadRequestException("이미 추첨한 상태입니다.");
}
var managerIds = await _context.Users
.Where(u => u.IsManager)
.Select(u => u.Id)
.ToListAsync();
var managers = await _context.Orders
.Where(o => o.OrderedAt > at - OrderTolerance && o.OrderedAt < at)
.Where(o => managerIds.Contains(o.UserId))
.ToListAsync();
var candidates = await _context.Orders
.Where(o => o.OrderedAt > at - OrderTolerance && o.OrderedAt < at)
.Where(o => !managerIds.Contains(o.UserId))
.ToListAsync();
var neededCount = Math.Max(count - managers.Count, 0);
if (neededCount < candidates.Count)
{
candidates.Shuffle();
candidates = candidates.GetRange(0, neededCount);
}
if (managers.Count > 0)
{
managers.ForEach(o => o.PickedAt = at);
_context.UpdateRange(managers);
}
if (candidates.Count > 0)
{
candidates.ForEach(o => o.PickedAt = at);
_context.UpdateRange(candidates);
}
managers.AddRange(candidates);
return(managers);
}
