using System;

namespace Assistance {

	namespace Drawing {

		public class Helper {

			public static Rectangle getBounds(Cairo.Context context) {

				double w = 1.0;

				double h = 1.0;

				if (context.GetTarget() is Cairo.ImageSurface) {

					Cairo.ImageSurface surface = (Cairo.ImageSurface)context.GetTarget();

					w = surface.Width;

					h = surface.Height;

				}

				Point[] corners = new Point[] {

					new Point(0.0, 0.0),

					new Point(  w, 0.0),

					new Point(  w,   h),

					new Point(0.0,   h) };

				Rectangle bounds = new Rectangle();

				for(int i = 0; i < corners.Length; ++i) {

					double x = corners[i].x;

					double y = corners[i].y;

					context.DeviceToUser(ref x, ref y);

					if (i == 0)

						bounds = new Rectangle(x, y);

					else

						bounds = bounds.expand(new Point(x, y));

				}

				return bounds;

			}

		}

		public struct Color {

			public double r, g, b, a;

			public Color(string name, double alpha = 1.0) {

				Gdk.Color c = new Gdk.Color();

				if (!Gdk.Color.Parse(name, ref c))

					Console.Error.WriteLine("Color [" + name + "] not found");

				this.r = (double)c.Red/65535.0;

				this.g = (double)c.Green/65535.0;

				this.b = (double)c.Blue/65535.0;

				this.a = alpha;

			}

			public Color(double r, double g, double b, double a = 1.0) {

				this.r = r;

				this.g = g;

				this.b = b;

				this.a = a;

			}

			public void apply(Cairo.Context context) {

				context.SetSourceRGBA(r, g, b, a);

			}

		}

		public struct Pen {

			public Color color;

			public double width;

			public Pen(string color, double width = 1.0, double alpha = 1.0) {

				this.color = new Color(color, alpha);

				this.width = width;

			}

			public void apply(Cairo.Context context) {

				color.apply(context);

				context.LineWidth = width;

			}

		}

		public struct Brush {

			public Color color;

			public Brush(string color, double alpha = 1.0) {

				this.color = new Color(color, alpha);

			}

			public void apply(Cairo.Context context) {

				color.apply(context);

			}

		}

	}

}