feat(ui): port retail selected-stack quantity

Bind the authored stack count entry and horizontal slider to one Core split-quantity owner, preserve retail count-first naming and exact 1000-step rounding, refresh on stack changes, and consume the selected amount during merges. Conformance covers the production DAT fixture and retained pointer/focus paths.

Co-Authored-By: Codex <codex@openai.com>

tests/AcDream.App.Tests/UI/Layout/DatWidgetFactoryTests.cs

@@ -199,6 +199,42 @@ public class DatWidgetFactoryTests
         Assert.IsType<UiScrollbar>(e);
     }
 
+    [Fact]
+    public void Type11_HorizontalScrollbar_usesDirectRetailTrackAndThumbChildren()
+    {
+        const uint Track = 0x06004CF6u;
+        const uint Thumb = 0x06005DC3u;
+        var info = new ElementInfo { Type = 11, Id = 0x100001A4u, Width = 90, Height = 14 };
+        var track = new ElementInfo { Id = 4u, Type = 3u, Width = 90, Height = 14 };
+        track.States[UiStateInfo.DirectStateId] = new UiStateInfo
+            { Id = UiStateInfo.DirectStateId, Image = new UiImageMedia(Track, 1) };
+        var thumb = new ElementInfo { Id = 1u, Type = 3u, Width = 16, Height = 14 };
+        thumb.States[UiStateInfo.DirectStateId] = new UiStateInfo
+            { Id = UiStateInfo.DirectStateId, Image = new UiImageMedia(Thumb, 1) };
+        info.Children.Add(track);
+        info.Children.Add(thumb);
+
+        var bar = Assert.IsType<UiScrollbar>(DatWidgetFactory.Create(info, NoTex, null));
+
+        Assert.True(bar.Horizontal);
+        Assert.Equal(Track, bar.TrackSprite);
+        Assert.Equal(Thumb, bar.ThumbSprite);
+        Assert.Equal(0u, bar.UpSprite);
+        Assert.Equal(0u, bar.DownSprite);
+    }
+
+    [Fact]
+    public void RetailToolbarFixture_buildsEditableStackEntry_andAuthoredHorizontalSlider()
+    {
+        ImportedLayout layout = FixtureLoader.LoadToolbar();
+
+        Assert.IsType<UiField>(layout.FindElement(0x100001A3u));
+        var bar = Assert.IsType<UiScrollbar>(layout.FindElement(0x100001A4u));
+        Assert.True(bar.Horizontal);
+        Assert.Equal(0x06004CF6u, bar.TrackSprite);
+        Assert.Equal(0x06005DC3u, bar.ThumbSprite);
+    }
+
     // ── Test 5e: Type 3 is NOT registered — chrome/containers stay generic ────
     //
     // Retail Type 3 = UIElement_Field, but acdream's Type-3 dat elements (vitals/chat

tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs

@@ -60,7 +60,8 @@ public class InventoryControllerTests
         List<(uint source, uint target)>? mergeNotices = null,
         string? ownerName = null,
         Action? onClose = null,
-        SelectionState? selection = null)
+        SelectionState? selection = null,
+        StackSplitQuantityState? stackSplitQuantity = null)
         => InventoryController.Bind(layout, objects, () => Player,
             iconIds: (_, _, _, _, _) => 0u,
             strength: () => strength, datFont: null,
@@ -71,7 +72,8 @@ public class InventoryControllerTests
             sendStackableMerge: merges is null ? null : (s, t, a) => merges.Add((s, t, a)),
             notifyMergeAttempt: mergeNotices is null ? null : (s, t) => mergeNotices.Add((s, t)),
             onClose: onClose,
-            selection: selection ?? new SelectionState());
+            selection: selection ?? new SelectionState(),
+            stackSplitQuantity: stackSplitQuantity);
 
     private static UiButton MakeButton(uint id)
     {
@@ -604,6 +606,35 @@ public class InventoryControllerTests
         Assert.Equal(0xBu, selection.SelectedObjectId);
     }
 
+    [Fact]
+    public void Drop_selectedStack_usesSharedToolbarSplitQuantity()
+    {
+        var (layout, grid, _, _, _, _, _, _) = BuildLayout();
+        var objects = new ClientObjectTable();
+        objects.AddOrUpdate(new ClientObject
+        {
+            ObjectId = 0xA, WeenieClassId = 0x1234, StackSize = 40, StackSizeMax = 100,
+        });
+        objects.MoveItem(0xA, Player, 0);
+        objects.AddOrUpdate(new ClientObject
+        {
+            ObjectId = 0xB, WeenieClassId = 0x1234, StackSize = 50, StackSizeMax = 100,
+        });
+        objects.MoveItem(0xB, Player, 1);
+        var selection = new SelectionState();
+        selection.Select(0xAu, SelectionChangeSource.Inventory);
+        var split = new StackSplitQuantityState();
+        split.Reset(40u);
+        split.SetValue(7u);
+        var merges = new List<(uint source, uint target, uint amount)>();
+        var ctrl = Bind(layout, objects, merges: merges, selection: selection,
+            stackSplitQuantity: split);
+
+        ctrl.HandleDropRelease(grid, grid.GetItem(1)!, Payload(0xAu));
+
+        Assert.Equal(new[] { (0xAu, 0xBu, 7u) }, merges);
+    }
+
     [Fact]
     public void Drop_differentStackType_fallsThroughToNormalInventoryInsert()
     {

tests/AcDream.App.Tests/UI/Layout/SelectedObjectControllerTests.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Numerics;
 using AcDream.App.UI;
 using AcDream.App.UI.Layout;
+using AcDream.Core.Items;
 using AcDream.Core.Selection;
 using Xunit;
 
@@ -59,6 +60,14 @@ public class SelectedObjectControllerTests
         dict[SelectedObjectController.HealthMeterId] = healthMeterEl;
         root.AddChild(healthMeterEl);
 
+        var stackEntry = new UiField { Width = 50, Height = 14, Visible = true };
+        dict[SelectedObjectController.StackSizeEntryId] = stackEntry;
+        root.AddChild(stackEntry);
+
+        var stackSlider = new UiScrollbar { Width = 90, Height = 14, Visible = true };
+        dict[SelectedObjectController.StackSizeSliderId] = stackSlider;
+        root.AddChild(stackSlider);
+
         return (new ImportedLayout(root, dict), nameEl, overlayEl, healthMeterEl);
     }
 
@@ -67,7 +76,9 @@ public class SelectedObjectControllerTests
     private sealed class Harness
     {
         public readonly SelectionState Selection = new();
+        public readonly StackSplitQuantityState SplitQuantity = new();
         public Action<uint, float>? HealthHandler;
+        public Action<ClientObject>? ObjectUpdatedHandler;
         public readonly List<uint> QueryHealthCalls = new();
 
         public readonly Dictionary<uint, bool>   HealthTargetMap = new();
@@ -100,7 +111,13 @@ public class SelectedObjectControllerTests
                 hasHealth:       g => HasHealthMap.TryGetValue(g, out var v) && v,
                 stackSize:       g => StackMap.TryGetValue(g, out var v) ? v : 0u,
                 sendQueryHealth: g => QueryHealthCalls.Add(g),
-                datFont:         datFont);
+                datFont:         datFont,
+                splitQuantity:   SplitQuantity,
+                subscribeObjectUpdated: h => ObjectUpdatedHandler = h,
+                unsubscribeObjectUpdated: h =>
+                {
+                    if (ObjectUpdatedHandler == h) ObjectUpdatedHandler = null;
+                });
     }
 
     // ── B1: Bind initialisation ──────────────────────────────────────────────
@@ -247,6 +264,58 @@ public class SelectedObjectControllerTests
         Assert.False(healthMeterEl.Visible);
     }
 
+    [Fact]
+    public void SelectStackedItem_showsRetailCountEntryAndSlider_atFullStack()
+    {
+        const uint Guid = 0xBB03u;
+        var (layout, nameEl, _, _) = FakeLayout();
+        var h = new Harness();
+        h.NameMap[Guid] = "Healing Kits";
+        h.StackMap[Guid] = 17u;
+        h.Bind(layout);
+
+        h.FireSelection(Guid);
+
+        var entry = Assert.IsType<UiField>(layout.FindElement(SelectedObjectController.StackSizeEntryId));
+        var slider = Assert.IsType<UiScrollbar>(layout.FindElement(SelectedObjectController.StackSizeSliderId));
+        Assert.True(entry.Visible);
+        Assert.True(slider.Visible);
+        Assert.Equal("17", entry.Text);
+        Assert.Equal(17u, h.SplitQuantity.Value);
+        Assert.Equal(17u, h.SplitQuantity.Maximum);
+        Assert.Equal(1f, slider.ScalarValue!());
+        Assert.Equal("17 Healing Kits", nameEl.Children.OfType<UiText>().Single().LinesProvider().Single().Text);
+
+        slider.ScalarChanged!(0.5f);
+        Assert.Equal(9u, h.SplitQuantity.Value);
+        Assert.Equal("9", entry.Text);
+
+        entry.SetText("999");
+        entry.Submit();
+        Assert.Equal(17u, h.SplitQuantity.Value);
+        Assert.Equal("17", entry.Text);
+    }
+
+    [Fact]
+    public void StackSizeUpdate_refreshesSelectedControls_andHidesThemAtOne()
+    {
+        const uint Guid = 0xBB04u;
+        var (layout, _, _, _) = FakeLayout();
+        var h = new Harness();
+        h.NameMap[Guid] = "Healing Kits";
+        h.StackMap[Guid] = 5u;
+        h.Bind(layout);
+        h.FireSelection(Guid);
+
+        h.StackMap[Guid] = 1u;
+        h.ObjectUpdatedHandler!(new ClientObject { ObjectId = Guid, StackSize = 1 });
+
+        Assert.False(layout.FindElement(SelectedObjectController.StackSizeEntryId)!.Visible);
+        Assert.False(layout.FindElement(SelectedObjectController.StackSizeSliderId)!.Visible);
+        Assert.Equal(1u, h.SplitQuantity.Value);
+        Assert.Equal(1u, h.SplitQuantity.Maximum);
+    }
+
     // ── H3: Non-health target (friendly NPC / scenery / Door) ───────────────
 
     [Fact]

tests/AcDream.App.Tests/UI/UiFieldTests.cs

@@ -69,4 +69,29 @@ public class UiFieldTests
         for (int i = 0; i < 150; i++) { input.InsertChar('x'); input.Submit(); }
         Assert.True(input.HistoryCount <= 100);
     }
+
+    [Fact]
+    public void CharacterFilter_rejectsDisallowedInput()
+    {
+        var input = new UiField { CharacterFilter = static c => char.IsAsciiDigit(c) };
+
+        input.InsertChar('4');
+        input.InsertChar('x');
+        input.InsertChar('2');
+
+        Assert.Equal("42", input.Text);
+    }
+
+    [Fact]
+    public void SelectAllOnFocus_survivesInitiatingMouseDown_andTypingReplacesValue()
+    {
+        var input = new UiField { SelectAllOnFocus = true, Selectable = true };
+        input.SetText("17");
+
+        input.OnEvent(new UiEvent(0u, input, UiEventType.FocusGained));
+        input.OnEvent(new UiEvent(0u, input, UiEventType.MouseDown, Data1: 2));
+        input.InsertChar('5');
+
+        Assert.Equal("5", input.Text);
+    }
 }

tests/AcDream.App.Tests/UI/UiScrollbarTests.cs

@@ -78,4 +78,26 @@ public class UiScrollbarTests
         Assert.Equal(100f, h, 3f);
         Assert.Equal(16f, y, 3f); // travel = 0 → y = trackTop
     }
+
+    [Fact]
+    public void HorizontalScalar_clickAndDrag_updatesNormalizedValue()
+    {
+        float value = 1f;
+        var bar = new UiScrollbar
+        {
+            Width = 90f,
+            Height = 14f,
+            Horizontal = true,
+            ScalarValue = () => value,
+            ScalarChanged = next => value = next,
+        };
+
+        Assert.True(bar.OnEvent(new UiEvent(0u, bar, UiEventType.MouseDown, Data1: 8)));
+        Assert.Equal(0f, value, 3);
+
+        Assert.True(bar.OnEvent(new UiEvent(0u, bar, UiEventType.MouseMove, Data1: 45)));
+        Assert.Equal(0.5f, value, 3);
+
+        Assert.True(bar.OnEvent(new UiEvent(0u, bar, UiEventType.MouseUp, Data1: 45)));
+    }
 }