From 40aa38d35337cfb30c607f140c72b7fee2733def Mon Sep 17 00:00:00 2001
From: Alek-ban <alek.kovkov124@gmail.com>
Date: Tue, 10 Feb 2026 15:03:23 +0300
Subject: [PATCH] feat: SectionPanel Add scroll flugs Add carusel scroll Add
 animation

---
 GSS2.Core/Extension/EnumerableExtensions.cs |   2 +-
 GSS2.Test/ViewModels/MainViewModel.cs       |   2 +
 GSS2.Test/Views/MainView.axaml              |   6 +-
 GSS2.UI.Core/SectionPanel.cs                | 215 +++++++++++++++-----
 4 files changed, 174 insertions(+), 51 deletions(-)

diff --git a/GSS2.Core/Extension/EnumerableExtensions.cs b/GSS2.Core/Extension/EnumerableExtensions.cs
index 608aca5..412d17e 100644
--- a/GSS2.Core/Extension/EnumerableExtensions.cs
+++ b/GSS2.Core/Extension/EnumerableExtensions.cs
@@ -1,6 +1,6 @@
 namespace GSS2.Core.Extentions;
 
-static class EnumerableExtensions
+public static class EnumerableExtensions
 {
     public static IEnumerable<(int i, T value)> Enumerate<T>(this IEnumerable<T> values) => values.Select((value, i) => (i, value));
 }
diff --git a/GSS2.Test/ViewModels/MainViewModel.cs b/GSS2.Test/ViewModels/MainViewModel.cs
index 1cfad08..21cd7d0 100644
--- a/GSS2.Test/ViewModels/MainViewModel.cs
+++ b/GSS2.Test/ViewModels/MainViewModel.cs
@@ -17,6 +17,8 @@ public partial class MainViewModel : ViewModelBase
     [ObservableProperty] private IRelayCommand _buttonUpClick;
     [ObservableProperty] private IRelayCommand _buttonDownClick;
     [ObservableProperty] private int _currentIndex;
+    [ObservableProperty] private bool _canScrollForward;
+    [ObservableProperty] private bool _canScrollBackward;
 
     public MainViewModel(ILogger<MainViewModel> logger, CameraViewModel cameraViewModel, ResourcesViewModel resourcesViewModel, CameraService cameraService)
     {
diff --git a/GSS2.Test/Views/MainView.axaml b/GSS2.Test/Views/MainView.axaml
index 4b61d85..1e3e9be 100644
--- a/GSS2.Test/Views/MainView.axaml
+++ b/GSS2.Test/Views/MainView.axaml
@@ -7,9 +7,9 @@
              x:DataType="local_vm:MainViewModel"
              x:Class="GSS2.Test.Views.MainView">
     <Grid ColumnDefinitions="*,100" RowDefinitions="*,*">
-        <Button Grid.Row="0" Grid.Column="1"  VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Command="{Binding ButtonUpClick}"/>
-        <Button Grid.Row="1" Grid.Column="1"  VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Command="{Binding ButtonDownClick}"/>
-        <core:SectionPanel Grid.Row="0" Grid.RowSpan="2" Grid.Column="0" CurrentIndex="{Binding CurrentIndex}">
+        <Button Grid.Row="0" Grid.Column="1"  VerticalAlignment="Stretch" HorizontalAlignment="Stretch" IsEnabled="{Binding CanScrollBackward}" Command="{Binding ButtonUpClick}"/>
+        <Button Grid.Row="1" Grid.Column="1"  VerticalAlignment="Stretch" HorizontalAlignment="Stretch" IsEnabled="{Binding CanScrollForward}" Command="{Binding ButtonDownClick}"/>
+        <core:SectionPanel Grid.Row="0" Grid.RowSpan="2" Grid.Column="0" ClipToBounds="True" CanScrollForward="{Binding CanScrollForward}" CanScrollBackward="{Binding CanScrollBackward}" CurrentIndex="{Binding CurrentIndex}"> 
             <ContentControl VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Content="{Binding ResourcesViewModel}" />
             <ContentControl VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Content="{Binding CameraViewModel}" />
             <Grid ColumnDefinitions="100, *">
diff --git a/GSS2.UI.Core/SectionPanel.cs b/GSS2.UI.Core/SectionPanel.cs
index c4b6f64..2707c9f 100644
--- a/GSS2.UI.Core/SectionPanel.cs
+++ b/GSS2.UI.Core/SectionPanel.cs
@@ -1,96 +1,217 @@
 using Avalonia;
+using Avalonia.Animation;
 using Avalonia.Controls;
+using Avalonia.Layout;
 using Avalonia.Media;
+using Avalonia.Styling;
+using Avalonia.Threading;
+
+using GSS2.Core.Extentions;
 
 namespace GSS2.UI.Core;
 
-public enum SectionDirection
-{
-    UpDown,
-    DownUp,
-    LeftRight,
-    RightLeft
-}
-
 public class SectionPanel : Panel
 {
-    public static readonly StyledProperty<int> CurrentIndexProperty = AvaloniaProperty.Register<SectionPanel, int>(nameof(CurrentIndex), 0);
+    public static readonly StyledProperty<int> CurrentIndexProperty = AvaloniaProperty.Register<SectionPanel, int>(
+        name: nameof(CurrentIndex),
+        defaultValue: 0,
+        coerce: (obj, value) =>
+        {
+            if (obj is not SectionPanel sectionPanel)
+                return value;
+            if (sectionPanel.Cyclic)
+                return value;
+            return Math.Clamp(value, 0, sectionPanel.Children.Count() - 1);
+        });
     public int CurrentIndex
     {
         get => GetValue(CurrentIndexProperty);
         set => SetValue(CurrentIndexProperty, value);
     }
-    public static readonly StyledProperty<double> AnimationSpeedProperty = AvaloniaProperty.Register<SectionPanel, double>(nameof(AnimationSpeed), 300);
+    public static readonly StyledProperty<bool> EnableAnimationProperty = AvaloniaProperty.Register<SectionPanel, bool>(nameof(EnableAnimation), true);
+    public bool EnableAnimation
+    {
+        get => GetValue(EnableAnimationProperty);
+        set => SetValue(EnableAnimationProperty, value);
+    }
+    public static readonly StyledProperty<double> AnimationSpeedProperty = AvaloniaProperty.Register<SectionPanel, double>(nameof(AnimationSpeed), 500);
     public double AnimationSpeed
     {
         get => GetValue(AnimationSpeedProperty);
         set => SetValue(AnimationSpeedProperty, value);
     }
-    public static readonly StyledProperty<SectionDirection> DirectionProperty = AvaloniaProperty.Register<SectionPanel, SectionDirection>(nameof(Direction), SectionDirection.UpDown);
-    public SectionDirection Direction
+    public static readonly StyledProperty<Orientation> OrientationProperty = AvaloniaProperty.Register<SectionPanel, Orientation>(nameof(Orientation), Orientation.Vertical);
+    public Orientation Orientation
     {
-        get => GetValue(DirectionProperty);
-        set => SetValue(DirectionProperty, value);
+        get => GetValue(OrientationProperty);
+        set => SetValue(OrientationProperty, value);
     }
+    public static readonly StyledProperty<bool> CyclicProperty = AvaloniaProperty.Register<SectionPanel, bool>(nameof(Cyclic), false);
+    public bool Cyclic
+    {
+        get => GetValue(CyclicProperty);
+        set => SetValue(CyclicProperty, value);
+    }
+    public static readonly StyledProperty<bool> CanScrollForwardProperty = AvaloniaProperty.Register<SectionPanel, bool>(nameof(CanScrollForward), false, defaultBindingMode: Avalonia.Data.BindingMode.OneWayToSource);
+    public bool CanScrollForward
+    {
+        get => GetValue(CanScrollForwardProperty);
+        set => SetValue(CanScrollForwardProperty, value);
+    }
+    public static readonly StyledProperty<bool> CanScrollBackwardProperty = AvaloniaProperty.Register<SectionPanel, bool>(nameof(CanScrollBackward), false, defaultBindingMode: Avalonia.Data.BindingMode.OneWayToSource);
+    public bool CanScrollBackward
+    {
+        get => GetValue(CanScrollBackwardProperty);
+        set => SetValue(CanScrollBackwardProperty, value);
+    }
+
+    private readonly Dictionary<Control, int> _childIndeces = new Dictionary<Control, int>();
+    private bool _initialized = false;
+    private int _previousIndex = 0;
 
     public SectionPanel()
     : base()
     {
-        CurrentIndexProperty.Changed.AddClassHandler<SectionPanel>((panel, _) => panel.InvalidateArrange());
+        CurrentIndexProperty.Changed.AddClassHandler<SectionPanel>((panel, ea) =>
+        {
+            CanScrollForward = Cyclic || CurrentIndex != Children.Count() - 1;
+            CanScrollBackward = Cyclic || CurrentIndex != 0;
+            panel.InvalidateArrange();
+        });
+        Children.CollectionChanged += (_, ea) =>
+        {
+            CanScrollForward = Cyclic || CurrentIndex != Children.Count() - 1;
+            CanScrollBackward = Cyclic || CurrentIndex != 0;
+        };
     }
 
     protected override Size MeasureOverride(Size availableSize)
     {
         foreach (var child in Children)
             child.Measure(availableSize);
-
-        Console.WriteLine(availableSize);
         return availableSize;
     }
     protected override Size ArrangeOverride(Size finalSize)
     {
-        for (int i = 0; i < Children.Count; i++)
+        if (!_initialized)
         {
-            var child = Children[i];
-
-            var rect = Direction switch
+            foreach (var (i, child) in Children.Enumerate())
             {
-                SectionDirection.UpDown => new Rect(0, i * finalSize.Height, finalSize.Width, finalSize.Height),
-                SectionDirection.DownUp => new Rect(0, -i * finalSize.Height, finalSize.Width, finalSize.Height),
-                SectionDirection.LeftRight => new Rect(i * finalSize.Width, 0, finalSize.Width, finalSize.Height),
-                SectionDirection.RightLeft => new Rect(-i * finalSize.Width, 0, finalSize.Width, finalSize.Height),
-
-                _ => default
-            };
-
-            child.Arrange(rect);
+                var rect = Orientation switch
+                {
+                    Orientation.Vertical => new Rect(0, i * finalSize.Height, finalSize.Width, finalSize.Height),
+                    Orientation.Horizontal => new Rect(i * finalSize.Width, 0, finalSize.Width, finalSize.Height),
+                    _ => default
+                };
+                _childIndeces.Add(child, i);
+                child.Arrange(rect);
+            }
+            _initialized = true;
         }
-
-        ApplyOffset(finalSize);
+        else if (Children.Count() > 1)
+            Dispatcher.UIThread.Post(async () => _ = ApplyOffset(finalSize, true), DispatcherPriority.Render);
 
         return finalSize;
     }
-    private void ApplyOffset(Size size)
-    {
-        double offset = Direction switch
-        {
-            SectionDirection.UpDown => -CurrentIndex * size.Height,
-            SectionDirection.DownUp => CurrentIndex * size.Height,
-            SectionDirection.LeftRight => -CurrentIndex * size.Width,
-            SectionDirection.RightLeft => CurrentIndex * size.Width,
-            _ => 0
-        };
 
-        var transform = RenderTransform as TranslateTransform;
+    private async Task ApplyOffset(Size size, bool animate)
+    {
+        int indexShift = CurrentIndex - _previousIndex;
+
+        while (indexShift != 0)
+        {
+            int indexSingleShift = indexShift / Math.Abs(indexShift);
+
+            var firstIndex = _childIndeces.Min(ch => ch.Value);
+            var lastIndex = _childIndeces.Max(ch => ch.Value);
+
+            if (indexSingleShift == -1 &&
+                _previousIndex - 1 < firstIndex)
+            {
+                var newIndex = firstIndex - 1;
+                var (child, _) = _childIndeces.MaxBy(ch => ch.Value);
+                InstantTransform(child, -Children.Count(), size);
+                _childIndeces[child] = newIndex;
+            }
+
+            if (indexSingleShift == 1 &&
+                _previousIndex + 1 > lastIndex)
+            {
+                var newIndex = lastIndex + 1;
+                var (child, _) = _childIndeces.MinBy(ch => ch.Value);
+                InstantTransform(child, Children.Count(), size);
+                _childIndeces[child] = newIndex;
+            }
+
+            List<Task> animations = new List<Task>();
+            foreach (var (i, child) in Children.Enumerate())
+            {
+                double offset = Orientation switch
+                {
+                    Orientation.Vertical => -indexSingleShift * size.Height,
+                    Orientation.Horizontal => -indexSingleShift * size.Width,
+                    _ => 0
+                };
+
+                if (!animate || !EnableAnimation)
+                    InstantTransform(child, offset);
+                else
+                    animations.Add(AnimationTransform(child, offset, Math.Abs(indexShift)));
+            }
+
+            if (animations.Count() > 0)
+                await Task.WhenAll(animations);
+
+            indexShift -= indexSingleShift;
+            _previousIndex += indexSingleShift;
+        }
+    }
+
+    private void InstantTransform(Control control, double offset, Size? size = null)
+    {
+        var transform = control.RenderTransform as TranslateTransform;
         if (transform is null)
         {
             transform = new TranslateTransform();
-            RenderTransform = transform;
+            control.RenderTransform = transform;
         }
+        if (control.RenderTransformOrigin != RelativePoint.TopLeft)
+            control.RenderTransformOrigin = RelativePoint.TopLeft;
 
-        if (Direction is SectionDirection.LeftRight or SectionDirection.RightLeft)
-            transform.X = offset;
+        if (Orientation is Orientation.Vertical)
+            transform.Y += offset * (size is null ? 1 : size.Value.Height);
         else
-            transform.Y = offset;
+            transform.X += offset * (size is null ? 1 : size.Value.Width);
+    }
+    private Task AnimationTransform(Control control, double offset, double speedRatio)
+    {
+        var transform = control.RenderTransform as TranslateTransform;
+        if (transform is null)
+        {
+            transform = new TranslateTransform();
+            control.RenderTransform = transform;
+        }
+        if (control.RenderTransformOrigin != RelativePoint.TopLeft)
+            control.RenderTransformOrigin = RelativePoint.TopLeft;
+
+        var animation = new Animation
+        {
+            Duration = TimeSpan.FromMilliseconds(Math.Clamp(AnimationSpeed / speedRatio, 120, 1000)),
+            FillMode = FillMode.Forward,
+            Children =
+                {
+                new KeyFrame
+                {
+                    Cue = new Cue(1),
+                    Setters =
+                    {
+                        Orientation is Orientation.Vertical ?
+                            new Setter(TranslateTransform.YProperty, transform.Y + offset) :
+                            new Setter(TranslateTransform.XProperty, transform.X + offset)
+                    }
+                }
+                }
+        };
+        return animation.RunAsync(control);
     }
 }
\ No newline at end of file