DYN-8564: run autocomplete search in background thread

src/DynamoCoreWpf/Controls/NodeAutoCompleteSearchControl.xaml

@@ -7,6 +7,8 @@
              xmlns:p="clr-namespace:Dynamo.Wpf.Properties"
              xmlns:uicontrols="clr-namespace:Dynamo.UI.Controls"
              xmlns:resx="clr-namespace:Dynamo.Properties;assembly=DynamoCore"
+             xmlns:local="clr-namespace:Dynamo.PackageManager.UI"
+             xmlns:dynconverters="clr-namespace:Dynamo.Controls"
              mc:Ignorable="d"
              WindowStyle="None"
              AllowsTransparency="True"
@@ -43,6 +45,7 @@
                         Value="{StaticResource LibraryScrollViewerControlTemplate}" />
             </Style>
             <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
+            <dynconverters:InverseBoolToVisibilityConverter x:Key="InverseBooleanToVisibilityConverter" />
         </ResourceDictionary>
     </Window.Resources>
 
@@ -256,7 +259,17 @@
                     <ColumnDefinition Width="Auto" />
                     <ColumnDefinition Width="*" />
                 </Grid.ColumnDefinitions>
+                <local:LoadingAnimationStripeControl
+                    Grid.Column="0"
+                    VerticalAlignment="Center"
+                    Height="35"
+                    MinWidth="240"
+                    AnimationSpeed="10"
+                    Visibility="{Binding ResultsLoaded, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource InverseBooleanToVisibilityConverter}}" 
+                    Margin="8,8,0,8"
+                />
                 <Border BorderThickness="1"
+                        Visibility="{Binding ResultsLoaded, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource BooleanToVisibilityConverter}}" 
                         Background="{StaticResource WorkspaceBackgroundHomeBrush}"
                         CornerRadius="5"
                         Padding="5"
@@ -311,6 +324,7 @@
                 </Border>
 
                 <Button x:Name="btnSuggestions"
+                        IsEnabled="{Binding ResultsLoaded}"
                         Click="DisplaySuggestions"
                         Grid.Column="1">
                     <Button.ToolTip>

src/DynamoCoreWpf/PublicAPI.Unshipped.txt

@@ -2468,6 +2468,8 @@ Dynamo.ViewModels.NodeAutoCompleteSearchViewModel.DisplayLowConfidence.set -> vo
 Dynamo.ViewModels.NodeAutoCompleteSearchViewModel.HideAutocompleteMethodOptions.get -> bool
 Dynamo.ViewModels.NodeAutoCompleteSearchViewModel.IsDisplayingMLRecommendation.get -> bool
 Dynamo.ViewModels.NodeAutoCompleteSearchViewModel.IsMLAutocompleteTOUApproved.get -> bool
+Dynamo.ViewModels.NodeAutoCompleteSearchViewModel.ResultsLoaded.get -> bool
+Dynamo.ViewModels.NodeAutoCompleteSearchViewModel.ResultsLoaded.set -> void
 Dynamo.ViewModels.NodeDialogEventArgs
 Dynamo.ViewModels.NodeDialogEventArgs.Handled.get -> bool
 Dynamo.ViewModels.NodeDialogEventArgs.Handled.set -> void

src/DynamoCoreWpf/ViewModels/Search/NodeAutoCompleteSearchViewModel.cs

@@ -4,6 +4,7 @@
 using System.IO;
 using System.Linq;
 using System.Text.RegularExpressions;
+using System.Threading.Tasks;
 using Dynamo.Configuration;
 using Dynamo.Engine;
 using Dynamo.Graph.Connectors;
@@ -47,6 +48,23 @@ public class NodeAutoCompleteSearchViewModel : SearchViewModel
         private const string nodeClusterAutocompleteMLEndpoint = "MLNodeClusterAutocomplete";
         internal bool IsOpen { get; set; }
 
+        private bool resultsLoaded;
+
+        /// <summary>
+        /// Flag that indicates whether results are loading (false) or they have loaded (true).
+        /// This is set as true for both succesfully and unsuccessfully loading the results.
+        /// </summary>
+        [Obsolete("This method will be removed in a future version of Dynamo")]
+        public bool ResultsLoaded
+        {
+            get { return resultsLoaded; }
+            set
+            {
+                resultsLoaded = value;
+                RaisePropertyChanged(nameof(ResultsLoaded));
+            }
+        }
+
         // Lucene search utility to perform indexing operations just for NodeAutocomplete.
         internal LuceneSearchUtility LuceneUtility
         {
@@ -161,6 +179,7 @@ public bool DisplayLowConfidence
         }
 
         internal event Action<NodeModel> ParentNodeRemoved;
+        private Guid LastRequestGuid;
 
         /// <summary>
         /// Constructor
@@ -290,27 +309,55 @@ internal MLNodeAutoCompletionRequest GenerateRequestForMLAutocomplete()
 
         internal void ShowNodeAutocompleMLResults()
         {
+            //this should run on the UI thread, so thread safety is not a concern
+            LastRequestGuid = Guid.NewGuid();
+            var myRequest = LastRequestGuid;
+
             MLNodeAutoCompletionResponse MLresults = null;
 
             var request = GenerateRequestForMLAutocomplete();
 
             string jsonRequest = JsonConvert.SerializeObject(request);
 
             // Get results from the ML API.
-            try
+            ResultsLoaded = false;
+            Task.Run(() =>
             {
-                MLresults = GetMLNodeAutocompleteResults(jsonRequest);
+                try
+                {
+                    MLresults = GetMLNodeAutocompleteResults(jsonRequest);
+                    this.dynamoViewModel.UIDispatcher.BeginInvoke(() => UpdateUIWithRresults(MLresults, myRequest));
+                }
+                catch (Exception ex)
+                {
+                    this.dynamoViewModel.UIDispatcher.BeginInvoke(() =>
+                    {
+                        ResultsLoaded = true; //fail gracefully
+                        dynamoViewModel.Model.Logger.Log("Unable to fetch ML Node autocomplete results: " + ex.Message);
+                        DisplayAutocompleteMLStaticPage = true;
+                        AutocompleteMLTitle = Resources.LoginNeededTitle;
+                        AutocompleteMLMessage = Resources.LoginNeededMessage;
+                        Analytics.TrackEvent(Actions.View, Categories.NodeAutoCompleteOperations, "UnabletoFetch");
+                        return;
+                    });
+                }
+            });
+        }
+        private void UpdateUIWithRresults(MLNodeAutoCompletionResponse MLresults, Guid myRequest)
+        {
+            if (LastRequestGuid != myRequest)
+            {
+                //a newer request came, we're no longer interested in the results of this one
+                //only latest request has the right to be committed to the UI and internal data structures
+                return;
             }
-            catch (Exception ex)
+            if (!IsOpen)
             {
-                dynamoViewModel.Model.Logger.Log("Unable to fetch ML Node autocomplete results: " + ex.Message);
-                DisplayAutocompleteMLStaticPage = true;
-                AutocompleteMLTitle = Resources.LoginNeededTitle;
-                AutocompleteMLMessage = Resources.LoginNeededMessage;
-                Analytics.TrackEvent(Actions.View, Categories.NodeAutoCompleteOperations, "UnabletoFetch");
+                // view disappeared while the background thread was waiting for the server response.
+                // Ignore the results as we're no longer interested.
                 return;
             }
-
+            ResultsLoaded = true;
             // no results
             if (MLresults == null || MLresults.Results.Count() == 0)
             {

src/NodeAutoCompleteViewExtension/ViewModels/NodeAutoCompleteBarViewModel.cs

@@ -994,7 +994,7 @@ internal void PopulateAutoComplete()
                     if (!IsOpen)
                     {
                         // view disappeared while the background thread was waiting for the server response.
-                        // Ignore the results are we're no longer interested.
+                        // Ignore the results as we're no longer interested.
                         return;
                     }