using System;

using System.Drawing;

using System.Drawing.Imaging;

using System.Collections.Generic;

namespace Assistance {

	public class ActivePoint {

		public enum Type {

			Circle,

			CircleFill,

			CircleCross,

		};

		public class Owner {

			public readonly Document document;

			public readonly List<activepoint> points = new List<activepoint>();</activepoint></activepoint>

			public Owner(Document document) { this.document = document; }

			public virtual void onMovePoint(ActivePoint point, Point position) { point.position = position; }

			public virtual void bringToFront() { }

			public virtual void remove() { foreach(ActivePoint point in points) document.points.Remove(point); }

		}

		public static readonly double radius = 10.0;

		public static readonly double crossSize = 1.2*radius;

		public static readonly Pen pen = Pens.Gray;

		public static readonly Brush brush = Brushes.LightGray;

		public static readonly Pen penActive = Pens.Blue;

		public static readonly Brush brushActive = Brushes.LightBlue;

		public readonly Document document;

		public readonly Owner owner;

		public readonly Type type;

		public Point position;

		public ActivePoint(Owner owner, Type type, Point position = new Point()) {

			this.document = owner.document;

			this.owner = owner;

			this.type = type;

			this.position = position;

			document.points.Add(this);

			owner.points.Add(this);

		}

		public bool isInside(Point p) {

			return (position - p).lenSqr() <= radius*radius;

		}

		public void bringToFront() {

			owner.bringToFront();

			owner.points.Remove(this);

			owner.points.Add(this);

			document.points.Remove(this);

			document.points.Add(this);

		}

		private Pen getPen(bool active) {

			return active ? penActive : pen;

		}

		private Brush getBrush(bool active) {

			return active ? brushActive : brush;

		}

		private void drawCircle(Graphics g, bool active) {

			g.DrawEllipse(getPen(active), (float)(position.x - radius), (float)(position.y - radius), (float)(2.0*radius), (float)(2.0*radius));

		}

		private void fillCircle(Graphics g, bool active) {

			g.FillEllipse(getBrush(active), (float)(position.x - radius), (float)(position.y - radius), (float)(2.0*radius), (float)(2.0*radius));

		}

		private void drawCross(Graphics g, bool active) {

			g.DrawLine(getPen(active), (float)(position.x - crossSize), (float)position.y, (float)(position.x + crossSize), (float)position.y);

			g.DrawLine(getPen(active), (float)position.x, (float)(position.y - crossSize), (float)position.x, (float)(position.y + crossSize));

		}

		public void draw(Graphics g, bool active = false) {

			switch(type) {

			case Type.Circle:

				drawCircle(g, active);

				break;

			case Type.CircleFill:

				fillCircle(g, active);

				drawCircle(g, active);

				break;

			case Type.CircleCross:

				drawCircle(g, active);

				drawCross(g, active);

				break;

			}

		}

	}

}