/// <summary>
/// Finds and dequeues a message from the queue.
/// If there is not message, returns null
/// </summary>
private async Task <Tuple <QueueMessage, int, int> > DequeueMessage(bool fifo, bool getInfo, ClearDecision clear)
{
QueueMessage message = null;
int prioMessageCount = 0;
int messageCount = 0;
await _queue.RunInListSync(() =>
{
//pull from prefential messages
if (_queue.PriorityMessagesList.Count > 0)
{
if (fifo)
{
// ReSharper disable once PossibleNullReferenceException
message = _queue.PriorityMessagesList.First.Value;
_queue.PriorityMessagesList.RemoveFirst();
}
else
{
// ReSharper disable once PossibleNullReferenceException
message = _queue.PriorityMessagesList.Last.Value;
_queue.PriorityMessagesList.RemoveLast();
}
if (message != null)
{
message.IsInQueue = false;
}
}
//if there is no prefential message, pull from standard messages
if (message == null && _queue.MessagesList.Count > 0)
{
if (fifo)
{
// ReSharper disable once PossibleNullReferenceException
message = _queue.MessagesList.First.Value;
_queue.MessagesList.RemoveFirst();
}
else
{
// ReSharper disable once PossibleNullReferenceException
message = _queue.MessagesList.Last.Value;
_queue.MessagesList.RemoveLast();
}
if (message != null)
{
message.IsInQueue = false;
}
}
if (getInfo)
{
prioMessageCount = _queue.PriorityMessageCount();
messageCount = _queue.MessageCount();
}
if (clear == ClearDecision.All)
{
_queue.ClearAllMessages();
}
else if (clear == ClearDecision.HighPriority)
{
_queue.ClearHighPriorityMessages();
}
else if (clear == ClearDecision.DefaultPriority)
{
_queue.ClearRegularMessages();
}
});
return(new Tuple <QueueMessage, int, int>(message, prioMessageCount, messageCount));
}
