using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RazorEngineTest
{
    using System.Windows;
    using System.Windows.Documents;
    using System.Windows.Media;

    public class DropPlacementAdorner : Adorner
    {
        private readonly string _position;
        private static readonly Pen _pen;

        static DropPlacementAdorner()
        {
            // 定义装饰器的画笔
            _pen = new Pen(Brushes.Red, 5.0);
            _pen.Freeze();
        }

        public DropPlacementAdorner(UIElement adornedElement, string position)
            : base(adornedElement)
        {
            _position = position;
            IsHitTestVisible = false;
        }

        protected override void OnRender(DrawingContext drawingContext)
        {
            var adornedElementRect = new Rect(AdornedElement.RenderSize);

            // 根据位置信息绘制不同的视觉效果
            switch (_position)
            {
                case "上":
                    drawingContext.DrawLine(_pen,
                        new Point(0, 0),
                        new Point(adornedElementRect.Right, 0));
                    break;
                case "下":
                    drawingContext.DrawLine(_pen,
                        new Point(0, adornedElementRect.Bottom),
                        new Point(adornedElementRect.Right, adornedElementRect.Bottom));
                    break;
                case "左":
                    drawingContext.DrawLine(_pen,
                        new Point(0, 0),
                        new Point(0, adornedElementRect.Bottom));
                    break;
                case "右":
                    drawingContext.DrawLine(_pen,
                        new Point(adornedElementRect.Right, 0),
                        new Point(adornedElementRect.Right, adornedElementRect.Bottom));
                    break;
                case "中":
                    drawingContext.DrawRectangle(null, _pen, adornedElementRect);
                    break;
                default:break;
            }
        }
    }
}