using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Media;
using System.ComponentModel;
using System.Windows.Markup;
using Microsoft.Research.DynamicDataDisplay.Common.Auxiliary;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;

namespace Microsoft.Research.DynamicDataDisplay.Common.Palettes
{
	[ContentProperty("ColorSteps")]
	public sealed class UniformLinearPalette : IPalette, ISupportInitialize
	{
		private double[] points;

		private ObservableCollection<Color> colors = new ObservableCollection<Color>();
		public ObservableCollection<Color> Colors
		{
			get { return colors; }
		}

		private List<PaletteColorStep> colorSteps = new List<PaletteColorStep>();
		[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
		[EditorBrowsable(EditorBrowsableState.Never)]
		public List<PaletteColorStep> ColorSteps
		{
			get { return colorSteps; }
		}

		[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
		private void RaiseChanged()
		{
			Changed.Raise(this);
		}
		public event EventHandler Changed;

		public UniformLinearPalette() { }

		public UniformLinearPalette(params Color[] colors)
		{
			if (colors == null) throw new ArgumentNullException("colors");
			if (colors.Length < 2) throw new ArgumentException(Strings.Exceptions.PaletteTooFewColors);

			this.colors = new ObservableCollection<Color>(colors);
			FillPoints(colors.Length);
		}

		private void FillPoints(int size)
		{
			points = new double[size];
			for (int i = 0; i < size; i++)
			{
				points[i] = i / (double)(size - 1);
			}
		}

		private bool increaseBrightness = true;
		[DefaultValue(true)]
		public bool IncreaseBrightness
		{
			get { return increaseBrightness; }
			set { increaseBrightness = value; }
		}

		public Color GetColor(double t)
		{
			Verify.AssertIsFinite(t);
			Verify.IsTrue(0 <= t && t <= 1);

			if (t <= 0)
				return colors[0];
			else if (t >= 1)
				return colors[colors.Count - 1];
			else
			{
				int i = 0;
				while (points[i] < t)
					i++;

				double ratio = (points[i] - t) / (points[i] - points[i - 1]);

				Verify.IsTrue(0 <= ratio && ratio <= 1);

				Color c0 = colors[i - 1];
				Color c1 = colors[i];
				Color res = Color.FromRgb(
					(byte)(c0.R * ratio + c1.R * (1 - ratio)),
					(byte)(c0.G * ratio + c1.G * (1 - ratio)),
					(byte)(c0.B * ratio + c1.B * (1 - ratio)));

				// Increasing saturation and brightness
				if (increaseBrightness)
				{
					HsbColor hsb = res.ToHsbColor();
					//hsb.Saturation = 0.5 * (1 + hsb.Saturation);
					hsb.Brightness = 0.5 * (1 + hsb.Brightness);
					return hsb.ToArgbColor();
				}
				else
				{
					return res;
				}
			}
		}

		#region ISupportInitialize Members

		bool beganInit = false;
		public void BeginInit()
		{
			beganInit = true;
		}

		public void EndInit()
		{
			if (beganInit)
			{
				colors = new ObservableCollection<Color>(colorSteps.Select(step => step.Color));
				FillPoints(colors.Count);
			}
		}

		#endregion
	}
}