feat(windows): reversible six-second deletion for single and selected tasks

docs/UX-BENCHMARKS.md

@@ -90,8 +90,8 @@ Scheduled（有日期的）。
   清除日期同时清除时间，避免任务残留不可见的 due_time。
 - ✅ Linux：基于 GTK 原生多选（#33）增加可见的批量完成和批量移动操作栏，
   同时适用于当前列表和全局搜索。刷新时按任务 ID 保留选择。
-- 🔜 **尚未完成**：Windows 批量删除及撤销、行内详情展开；
-  Linux 批量排期/删除及撤销；以及三平台按真实快捷键进行实机回归。
+- ✅ Windows 单条/批量删除采用 6 秒延后提交：先隐藏选中任务，期间撤销可直接恢复原任务 ID 与元数据，超时才发送后端删除 RPC；失败时恢复任务。
+- 🔜 **尚未完成**：Windows 行内详情展开；Linux 批量删除及撤销；以及三平台按真实快捷键进行实机回归。
 
 ### 2.5 Quick Find
 

scripts/e2e/e2e-windows.ps1

@@ -264,6 +264,40 @@ try {
         return $false
     })
 
+    # A batch deletion must be fully reversible without giving tasks
+    # replacement IDs (including their list ownership and due metadata).
+    $undoName1 = 'Undo safety task one'
+    $undoName2 = 'Undo safety task two'
+    foreach ($title in @($undoName1, $undoName2)) {
+        $quickAdd.GetCurrentPattern(
+            [System.Windows.Automation.ValuePattern]::Pattern).SetValue($title)
+        $quickAdd.SetFocus()
+        [System.Windows.Forms.SendKeys]::SendWait('{ENTER}')
+        [void](Wait-Until ("saved task: {0}" -f $title) {
+            Find-ByName $window $title
+        })
+    }
+    Select-TaskForBatch $undoName1 $false
+    Select-TaskForBatch $undoName2 $true
+    $deleteBatch = Wait-Until 'bulk-delete action' {
+        Find-ById $window 'bulk-delete'
+    }
+    $deleteBatch.GetCurrentPattern(
+        [System.Windows.Automation.InvokePattern]::Pattern).Invoke()
+    $undo = Wait-Until 'undo-delete action' {
+        $item = Find-ById $window 'undo-delete'
+        if ($null -ne $item -and
+            -not $item.Current.IsOffscreen) { return $item }
+        return $null
+    }
+    $undo.GetCurrentPattern(
+        [System.Windows.Automation.InvokePattern]::Pattern).Invoke()
+    foreach ($title in @($undoName1, $undoName2)) {
+        [void](Wait-Until ("task restored without backend delete: {0}" -f $title) {
+            Find-ByName $window $title
+        })
+    }
+
     $nodes = $window.FindAll(
         [System.Windows.Automation.TreeScope]::Descendants,
         [System.Windows.Automation.Condition]::TrueCondition)
@@ -302,6 +336,7 @@ try {
             'view switches preserve task list ownership',
             'global search shows the real owning list for every task',
             'Ctrl/Shift multi-selection completes two tasks in one command',
+            'bulk deletion undo restores original rows before backend mutation',
             'batch scheduling is visible and enabled when multiple tasks are selected',
             'native window close stopped the process'
         )

windows/MainWindow.xaml

@@ -355,6 +355,9 @@
                     <Button x:Name="BulkScheduleButton"
                             AutomationProperties.AutomationId="bulk-schedule"
                             Click="OnBulkScheduleClicked" />
+                    <Button x:Name="BulkDeleteButton"
+                            AutomationProperties.AutomationId="bulk-delete"
+                            Click="OnBulkDeleteClicked" />
                 </StackPanel>
 
                 <Grid Grid.Row="2">
@@ -499,12 +502,21 @@
 
         <!-- Status bar -->
         <Border Grid.Row="3" Background="{ThemeResource TasklySidebarBrush}">
-            <TextBlock
-                x:Name="StatusText"
-                Margin="12,4"
-                FontSize="12"
-                Foreground="{ThemeResource TasklySecondaryTextBrush}"
-                TextTrimming="CharacterEllipsis" />
+            <StackPanel Orientation="Horizontal" Spacing="8" VerticalAlignment="Center">
+                <TextBlock
+                    x:Name="StatusText"
+                    Margin="12,4"
+                    FontSize="12"
+                    VerticalAlignment="Center"
+                    Foreground="{ThemeResource TasklySecondaryTextBrush}"
+                    TextTrimming="CharacterEllipsis" />
+                <Button x:Name="UndoDeleteButton"
+                        AutomationProperties.AutomationId="undo-delete"
+                        Click="OnUndoDeleteClicked"
+                        Visibility="Collapsed"
+                        MinWidth="58"
+                        Padding="10,2" />
+            </StackPanel>
         </Border>
     </Grid>
 </Window>

windows/MainWindow.xaml.cpp

@@ -755,6 +755,8 @@ void MainWindow::ApplyLanguage() {
   BulkCompleteButton().Content(winrt::box_value(t("bulkComplete")));
   BulkMoveButton().Content(winrt::box_value(t("menuMoveToList")));
   BulkScheduleButton().Content(winrt::box_value(t("bulkSchedule")));
+  BulkDeleteButton().Content(winrt::box_value(t("listDelete")));
+  UndoDeleteButton().Content(winrt::box_value(t("bannerUndo")));
   RenderSidebar();
   RenderTasks();
 }
@@ -977,6 +979,7 @@ void MainWindow::RenderTasks() {
   }
   TaskList().Items().Clear();
   for (auto const& task : tasks_) {
+    if (suppressed_deleted_task_ids_.count(task.id) != 0) continue;
     auto row = MakeTaskRow(task);
     TaskList().Items().Append(row);
     if (selected_ids.count(task.id) != 0) {
@@ -1011,6 +1014,7 @@ void MainWindow::RenderSearchResults() {
   }
   SearchResults().Items().Clear();
   for (auto const& task : search_results_) {
+    if (suppressed_deleted_task_ids_.count(task.id) != 0) continue;
     auto row = MakeTaskRow(task, /*search_result=*/true);
     SearchResults().Items().Append(row);
     if (selected_ids.count(task.id) != 0) {
@@ -1563,6 +1567,9 @@ winrt::fire_and_forget MainWindow::OpenDatabaseAsync(std::wstring const& path) {
   if (backend_ == nullptr || !backend_->running() || path.empty()) {
     co_return;
   }
+  // Pending deletions must never commit against another database that
+  // happens to contain the same numeric task IDs.
+  if (!pending_delete_ids_.empty()) UndoPendingDeletion();
   auto const dispatcher = DispatcherQueue();
   auto const weak = get_weak();
   auto backend = backend_;
@@ -1575,6 +1582,7 @@ winrt::fire_and_forget MainWindow::OpenDatabaseAsync(std::wstring const& path) {
             auto const snapshot = result.get();
             dispatcher.TryEnqueue([weak, snapshot] {
               if (auto window = weak.get()) {
+                window->suppressed_deleted_task_ids_.clear();
                 // Restore the last-selected list when it still exists —
                 // checked against the incoming snapshot because ApplySnapshot
                 // owns the render pass.
@@ -1843,22 +1851,30 @@ winrt::fire_and_forget MainWindow::DeleteTaskAsync(std::int64_t id) {
   try {
     rivet_app::API api(*backend);
     (void)api.delete_task_async(
-        id, [dispatcher, weak](rivet_app::Result<bool> result) {
+        id, [dispatcher, weak, id](rivet_app::Result<bool> result) {
           try {
-            result.get();
+            if (!result.get()) {
+              throw std::runtime_error("task deletion was not acknowledged");
+            }
             dispatcher.TryEnqueue([weak] {
               if (auto window = weak.get()) window->RefreshSearchIfActive();
             });
           } catch (std::exception const& e) {
             auto message = std::string(e.what());
-            dispatcher.TryEnqueue([weak, message = std::move(message)] {
+            dispatcher.TryEnqueue([weak, id, message = std::move(message)] {
               if (auto window = weak.get()) {
+                window->suppressed_deleted_task_ids_.erase(id);
+                window->RenderTasks();
+                window->RenderSearchResults();
                 window->SetError(message);
               }
             });
           }
         });
   } catch (std::exception const& e) {
+    suppressed_deleted_task_ids_.erase(id);
+    RenderTasks();
+    RenderSearchResults();
     SetError(e.what());
   }
 }
@@ -2068,6 +2084,7 @@ void MainWindow::OnCloseDatabase(
   if (backend_ == nullptr || !backend_->running()) {
     return;
   }
+  if (!pending_delete_ids_.empty()) UndoPendingDeletion();
   auto const dispatcher = DispatcherQueue();
   auto const weak = get_weak();
   auto backend = backend_;
@@ -2080,6 +2097,7 @@ void MainWindow::OnCloseDatabase(
             if (auto window = weak.get()) {
               window->lists_.clear();
               window->tasks_.clear();
+              window->suppressed_deleted_task_ids_.clear();
               window->current_counts_ = {};
               // The next snapshot must render even if it matches the one the
               // closed database ended with.
@@ -2419,6 +2437,78 @@ void MainWindow::OnBulkScheduleClicked(
   menu.ShowAt(BulkScheduleButton());
 }
 
+void MainWindow::StageTaskDeletion(
+    std::vector<std::int64_t> const& ids) {
+  if (backend_ == nullptr || !backend_->running()) return;
+  // Only one undo batch at a time. Starting another deletion commits
+  // the previous one and opens a fresh six-second window.
+  if (!pending_delete_ids_.empty()) CommitPendingDeletion();
+  for (auto const id : ids) {
+    if (FindTaskForAction(id) == nullptr) continue;
+    if (suppressed_deleted_task_ids_.insert(id).second) {
+      pending_delete_ids_.push_back(id);
+    }
+  }
+  if (pending_delete_ids_.empty()) return;
+  if (!delete_undo_timer_) {
+    delete_undo_timer_ = DispatcherQueue().CreateTimer();
+    delete_undo_timer_.Interval(std::chrono::seconds{6});
+    delete_undo_timer_.IsRepeating(false);
+    delete_undo_timer_.Tick([weak = get_weak()](auto&&, auto&&) {
+      if (auto window = weak.get()) window->CommitPendingDeletion();
+    });
+  }
+  delete_undo_timer_.Stop();
+  delete_undo_timer_.Start();
+  UndoDeleteButton().Visibility(mx::Visibility::Visible);
+  SetStatus(tf("bannerTasksDeleted",
+               std::to_wstring(pending_delete_ids_.size())));
+  RenderTasks();
+  RenderSearchResults();
+}
+
+void MainWindow::CommitPendingDeletion() {
+  if (delete_undo_timer_) delete_undo_timer_.Stop();
+  if (backend_ == nullptr || !backend_->running()) {
+    // Deletion has not been persisted, so restore every staged row.
+    UndoPendingDeletion();
+    SetStatus(t("taskListEmptyHint"));
+    return;
+  }
+  auto const ids = std::move(pending_delete_ids_);
+  pending_delete_ids_.clear();
+  UndoDeleteButton().Visibility(mx::Visibility::Collapsed);
+  for (auto const id : ids) {
+    // Keep rows visually hidden while their deletion RPCs complete.
+    // A failure removes suppression and makes the task visible again.
+    DeleteTaskAsync(id);
+  }
+}
+
+void MainWindow::UndoPendingDeletion() {
+  if (delete_undo_timer_) delete_undo_timer_.Stop();
+  for (auto const id : pending_delete_ids_) {
+    suppressed_deleted_task_ids_.erase(id);
+  }
+  pending_delete_ids_.clear();
+  UndoDeleteButton().Visibility(mx::Visibility::Collapsed);
+  SetStatus(t("bannerUndo"));
+  RenderTasks();
+  RenderSearchResults();
+}
+
+void MainWindow::OnUndoDeleteClicked(
+    winrt::Windows::Foundation::IInspectable const&,
+    Microsoft::UI::Xaml::RoutedEventArgs const&) {
+  UndoPendingDeletion();
+}
+
+void MainWindow::OnBulkDeleteClicked(
+    winrt::Windows::Foundation::IInspectable const&,
+    Microsoft::UI::Xaml::RoutedEventArgs const&) {
+  StageTaskDeletion(SelectedTaskIds());
+}
+
 void MainWindow::OnTaskListKeyDown(
     winrt::Windows::Foundation::IInspectable const& sender,
     Microsoft::UI::Xaml::Input::KeyRoutedEventArgs const& args) {
@@ -2666,7 +2756,7 @@ void MainWindow::OnDeleteTask(
     Microsoft::UI::Xaml::RoutedEventArgs const&) {
   auto const id = winrt::unbox_value<std::int64_t>(
       sender.as<mxc::MenuFlyoutItem>().Tag());
-  DeleteTaskAsync(id);
+  StageTaskDeletion({id});
 }
 
 }  // namespace winrt::RivetHost::implementation

windows/MainWindow.xaml.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <set>
+
 #include "pch.h"
 #include "GeneratedBackend.hpp"
 #include "MainWindow.g.h"
@@ -84,6 +86,10 @@ struct MainWindow : MainWindowT<MainWindow> {
                          Microsoft::UI::Xaml::RoutedEventArgs const&);
   void OnBulkScheduleClicked(winrt::Windows::Foundation::IInspectable const&,
                              Microsoft::UI::Xaml::RoutedEventArgs const&);
+  void OnBulkDeleteClicked(winrt::Windows::Foundation::IInspectable const&,
+                           Microsoft::UI::Xaml::RoutedEventArgs const&);
+  void OnUndoDeleteClicked(winrt::Windows::Foundation::IInspectable const&,
+                           Microsoft::UI::Xaml::RoutedEventArgs const&);
 
   // Update download action wired from XAML; event handlers must be public
   // because generated Connect() binds them through MainWindowT.
@@ -123,6 +129,9 @@ struct MainWindow : MainWindowT<MainWindow> {
                          std::int64_t target_list_id);
   void ScheduleSelectedTasks(std::vector<std::int64_t> const& ids,
                              std::wstring const& due);
+  void StageTaskDeletion(std::vector<std::int64_t> const& ids);
+  void CommitPendingDeletion();
+  void UndoPendingDeletion();
   void RefreshQuickAddPreview();
   void ApplyTitleBarTheme();
   void OnEffectiveThemeChanged();
@@ -202,6 +211,10 @@ struct MainWindow : MainWindowT<MainWindow> {
   std::vector<rivet_app::TodoList> lists_;
   std::vector<rivet_app::Task> tasks_;
   std::vector<rivet_app::Task> search_results_;
+  // Deletions are staged for six seconds, retaining original task IDs.
+  std::set<std::int64_t> suppressed_deleted_task_ids_;
+  std::vector<std::int64_t> pending_delete_ids_;
+  Microsoft::UI::Dispatching::DispatcherQueueTimer delete_undo_timer_{nullptr};
   std::wstring current_search_;
   ViewKind view_{ViewKind::All};
   std::int64_t view_list_id_{0};