using System.Drawing.Drawing2D;
using SharpMap;
using SharpMap.Rendering.Decoration;
using System;
using System.Drawing;

using System.Globalization;


namespace HeuristicLab.BioBoost.Views.MapViews {
  public class GradientLegend : MapDecoration {
    public Size Size { get; set; }
    public double MinValue { get; set; }
    public double MaxValue { get; set; }
    public ColorBlend ColorBlend { get; set; }
    public Point Offset { get; set; }
    public Font Font { get; set; }
    public String Unit { get; set; }

    public GradientLegend() {
      Size = new Size(150, 20);
      Anchor = MapDecorationAnchor.LeftBottom;
      MinValue = 0;
      MaxValue = 1;
      Offset = new Point(10, 10);
      // color blend does not match the gradient legend exactly
      /*
       ColorBlend  = new ColorBlend {
      Colors = new[] {
        Color.FromArgb(0, 0, 127),
        Color.FromArgb(0, 0, 255),
        Color.FromArgb(0, 255, 255),
        Color.FromArgb(0, 255, 0),
        Color.FromArgb(127, 255, 0),
        Color.FromArgb(255, 255, 0),
        Color.FromArgb(255, 127, 0),
        Color.FromArgb(255, 0, 0),
        Color.FromArgb(127, 0, 0)},
      Positions = new[] { 0.0f, 0.125f, 0.25f, 0.375f, 0.5f, 0.625f, 0.75f, 0.875f, 1f }
       };
       */
      // GradientLegend uses ColorBlend from System.Drawing and we need to convert it to a SharpMap colorblend here
      ColorBlend = new ColorBlend() {
        Colors = LazyValueLayerGenerator.DefaultColorBlend.Colors,
        Positions = LazyValueLayerGenerator.DefaultColorBlend.Positions
      };
      Font = (Font)SystemFonts.DefaultFont.Clone();
    }

    protected override Size InternalSize(Graphics g, Map map) {
      return new Size(Size.Width + Offset.X + 4, Size.Height + Offset.Y + 3);
    }

    protected override void OnRender(Graphics g, Map map) {
      var pos = new PointF(g.ClipBounds.Left + Offset.X, g.ClipBounds.Bottom - Offset.Y - Size.Height);
      var brush = new System.Drawing.Drawing2D.LinearGradientBrush(pos, new PointF(pos.X + Size.Width, pos.Y), Color.Black, Color.Black) {
        InterpolationColors = ColorBlend
      };
      g.FillRectangle(new SolidBrush(Color.FromArgb(127, 255, 255, 255)),
        pos.X - 1, pos.Y - 1, Size.Width + 3, Size.Height + 2);
      var minStr = MinValue.ToString(CultureInfo.InvariantCulture);
      var maxStr = MaxValue.ToString("G4", CultureInfo.InvariantCulture);
      if (!String.IsNullOrEmpty(Unit)) maxStr += " " + Unit;
      var minDim = g.MeasureString(minStr, Font);
      var maxDim = g.MeasureString(maxStr, Font);
      var textHeight = Math.Min(minDim.Height, maxDim.Height);
      g.FillRectangle(brush, pos.X, pos.Y + textHeight, Size.Width, Size.Height - textHeight - 2);
      g.DrawString(minStr, Font, Brushes.Black, pos.X, pos.Y);
      g.DrawString(maxStr, Font, Brushes.Black, pos.X + Size.Width - maxDim.Width - 2, pos.Y);
      g.DrawLine(Pens.Black, pos.X, pos.Y, pos.X, pos.Y + Size.Height);
      g.DrawLine(Pens.Black, pos.X + Size.Width, pos.Y, pos.X + Size.Width, pos.Y + Size.Height);

      g.DrawLine(Pens.Black, pos.X + Size.Width / 4, pos.Y + textHeight, pos.X + Size.Width / 4, pos.Y + Size.Height);
      g.DrawLine(Pens.Black, pos.X + Size.Width / 2, pos.Y + textHeight / 2, pos.X + Size.Width / 2, pos.Y + Size.Height);
      g.DrawLine(Pens.Black, pos.X + Size.Width / 4 * 3, pos.Y + textHeight, pos.X + Size.Width / 4 * 3, pos.Y + Size.Height);
    }

  }
}