Optimize mail list selection and draft pruning

Wino.Mail.ViewModels.Tests/Collections/WinoMailCollectionTests.cs

@@ -81,6 +81,26 @@ public class WinoMailCollectionTests
         container.ThreadViewModel.Should().BeNull();
     }
 
+    [Fact]
+    public async Task RemoveAsync_ShouldPruneRemainingNonDraftSingle_WhenDraftPruningIsEnabled()
+    {
+        var sut = CreateCollection();
+        sut.PruneSingleNonDraftItems = true;
+
+        var nonDraft = CreateMailCopy(threadId: "shared-thread", creationDate: DateTime.UtcNow.AddMinutes(-1));
+        var draft = CreateMailCopy(threadId: "shared-thread", creationDate: DateTime.UtcNow);
+        draft.IsDraft = true;
+        draft.AssignedFolder = new MailItemFolder { SpecialFolderType = SpecialFolderType.Draft };
+
+        await sut.AddAsync(nonDraft);
+        await sut.AddAsync(draft);
+
+        await sut.RemoveAsync(draft);
+
+        FlattenItems(sut).Should().BeEmpty();
+        sut.ContainsMailUniqueId(nonDraft.UniqueId).Should().BeFalse();
+    }
+
     [Fact]
     public async Task RemoveAsync_ShouldRemoveSingleItem()
     {
@@ -252,6 +272,31 @@ public class WinoMailCollectionTests
         }
     }
 
+    [Fact]
+    public async Task ExecuteSelectionBatchAsync_ShouldRaiseSelectionChangedOnce()
+    {
+        var sut = CreateCollection();
+        var first = CreateMailCopy(threadId: "thread-1");
+        var second = CreateMailCopy(threadId: "thread-2");
+
+        await sut.AddAsync(first);
+        await sut.AddAsync(second);
+
+        var items = FlattenMailItems(sut);
+        var eventCount = 0;
+        sut.ItemSelectionChanged += (_, _) => eventCount++;
+
+        await sut.ExecuteSelectionBatchAsync(() =>
+        {
+            items[0].IsSelected = true;
+            items[1].IsSelected = true;
+            items[0].IsSelected = false;
+        });
+
+        eventCount.Should().Be(1);
+        sut.SelectedItems.Should().ContainSingle();
+    }
+
     private static WinoMailCollection CreateCollection() => new()
     {
         CoreDispatcher = new ImmediateDispatcher()

Wino.Mail.ViewModels/Collections/WinoMailCollection.cs

@@ -44,6 +44,8 @@ public class WinoMailCollection : ObservableRecipient, IRecipient<SelectedItemsC
 
     private readonly ObservableGroupedCollection<object, IMailListItem> _mailItemSource = new ObservableGroupedCollection<object, IMailListItem>();
     private readonly SemaphoreSlim _mutationGate = new(1, 1);
+    private int _selectionNotificationSuppressionCount;
+    private bool _selectionNotificationPending;
 
     public ReadOnlyObservableGroupedCollection<object, IMailListItem> MailItems { get; }
 
@@ -305,6 +307,36 @@ public class WinoMailCollection : ObservableRecipient, IRecipient<SelectedItemsC
         return null;
     }
 
+    public ThreadMailItemViewModel GetThreadByMailUniqueId(Guid uniqueId)
+    {
+        if (_uniqueIdToThreadMap.TryGetValue(uniqueId, out var threadViewModel))
+        {
+            return threadViewModel;
+        }
+
+        _ = Find(uniqueId);
+
+        return _uniqueIdToThreadMap.TryGetValue(uniqueId, out threadViewModel) ? threadViewModel : null;
+    }
+
+    public List<ThreadMailItemViewModel> GetThreadItems()
+    {
+        var threads = new List<ThreadMailItemViewModel>();
+
+        foreach (var group in _mailItemSource)
+        {
+            foreach (var item in group)
+            {
+                if (item is ThreadMailItemViewModel threadItem)
+                {
+                    threads.Add(threadItem);
+                }
+            }
+        }
+
+        return threads;
+    }
+
     private async Task InsertItemInternalAsync(object groupKey, IMailListItem mailItem)
     {
         UpdateUniqueIdHashes(mailItem, true);
@@ -1049,14 +1081,35 @@ public class WinoMailCollection : ObservableRecipient, IRecipient<SelectedItemsC
     public bool IsAllItemsSelected => AllItems.Any() && AllItems.All(a => a.IsSelected);
     public bool HasSingleItemSelected => SelectedItemsCount == 1;
 
-    public async Task ExecuteWithoutRaiseSelectionChangedAsync(Action<IMailListItem> action, bool includeThreads)
+    public async Task ExecuteSelectionBatchAsync(Action action, bool notifySelectionChanged = true)
     {
         try
         {
-            // Do not listen to individual selection changes while we are doing bulk selection.
+            _selectionNotificationSuppressionCount++;
-            Messenger.Unregister<SelectedItemsChangedMessage>(this);
+            await ExecuteUIThread(action);
+        }
+        catch (Exception)
+        {
+        }
+        finally
+        {
+            _selectionNotificationSuppressionCount = Math.Max(0, _selectionNotificationSuppressionCount - 1);
 
-            await ExecuteUIThread(() =>
+            if (_selectionNotificationSuppressionCount == 0)
+            {
+                var shouldNotify = notifySelectionChanged || _selectionNotificationPending;
+                _selectionNotificationPending = false;
+
+                if (shouldNotify)
+                {
+                    await NotifySelectionChangesAsync();
+                }
+            }
+        }
+    }
+
+    public Task ExecuteWithoutRaiseSelectionChangedAsync(Action<IMailListItem> action, bool includeThreads)
+        => ExecuteSelectionBatchAsync(() =>
         {
             if (includeThreads)
             {
@@ -1073,19 +1126,6 @@ public class WinoMailCollection : ObservableRecipient, IRecipient<SelectedItemsC
                 }
             }
         });
-        }
-        catch (Exception)
-        {
-        }
-        finally
-        {
-            Messenger.Unregister<SelectedItemsChangedMessage>(this);
-            Messenger.Register<SelectedItemsChangedMessage>(this);
-            Messenger.Send(new SelectedItemsChangedMessage());
-
-            await NotifySelectionChangesAsync();
-        }
-    }
 
     public Task ToggleSelectAllAsync()
     {
@@ -1144,7 +1184,16 @@ public class WinoMailCollection : ObservableRecipient, IRecipient<SelectedItemsC
         }
     }
 
-    public void Receive(SelectedItemsChangedMessage message) => _ = NotifySelectionChangesAsync();
+    public void Receive(SelectedItemsChangedMessage message)
+    {
+        if (_selectionNotificationSuppressionCount > 0)
+        {
+            _selectionNotificationPending = true;
+            return;
+        }
+
+        _ = NotifySelectionChangesAsync();
+    }
 
     private async Task NotifySelectionChangesAsync()
     {

Wino.Mail.ViewModels/MailListPageViewModel.cs

@@ -1120,6 +1120,8 @@ public partial class MailListPageViewModel : MailBaseViewModel,
             if (ActiveFolder == null)
                 return;
 
+            MailCollection.PruneSingleNonDraftItems = IsActiveDraftFolder();
+
             await ExecuteUIThread(() => { IsInitializingFolder = true; });
 
             // Folder is changed during initialization.

Wino.Mail.WinUI/Controls/ListView/WinoThreadMailItemViewModelListViewItem.cs

@@ -12,6 +12,9 @@ namespace Wino.Mail.WinUI.Controls.ListView;
 [GeneratedBindableCustomProperty]
 public partial class WinoThreadMailItemViewModelListViewItem : ListViewItem
 {
+    private WinoExpander? _expander;
+    private WinoListView? _threadListView;
+
     [GeneratedDependencyProperty]
     public partial bool IsThreadExpanded { get; set; }
 
@@ -28,14 +31,27 @@ public partial class WinoThreadMailItemViewModelListViewItem : ListViewItem
 
     public WinoListView? GetWinoListViewControl()
     {
-        var expander = GetExpander();
+        if (_threadListView?.XamlRoot != null)
-
+        {
-        if (expander?.Content is WinoListView control) return control;
+            return _threadListView;
-
-        return null;
         }
 
-    public WinoExpander? GetExpander() => WinoVisualTreeHelper.FindDescendants<WinoExpander>(this).FirstOrDefault();
+        var expander = GetExpander();
+        _threadListView = expander?.Content as WinoListView;
+
+        return _threadListView;
+    }
+
+    public WinoExpander? GetExpander()
+    {
+        if (_expander?.XamlRoot != null)
+        {
+            return _expander;
+        }
+
+        _expander = WinoVisualTreeHelper.FindDescendants<WinoExpander>(this).FirstOrDefault();
+        return _expander;
+    }
 
     partial void OnItemPropertyChanged(DependencyPropertyChangedEventArgs e)
     {
@@ -51,5 +67,8 @@ public partial class WinoThreadMailItemViewModelListViewItem : ListViewItem
         {
             IsCustomSelected = false;
         }
+
+        _expander = null;
+        _threadListView = null;
     }
 }

Wino.Mail.WinUI/Views/Mail/MailListPage.xaml.cs

@@ -57,6 +57,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
     private const int SELECTION_SETTLE_DELAY_MS = 120;
     private const int RENDERING_FRAME_RELEASE_DELAY_MS = 2000;
     private int _idleNavigationRequestVersion = 0;
+    private int _mailActivationRequestVersion = 0;
     private IPopoutClient? _activePopoutClient;
     private readonly Dictionary<FrameworkElement, HostedContentPopoutWindow> _hostedPopoutWindows = [];
     private PendingHostedPopoutNavigation? _pendingHostedPopoutNavigation;
@@ -108,6 +109,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
         base.OnNavigatedFrom(e);
 
         InvalidatePendingIdleNavigation();
+        InvalidatePendingMailActivation();
         DetachPopoutClient();
 
         this.Bindings.StopTracking();
@@ -269,23 +271,30 @@ public sealed partial class MailListPage : MailListPageAbstract,
         }
 
         // Context menu on a thread should target the whole thread and keep it expanded.
-        await ViewModel.MailCollection.UnselectAllAsync();
+        await ViewModel.MailCollection.ExecuteSelectionBatchAsync(() =>
-        await ViewModel.MailCollection.ExecuteWithoutRaiseSelectionChangedAsync(item =>
         {
-            if (item is ThreadMailItemViewModel thread && !ReferenceEquals(thread, threadItem))
+            foreach (var group in ViewModel.MailCollection.MailItems)
             {
-                thread.IsThreadExpanded = false;
+                foreach (var item in group)
-            }
+                {
-        }, true);
+                    if (item is ThreadMailItemViewModel thread)
+                    {
+                        thread.IsSelected = ReferenceEquals(thread, threadItem);
+                        thread.IsThreadExpanded = ReferenceEquals(thread, threadItem);
 
-        threadItem.IsSelected = true;
+                        foreach (var threadMail in thread.ThreadEmails)
-        threadItem.IsThreadExpanded = true;
-
-        foreach (var threadMail in threadItem.ThreadEmails)
                         {
-            threadMail.IsSelected = true;
+                            threadMail.IsSelected = ReferenceEquals(thread, threadItem);
                         }
                     }
+                    else if (item is MailItemViewModel mailItem)
+                    {
+                        mailItem.IsSelected = false;
+                    }
+                }
+            }
+        });
+    }
 
     private async Task<MailOperationMenuItem> GetMailOperationFromFlyoutAsync(IEnumerable<MailOperationMenuItem> availableActions,
                                                                               UIElement showAtElement,
@@ -311,9 +320,21 @@ public sealed partial class MailListPage : MailListPageAbstract,
     }
 
     void IRecipient<ActiveMailItemChangedEvent>.Receive(ActiveMailItemChangedEvent message)
+    {
+        int requestVersion = ++_mailActivationRequestVersion;
+
+        DispatcherQueue.TryEnqueue(Microsoft.UI.Dispatching.DispatcherQueuePriority.Low, () =>
+        {
+            if (requestVersion != _mailActivationRequestVersion) return;
+
+            ApplyActiveMailItemChange(message.SelectedMailItemViewModel);
+        });
+    }
+
+    private void ApplyActiveMailItemChange(MailItemViewModel? selectedMailItemViewModel)
     {
         // No active mail item. Go to empty page.
-        if (message.SelectedMailItemViewModel == null)
+        if (selectedMailItemViewModel == null)
         {
             _ = NavigateIdleWhenSelectionSettlesAsync();
         }
@@ -322,7 +343,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
             InvalidatePendingIdleNavigation();
 
             // Navigate to composing page.
-            if (message.SelectedMailItemViewModel.IsDraft)
+            if (selectedMailItemViewModel.IsDraft)
             {
                 NavigationTransitionType composerPageTransition = NavigationTransitionType.None;
 
@@ -347,20 +368,18 @@ public sealed partial class MailListPage : MailListPageAbstract,
                 else
                     composerPageTransition = NavigationTransitionType.DrillIn;
 
-                ViewModel.NavigationService.Navigate(WinoPage.ComposePage, message.SelectedMailItemViewModel, NavigationReferenceFrame.RenderingFrame, composerPageTransition);
+                ViewModel.NavigationService.Navigate(WinoPage.ComposePage, selectedMailItemViewModel, NavigationReferenceFrame.RenderingFrame, composerPageTransition);
             }
             else
             {
                 // Find the MIME and go to rendering page.
 
-                if (message.SelectedMailItemViewModel == null) return;
-
                 if (IsComposingPageActive())
                 {
                     PrepareComposePageWebViewTransition();
                 }
 
-                ViewModel.NavigationService.Navigate(WinoPage.MailRenderingPage, message.SelectedMailItemViewModel, NavigationReferenceFrame.RenderingFrame);
+                ViewModel.NavigationService.Navigate(WinoPage.MailRenderingPage, selectedMailItemViewModel, NavigationReferenceFrame.RenderingFrame);
             }
         }
 
@@ -427,6 +446,14 @@ public sealed partial class MailListPage : MailListPageAbstract,
         }
     }
 
+    private void InvalidatePendingMailActivation()
+    {
+        unchecked
+        {
+            _mailActivationRequestVersion++;
+        }
+    }
+
     private async Task NavigateIdleWhenSelectionSettlesAsync()
     {
         int requestVersion = ++_idleNavigationRequestVersion;
@@ -765,42 +792,13 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
         // Lazily built caches for this invocation.
         List<ThreadMailItemViewModel>? threadItems = null;
-        Dictionary<string, ThreadMailItemViewModel>? threadById = null;
 
         List<ThreadMailItemViewModel> GetThreadItems()
         {
-            if (threadItems != null) return threadItems;
+            return threadItems ??= ViewModel.MailCollection.GetThreadItems();
-
-            threadItems = [];
-
-            foreach (var group in ViewModel.MailCollection.MailItems)
-            {
-                foreach (var item in group)
-                {
-                    if (item is ThreadMailItemViewModel thread)
-                    {
-                        threadItems.Add(thread);
-                    }
-                }
         }
 
-            return threadItems;
+        ThreadMailItemViewModel? FindParentThread(MailItemViewModel mail) => ViewModel.MailCollection.GetThreadByMailUniqueId(mail.MailCopy.UniqueId);
-        }
-
-        ThreadMailItemViewModel? FindParentThread(MailItemViewModel mail)
-        {
-            if (string.IsNullOrEmpty(mail.ThreadId))
-            {
-                return null;
-            }
-
-            threadById ??= GetThreadItems()
-                .Where(t => !string.IsNullOrEmpty(t.ThreadId))
-                .GroupBy(t => t.ThreadId, StringComparer.Ordinal)
-                .ToDictionary(g => g.Key, g => g.First(), StringComparer.Ordinal);
-
-            return threadById.TryGetValue(mail.ThreadId, out var threadItem) ? threadItem : null;
-        }
 
         void CollapseAllThreadsExcept(ThreadMailItemViewModel? except)
         {
@@ -813,6 +811,29 @@ public sealed partial class MailListPage : MailListPageAbstract,
             }
         }
 
+        void ResetSelectionState()
+        {
+            foreach (var group in ViewModel.MailCollection.MailItems)
+            {
+                foreach (var item in group)
+                {
+                    if (item is ThreadMailItemViewModel thread)
+                    {
+                        thread.IsSelected = false;
+
+                        foreach (var child in thread.ThreadEmails)
+                        {
+                            child.IsSelected = false;
+                        }
+                    }
+                    else if (item is MailItemViewModel mail)
+                    {
+                        mail.IsSelected = false;
+                    }
+                }
+            }
+        }
+
         static void SyncThreadSelectionFromChildren(ThreadMailItemViewModel? thread)
         {
             if (thread == null) return;
@@ -836,68 +857,58 @@ public sealed partial class MailListPage : MailListPageAbstract,
             }
         }
 
+        await ViewModel.MailCollection.ExecuteSelectionBatchAsync(() =>
+        {
             if (isCtrlPressed)
             {
                 switch (clickedItem)
                 {
                     case ThreadMailItemViewModel thread:
                         {
-                        // Determine if thread + all children currently selected
                             bool allSelected = thread.IsSelected && thread.ThreadEmails.All(e => e.IsSelected);
                             if (allSelected)
                             {
-                            // Unselect thread & all children
                                 thread.IsSelected = false;
                                 foreach (var child in thread.ThreadEmails)
                                     child.IsSelected = false;
                             }
                             else
                             {
-                            // Select thread & all children (do NOT disturb other selections in CTRL mode)
                                 thread.IsSelected = true;
                                 foreach (var child in thread.ThreadEmails)
                                     child.IsSelected = true;
-                            // Keep it expanded so user can see items
                                 thread.IsThreadExpanded = true;
                             }
                             break;
                         }
                     case MailItemViewModel mail:
                         {
-                        // Toggle just this item; no collapse/unselect of others in multi-select mode.
                             mail.IsSelected = !mail.IsSelected;
                             SyncThreadSelectionFromChildren(FindParentThread(mail));
                             break;
                         }
                 }
-            return; // Multi-select path ends here.
+
+                return;
             }
 
-        // SINGLE-SELECTION (exclusive) MODE WITH TOGGLE SUPPORT
             if (clickedItem is ThreadMailItemViewModel clickedThread)
             {
                 bool wasThreadSelected = clickedThread.IsSelected;
                 bool wasThreadExpanded = clickedThread.IsThreadExpanded;
-
-            // Check if any child in this thread is already selected (e.g., from notification click)
                 var alreadySelectedChild = clickedThread.ThreadEmails.FirstOrDefault(e => e.IsSelected);
 
-            // Reset everything first (exclusive selection scenario)
+                ResetSelectionState();
-            await ViewModel.MailCollection.UnselectAllAsync();
                 CollapseAllThreadsExcept(clickedThread);
 
                 if (wasThreadSelected && wasThreadExpanded)
                 {
-                // Toggle off -> leave nothing selected (all unselected, thread collapsed)
                     clickedThread.IsThreadExpanded = false;
                     return;
                 }
 
-            // Select thread header
                 clickedThread.IsSelected = true;
 
-            // If a child was already selected (e.g., from notification), keep that selection
-            // Otherwise, select the first child
                 if (alreadySelectedChild != null)
                 {
                     alreadySelectedChild.IsSelected = true;
@@ -911,37 +922,29 @@ public sealed partial class MailListPage : MailListPageAbstract,
                     }
                 }
 
-            clickedThread.IsThreadExpanded = true; // Show contents of active thread
+                clickedThread.IsThreadExpanded = true;
             }
             else if (clickedItem is MailItemViewModel clickedMail)
             {
                 bool wasSelected = clickedMail.IsSelected;
-
-            // Determine if this mail belongs to an already selected & expanded thread.
-            // If so, we only want to switch the selection inside that thread without collapsing or unselecting the thread header.
                 ThreadMailItemViewModel? parentThread = FindParentThread(clickedMail);
-
                 bool isInSelectedExpandedThread = parentThread != null && parentThread.IsSelected && parentThread.IsThreadExpanded;
 
                 if (isInSelectedExpandedThread)
                 {
-                // Switch selection within the thread: unselect previously selected children, select the clicked one.
+                    var selectedParentThread = parentThread!;
-                if (parentThread?.ThreadEmails != null)
+
+                    foreach (var child in selectedParentThread.ThreadEmails)
                     {
-                    foreach (var child in parentThread.ThreadEmails)
+                        child.IsSelected = child == clickedMail && !wasSelected;
-                    {
-                        child.IsSelected = child == clickedMail && !wasSelected; // If clicking an already selected child -> toggle off (none selected in thread except header)
-                    }
                     }
 
-                SyncThreadSelectionFromChildren(parentThread);
+                    SyncThreadSelectionFromChildren(selectedParentThread);
-                return; // Done.
+                    return;
                 }
 
-            // Normal single-item (non-thread or entering a thread via child) behavior.
+                ResetSelectionState();
-            await ViewModel.MailCollection.UnselectAllAsync();
 
-            // If parent thread is already expanded, keep it as-is to avoid collapse/expand animation.
                 if (parentThread != null && parentThread.IsThreadExpanded)
                 {
                     CollapseAllThreadsExcept(parentThread);
@@ -953,18 +956,18 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
                 if (parentThread != null && selectExpandThread)
                 {
-                // We're clicking an item inside a thread; select & expand the thread header as well.
                     parentThread.IsSelected = true;
                     parentThread.IsThreadExpanded = true;
                 }
 
                 if (!wasSelected)
                 {
-                clickedMail.IsSelected = true; // Toggle on
+                    clickedMail.IsSelected = true;
                 }
 
                 SyncThreadSelectionFromChildren(parentThread);
             }
+        });
     }
 
     private async void WinoListViewItemClicked(object sender, ItemClickEventArgs e)