using System;
using System.Xml;

using SharpVectors.Dom.Css;

namespace SharpVectors.Dom.Svg
{
	public sealed class SvgLinearGradientElement : SvgGradientElement, ISvgLinearGradientElement
	{
        private ISvgAnimatedLength x1;
        private ISvgAnimatedLength y1;
        private ISvgAnimatedLength x2;
        private ISvgAnimatedLength y2;

		public SvgLinearGradientElement(string prefix, string localname, string ns, SvgDocument doc)
			: base(prefix, localname, ns, doc)
		{
		}

		#region ISvgLinearGradientElement Members

		public ISvgAnimatedLength X1
		{
			get
			{
				if (!HasAttribute("x1") && ReferencedElement != null)
				{
					return ReferencedElement.X1;
				}
				else
				{
					if (x1 == null)
					{
						x1 = new SvgAnimatedLength(this, "x1", SvgLengthDirection.Horizontal, "0%");
					}

					return x1;
				}
			}
		}

		public ISvgAnimatedLength Y1
		{
			get
			{
				if (!HasAttribute("y1") && ReferencedElement != null)
				{
					return ReferencedElement.Y1;
				}
				else
				{

					if (y1 == null)
					{
						y1 = new SvgAnimatedLength(this, "y1", SvgLengthDirection.Vertical, "0%");
					}

					return y1;
				}
			}
		}

		public ISvgAnimatedLength X2
		{
			get
			{
				if (!HasAttribute("x2") && ReferencedElement != null)
				{
					return ReferencedElement.X2;
				}
				else
				{

					if (x2 == null)
					{
						x2 = new SvgAnimatedLength(this, "x2", SvgLengthDirection.Horizontal, "100%");
					}

					return x2;
				}
			}
		}

		public ISvgAnimatedLength Y2
		{
			get
			{
				if (!HasAttribute("y2") && ReferencedElement != null)
				{
					return ReferencedElement.Y2;
				}
				else
				{   
					if (y2 == null)
					{
						y2 = new SvgAnimatedLength(this, "y2", SvgLengthDirection.Vertical, "0%");
					}

					return y2;
				}
			}
		}
		#endregion

		#region ISvgURIReference Members

		public new SvgLinearGradientElement ReferencedElement
		{
			get
			{
				return base.ReferencedElement as SvgLinearGradientElement;
			}
		}

		#endregion

		#region Update handling
		/*public override void OnAttributeChange(XmlNodeChangedAction action, XmlAttribute attribute)
		{
			base.OnAttributeChange(action, attribute);

			if(attribute.NamespaceURI.Length == 0)
			{
				switch(attribute.LocalName)
				{
					case "x1":
						x1 = null;
						break;
					case "y1":
						y1 = null;
						break;
					case "x2":
						x2 = null;
						break;
					case "y2":
						y2 = null;
						break;
				}
			}
		}*/
		#endregion
	}
}