namespace TACO.Widgets
{
	using System;
	using System.Drawing;
	using System.Drawing.Drawing2D;

	public class CanvasSelection : CanvasElement
	{
		private CanvasElement mTarget = null;

		public CanvasSelection(CanvasElement target)
			: base("##selection")
		{
			Target = target;
		}

		public override string Name
		{
			get { return "Selection"; }
		}

		public CanvasElement Target
		{
			get { return mTarget; }
			set
			{
				if (mTarget == value)
					return;

				if (value == null)
				{
					mTarget.VisibilityChanged -= OnElementVisibilityChanged;
					mTarget.BoundsChanged     -= OnElementBoundsChanged;
					Visible = false;
				}

				mTarget = value;

				if (mTarget != null)
				{
					mTarget.VisibilityChanged += OnElementVisibilityChanged;
					mTarget.BoundsChanged     += OnElementBoundsChanged;

					Visible = true;

					SetBounds(mTarget.Bounds);
				}
			}
		}

		public override void Draw(Graphics g)
		{
			Pen pen = new Pen(Color.Black, 1);
			pen.DashStyle = DashStyle.Dash;

			g.DrawRectangle(pen, new Rectangle(Bounds.X, Bounds.Y,
											   Bounds.Width - 1,
											   Bounds.Height - 1));

			pen.Dispose();
		}

		private void OnElementBoundsChanged(object o, BoundsChangedArgs args)
		{
			SetBounds(Target.Bounds);
		}

		private void OnElementVisibilityChanged(object o, System.EventArgs args)
		{
			if (!Target.Visible)
				Target = null;
		}
	}
}