using System;

namespace EllipseTruncate {

	public class ActiveAngleRange {

		public double width = 0.1;

		public Point point;

		public double radius;

		public AngleRange.Entry current;

		public AngleRange a = new AngleRange();

		public AngleRange b = new AngleRange();

		public ActiveAngleRange(Point point, double radius) {

			this.point = point;

			this.radius = radius;

		}

		public void add() {

			a.add(current);

			current = new AngleRange.Entry();

		}

		public void xor() {

			a.xor(current);

			current = new AngleRange.Entry();

		}

		public void subtract() {

			a.subtract(current);

			current = new AngleRange.Entry();

		}

		public void scale(Cairo.Context context, double level = 1.0) {

			double k = Math.Pow(1.0 + 1.5*width, level);

			context.Scale(k, k);

		}

		public void draw(Cairo.Context context, uint a0, uint a1, double level = 0.0) {

			if (a0 == a1) return;

			context.Save();

			scale(context, level);

			context.LineWidth = width;

			double aa0 = AngleRange.toDouble(a0);

			double aa1 = AngleRange.toDouble(a1);

			if (a1 < a0) aa1 += AngleRange.period;

			if (aa1 < aa0) return;

			context.Arc(0.0, 0.0, 1.0, aa0, aa1);

			context.Stroke();

			context.Restore();

		}

		public void draw(Cairo.Context context, AngleRange r, double level = 0.0) {

			context.Save();

			scale(context, level);

			if (r.isEmpty()) {

				context.LineWidth = 0.25*width;

				context.SetDash(new double[] { 0.1, 0.02 }, 0.0);

				context.Arc(0.0, 0.0, 1.0, 0.0, 2.0*Math.PI);

				context.Stroke();

			} else

			if (r.isFull()) {

				context.LineWidth = width;

				context.Arc(0.0, 0.0, 1.0, 0.0, 2.0*Math.PI);

				context.Stroke();

				context.LineWidth = 0.25*width;

				context.SetDash(new double[] { 0.1, 0.03 }, 0.0);

				context.Arc(0.0, 0.0, 1.0, 0.0, 2.0*Math.PI);

				context.Stroke();

			} else {

				context.LineWidth = 0.25*width;

				context.Arc(0.0, 0.0, 1.0, 0.0, 2.0*Math.PI);

				context.Stroke();

				bool f = r.flip;

				uint prev = r.angles[r.angles.Count - 1];

				foreach(uint a in r.angles) {

					if (f) draw(context, prev, a);

					prev = a; f = !f;

				}

			}

			if (!r.check()) {

				context.LineWidth = width;

				context.SetDash(new double[] { 0.1, 0.02 }, 0.0);

				context.Arc(0.0, 0.0, 1.0, 0.0, 2.0*Math.PI);

				context.Stroke();

			}

			context.Restore();

		}

		public void draw(Cairo.Context context) {

			context.Save();

			context.Translate(point.x, point.y);

			context.Scale(radius, radius);

			AngleRange x = new AngleRange();

			// back circle

			context.SetSourceRGBA(1.0, 0.0, 0.0, 0.1);

			context.Arc(0.0, 0.0, 1.0, 0.0, 2.0*Math.PI);

			context.Fill();

			// a

			context.SetSourceRGBA(0.0, 0.0, 0.0, 0.5);

			draw(context, a);

			// b

			context.SetSourceRGBA(0.0, 0.0, 1.0, 0.5);

			draw(context, b, 1.0);

			// current

			context.SetSourceRGBA(0.0, 0.0, 1.0, 0.5);

			if (!current.isEmpty())

				draw(context, current.a0, current.a1);

			// !a

			context.SetSourceRGBA(0.5, 0.5, 0.5, 0.5);

			x.set(a); x.invert();	

			draw(context, x, -1.0);

			scale(context);

			// a xor b

			scale(context);

			context.SetSourceRGBA(0.0, 0.5, 0.0, 0.5);

			x.set(a);

			x.xor(b);

			draw(context, x);

			// a | b

			scale(context);

			context.SetSourceRGBA(0.0, 0.5, 0.0, 0.5);

			x.set(a);

			x.add(b);

			draw(context, x);

			// a & ~b

			scale(context);

			context.SetSourceRGBA(0.0, 0.5, 0.0, 0.5);

			x.set(a);

			x.subtract(b);

			draw(context, x);

			// a & b

			scale(context);

			context.SetSourceRGBA(0.0, 0.5, 0.0, 0.5);

			x.set(a);

			x.intersect(b);

			draw(context, x);

			context.Restore();

		}

	}

}