#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2018 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.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using HeuristicLab.Common.Resources;
using HeuristicLab.Core.Views;
using HeuristicLab.Encodings.IntegerVectorEncoding;
using HeuristicLab.MainForm;
using HeuristicLab.MainForm.WindowsForms;

namespace HeuristicLab.Problems.GeneralizedQuadraticAssignment.Views {
  [View("GQAPAssignmentView")]
  [Content(typeof(GQAPAssignment), IsDefaultView = true)]
  public partial class GQAPAssignmentView : ItemView {
    private static readonly double BrightnessLevel = 0.5;

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

    public GQAPAssignmentView() {
      InitializeComponent();
      recalculateButton.Text = string.Empty;
      recalculateButton.Image = VSImageLibrary.Refresh;
    }

    #region Register Content Events
    protected override void DeregisterContentEvents() {
      DeregisterSolutionEvents();
      Content.PropertyChanged -= Content_PropertyChanged;
      base.DeregisterContentEvents();
    }
    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();
      Content.PropertyChanged += Content_PropertyChanged;
      RegisterSolutionEvents();
    }

    private void DeregisterSolutionEvents() {
      if (Content.Solution != null) Content.Solution.PropertyChanged -= Content_SolutionPropertyChanged;
    }
    private void RegisterSolutionEvents() {
      if (Content.Solution != null) Content.Solution.PropertyChanged += Content_SolutionPropertyChanged;
    }
    #endregion

    protected override void OnContentChanged() {
      base.OnContentChanged();
      UpdateEvaluation();
      UpdateAssignment();
      if (Content != null && Content.Solution != null) assignmentView.Content = Content.Solution.Assignment;
      else assignmentView.Content = null;
    }

    protected override void SetEnabledStateOfControls() {
      base.SetEnabledStateOfControls();
      recalculateButton.Enabled = Content != null && Content.Solution != null && !Locked && !ReadOnly;
    }

    #region Content Event Handlers
    private void Content_PropertyChanged(object sender, PropertyChangedEventArgs e) {
      switch (e.PropertyName) {
        case nameof(Content.Solution): RegisterSolutionEvents(); UpdateEvaluation(); UpdateAssignment(); break;
        case nameof(Content.ProblemInstance): UpdateEvaluation(); UpdateAssignment(); break;
        default: break;
      }
      SetEnabledStateOfControls();
    }

    private void Content_SolutionPropertyChanged(object sender, PropertyChangedEventArgs e) {
      switch (e.PropertyName) {
        case nameof(Content.Solution.Assignment): UpdateAssignment(); break;
        case nameof(Content.Solution.Evaluation): UpdateEvaluation(); break;
        default: break;
      }
    }

    private void Content_Assignment_ToStringChanged(object sender, EventArgs e) {
      UpdateAssignment();
    }
    #endregion

    #region Event Handlers
    private void assignmentTreeView_AfterSelect(object sender, TreeViewEventArgs e) {
      if (Content != null && Content.Solution != null) {
        assignmentTreeView.BeginUpdate();
        try {
          if (assignmentTreeView.SelectedNode == null) {
            ColorByInstallationCosts();
          } else {
            var equipmentNode = (assignmentTreeView.SelectedNode as EquipmentNode);
            if (equipmentNode != null) {
              ColorByWeight(equipmentNode);
            }
            var locationNode = (assignmentTreeView.SelectedNode as LocationNode);
            if (locationNode != null) {
              ColorByWeight(locationNode);
            }
          }
        } finally { assignmentTreeView.EndUpdate(); }
      }
    }

    private void assignmentTreeView_MouseUp(object sender, MouseEventArgs e) {
      var hit = assignmentTreeView.HitTest(e.X, e.Y);
      if (hit.Node == null || hit.Location == TreeViewHitTestLocations.None || hit.Location == TreeViewHitTestLocations.RightOfLabel) {
        assignmentTreeView.SelectedNode = null;
        ColorByInstallationCosts();
      }
    }
    #endregion

    #region Helpers
    private void UpdateEvaluation() {
      if (InvokeRequired) Invoke((Action)UpdateEvaluation);
      else {
        if (Content == null || Content.Solution == null) {
          qualityLabel.Text = "-";
          flowDistanceQualityLabel.Text = "-";
          installationQualityLabel.Text = "-";
          overbookedCapacityLabel.Text = "-";
        } else {
          qualityLabel.Text = Content.ProblemInstance.ToSingleObjective(Content.Solution.Evaluation).ToString();
          flowDistanceQualityLabel.Text = Content.Solution.Evaluation.FlowCosts.ToString();
          installationQualityLabel.Text = Content.Solution.Evaluation.InstallationCosts.ToString();
          overbookedCapacityLabel.Text = Content.Solution.Evaluation.ExcessDemand.ToString();
        }
      }
    }

    private void UpdateAssignment() {
      if (InvokeRequired) Invoke((Action)UpdateAssignment);
      else {
        assignmentTreeView.Nodes.Clear();
        if (Content != null && Content.Solution != null) {
          IntegerVector assignment = Content.Solution.Assignment;
          Dictionary<int, TreeNode> locationNodes = new Dictionary<int, TreeNode>();
          for (int i = 0; i < assignment.Length; i++) {
            if (!locationNodes.ContainsKey(assignment[i])) {
              string locationName = assignment[i].ToString();
              if (Content.ProblemInstance.LocationNames != null && Content.ProblemInstance.LocationNames.Length > assignment[i])
                locationName = Content.ProblemInstance.LocationNames[assignment[i]];
              locationNodes.Add(assignment[i], new LocationNode(assignment[i], locationName));
            }
            string equipmentName = i.ToString();
            if (Content.ProblemInstance.EquipmentNames != null && Content.ProblemInstance.EquipmentNames.Length > i)
              equipmentName = Content.ProblemInstance.EquipmentNames[i];
            locationNodes[assignment[i]].Nodes.Add(new EquipmentNode(i, equipmentName));
          }

          assignmentTreeView.BeginUpdate();
          try {
            foreach (var node in locationNodes.OrderBy(x => x.Key).Select(x => x.Value)) {
              assignmentTreeView.Nodes.Add(node);
              node.Expand();
            }
            ColorByInstallationCosts();
          } finally { assignmentTreeView.EndUpdate(); }
        }
      }
    }

    private void ColorByInstallationCosts() {
      var installationCosts = new Dictionary<EquipmentNode, double>();
      foreach (var node in GetAllSubNodes(assignmentTreeView.Nodes).OfType<EquipmentNode>()) {
        int location = Content.Solution.Assignment[node.Equipment];
        installationCosts[node] = Content.ProblemInstance.InstallationCosts[node.Equipment, location];
      }
      double max = installationCosts.Values.Max();
      foreach (var kvp in installationCosts) {
        if (max == 0) {
          kvp.Key.BackColor = assignmentTreeView.BackColor;
          kvp.Key.ForeColor = assignmentTreeView.ForeColor;
        } else {
          int colorComponent = (int)(255 * Math.Pow((max - kvp.Value) / max, 2));
          kvp.Key.BackColor = Color.FromArgb(255, colorComponent, colorComponent);
          if (kvp.Key.BackColor.GetBrightness() < BrightnessLevel) kvp.Key.ForeColor = Color.White;
          else kvp.Key.ForeColor = Color.Black;
        }
      }
    }

    private void ColorByWeight(EquipmentNode selectedNode) {
      int equipment = selectedNode.Equipment;
      double rowSum = 0, colSum = 0;
      for (int i = 0; i < Content.ProblemInstance.Weights.Columns; i++)
        if (i != equipment) rowSum += Content.ProblemInstance.Weights[equipment, i];
      for (int i = 0; i < Content.ProblemInstance.Weights.Rows; i++)
        if (i != equipment) colSum += Content.ProblemInstance.Weights[i, equipment];

      var otherEquipments = GetAllSubNodes(assignmentTreeView.Nodes)
        .OfType<EquipmentNode>()
        .Where(x => x != selectedNode);

      selectedNode.BackColor = assignmentTreeView.BackColor;
      selectedNode.ForeColor = assignmentTreeView.ForeColor;
      foreach (var other in otherEquipments) {
        if (rowSum == 0 && colSum == 0) {
          other.BackColor = assignmentTreeView.BackColor;
          other.ForeColor = assignmentTreeView.ForeColor;
        } else {
          double rowInvProportion = rowSum == 0 ? 1.0 : (rowSum - Content.ProblemInstance.Weights[equipment, other.Equipment]) / rowSum;
          double colInvProportion = colSum == 0 ? 1.0 : (colSum - Content.ProblemInstance.Weights[other.Equipment, equipment]) / colSum;
          int colorComponent = (int)(255 * Math.Pow(Math.Min(rowInvProportion, colInvProportion), 2));
          other.BackColor = Color.FromArgb(colorComponent, 255, colorComponent);
          if (other.BackColor.GetBrightness() < BrightnessLevel) other.ForeColor = Color.White;
          else other.ForeColor = Color.Black;
        }
      }
    }

    private void ColorByWeight(LocationNode selectedNode) {
      var equipments = new HashSet<int>(Content.Solution.Assignment.Select((v, i) => new { Index = i, Value = v })
        .Where(x => x.Value == selectedNode.Location).Select(x => x.Index));
      var rowSums = new Dictionary<int, double>(equipments.Count);
      var colSums = new Dictionary<int, double>(equipments.Count);
      foreach (var e in equipments) {
        rowSums[e] = 0;
        colSums[e] = 0;
        for (int i = 0; i < Content.ProblemInstance.Weights.Columns; i++) {
          if (!equipments.Contains(i)) rowSums[e] += Content.ProblemInstance.Weights[e, i];
          if (!equipments.Contains(i)) colSums[e] += Content.ProblemInstance.Weights[i, e];
        }
      }
      var equipmentNodes = GetAllSubNodes(assignmentTreeView.Nodes)
        .OfType<EquipmentNode>();

      var relevantEquipments = new HashSet<int>(equipments.Where(x => rowSums[x] > 0 || colSums[x] > 0));
      foreach (var other in equipmentNodes) {
        if (!relevantEquipments.Any() || equipments.Contains(other.Equipment)) {
          other.BackColor = assignmentTreeView.BackColor;
          other.ForeColor = assignmentTreeView.ForeColor;
        } else {
          double rowInvProportion = relevantEquipments.Min(x => rowSums[x] == 0 ? 1.0 : (rowSums[x] - Content.ProblemInstance.Weights[x, other.Equipment]) / rowSums[x]);
          double colInvProportion = relevantEquipments.Min(x => colSums[x] == 0 ? 1.0 : (colSums[x] - Content.ProblemInstance.Weights[other.Equipment, x]) / colSums[x]);
          int colorComponent = (int)(255 * Math.Pow(Math.Min(rowInvProportion, colInvProportion), 2));
          other.BackColor = Color.FromArgb(colorComponent, 255, colorComponent);
          if (other.BackColor.GetBrightness() < BrightnessLevel) other.ForeColor = Color.White;
          else other.ForeColor = Color.Black;
        }
      }
    }

    private IEnumerable<TreeNode> GetAllSubNodes(TreeNodeCollection nodes) {
      foreach (TreeNode node in nodes) {
        yield return node;
        foreach (TreeNode subNode in GetAllSubNodes(node.Nodes))
          yield return subNode;
      }
    }
    #endregion

    #region Helper Classes
    private class LocationNode : TreeNode {
      public int Location { get; set; }

      public LocationNode() : base() { }
      public LocationNode(int location, string name)
        : base(name) {
        Location = location;
      }
    }

    private class EquipmentNode : TreeNode {
      public int Equipment { get; set; }

      public EquipmentNode() : base() { }
      public EquipmentNode(int equipment, string name)
        : base(name) {
        Equipment = equipment;
      }
    }
    #endregion

    private void recalculateButton_Click(object sender, EventArgs e) {
      Content.Solution.Evaluation = Content.ProblemInstance.Evaluate(Content.Solution.Assignment);
    }
  }
}