using System.Data;
using GeoAPI.Geometries;
using NetTopologySuite.Geometries;
using SharpMap.Data;
using SharpMap.Data.Providers;
using SharpMap.Layers;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;

namespace HeuristicLab.BioBoost.Views.MapViews {
  public class LazyVectorLayerGenerator : ILazyLayerGenerator {

    private GeometryFeatureProvider geom;
    private IEnumerable<string> locationNames;
    private IEnumerable<int> transportTargets;
    private IEnumerable<double> transportAmounts;
    private ILayer layer;
    public String LayerName { get; set; }
    public Color VectorColor { get; set; }
    public int LineOffset { get; set; }

    public LazyVectorLayerGenerator(GeometryFeatureProvider geom,
      IEnumerable<string> locationNames,
      IEnumerable<int> transportTargets,
      IEnumerable<double> transportAmounts,
      Color vectorColor,
      String layerName) {
      this.geom = geom;
      if (locationNames == null) throw new ArgumentNullException("locationNames");
      if (transportTargets == null) throw new ArgumentNullException("transportTargets");
      this.locationNames = locationNames;
      this.transportTargets = transportTargets;
      this.transportAmounts = transportAmounts;
      this.VectorColor = vectorColor;
      this.LayerName = layerName;
    }

    public ILayer Layer {
      get {
        if (layer == null) BuildLayer();
        return layer;
      }
    }

    private void BuildLayer() {
      string[] locationNames = this.locationNames.ToArray();
      int[] transportTargets = this.transportTargets.ToArray();
      double[] transportAmounts = this.transportAmounts == null ? null : this.transportAmounts.ToArray();
      this.locationNames = null;
      this.transportTargets = null;
      var nameIndex = locationNames.Select((loc, idx) => new { loc, idx }).ToDictionary(p => p.loc, p => p.idx);
      var centroids = new Coordinate[locationNames.Length];
      foreach (FeatureDataRow row in geom.Features) {
        int idx;
        if (nameIndex.TryGetValue((string)row["NUTS_ID"], out idx)) {
          var centroid = row.Geometry.Centroid;
          try {
            if (!centroid.Within(row.Geometry)) centroid = row.Geometry.InteriorPoint;
          } catch (Exception x) { }
          centroids[idx] = centroid.Coordinate;
        }
      }
      var dataTable = new FeatureDataTable();
      dataTable.Columns.Add("NUTS_ID_SRC");
      dataTable.Columns.Add("NUTS_ID_DEST");

      // var transports = new Collection<IGeometry>();
      // GeoAPI.GeometryServiceProvider.Instance = new NetTopologySuite.NtsGeometryServices();
      // var f = GeoAPI.GeometryServiceProvider.Instance.CreateGeometryFactory(4326);
      for (int i = 0; i < locationNames.Length; i++) {
        if (transportAmounts != null && transportAmounts[i] <= 0) continue;
        IGeometry g = null;
        var j = transportTargets[i];
        var source = centroids[i];
        if (source == null) continue;
        if (i == j)
          g = new NetTopologySuite.Geometries.Point(source);
        if (j == -1) continue;
        var target = j < centroids.Length && j >= 0 ? centroids[j] : null;
        if (target != null)
          g = new LineString(new[] { source, target });

        var row = dataTable.NewRow();
        row.Geometry = g;
        row["NUTS_ID_SRC"] = locationNames[i];
        row["NUTS_ID_DEST"] = locationNames[j];
        dataTable.AddRow(row);
      }

      var geometryProv = new GeometryFeatureProvider(dataTable);
      var vectorLayer = new VectorLayer(LayerName, geometryProv);
      vectorLayer.SmoothingMode = SmoothingMode.HighQuality;
      vectorLayer.Style.Line.SetLineCap(LineCap.NoAnchor, LineCap.ArrowAnchor, DashCap.Flat);
      vectorLayer.Style.Line.CustomEndCap = new AdjustableArrowCap(3, 5);
      vectorLayer.Style.Line.Color = VectorColor;
      vectorLayer.Style.Line.Width = 1;
      vectorLayer.Style.LineOffset = LineOffset;
      vectorLayer.Style.PointColor = new SolidBrush(VectorColor);
      vectorLayer.Style.PointSize = 2;
      this.layer = vectorLayer;
    }
  }
}