using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Media;

namespace Microsoft.Research.DynamicDataDisplay.Common.Palettes
{
	/// <summary>
	/// Represents a base class for decorating palette, which wraps another palette and intercepts calls to it.
	/// </summary>
	public abstract class DecoratorPaletteBase : PaletteBase
	{
		/// <summary>
		/// Initializes a new instance of the <see cref="DecoratorPaletteBase"/> class.
		/// </summary>
		protected DecoratorPaletteBase() { }

		/// <summary>
		/// Initializes a new instance of the <see cref="DecoratorPaletteBase"/> class.
		/// </summary>
		/// <param name="palette">The palette.</param>
		public DecoratorPaletteBase(IPalette palette)
		{
			Palette = palette;
		}

		private IPalette palette = null;
		/// <summary>
		/// Gets or sets the palette being decorated.
		/// </summary>
		/// <value>The palette.</value>
		public IPalette Palette
		{
			get { return palette; }
			set
			{
				if (value == null)
					throw new ArgumentNullException("value");

				if (palette != null)
					palette.Changed -= OnChildPaletteChanged;

				palette = value;
				palette.Changed += OnChildPaletteChanged;

				RaiseChanged();
			}
		}

		void OnChildPaletteChanged(object sender, EventArgs e)
		{
			RaiseChanged();
		}

		/// <summary>
		/// Gets the color by interpolation coefficient.
		/// </summary>
		/// <param name="t">Interpolation coefficient, should belong to [0..1].</param>
		/// <returns>Color.</returns>
		public override Color GetColor(double t)
		{
			return palette.GetColor(t);
		}
	}
}