Log whether a donut drag ended in a drop, and why a drop didn't convert (#784)

src/Filee.App/Services/RadialController.cs

@@ -262,10 +262,10 @@ private RadialWindow EnsureWindow()
             }
         };
         // One line per drag, to tell "the drag never reached the donut" from "it did but nothing lit up" when someone
-        // reports a donut that doesn't react.
-        window.DragSummary += (events, hit, lit) =>
-            log.LogInformation("Drag over the donut: {Events} move event(s), ended on {Kind} {Index}, drawn lit {Lit:0.00}",
-                events, hit.Kind, hit.Index, lit);
+        // reports a donut that doesn't react, and a drop from a drag the system ended without one (#784).
+        window.DragSummary += (events, hit, lit, dropped) =>
+            log.LogInformation("Drag over the donut: {Events} move event(s), ended on {Kind} {Index}, drawn lit {Lit:0.00}{Drop}",
+                events, hit.Kind, hit.Index, lit, dropped ? "" : ", left without a drop");
         window.EscapePressed += () => Close();
         window.Deactivated += (_, _) =>
         {
@@ -322,13 +322,19 @@ private void Convert(int index, int sub, IReadOnlyList<string> files, WebDrop? w
         var orphaned = web is null && files.Any(WebDrop.IsPlaceholder);
         if (viewModel.PresetAt(index, sub) is not { } preset || SourcesFor(preset, files) is not { Count: > 0 } sources || orphaned)
         {
+            // Said in the log, as a drop that closes the donut looks the same as one the system never delivered (#784).
+            log.LogInformation("The donut closed without converting: {Reason}",
+                viewModel.PresetAt(index, sub) is not { } slice ? $"no preset at slice {index}/{sub}"
+                : orphaned ? "the browser drop behind the files is gone"
+                : $"none of the {files.Count} file(s) fit preset {slice.Id}");
             web?.Dispose();
             Close();
             return;
         }
 
         if (preset.IsTool)
         {
+            log.LogInformation("Opening {Preset} for {Count} file(s)", preset.Id, sources.Count);
             var near = _window?.Position;
             Close(animate: false);
             if (web is null)

src/Filee.App/Views/RadialWindow.axaml.cs

@@ -42,10 +42,10 @@ public RadialWindow()
     public event Action? DragLeft;
 
     /// <summary>
-    /// After a drag ends (drop or leave): how many drag-over events came in, where the last one was and how far that
-    /// slice was drawn lit up (0 to 1).
+    /// After a drag ends (drop or leave): how many drag-over events came in, where the last one was, how far that
+    /// slice was drawn lit up (0 to 1) and whether it ended in a drop.
     /// </summary>
-    public event Action<int, DonutHit, double>? DragSummary;
+    public event Action<int, DonutHit, double, bool>? DragSummary;
 
     private int _dragOverEvents;
     private bool _dragOffersFiles;
@@ -88,15 +88,15 @@ private void OnDragOver(object? sender, DragEventArgs e)
 
     private void OnDragLeave(object? sender, DragEventArgs e)
     {
-        DragSummary?.Invoke(_dragOverEvents, _lastDragHit, Donut.LitAmount(_lastDragHit.Index));
+        DragSummary?.Invoke(_dragOverEvents, _lastDragHit, Donut.LitAmount(_lastDragHit.Index), false);
         Donut.ExternalDragLeft(_lastDragAt);
         DragLeft?.Invoke();
     }
 
     private void OnDrop(object? sender, DragEventArgs e)
     {
         var hit = Donut.HitTest(e.GetPosition(Donut));
-        DragSummary?.Invoke(_dragOverEvents, hit, Donut.LitAmount(hit.Index));
+        DragSummary?.Invoke(_dragOverEvents, hit, Donut.LitAmount(hit.Index), true);
         Donut.CollapseGroup();
         Donut.SetExternalHighlight(-1);
         e.DragEffects = Donut.Converts(hit) ? DragDropEffects.Copy : DragDropEffects.None;