improve Frontend

src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml.cs

@@ -1,17 +1,150 @@
+using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.VisualTree;
 using ClaudeDo.Ui.ViewModels.Islands;
 
 namespace ClaudeDo.Ui.Views.Islands;
 
 public partial class TasksIslandView : UserControl
 {
+    private static readonly DataFormat<string> TaskRowFormat =
+        DataFormat.CreateStringApplicationFormat("claudedo-task-row");
+
     public TasksIslandView()
     {
         InitializeComponent();
+        // Tunnel handler runs BEFORE Button's class handler so we can start a drag
+        // without the Button first marking the event as handled.
+        AddHandler(PointerPressedEvent, OnTunnelPointerPressed, RoutingStrategies.Tunnel);
         DataContextChanged += (_, _) =>
         {
             if (DataContext is TasksIslandViewModel vm)
                 vm.FocusAddTaskRequested += (_, _) => AddTaskBox.Focus();
         };
     }
+
+    private async void OnTunnelPointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (DataContext is not TasksIslandViewModel vm || !vm.CanReorder) return;
+        if (e.Source is not Visual src) return;
+
+        var button = src as Button ?? src.FindAncestorOfType<Button>();
+        if (button?.DataContext is not TaskRowViewModel row) return;
+        if (row.IsRunning) return;
+        if (!e.GetCurrentPoint(button).Properties.IsLeftButtonPressed) return;
+
+        var data = new DataTransfer();
+        data.Add(DataTransferItem.Create(TaskRowFormat, row.Id));
+        try
+        {
+            await DragDrop.DoDragDropAsync(e, data, DragDropEffects.Move);
+        }
+        finally
+        {
+            vm.ClearDropHints();
+        }
+    }
+
+    private void OnRowPointerPressed(object? sender, PointerPressedEventArgs e) { }
+    private void OnRowPointerMoved(object? sender, PointerEventArgs e) { }
+    private void OnRowPointerReleased(object? sender, PointerReleasedEventArgs e) { }
+
+    private void OnRowDragOver(object? sender, DragEventArgs e)
+    {
+        if (DataContext is not TasksIslandViewModel vm) { e.DragEffects = DragDropEffects.None; return; }
+        if (!e.DataTransfer?.Contains(TaskRowFormat) ?? true)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+        if (sender is not Button b || b.DataContext is not TaskRowViewModel target || target.IsRunning)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+
+        var sourceId = e.DataTransfer?.TryGetValue(TaskRowFormat);
+        if (string.IsNullOrEmpty(sourceId) || sourceId == target.Id)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+
+        var placeBelow = e.GetPosition(b).Y > b.Bounds.Height / 2;
+
+        // Canonicalize: "drop below X" == "drop above X+1". Render the indicator
+        // above X+1 when there is one; only the last row in a section shows a below-line.
+        TaskRowViewModel hintRow = target;
+        bool hintBelow = false;
+        if (placeBelow)
+        {
+            var next = FindNextInSameSection(vm, target);
+            if (next is not null && !next.IsRunning)
+            {
+                hintRow = next;
+                hintBelow = false;
+            }
+            else
+            {
+                hintRow = target;
+                hintBelow = true;
+            }
+        }
+
+        // A hint that lands right where the dragged row already sits is a no-op.
+        if (hintRow.Id == sourceId)
+        {
+            e.DragEffects = DragDropEffects.None;
+            vm.ClearDropHints();
+            return;
+        }
+
+        vm.SetDropHint(hintRow, hintBelow);
+        e.DragEffects = DragDropEffects.Move;
+    }
+
+    private static TaskRowViewModel? FindNextInSameSection(TasksIslandViewModel vm, TaskRowViewModel row)
+    {
+        foreach (var section in new[] { vm.OverdueItems, vm.OpenItems, vm.CompletedItems })
+        {
+            var idx = section.IndexOf(row);
+            if (idx >= 0) return idx + 1 < section.Count ? section[idx + 1] : null;
+        }
+        return null;
+    }
+
+    private async void OnRowDrop(object? sender, DragEventArgs e)
+    {
+        if (DataContext is not TasksIslandViewModel vm) return;
+        try
+        {
+            if (sender is not Button b || b.DataContext is not TaskRowViewModel target) return;
+            if (target.IsRunning) return;
+
+            var sourceId = e.DataTransfer?.TryGetValue(TaskRowFormat);
+            if (string.IsNullOrEmpty(sourceId) || sourceId == target.Id) return;
+
+            var source = FindRowById(vm, sourceId);
+            if (source is null || source.IsRunning) return;
+
+            var placeBelow = e.GetPosition(b).Y > b.Bounds.Height / 2;
+            await vm.ReorderAsync(source, target, placeBelow);
+        }
+        finally
+        {
+            vm.ClearDropHints();
+        }
+    }
+
+    private static TaskRowViewModel? FindRowById(TasksIslandViewModel vm, string id)
+    {
+        foreach (var r in vm.Items)
+            if (r.Id == id) return r;
+        return null;
+    }
 }