using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;

namespace XP.ImageProcessing.RoiControl.Models
{
    /// <summary>一次角度测量的所有视觉元素（顶点V + 射线端点A/B + 两条射线 + 弧线 + 标签）</summary>
    public class AngleGroup
    {
        public Ellipse DotV { get; set; }   // 顶点
        public Ellipse DotA { get; set; }   // 射线端点A
        public Ellipse DotB { get; set; }   // 射线端点B
        public Line LineA { get; set; }     // 射线VA
        public Line LineB { get; set; }     // 射线VB
        public Path Arc { get; set; }       // 角度弧线
        public TextBlock Label { get; set; }
        public Point V { get; set; }
        public Point A { get; set; }
        public Point B { get; set; }

        public double AngleDeg
        {
            get
            {
                double vax = A.X - V.X, vay = A.Y - V.Y;
                double vbx = B.X - V.X, vby = B.Y - V.Y;
                double lenA = Math.Sqrt(vax * vax + vay * vay);
                double lenB = Math.Sqrt(vbx * vbx + vby * vby);
                if (lenA < 0.001 || lenB < 0.001) return 0;
                double dot = vax * vbx + vay * vby;
                double cos = Math.Clamp(dot / (lenA * lenB), -1.0, 1.0);
                return Math.Acos(cos) * 180.0 / Math.PI;
            }
        }

        public void UpdateVisuals()
        {
            // 射线
            LineA.X1 = V.X; LineA.Y1 = V.Y; LineA.X2 = A.X; LineA.Y2 = A.Y;
            LineA.Visibility = Visibility.Visible;
            LineB.X1 = V.X; LineB.Y1 = V.Y; LineB.X2 = B.X; LineB.Y2 = B.Y;
            LineB.Visibility = Visibility.Visible;

            // 弧线
            double vax = A.X - V.X, vay = A.Y - V.Y;
            double vbx = B.X - V.X, vby = B.Y - V.Y;
            double lenA = Math.Sqrt(vax * vax + vay * vay);
            double lenB = Math.Sqrt(vbx * vbx + vby * vby);

            if (lenA < 1 || lenB < 1) { Arc.Visibility = Visibility.Collapsed; return; }

            double arcRadius = Math.Min(30, Math.Min(lenA, lenB) * 0.3);
            if (arcRadius < 8) arcRadius = 8;

            double angleARad = Math.Atan2(vay, vax);
            double angleBRad = Math.Atan2(vby, vbx);
            double cross = vax * vby - vay * vbx;
            double angleDeg = AngleDeg;
            bool isLargeArc = angleDeg > 180;
            var sweepDir = cross >= 0 ? SweepDirection.Clockwise : SweepDirection.Counterclockwise;

            var startPt = new Point(V.X + arcRadius * Math.Cos(angleARad), V.Y + arcRadius * Math.Sin(angleARad));
            var endPt = new Point(V.X + arcRadius * Math.Cos(angleBRad), V.Y + arcRadius * Math.Sin(angleBRad));

            var arcSeg = new ArcSegment(endPt, new Size(arcRadius, arcRadius), 0, isLargeArc, sweepDir, true);
            var fig = new PathFigure(startPt, new[] { arcSeg }, false);
            Arc.Data = new PathGeometry(new[] { fig });
            Arc.Visibility = Visibility.Visible;

            // 标签位置
            double midAngle = (angleARad + angleBRad) / 2.0;
            double testX = Math.Cos(midAngle), testY = Math.Sin(midAngle);
            double testCross = vax * testY - vay * testX;
            if ((cross >= 0 && testCross < 0) || (cross < 0 && testCross >= 0))
                midAngle += Math.PI;

            double labelDist = arcRadius + 16;
            Label.Text = $"{angleDeg:F1}°";
            Canvas.SetLeft(Label, V.X + labelDist * Math.Cos(midAngle) - 15);
            Canvas.SetTop(Label, V.Y + labelDist * Math.Sin(midAngle) - 8);
            Label.Visibility = Visibility.Visible;
        }
    }
}