public static IObservable <TReturn> CreateDatatransferWithHandshake <TReturn>(this IPlc plc, string triggerAddress, string ackTriggerAddress, Func <IPlc, Task <TReturn> > readData, bool initialTransfer)
{
return(Observable.Create <TReturn>(async observer =>
{
var subscriptions = new CompositeDisposable();
var notification = plc
.CreateNotification <bool>(triggerAddress, TransmissionMode.OnChange, TimeSpan.Zero)
.Publish()
.RefCount();
if (initialTransfer)
{
var initialValue = await ReadData(plc, readData);
observer.OnNext(initialValue);
}
notification
.Where(trigger => trigger)
.Select(_ => ReadDataAndAcknowlodge(plc, readData, ackTriggerAddress))
.Subscribe(observer)
.AddDisposableTo(subscriptions);
notification
.Where(trigger => !trigger)
.Select(_ => plc.SetValue(ackTriggerAddress, false))
.Subscribe()
.AddDisposableTo(subscriptions);
return subscriptions;
}));
}