fleshing out snackbar message queue

Author: ButchersBoy

MaterialDesignThemes.Wpf/Snackbar.cs

@@ -1,6 +1,8 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
@@ -44,7 +46,7 @@ ..maybe the message queue is the controller...i dunno right now...
 
         Multiple windows...having the option for one shared queue is nice...if a notification comes in, we can route to the foreground window...
 
-
+        * need to pause timers if a dialog is shown
 
         <Snackbar MessageQueue="{Binding MessageQueue}" />
 
@@ -57,52 +59,137 @@ public interface ISnackbarMessageQueue
         void Post(object content, object actionContent, Action actionHandler);
 
         void Post<TArgument>(object content, object actionContent, Action<TArgument> actionHandler, TArgument actionArgument);
-    }
+    }   
 
-    internal class SnackbarMessageQueueRegistration
+    internal class SnackbarMessage
     {
-        public SnackbarMessageQueueRegistration(Snackbar2 snackbar2)
+        public SnackbarMessage(object content, object actionContent = null, object actionHandler = null, object actionArgument = null, Type argumentType = null)
         {
-            Snackbar2 = snackbar2;
+            Content = content;
+            ActionContent = actionContent;
+            ActionHandler = actionHandler;
+            ActionArgument = actionArgument;
+            ArgumentType = argumentType;
         }
 
-        public Snackbar2 Snackbar2 { get; }
+        public object Content { get; }
+
+        public object ActionContent { get; }
+
+        public object ActionHandler { get; }
+
+        public object ActionArgument { get; }
+
+        public Type ArgumentType { get; }
     }
 
-    public class SnackbarMessageQueue : ISnackbarMessageQueue
+    public class SnackbarMessageQueue : ISnackbarMessageQueue, IDisposable
     {
-        private readonly IList<SnackbarMessageQueueRegistration> _pairedSnackbars = new List<SnackbarMessageQueueRegistration>();
+        private readonly HashSet<Snackbar2> _pairedSnackbars = new HashSet<Snackbar2>();
+        private readonly Queue<SnackbarMessage> _snackbarMessages = new Queue<SnackbarMessage>();        
+        private readonly ManualResetEvent _disposedEvent = new ManualResetEvent(false);
+        private bool _isDisposed;
+
+        public SnackbarMessageQueue()
+        {
+            Task.Factory.StartNew(Pump);
+        }
 
         //oh if only I had Disposable.Create in this lib :)  tempted to copy it in like dragabalz, 
         //but this is an internal method so no one will know my direty Action disposer...
         internal Action Pair(Snackbar2 snackbar)
         {
-            //assume this internal method is on Dispatcher
-
             if (snackbar == null) throw new ArgumentNullException(nameof(snackbar));
 
-      //      if (_pairedSnackbars)
-        //    _pairedSnackbars.Add(snackbar);
-
-          //  return () => _pairedSnackbars.Remove(snackbar);
-            return null;
+            _pairedSnackbars.Add(snackbar);
 
-            //TODO worry about loading unloading...could cause a little leaky if u not carefull...
+            return () => _pairedSnackbars.Remove(snackbar);            
         }
 
         public void Post(object content)
         {
-            throw new NotImplementedException();
+            if (content == null) throw new ArgumentNullException(nameof(content));
+
+            _snackbarMessages.Enqueue(new SnackbarMessage(content));
+            _messageWaitingEvent.Set();
         }
 
         public void Post(object content, object actionContent, Action actionHandler)
         {
-            throw new NotImplementedException();
+            if (content == null) throw new ArgumentNullException(nameof(content));
+
+            _snackbarMessages.Enqueue(new SnackbarMessage(content, actionContent, actionHandler));
+            _messageWaitingEvent.Set();
         }
 
         public void Post<TArgument>(object content, object actionContent, Action<TArgument> actionHandler, TArgument actionArgument)
         {
-            throw new NotImplementedException();
+            if (content == null) throw new ArgumentNullException(nameof(content));
+
+            if (actionContent != null ^ actionHandler != null ^ actionArgument != null)
+            {
+                throw new ArgumentException("All action arguments must be provided if any are provided.", nameof(actionContent));
+            }
+
+            var argumentType = actionArgument != null ? typeof(TArgument) : null;
+
+            _snackbarMessages.Enqueue(new SnackbarMessage(content, actionContent, actionHandler, actionArgument, argumentType));
+            _messageWaitingEvent.Set();
+        }
+        
+        private readonly ManualResetEvent _messageWaitingEvent = new ManualResetEvent(false);
+
+        private async void Pump()
+        {
+            while (!_isDisposed)
+            {
+                var eventId = WaitHandle.WaitAny(new WaitHandle[] {_disposedEvent, _messageWaitingEvent});
+                if (eventId == 0) continue;
+                
+                //find a target
+                var snackbar = _pairedSnackbars.FirstOrDefault(sb =>
+                {
+                    if (!sb.IsLoaded || sb.Visibility != Visibility.Visible) return false;
+                    var window = Window.GetWindow(sb);
+                    return window != null && window.WindowState != WindowState.Minimized;
+                });
+
+                if (snackbar != null)
+                {
+                    var message = _snackbarMessages.Dequeue();
+                    //TODO check duplicates
+                    //TODO manage awaiting of animations
+                    //TODO action callbacks
+                    await Show(snackbar, message);
+
+                    //THOUGHT: I think we need a complete "SnackbarMessage" control, within the Snackbar...to ensure the callbacks are safely wired to the correct Post message 
+                }                
+
+                if (_snackbarMessages.Count > 0)
+                    _messageWaitingEvent.Set();
+            }         
+            
+        }
+
+        private async Task Show(Snackbar2 snackbar, SnackbarMessage message)
+        {
+            await Task.Run(() =>
+            {
+                //TODO set message on snackbar
+                snackbar.Dispatcher.BeginInvoke(new Action(() => { }));
+
+                //wait
+                _disposedEvent.WaitOne(3000);
+
+                //remove message on snackbar
+                snackbar.Dispatcher.BeginInvoke(new Action(() => { }));
+            });
+        }
+
+        public void Dispose()
+        {
+            _isDisposed = true;
+            _disposedEvent.Set();
         }
     }