#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.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using GeoAPI.Geometries;
using HeuristicLab.BioBoost.ProblemDescription;
using HeuristicLab.BioBoost.Representation;
using HeuristicLab.BioBoost.Utils;
using HeuristicLab.BioBoost.Views.MapViews;
using HeuristicLab.Core.Views;
using HeuristicLab.MainForm;
using HeuristicLab.PluginInfrastructure;
using NetTopologySuite.Geometries;
using SharpMap.Data;
using SharpMap.Forms;
using SharpMap.Layers;
using SharpMap.Rendering.Decoration;
using SharpMap.Rendering.Decoration.ScaleBar;
using Point = System.Drawing.Point;

namespace HeuristicLab.BioBoost.Views {

  [Content(typeof(BioBoostCompoundSolution))]
  public partial class BioBoostCompoundSolutionEditor : ItemView {

    private readonly GradientLegend utilizationLegend;

    private SharpMap.Rendering.Thematics.ColorBlend vectorColorBlend =
      new SharpMap.Rendering.Thematics.ColorBlend(new[] {
        Color.FromArgb(0, 0, 255),
        Color.FromArgb(128, 0, 128),
        Color.FromArgb(255, 0, 0),
      }, new[] { 0f, .5f, 1f });

    public const string AllRegionsName = "All";

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

    public BioBoostCompoundSolutionEditor() {
      InitializeComponent();

      mapBox.Map.Decorations.Add(new ScaleBar {
        Anchor = MapDecorationAnchor.RightBottom,
        BarColor1 = Color.White,
        BarColor2 = Color.Black,
        BarStyle = ScaleBarStyle.Meridian,
        MapUnit = (int)Unit.Degree,
        BarUnit = (int)Unit.Kilometer,
      });

      utilizationLegend = new GradientLegend();
      mapBox.Map.Decorations.Add(utilizationLegend);
      mapBox.Map.Decorations.Add(new NorthArrow());
      mapBox.ActiveTool = MapBox.Tools.None;
    }



    protected override void SetEnabledStateOfControls() {
      base.SetEnabledStateOfControls();
      ReadOnly = Locked || Content == null;
      mapBox.Enabled = !Locked && Content != null;
      transportLayersListBox.Enabled = !Locked && Content != null;
      utilizationLayersListBox.Enabled = !Locked && Content != null;
    }

    #region content events
    protected override void OnContentChanged() {
      if (InvokeRequired) {
        Invoke((Action)OnContentChanged);
      } else {
        base.OnContentChanged();
        if (Content == null) {
          Clear();
        } else {
          Update();
        }
      }
    }
    protected override void DeregisterContentEvents() {
      Content.SolutionChanged -= SolutionChanged;
      base.DeregisterContentEvents();
    }

    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();
      Content.SolutionChanged += SolutionChanged;
    }

    private void SolutionChanged(object sender, EventArgs e) {
      if (InvokeRequired) {
        Invoke(new EventHandler<EventArgs>(SolutionChanged), sender, e);
      } else {
        Update();
      }
    }
    #endregion


    #region Main Logic
    private void Clear() {
      qualityLabel.Text = string.Empty;
      feedstockCostsLabel.Text = string.Empty;
      transportCostsLabel.Text = string.Empty;
      utilizationLayersListBox.Items.Clear();
      transportLayersListBox.Items.Clear();
      mapBox.Map.Layers.Clear(); // only two layers are active at any time (representing the layers selected in the list boxes on the left)
    }

    private void Update() {
      // store currently selected items
      var selectedValueLayerName = GetSelectedLayer(utilizationLayersListBox);
      var selectedVectorLayerName = GetSelectedLayer(transportLayersListBox);

      // clear everything
      Clear();
      FillQualityInformation();
      FillValueLayersListBox();
      FillVectorLayersListBox();

      // restore selection if possible
      // when we couldn't restore the value or vector layer then there has been a larger change (unexpected) and we need to reset the zoom level
      // this also makes sure that the zoom level is set correctly when the solution is initially displayed
      if (!TrySetSelectedLayer(utilizationLayersListBox, selectedValueLayerName) |
          !TrySetSelectedLayer(transportLayersListBox, selectedVectorLayerName)) {
        ResetZoom();
      }
      mapBox.Refresh();
    }

    private void FillQualityInformation() {
      qualityLabel.Text = string.Format("Solution quality: {0:F4}", Content.Quality);
      feedstockCostsLabel.Text = string.Format("Feedstock [Mio€/a]: {0:N1}", Content.TotalFeedstockCosts / 1E6);
      transportCostsLabel.Text = string.Format("Transport [Mio€/a]: {0:N1}", Content.TotalTransportCosts / 1E6);
      costPerFuelLabel.Text = string.Format("Transport Fuel Costs [€/t]: {0:N1}", Content.TotalCosts / Content.TotalTransportFuelAmount);
    }


    private void FillValueLayersListBox() {
      // we only add items for layers that we are allowed to change (layers that correspond to a vector in the representation)
      // add utilizations for all feedstock
      utilizationLayersListBox.BeginUpdate();
      foreach (var pair in Content.UtilizationVectors) {
        var newItem = new ListBoxItem<double[]> {
          Color = Color.White,
          Text = pair.Item1,
          Value = pair.Item2
        };
        utilizationLayersListBox.Items.Add(newItem);
      }
      utilizationLayersListBox.EndUpdate();
    }

    private void FillVectorLayersListBox() {
      // we only add items for vectors that we are allowed to change
      // add transport vector layers for all products
      transportLayersListBox.BeginUpdate();
      int i = 0;
      int n = Content.TransportVectors.Count();
      foreach (var pair in Content.TransportVectors) {
        var newItem = new ListBoxItem<int[]> {
          Color = vectorColorBlend.GetColor(1f * i++ / (float)n),
          Text = pair.Item1,
          Value = pair.Item2
        };
        transportLayersListBox.Items.Add(newItem);
      }
      transportLayersListBox.EndUpdate();
    }

    private void UpdateMapLayers() {
      mapBox.Map.Layers.Clear();
      AddSelectedValueLayer(); // values first ...
      AddSelectedVectorLayer(); // ... then vectors (because they need to be drawn last)
      AddWorstTransportsVectorLayer();
      mapBox.Refresh();
    }

    private void AddWorstTransportsVectorLayer() {
      var geom = Content.Geometry;
      var locs = Content.LocationNames;
      var selectedProduct = GetSelectedLayer(transportLayersListBox);
      if (selectedProduct == string.Empty) return;
      int[] worstTransports = new int[locs.Length];
      for (int i = 0; i < worstTransports.Length; i++) {
        worstTransports[i] = -1;
      }
      foreach (var transport in CalcNonDominatedTransports()) {
        if (transport.Product != selectedProduct) continue;
        worstTransports[transport.SrcRegionIdx] = transport.DestRegionIdx;
      }

      var allTransports = Content.Transports.Where(t => t.Product == selectedProduct).ToArray();

      // for all regions find the matching transport (if there is one)
      var transportAmounts = locs
        .Select(loc => allTransports.FirstOrDefault(t => t.SrcRegion == loc))
        .Select(trans => trans == null ? 0.0 : trans.Amount)
        .ToArray();

      var generator = new LazyVectorLayerGenerator(geom, locs, worstTransports, transportAmounts, Color.Red, "Worst Transports");

      mapBox.Map.Layers.Add(generator.Layer);
    }


    private void AddSelectedVectorLayer() {
      var selectedVectorLayerItem = transportLayersListBox.SelectedItem as ListBoxItem<int[]>;
      if (selectedVectorLayerItem == null) return;

      var selectedProduct = GetSelectedLayer(transportLayersListBox);

      var geom = Content.Geometry;
      var locs = Content.LocationNames;

      var allTranports = Content.Transports.Where(t => t.Product == selectedProduct).ToArray();

      // foreach location find the transport amounts (if there is any)
      var amounts = locs
        .Select(loc => allTranports.FirstOrDefault(trans => trans.SrcRegion == loc))
        .Select(trans => trans == null ? 0.0 : trans.Amount)
        .ToArray();

      var generator = new LazyVectorLayerGenerator(geom, locs, selectedVectorLayerItem.Value, amounts, selectedVectorLayerItem.Color, "Transports");

      mapBox.Map.Layers.Add(generator.Layer);
    }

    private void AddSelectedValueLayer() {
      var selectedValueLayerItem = utilizationLayersListBox.SelectedItem as ListBoxItem<double[]>;
      if (selectedValueLayerItem == null) return;

      var geom = Content.Geometry;
      var locs = Content.LocationNames;

      var generator = new LazyValueLayerGenerator(geom, locs, selectedValueLayerItem.Value, "Utilizations");

      mapBox.Map.Layers.Add(generator.Layer);
    }


    // clicking on the map changes the underlying solution and causes a reevaluation
    // this is called by the mouse-up event handler
    private async void DispatchMouseUp(string startRegion, string endRegion, Tuple<string, string> arrow, Point mousePos) {
      // some operations on the content might fail ... show an error dialog in this case
      try {
        if (arrow != null && startRegion == endRegion) {
          // an vector was clicked => remove it
          Content.SetTransport(GetSelectedLayer(transportLayersListBox), arrow.Item1, arrow.Item1);
          // remove the vector
        } else if (startRegion != string.Empty && endRegion == startRegion &&
                   Util.Distance(startPos, mousePos) < 4) {
          // no vector but
          // region was clicked (no dragging) => update utilization
          var currentUtil = Content.GetUtilization(GetSelectedLayer(utilizationLayersListBox), endRegion);
          var newUtil = await ShowTrackBar(new Point(mousePos.X - 10, mousePos.Y - 10), currentUtil);
          Content.SetUtilization(GetSelectedLayer(utilizationLayersListBox), endRegion, newUtil);
        } else if (startRegion != string.Empty && endRegion != string.Empty) {
          // we dragged from one region to another (possibly the same region
          Content.SetTransport(GetSelectedLayer(transportLayersListBox), startRegion, endRegion);
        }
      } catch (SystemException e) {
        var dialog = new ErrorDialog(e);
        dialog.ShowDialog(this);
      }
    }

    public void OptimizeTransports() {
      // FullLocalSearchForTransports();
      // NearestPlantLocalSearchForTransports();
      PruneLongAndSmallTransports();
    }

    private IEnumerable<BioBoostCompoundSolution.TransportInfo> CalcNonDominatedTransports() {
      var transports = Content.Transports.ToArray();
      var transportDistances = transports.Select(t => t.Distance).ToArray();
      var transportAmounts = transports.Select(t => t.Amount).ToArray();

      for (int i = 0; i < transports.Length; i++) {
        if (!IsDominated(i, transportDistances, transportAmounts)) {
          yield return transports[i];
        }
      }
    }

    private void PruneLongAndSmallTransports() {

      var nonDominatedTransports = CalcNonDominatedTransports().ToArray();

      var oldQ = Content.Quality;
      var curQ = Content.Quality;
      var curContent = (BioBoostCompoundSolution)Content.Clone();
      foreach (var transport in nonDominatedTransports) {
        curContent.SetTransport(transport.Product, transport.SrcRegionIdx, transport.SrcRegionIdx);
      }
      curQ = curContent.Quality;

      SetStatusInfo(string.Format("Deleted {0} transports. Total quality improvement: {1:F4}", nonDominatedTransports.Length,
        curQ - Content.Quality));
      Content.UpdateTo(curContent);
    }

    private bool IsDominated(int idx, double[] transportDistances, double[] transportAmounts) {
      // check if there is any other transport that has a larger distance and a smaller amount
      var dominatingIdx =
        Enumerable.Range(0, transportDistances.Length)
        .Where((otherIdx) => idx != otherIdx)
        .Where((otherIdx) => transportDistances[otherIdx] > transportDistances[idx])
        .Where((otherIdx) => transportAmounts[otherIdx] < transportAmounts[idx]);
      return (dominatingIdx.Any());
    }

    /*
    private void NearestPlantLocalSearchForTransports() {
      // for each transport check if we can reroute it to a nearer plant (with minor loss in quality 1%)
      const double maxRelativeQualityChange = -0.001;
      var oldQ = Content.Quality;
      var curQ = Content.Quality;
      var curContent = (BioBoostCompoundSolution)Content.Clone();
      // TODO: assumes that there is only one distance matrix and all products are transported using this matrix!!
      Debug.Assert(Content.ProblemDataReference.Parameters.Count(p => p.Name.EndsWith("DistanceMatrix")) == 1);
      var distanceMatrix = (DistanceMatrix)Content.ProblemDataReference.Parameters.First(p => p.Name.EndsWith("DistanceMatrix")).ActualValue;

      // for each product a list of possible targets (possible targets stay fixed in optimization)
      var curTransportTargets = curContent.TransportVectors
        .Select(kvp => new KeyValuePair<string, int[]>(kvp.Item1, kvp.Item2.Distinct().Where(i => i >= 0).OrderBy(t => t).ToArray()))
        .ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

      // for each product and for each region a list of the max 5 nearest plants
      var nearestPlantIdx = new Dictionary<string, int[][]>();
      foreach (var product in curTransportTargets.Keys) {
        nearestPlantIdx.Add(product, new int[curContent.LocationNames.Length][]);
        var nIdx = nearestPlantIdx[product];
        for (int src = 0; src < nIdx.Length; src++) {
          var plantsByDistance =
            curTransportTargets[product].OrderBy(possibleTarget => distanceMatrix[src, possibleTarget]);
          var nPlants = Math.Min(plantsByDistance.Count(), 3);
          nIdx[src] = plantsByDistance.Take(nPlants).ToArray();
        }
      }

      // generate possible changes
      // either change the transport to the nearest existing plant ...
      // ... or if the transport is within the same region then to the second nearest plant (reduces plants)
      var changes = new List<Tuple<string, int, int>>(); // product x source x dest
      foreach (var kvp in curContent.TransportVectors) {
        var prod = kvp.Item1;
        var curDest = kvp.Item2;
        for (int src = 0; src < curDest.Length; src++) {
          var dest = curDest[src];
          if (dest == -1)
            continue; // don't allow transports if the current transport target is -1 
          foreach (var alternativeDest in nearestPlantIdx[prod][src]) {
            if (alternativeDest != dest)
              changes.Add(Tuple.Create(prod, src, alternativeDest));
          }
        }
      }

      var improvements = new List<double>();
      // evalute changes (full evaluation)
      for (int i = 0; i < changes.Count; i++) {
        // apply each change in turn to a clone of the solution and check the change in quality
        var change = changes[i];
        var tmpContent = (BioBoostCompoundSolution)curContent.Clone();
        tmpContent.SetTransport(change.Item1, change.Item2, change.Item3); // product, src, dest
        improvements.Add(tmpContent.Quality - curQ); // if quality after change is worse than current quality improvement is negative
      }

      var sortedChanges =
        changes.Zip(improvements, (change, improvement) => new { change, improvement })
        .OrderByDescending(p => p.improvement) // positive improvements first
        .ToArray();

      int changeCount = 0;
      int changeIdx = 0;

      bool changed = true; // has there been a change in this iteration
      // while there is a total deterioation not worse than -1%
      var totalChange = 0.0;
      while (changeIdx < sortedChanges.Length && changed && totalChange > (oldQ * maxRelativeQualityChange)) {
        changed = false;
        var change = sortedChanges[changeIdx].change;
        var improvement = sortedChanges[changeIdx].improvement;
        // and each step is not worse than -1%
        if (improvement > curQ * maxRelativeQualityChange) {
          changeCount++;
          totalChange += improvement;
          curContent.SetTransport(change.Item1, change.Item2, change.Item3); // product, src, dest
          curQ = curContent.Quality; // update current quality
          changed = true;
        }
        changeIdx++;
      }

      Content.UpdateTo(curContent);
      SetStatusInfo(string.Format("Changed {0} transports. Total quality improvement: {1:F4}", changeCount,
        Content.Quality - oldQ));
    }
    */

    /*
    private void FullLocalSearchForTransports() {
      // for each transport check if we can reroute the transport to any other location (which already is a transport target for this product type)
      // local search using best improvement
      double oldQ;
      var curQ = Content.Quality;
      var curContent = (BioBoostCompoundSolution)Content.Clone();

      // for each product a list of possible targets (possible targets stay fixed in optimization)
      var curTransportTargets = curContent.TransportVectors
        .Select(kvp => new KeyValuePair<string, int[]>(kvp.Item1, kvp.Item2.Distinct().OrderBy(t => t).ToArray()))
        .ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

      int changeCount = 0;
      do {
        // store current quality (to check if we found an improvement)
        oldQ = curQ;

        // generate possible changes
        var changes = new List<Tuple<string, int, int>>(); // product x source x dest
        foreach (var kvp in curContent.TransportVectors) {
          var prod = kvp.Item1;
          var curDest = kvp.Item2;
          foreach (var alternativeDest in curTransportTargets[prod]) {
            if (alternativeDest == -1) continue; // don't allow transport to new locations (without plants)
            for (int src = 0; src < curDest.Length; src++) {
              var dest = curDest[src];
              if (dest == -1) continue; // don't allow transports if the current transport target is -1 (TODO: check with erik)

              if (dest != alternativeDest) {
                changes.Add(Tuple.Create(prod, src, alternativeDest));
              }
            }
          }
        }

        // evalute changes (full evaluation)
        var bestImprovement = double.NegativeInfinity;
        var bestChangeIdx = -1;
        for (int i = 0; i < changes.Count; i++) {
          // apply each change in turn to a clone of the solution and check the change in quality
          var change = changes[i];
          var tmpContent = (BioBoostCompoundSolution)curContent.Clone();
          tmpContent.SetTransport(change.Item1, change.Item2, change.Item3); // product, src, dest
          var improvement = tmpContent.Quality - curQ;
          if (improvement > bestImprovement) {
            bestImprovement = improvement;
            bestChangeIdx = i;
          }
        }
        if (bestImprovement > 0) {
          changeCount++;
          var bestChange = changes[bestChangeIdx];
          curContent.SetTransport(bestChange.Item1, bestChange.Item2, bestChange.Item3); // product, src, dest
          curQ = curContent.Quality; // update current quality
        }

        // apply best change
      } while (oldQ < curQ);

      SetStatusInfo(string.Format("Changed {0} transports. Total quality improvement: {1:F4}", changeCount,
        curQ - Content.Quality));
      Content.UpdateTo(curContent);
    }*/


    public void OptimizeUtilizations() {
      double oldQ;
      var curQ = Content.Quality;
      var curContent = (BioBoostCompoundSolution)Content.Clone();
      int changeCount = 0;
      do {
        oldQ = curQ;

        // for each product and region check if the quality increases if we set the utilization to zero
        // local search using first improvement
        var changes = new List<Tuple<string, int, double>>(); // product x region x utilization
        foreach (var pair in curContent.UtilizationVectors) {
          var prod = pair.Item1;
          var util = pair.Item2;
          for (int regIdx = 0; regIdx < util.Length; regIdx++) {
            if (util[regIdx] > 0) {
              changes.Add(Tuple.Create(prod, regIdx, 0.0));
            }
          }
        }

        var bestImprovement = double.NegativeInfinity;
        var bestChange = changes.First();
        foreach (var change in changes) {
          var tmpContent = (BioBoostCompoundSolution)curContent.Clone();
          tmpContent.SetUtilization(change.Item1, change.Item2, change.Item3);
          var newQ = tmpContent.Quality;
          var improvement = newQ - curQ; // positive improvements (new quality is higher than current quality
          if (improvement > bestImprovement) {
            bestImprovement = improvement;
            bestChange = change;
          }
        }

        // apply if we found a possible improvement
        if (bestImprovement > 0) {
          curContent.SetUtilization(bestChange.Item1, bestChange.Item2, bestChange.Item3);
          curQ = curContent.Quality;
          changeCount++;
        }
      } while (oldQ < curQ);

      SetStatusInfo(string.Format("Changed {0} utilizations. Total quality improvement: {1:F4}", changeCount,
        curQ - Content.Quality));
      Content.UpdateTo(curContent);
    }

    private void SetStatusInfo(string message) {
      if (InvokeRequired) {
        Invoke((Action<string>)SetStatusInfo, message);
      } else {
        toolStripStatusLabel.Text = message;
      }
    }

    private void UpdateTransportInfo(Tuple<string, string> vector) {
      transportInfoLabel.Text = string.Empty; // clear
      if (vector != null) {
        var transportProduct = GetSelectedLayer(transportLayersListBox);
        var transportInfo =
          Content.Transports.FirstOrDefault(
            info => info.Product == transportProduct && info.SrcRegion == vector.Item1 && info.DestRegion == vector.Item2);
        if (transportInfo != null) {

          var sb = new StringBuilder();
          sb.AppendFormat("{0} -> {1}", transportInfo.SrcRegion, transportInfo.DestRegion).AppendLine();
          sb.AppendFormat("{0} (Mode: {1})", transportInfo.Product, transportInfo.Mode).AppendLine();
          sb.AppendFormat("{0:N0} kt km", transportInfo.Distance * transportInfo.Amount / 1000.0).AppendLine();
          sb.AppendFormat("{0:N1} kt {1:N0} km", transportInfo.Amount / 1000.0, transportInfo.Distance);
          transportInfoLabel.Text = sb.ToString();
        }
      }
    }
    #endregion



    #region Event Handlers (child controls)
    private void vectorLayerNamesListBox_SelectedIndexChanged(object sender, EventArgs e) {
      UpdateMapLayers();
    }

    private void valueLayerNamesListBox_SelectedIndexChanged(object sender, EventArgs e) {
      UpdateMapLayers();
    }

    private void optimizeTransportsButton_Click(object sender, EventArgs e) {
      using (BackgroundWorker bg = new BackgroundWorker()) {
        Progress.Show(this, "Optimizing Transports...", ProgressMode.Indeterminate);
        bg.DoWork += (o, a) => OptimizeTransports();
        bg.RunWorkerCompleted += (o, a) => Progress.Hide(this);
        bg.RunWorkerAsync();
      }
    }

    private void optimizeUtilizationsButton_Click(object sender, EventArgs e) {
      using (BackgroundWorker bg = new BackgroundWorker()) {
        Progress.Show(this, "Optimizing Utilizations...", ProgressMode.Indeterminate);
        bg.DoWork += (o, a) => OptimizeUtilizations();
        bg.RunWorkerCompleted += (o, a) => Progress.Hide(this);
        bg.RunWorkerAsync();
      }
    }
    #endregion

    #region mouse events
    // TODO: it should be possible to allow panning and drawing arrows at the same time by implementing a CustomTool
    private void mapBox_MouseMove(Coordinate worldPos, MouseEventArgs imagePos) {
      var nuts_id = GetRegionAtWorldPos(worldPos);
      var nuts_name = GetRegionDescription(nuts_id);
      regionNameLabel.Text = nuts_id;
      regionDescriptionLabel.Text = nuts_name;
      mapBox.Cursor = String.IsNullOrEmpty(nuts_id) ? Cursors.Default : Cursors.Hand;
      var arrow = GetArrowAtWorldPos(worldPos);
      UpdateTransportInfo(arrow);
    }

    private Point startPos = new Point(0, 0);
    private Coordinate startWorldPos;
    private void mapBox_MouseDown(Coordinate worldPos, MouseEventArgs mouseEventArgs) {
      if (mouseEventArgs.Button == MouseButtons.Left) {
        startPos = mouseEventArgs.Location;
        startWorldPos = worldPos;
      }
    }

    private void mapBox_MouseUp(Coordinate endWorldPos, MouseEventArgs mousePos) {
      if (mousePos.Button == MouseButtons.Left) {
        var arrow = GetArrowAtWorldPos(startWorldPos);

        var startRegion = GetRegionAtWorldPos(startWorldPos);
        var endRegion = GetRegionAtWorldPos(endWorldPos);

        DispatchMouseUp(startRegion, endRegion, arrow, mousePos.Location);
      }
    }

    // custom drawing method for vector list box (for coloring of layers)
    private void vectorLayerNamesListBox_DrawItem(object sender, DrawItemEventArgs e) {
      var item = transportLayersListBox.Items[e.Index];
      var listBoxItem = item as ListBoxItem<int[]>;
      var backColor = listBoxItem.Color;
      var foreColor = Color.White;

      using (var backBrush = new SolidBrush(backColor)) {
        e.Graphics.FillRectangle(backBrush, e.Bounds);
      }
      using (var foreBrush = new SolidBrush(foreColor)) {
        e.Graphics.DrawString(
          listBoxItem.Text,
          transportLayersListBox.Font, foreBrush, e.Bounds);
      }
    }
    #endregion

    #region drag-and-drop of problem data

    private bool dropAllowed = false;
    protected override void OnDragDrop(DragEventArgs e) {
      if (e.Effect != DragDropEffects.None) {
        var problemData = (BioBoostProblemData)e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat);
        Content.ProblemDataReference = (BioBoostProblemData)problemData.Clone();
      }
    }

    protected override void OnDragEnter(DragEventArgs e) {
      var problemData = (BioBoostProblemData)e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat);
      dropAllowed = !ReadOnly && !Locked && problemData != null;
    }

    protected override void OnDragOver(DragEventArgs e) {
      e.Effect = dropAllowed ?
        DragDropEffects.Copy :
        DragDropEffects.None;
    }

    #endregion


    #region Auxiliar Methods
    private Task<double> ShowTrackBar(Point location, double value) {

      var wh = new AutoResetEvent(false);
      var tb = new TrackBar {
        TickStyle = TickStyle.None,
        Minimum = 0,
        Maximum = 100,
        Value = (int)Math.Round(value * 100),
        Location = location
      };
      var label = new Label();
      label.Location = new Point(location.X, location.Y - label.Height);
      label.Text = string.Format("Utilization: {0:F2}", value);
      label.Width = tb.Width;

      mapBox.Controls.Add(tb);
      mapBox.Controls.Add(label);

      tb.Focus();
      tb.ValueChanged += (sender, args) => {
        value = tb.Value / 100.0;
        label.Text = string.Format("Utilization: {0:F2}", value);
      };
      tb.LostFocus += (sender, args) => {
        mapBox.Controls.Remove(tb);
        mapBox.Controls.Remove(label);
        wh.Set();
      };


      return Task.Run(() => {
        wh.WaitOne();
        wh.Dispose();
        return value;
      });
    }

    // returns the NUTS_ID of the region if it has been hit
    private string GetRegionAtWorldPos(Coordinate loc) {
      var ds = new FeatureDataSet();
      var layer = mapBox.Map.Layers.OfType<VectorLayer>().SingleOrDefault(l => l.LayerName == "Utilizations");
      if (layer == null) return string.Empty;

      layer.ExecuteIntersectionQuery(new NetTopologySuite.Geometries.Point(loc), ds);
      return (from FeatureDataRow row in ds.Tables[0]
              select row["NUTS_ID"] as string).FirstOrDefault() ?? string.Empty; // default is string.Empty
    }

    // returns the source and target NUTS_ID (Tuple(src, trgt)) for an vector if it has been hit
    private Tuple<string, string> GetArrowAtWorldPos(Coordinate loc) {
      var ds = new FeatureDataSet();
      var layer = mapBox.Map.Layers.OfType<VectorLayer>().SingleOrDefault(l => l.LayerName == "Transports");
      if (layer == null) return null;

      var rect = new Coordinate[5];
      var delta = mapBox.Map.PixelWidth * 2; // for bounding box arount the click point
      rect[0] = new Coordinate(loc.X - delta, loc.Y - delta);
      rect[1] = new Coordinate(loc.X + delta, loc.Y - delta);
      rect[3] = new Coordinate(loc.X + delta, loc.Y + delta);
      rect[2] = new Coordinate(loc.X - delta, loc.Y + delta);
      rect[4] = new Coordinate(loc.X - delta, loc.Y - delta);
      layer.ExecuteIntersectionQuery(new NetTopologySuite.Geometries.Polygon(new LinearRing(rect)), ds);

      var arrow = (from FeatureDataRow row in ds.Tables[0]
                   select Tuple.Create((string)row["NUTS_ID_SRC"], (string)row["NUTS_ID_DEST"])
        ).FirstOrDefault();
      return arrow;
    }


    private string GetRegionDescription(string regionName) {
      if (regionName != null && Content.Geometry.Features.Columns.Contains("name")) {
        var row = Content.Geometry.Features.Rows.Cast<FeatureDataRow>().FirstOrDefault(r => (string)r["NUTS_ID"] == regionName);
        if (row != null)
          return row["name"].ToString();
      }
      return string.Empty;
    }


    private void ResetZoom() {
      if (mapBox.Map.Layers.Count > 0)
        mapBox.Map.ZoomToExtents();
      // mapBox.ActiveTool = MapBox.Tools.DrawLine;
      mapBox.Refresh();
    }


    private string GetSelectedLayer(ListBox listBox) {
      return
      listBox.SelectedItem == null ?
        string.Empty
        : listBox.SelectedItem.ToString();
    }


    private bool TrySetSelectedLayer(ListBox listBox, string text) {
      bool success = false;
      if (string.IsNullOrEmpty(text)) {
        listBox.SelectedIndex = 0;
      } else {
        int selectedIndex = 0;
        for (int i = 0; i < listBox.Items.Count; i++) {
          if (listBox.Items[i].ToString() == text) {
            selectedIndex = i;
            success = true;
            break;
          }
        }
        listBox.SelectedIndex = selectedIndex;
      }
      return success;
    }
    #endregion

    // only necessary for drawing of vector layer elements with color
    private class ListBoxItem<T> {
      public Color Color { get; set; }
      public string Text { get; set; }
      public T Value { get; set; }

      public override string ToString() {
        return Text;
      }
    }
  }
}