#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2014 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.Linq;
using HeuristicLab.Core.Views;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views;
using HeuristicLab.EvolutionTracking;
using HeuristicLab.MainForm;
using HeuristicLab.Visualization;

namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Views {
  [View("FragmentGraphView")]
  [Content(typeof(FragmentGraph), IsDefaultView = true)]
  public sealed partial class FragmentGraphView : ItemView {
    private const int PreferredHorizontalSpacing = 10;
    private const int PreferredVerticalSpacing = 25;

    private ReingoldTilfordLayoutEngine<TileLayoutNode> layoutEngine;
    private ReingoldTilfordLayoutEngine<ISymbolicExpressionTreeNode> symbolicExpressionEngine;

    private Dictionary<FragmentNode, TileLayoutNode> tileDictionary;

    private SymbolicExpressionTreeTile Root { get; set; }

    public new FragmentGraph Content {
      get { return (FragmentGraph)base.Content; }
      set { base.Content = value; }
    }

    public FragmentGraphView() {
      InitializeComponent();

      layoutEngine = new ReingoldTilfordLayoutEngine<TileLayoutNode>(n => n.Children) {
        HorizontalSpacing = PreferredHorizontalSpacing,
        VerticalSpacing = PreferredVerticalSpacing,
      };
      symbolicExpressionEngine = new ReingoldTilfordLayoutEngine<ISymbolicExpressionTreeNode>(n => n.Subtrees) {
        HorizontalSpacing = PreferredHorizontalSpacing,
        VerticalSpacing = PreferredVerticalSpacing,
        NodeWidth = 80,
        NodeHeight = 40
      };
      tileDictionary = new Dictionary<FragmentNode, TileLayoutNode>();
    }

    private void MakeTiles() {
      var chart = symbolicExpressionChartControl.Chart;
      tileDictionary.Clear();
      foreach (var node in Content.Nodes) {
        var graphNode = (IGenealogyGraphNode<ISymbolicExpressionTree>)node.Content;
        var tile = new SymbolicExpressionTreeTile(chart);
        tile.LayoutEngine = symbolicExpressionEngine;
        tile.Label = "Generation " + node.Content.Rank + Environment.NewLine +
                     "Quality " + String.Format("{0:0.000}", node.Content.Quality);
        tile.Root = graphNode.Content.Root;
        var tileNode = new TileLayoutNode { Tile = tile };
        tileDictionary.Add(node, tileNode);
      }
      foreach (var node in Content.Nodes.Where(n => n.OutArcs.Any())) {
        var layoutNode = tileDictionary[node];
        layoutNode.Children = new List<TileLayoutNode>(node.OutArcs.Select(a => tileDictionary[(FragmentNode)a.Target]));
      }
    }

    private void Draw() {
      var chart = symbolicExpressionChartControl.Chart;
      var nodes = Content.Nodes.ToList();
      var root = nodes[0];
      var fragmentRoot = tileDictionary[root];
      int maxTileWidth = 0, maxTileHeight = 0;
      var tiles = nodes.Select(x => tileDictionary[x].Tile).ToList();

      foreach (var tile in tiles) {
        var size = tile.Size;
        if (maxTileWidth < size.Width) maxTileWidth = size.Width;
        if (maxTileHeight < size.Height) maxTileHeight = size.Height;
      }
      layoutEngine.NodeWidth = maxTileWidth;
      layoutEngine.NodeHeight = maxTileHeight;
      layoutEngine.HorizontalSpacing = PreferredHorizontalSpacing;
      layoutEngine.VerticalSpacing = PreferredVerticalSpacing;

      var visualNodes = layoutEngine.CalculateLayout(fragmentRoot);

      symbolicExpressionChartControl.UpdateEnabled = false;
      foreach (var visualNode in visualNodes) {
        var tile = visualNode.Content.Tile;
        tile.Position = new Point(visualNode.X, visualNode.Y);
        symbolicExpressionChartControl.Add(tile);
      }

      // add connections between the tiles
      foreach (var node in nodes) {
        var aTile = tileDictionary[node].Tile;
        var aSize = aTile.Size;
        var aPos = aTile.Position;
        var graphNode = node.Content;

        if (node.SubtreeIndex > 0) {
          var subtree = graphNode.Content.Root.NodeAt(node.SubtreeIndex);
          foreach (var s in subtree.IterateNodesPrefix()) {
            var primitive = aTile.GetPrimitive(s);
            if (primitive != null) {
              var rpb = primitive as RectangularPrimitiveBase;
              if (rpb != null) {
                rpb.Pen = new Pen(Color.Black);
              }
            }
          }
        }
        if (node.FragmentIndex > 0) {
          var subtree = graphNode.Content.Root.NodeAt(node.FragmentIndex);
          foreach (var s in subtree.IterateNodesPrefix()) {
            var primitive = aTile.GetPrimitive(s);
            if (primitive != null) {
              var rpb = primitive as RectangularPrimitiveBase;
              if (rpb != null) {
                rpb.Brush = new SolidBrush(Color.LightGray);
              }
            }
          }
        }

        if (node.InArcs.Any()) {
          var parent = (FragmentNode)node.InArcs.First().Source;
          if (parent.OutArcs.First().Target == node) {
            var index = node.SubtreeIndex + (parent.FragmentIndex - parent.SubtreeIndex);
            // some mutations create discontinuities which invalidate the index
            if (index >= 0 && index < graphNode.Content.Length) {
              var subtree = graphNode.Content.NodeAt(index);
              var primitive = aTile.GetPrimitive(subtree);
              primitive.Brush = new SolidBrush(Color.LightCoral);
            }
          }
        }

        foreach (var child in node.OutArcs.Select(x => (FragmentNode)x.Target)) {
          var bTile = tileDictionary[child].Tile;
          var bSize = bTile.Size;
          var bPos = bTile.Position;

          var line = new Line(chart, new PointD(aPos.X + aSize.Width / 2.0, aPos.Y + aSize.Height), new PointD(bPos.X + bSize.Width / 2.0, bPos.Y)) {
            Pen = Pens.DimGray
          };
          symbolicExpressionChartControl.Add(line);
        }
      }
      // center display on the root of the fragment graph
      symbolicExpressionChartControl.Chart.Move(tileDictionary[root].Tile.Position.X, tileDictionary[root].Tile.Position.Y);
      symbolicExpressionChartControl.UpdateEnabled = true;
      symbolicExpressionChartControl.EnforceUpdate();
    }

    protected override void DeregisterContentEvents() {
      // TODO: Deregister your event handlers here
      base.DeregisterContentEvents();
    }

    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();
      // TODO: Register your event handlers here
    }

    #region Event Handlers (Content)
    // TODO: Put event handlers of the content here
    protected override void OnContentChanged() {
      base.OnContentChanged();
      if (Content != null) {
        MakeTiles();
        Draw();
      }
    }
    #endregion

    protected override void SetEnabledStateOfControls() {
      base.SetEnabledStateOfControls();
      // TODO: Enable or disable controls based on whether the content is null or the view is set readonly
    }

    #region Event Handlers (child controls)

    // TODO: Put event handlers of child controls here.

    #endregion
  }

  internal static class Util {
    internal static ISymbolicExpressionTreeNode NodeAt(this ISymbolicExpressionTree tree, int position) {
      return NodeAt(tree.Root, position);
    }
    internal static ISymbolicExpressionTreeNode NodeAt(this ISymbolicExpressionTreeNode root, int position) {
      return root.IterateNodesPrefix().ElementAt(position);
    }
  }

  internal class TileLayoutNode {
    public SymbolicExpressionTreeTile Tile { get; set; }

    private List<TileLayoutNode> children;
    public IEnumerable<TileLayoutNode> Children {
      get { return children ?? Enumerable.Empty<TileLayoutNode>(); }
      set { children = value.ToList(); }
    }
  }
}