Lattice/Lattice.UI.Docking.WinUI/Controls/LatticeSplitter.cs

using Lattice.Core.Docking.Abstractions;
using Lattice.Core.Docking.Engine;
using Lattice.Core.Docking.Models;
using Lattice.UI.Docking.Abstractions;
using Microsoft.UI.Input;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Input;
using Microsoft.UI.Xaml.Media;
using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace Lattice.UI;

public sealed class LatticeSplitter : Control, IDockSplitterControl, IDisposable
{
    private bool _disposed;
    private IDockElement? _model;
    private LayoutManager? _layoutManager;
    private IDockContextManager? _contextManager;
    private bool _isSelected;
    private bool _isActive;
    private bool _isDragging;

    public LatticeSplitter()
    {
        this.DefaultStyleKey = typeof(LatticeSplitter);
        this.ManipulationMode = ManipulationModes.TranslateX | ManipulationModes.TranslateY;

        this.PointerEntered += (s, e) =>
            this.ProtectedCursor = InputSystemCursor.Create(InputSystemCursorShape.SizeWestEast);
        this.PointerExited += (s, e) =>
            this.ProtectedCursor = InputSystemCursor.Create(InputSystemCursorShape.Arrow);

        this.ManipulationDelta += OnManipulationDelta;
        this.ManipulationStarted += (s, e) =>
        {
            IsDragging = true;
            DragStarted?.Invoke(this, EventArgs.Empty);
        };
        this.ManipulationCompleted += (s, e) =>
        {
            IsDragging = false;
            DragCompleted?.Invoke(this, EventArgs.Empty);
        };
    }

    public IDockElement? Model
    {
        get => _model;
        set
        {
            if (_model != value)
            {
                _model = value;
                OnPropertyChanged(nameof(Model));
            }
        }
    }

    public LayoutManager? LayoutManager
    {
        get => _layoutManager;
        set
        {
            if (_layoutManager != value)
            {
                _layoutManager = value;
                OnPropertyChanged(nameof(LayoutManager));
            }
        }
    }

    public IDockContextManager? ContextManager
    {
        get => _contextManager;
        set
        {
            if (_contextManager != value)
            {
                _contextManager = value;
                OnPropertyChanged(nameof(ContextManager));
            }
        }
    }

    public bool IsSelected
    {
        get => _isSelected;
        set
        {
            if (_isSelected != value)
            {
                _isSelected = value;
                OnPropertyChanged(nameof(IsSelected));
            }
        }
    }

    public bool IsActive
    {
        get => _isActive;
        set
        {
            if (_isActive != value)
            {
                _isActive = value;
                OnPropertyChanged(nameof(IsActive));
            }
        }
    }

    public bool CanDrag => false;
    public bool CanDrop => false;

    public object? PrepareDragData() => null;
    public bool HandleDrop(object data, DockPosition position) => false;

    public Core.Docking.Models.SplitDirection Orientation { get; set; }

    public bool IsDragging
    {
        get => _isDragging;
        set
        {
            if (_isDragging != value)
            {
                _isDragging = value;
                OnPropertyChanged(nameof(IsDragging));
            }
        }
    }

    public event EventHandler? DragStarted;
    public event EventHandler<SplitterDraggedEventArgs>? DragDelta;
    public event EventHandler? DragCompleted;
    public event PropertyChangedEventHandler? PropertyChanged;

    private void OnManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
    {
        if (this.DataContext is not DockGroup group) return;

        if (VisualTreeHelper.GetParent(this) is not Grid parentGrid ||
            parentGrid.ActualWidth <= 0 || parentGrid.ActualHeight <= 0)
            return;

        double totalSize = group.Orientation == SplitDirection.Horizontal
            ? parentGrid.ActualWidth
            : parentGrid.ActualHeight;

        if (totalSize <= 0) return;

        double delta = group.Orientation == SplitDirection.Horizontal
            ? e.Delta.Translation.X
            : e.Delta.Translation.Y;

        double ratioChange = delta / totalSize;
        group.SplitRatio = Math.Clamp(group.SplitRatio + ratioChange, 0.05, 0.95);

        DragDelta?.Invoke(this, new SplitterDraggedEventArgs(
            group.Orientation == SplitDirection.Horizontal ? delta : 0,
            group.Orientation == SplitDirection.Vertical ? delta : 0));
    }

    public void Refresh() { }

    public void ApplyTheme(IDockTheme theme) { }

    public void OnModelPropertyChanged(string propertyName) { }

    private void OnPropertyChanged([CallerMemberName] string? propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    public void Dispose()
    {
        if (!_disposed)
        {
            _disposed = true;
            GC.SuppressFinalize(this);
        }
    }
}