#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 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.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Windows.Forms;
using HeuristicLab.Core;
using HeuristicLab.Random;
using HeuristicLab.Visualization;
using Pen = System.Drawing.Pen;
using Rectangle = HeuristicLab.Visualization.Rectangle;
using Routing = HeuristicLab.VariableInteractionNetworks.Views.ConstrainedForceDirectedLayout.EdgeRouting;


namespace HeuristicLab.VariableInteractionNetworks.Views {
  public partial class DirectedGraphChart : ChartControl {
    private ConstrainedForceDirectedLayout layout;
    // provide direct and reverse mapping between graph objects and layout shapes
    private Dictionary<IPrimitive, IVertex> vertexMap;
    private Dictionary<IPrimitive, IArc> arcMap;
    private Dictionary<IArc, LinearPrimitiveBase> arcShapes;
    private Dictionary<IVertex, RectangularPrimitiveBase> vertexShapes;

    // graph layout options
    public double IdealEdgeLength { get; set; } = 50;
    public bool PerformEdgeRouting { get; set; } = false;
    public Routing RoutingMode { get; set; }

    public IVertex GetVertex(IPrimitive primitive) {
      IVertex v;
      vertexMap.TryGetValue(primitive, out v);
      return v;
    }

    public IArc GetArc(IPrimitive primitive) {
      IArc a;
      arcMap.TryGetValue(primitive, out a);
      return a;
    }

    public RectangularPrimitiveBase GetVertexShape(IVertex v) {
      RectangularPrimitiveBase p;
      vertexShapes.TryGetValue(v, out p);
      return p;
    }

    public LinearPrimitiveBase GetArcShape(IArc arc) {
      LinearPrimitiveBase l;
      arcShapes.TryGetValue(arc, out l);
      return l;
    }

    public ToolTip ToolTip {
      get { return toolTip; }
    }

    public DirectedGraphChart() {
      InitializeComponent();

      var directedGraphChartMode = new DirectedGraphChartMode(this);

      this.AddChartModes(directedGraphChartMode, new PanChartMode(this), new ZoomInChartMode(this), new ZoomOutChartMode(this));
      shapes = new Dictionary<Type, LabeledPrimitive>();
      SmoothingMode = SmoothingMode.HighQuality; // set antialiasing for nicer rendering
    }

    private IDirectedGraph graph;
    public IDirectedGraph Graph {
      get { return graph; }
      set {
        if (value == null || graph == value || !value.Vertices.Any()) return;
        graph = value;
        Draw();
      }
    }

    private void RegisterEvents() { }

    private void DeregisterEvents() { }

    public void Draw() {
      SuspendRendering();
      Chart.Group.Clear();
      vertexMap = new Dictionary<IPrimitive, IVertex>();
      arcMap = new Dictionary<IPrimitive, IArc>();
      var rng = new MersenneTwister();
      vertexShapes = new Dictionary<IVertex, RectangularPrimitiveBase>();
      arcShapes = new Dictionary<IArc, LinearPrimitiveBase>();
      var vertexRectangles = new Dictionary<IVertex, RectangleF>();
      foreach (var v in graph.Vertices) {
        var shape = CreateShape(v);
        shape.ToolTipText = v.Label;
        vertexMap[shape] = v;
        vertexShapes[v] = shape;
        var width = (float)shape.Size.Width;
        var height = (float)shape.Size.Height;
        var x = (float)(rng.NextDouble() * (Chart.Size.Width - width));
        var y = (float)(rng.NextDouble() * (Chart.Size.Height - height));
        vertexRectangles[v] = new RectangleF(x, y, width, height);
      }
      layout = new ConstrainedForceDirectedLayout {
        DefaultEdgeLength = IdealEdgeLength,
        PerformEdgeRouting = PerformEdgeRouting,
        LayoutWidth = (int)Chart.Size.Width,
        LayoutHeight = (int)Chart.Size.Height,
        MinHorizontalSpacing = 0,
        MinVerticalSpacing = 0,
        EdgeRoutingMode = RoutingMode
      };

      var arcs = graph.Vertices.SelectMany(x => x.InArcs).ToList();
      if (arcs.Count != graph.Arcs.Count())
        throw new Exception("Arcs count does not match!");

      layout.Run(vertexRectangles);
      var vertexPositions = layout.VertexPositions;
      var arcRoutes = layout.ArcRoutes;

      var max = arcRoutes.Keys.Max(x => x.Weight);

      // move shapes to the positions computed by the layout
      foreach (var pair in vertexPositions) {
        var shape = vertexShapes[pair.Key];
        var pos = vertexPositions[pair.Key];
        shape.Move(new Offset(pos.X, pos.Y));
      }

      foreach (var pair in arcRoutes) {
        var arc = pair.Key;
        var weight = arc.Weight;
        var points = pair.Value;
        var target = (LabeledPrimitive)vertexShapes[pair.Key.Target];
        var len = points.Length; // len = 2 when no edge routingMode is performed
        Pen pen;
        var penWidth = weight / max * 2;
        if (len == 2) {
          if (double.IsInfinity(penWidth) || double.IsNaN(penWidth)) penWidth = 1;
          pen = new Pen(Color.Black, (float)penWidth) { CustomEndCap = new AdjustableArrowCap(5, 3) };
          var start = points[0];
          var end = points[1];
          var line = new Line(Chart, new PointD(start.X, start.Y), new PointD(end.X, end.Y));
          var rect = target.Primitive as Rectangle;
          var ell = target.Primitive as Ellipse;
          PointD intersectionPoint;
          if (rect != null)
            intersectionPoint = rect.ComputeIntersect(line).FirstOrDefault();
          else if (ell != null)
            intersectionPoint = ell.ComputeIntersect(line).FirstOrDefault();
          else
            throw new InvalidOperationException("Unknown vertex shape.");
          if (intersectionPoint == default(PointD))
            intersectionPoint = end;
          line = new Line(Chart, new PointD(start.X, start.Y), intersectionPoint, pen) { ToolTipText = arc.Label };
          Chart.Group.Add(line);
          arcShapes[arc] = line;
          arcMap[line] = arc;
        } else {
          for (int i = 0; i < points.Length - 1; ++i) {
            Line line;
            var start = points[i];
            var end = points[i + 1];

            var segment = new Line(Chart, new PointD(start.X, start.Y), new PointD(end.X, end.Y));
            var rect = target.Primitive as Rectangle;
            var ell = target.Primitive as Ellipse;

            PointD endPoint;
            List<PointD> intersectionPoints;
            if (rect != null) {
              intersectionPoints = rect.ComputeIntersect(segment);
            } else if (ell != null) {
              intersectionPoints = ell.ComputeIntersect(segment);
            } else {
              throw new InvalidOperationException("Unknown vertex shape.");
            }
            if (intersectionPoints.Any()) {
              endPoint = intersectionPoints.First();
              pen = new Pen(Color.Black, (float)penWidth) { CustomEndCap = new AdjustableArrowCap(5, 3) };
            } else {
              endPoint = end;
              pen = new Pen(Color.Black, (float)penWidth);
            }
            line = new Line(Chart, new PointD(start.X, start.Y), endPoint, pen) { ToolTipText = arc.Label };
            Chart.Group.Add(line);
            if (intersectionPoints.Any()) {
              arcShapes[arc] = line;
              arcMap[line] = arc;
              break;
            }
          }
        }
      }
      // draw vertex shapes after the arcs so they appear on top
      foreach (var pair in vertexPositions) {
        var shape = vertexShapes[pair.Key];
        shape.RedrawRequired += ShapeRedrawRequired;
        Chart.Group.Add(shape);
      }
      ResumeRendering();
    }

    private void ShapeRedrawRequired(object sender, EventArgs args) {
      layout.Run();
    }

    private Dictionary<Type, LabeledPrimitive> shapes;
    public void AddShape(Type t, LabeledPrimitive shape) {
      shapes[t] = shape;
    }

    public void ClearShapes() {
      shapes.Clear();
    }

    private LabeledPrimitive CreateShape(IVertex v) {
      var type = v.GetType();
      if (!shapes.ContainsKey(type))
        throw new ArgumentException(string.Format("No shape was associated with vertex type {0}", type));
      var shape = shapes[type];
      var p = shape.Primitive;
      var rectangle = p as Rectangle;
      var ellipse = p as Ellipse;
      var brush = (SolidBrush)shape.Brush;

      if (rectangle != null) {
        var r = new Rectangle(this.Chart, shape.LowerLeft, shape.UpperRight, new Pen(shape.Pen.Color), new SolidBrush(brush.Color));
        return new LabeledPrimitive(r, v.Label, shape.Font);
      }
      if (ellipse != null) {
        var e = new Ellipse(this.Chart, shape.LowerLeft, shape.UpperRight, new Pen(shape.Pen.Color), new SolidBrush(brush.Color));
        return new LabeledPrimitive(e, v.Label, shape.Font);
      }
      throw new Exception(string.Format("Unknown shape {0}.", shape));
    }
  }
}