using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Shapes;

namespace Lattice.UI.Primitives;

/// <summary>
/// Визуальный оверлей, отображающий зоны приземления (Drop Zones) и якоря докинга.
/// </summary>
[TemplatePart(Name = "OverlayCanvas", Type = typeof(Canvas))]
[TemplatePart(Name = "DropPreview", Type = typeof(Rectangle))]
[TemplatePart(Name = "AnchorGroup", Type = typeof(Grid))]
public class DockAnchorOverlay : Control
{
    private Canvas? _overlayCanvas;
    private Rectangle? _dropPreview;
    private Grid? _anchorGroup;

    public DockAnchorOverlay()
    {
        // Привязываем стиль из Generic.xaml
        this.DefaultStyleKey = typeof(DockAnchorOverlay);

        // По умолчанию скрыт, показывается только во время Drag-and-Drop
        this.Visibility = Visibility.Collapsed;
    }

    protected override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        _overlayCanvas = GetTemplateChild("OverlayCanvas") as Canvas;
        _dropPreview = GetTemplateChild("DropPreview") as Rectangle;
        _anchorGroup = GetTemplateChild("AnchorGroup") as Grid;
    }

    /// <summary>
    /// Отображает превью будущей зоны закрепления.
    /// </summary>
    /// <param name="rect">Координаты и размер зоны.</param>
    public void ShowPreview(Windows.Foundation.Rect rect)
    {
        if (_dropPreview == null) return;

        _dropPreview.Visibility = Visibility.Visible;
        Canvas.SetLeft(_dropPreview, rect.X);
        Canvas.SetTop(_dropPreview, rect.Y);
        _dropPreview.Width = rect.Width;
        _dropPreview.Height = rect.Height;
    }

    /// <summary>
    /// Скрывает превью зоны.
    /// </summary>
    public void HidePreview()
    {
        if (_dropPreview != null)
            _dropPreview.Visibility = Visibility.Collapsed;
    }

    /// <summary>
    /// Центрирует группу якорей (ромб) относительно указанной точки.
    /// </summary>
    public void PositionAnchors(Windows.Foundation.Point centerPoint)
    {
        if (_anchorGroup == null) return;

        Canvas.SetLeft(_anchorGroup, centerPoint.X - (_anchorGroup.Width / 2));
        Canvas.SetTop(_anchorGroup, centerPoint.Y - (_anchorGroup.Height / 2));
    }
}