#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Drawing;
using HeuristicLab.Visualization;

namespace HeuristicLab.EvolutionaryTracking.Views {
  public class VisualGenealogyGraphArc : Line {
    public VisualGenealogyGraphNode Source;
    public VisualGenealogyGraphNode Target;

    public VisualGenealogyGraphArc(IChart chart, PointD start, PointD end)
      : base(chart, start, end) {
    }
    public VisualGenealogyGraphArc(IChart chart, double x1, double y1, double x2, double y2)
      : this(chart, new PointD(x1, y1), new PointD(x2, y2)) {
    }
    public VisualGenealogyGraphArc(IChart chart, PointD start, PointD end, Pen pen)
      : base(chart, start, end, pen) {
    }
    public VisualGenealogyGraphArc(IChart chart, VisualGenealogyGraphNode source, VisualGenealogyGraphNode target, Pen pen)
      : base(chart, source.Center, target.Center, pen) {
      Source = source;
      Target = target;
      UpdatePosition();
    }
    public VisualGenealogyGraphArc(IChart chart, double x1, double y1, double x2, double y2, Pen pen)
      : this(chart, new PointD(x1, y1), new PointD(x2, y2), pen) {
    }

    internal void UpdatePosition() {
      if (Source.Equals(Target)) return;
      // calculate the positions of the arc ends so that virtually the line will go through the centers of the two elliptical node shapes
      PointD c1 = Source.Center;
      PointD c2 = Target.Center;
      double x = Math.Abs(c1.X - c2.X);
      double y = Math.Abs(c1.Y - c2.Y);
      double theta = Math.Atan(y / x); // returns angle in radians
      // compute the intersection point between an ellipse-shaped node and a line passing through its center with the angular coordinate theta
      PointD p1 = Source.CalculateIntersection(theta);
      PointD p2 = Target.CalculateIntersection(theta);
      // translate coordinates to real-world values
      double p1X, p1Y, p2X, p2Y;
      if (c1.X > c2.X) {
        p1X = c1.X - p1.X;
        p2X = c2.X + p2.X;
      } else {
        p1X = c1.X + p1.X;
        p2X = c2.X - p2.X;
      }
      if (c1.Y > c2.Y) {
        p1Y = c1.Y - p1.Y;
        p2Y = c2.Y + p2.Y;
      } else {
        p1Y = c1.Y + p1.Y;
        p2Y = c2.Y - p1.Y;
      }
      if (double.IsNaN(p1X) || double.IsNaN(p1Y) || double.IsNaN(p2X) || double.IsNaN(p2Y))
        throw new Exception("Error calculating arc position.");
      p1.X = p1X;
      p1.Y = p1Y;
      p2.X = p2X;
      p2.Y = p2Y;
      SetPosition(p1, p2);
    }
  }
}