Ava UI: Add Notifications and Cleanup (#4275)

* Ava UI: Add Notifications and Cleanup

* Revert notifications on ErrorDialog

* remove unused code from game list views

* Fix cast

Ryujinx.Ava/UI/Helpers/NotificationHelper.cs

@@ -0,0 +1,65 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Notifications;
+using Avalonia.Threading;
+using Ryujinx.Ava.Common.Locale;
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Ryujinx.Ava.UI.Helpers
+{
+    public static class NotificationHelper
+    {
+        private const int MaxNotifications      = 4; 
+        private const int NotificationDelayInMs = 5000;
+
+        private static WindowNotificationManager _notificationManager;
+
+        private static readonly ManualResetEvent                 _templateAppliedEvent = new(false);
+        private static readonly BlockingCollection<Notification> _notifications        = new();
+
+        public static void SetNotificationManager(Window host)
+        {
+            _notificationManager = new WindowNotificationManager(host)
+            {
+                Position = NotificationPosition.BottomRight,
+                MaxItems = MaxNotifications,
+                Margin   = new Thickness(0, 0, 15, 40)
+            };
+
+            _notificationManager.TemplateApplied += (sender, args) =>
+            {
+                _templateAppliedEvent.Set();
+            };
+
+            Task.Run(async () =>
+            {
+                _templateAppliedEvent.WaitOne();
+
+                foreach (var notification in _notifications.GetConsumingEnumerable())
+                {
+                    Dispatcher.UIThread.Post(() =>
+                    {
+                        _notificationManager.Show(notification);
+                    });
+
+                    await Task.Delay(NotificationDelayInMs / MaxNotifications);
+                }
+            });
+        }
+
+        public static void Show(string title, string text, NotificationType type, bool waitingExit = false, Action onClick = null, Action onClose = null)
+        {
+            var delay = waitingExit ? TimeSpan.FromMilliseconds(0) : TimeSpan.FromMilliseconds(NotificationDelayInMs);
+
+            _notifications.Add(new Notification(title, text, type, delay, onClick, onClose));
+        }
+
+        public static void ShowError(string message)
+        {
+            Show(LocaleManager.Instance[LocaleKeys.DialogErrorTitle], $"{LocaleManager.Instance[LocaleKeys.DialogErrorMessage]}\n\n{message}", NotificationType.Error);
+        }
+    }
+}