using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Windows.Forms.DataVisualization.Charting;
using System.IO;

namespace VRPProblemAnalyzer {
  public class PictureGenerator {

    private static int TourWidth = 400;
    private static int TourHeight = 500;
    private static double MinDemandSize = 2;
    private static double MaxDemandSize = Math.Min(TourWidth, TourHeight) / 25.0;

    private static int TourBorder = (int)Math.Ceiling(MaxDemandSize);

    private static int ChartWidth = 300;
    private static int ChartHeight = TourHeight/2;
    
    private static int DemandSegments = 20;

    private static int DistanceSegments = 20;

    public static Image GeneratePicture(TSPLIBParser problemInstance, SolutionParser solution) {    
      Image tourVisualization = GenerateTourVisualization(problemInstance, solution);
      Image demandDistribution = GenerateDemandDistribution(problemInstance);
      Image distanceDistribution = GenerateDistanceDistribution(problemInstance);

      SizeF titleSize;
      using (var font = new Font("Helvetica", 20)) {
        using (var b = new Bitmap(1, 1)) {
          using (Graphics g = Graphics.FromImage(b)) {
            titleSize = g.MeasureString(problemInstance.Name, font);
          }
        }
        Bitmap bmp = new Bitmap(TourWidth+ChartWidth,
                                Math.Max(TourHeight,  2*ChartHeight) + (int)titleSize.Height);
        using (Graphics g = Graphics.FromImage(bmp)) {
          g.FillRectangle(Brushes.White, 0, 0, bmp.Width, bmp.Height);
          g.DrawString(problemInstance.Name, font, Brushes.Black, (bmp.Width-titleSize.Width)/2, 0);
          g.DrawImage(tourVisualization, (TourWidth-tourVisualization.Width)/2, titleSize.Height+(TourHeight-tourVisualization.Height)/2);
          g.DrawImage(demandDistribution, TourWidth, titleSize.Height);
          g.DrawImage(distanceDistribution, TourWidth, ChartHeight + titleSize.Height);
        }
        return bmp;
      }
    }

    private static Color[] TourColors = new[] {
      Color.FromArgb(100, 92, 20,237), Color.FromArgb(100,237,183, 20), Color.FromArgb(100,237, 20,219), Color.FromArgb(100, 20,237, 76),
      Color.FromArgb(100,237, 61, 20), Color.FromArgb(100,115, 78, 26), Color.FromArgb(100, 20,237,229), Color.FromArgb(100, 39,101, 19),
      Color.FromArgb(100,230,170,229), Color.FromArgb(100,142,136, 89), Color.FromArgb(100,157,217,166), Color.FromArgb(100, 31, 19,101),
      Color.FromArgb(100,173,237, 20), Color.FromArgb(100,230,231,161), Color.FromArgb(100,142, 89, 89), Color.FromArgb(100, 93, 89,142),
      Color.FromArgb(100,146,203,217), Color.FromArgb(100,101, 19, 75), Color.FromArgb(100,198, 20,237), Color.FromArgb(100,185,185,185),
      Color.FromArgb(100,179, 32, 32), Color.FromArgb(100, 18,119,115), Color.FromArgb(100,104,158,239), Color.Black};

    private static Image GenerateTourVisualization(TSPLIBParser problemInstance, SolutionParser solution) {
      double[,] coordinates = problemInstance.Vertices;

      double xMin = double.MaxValue, yMin = double.MaxValue, xMax = double.MinValue, yMax = double.MinValue;
      for (int i = 0; i < coordinates.GetLength(0); i++) {
        if (xMin > coordinates[i, 0]) xMin = coordinates[i, 0];
        if (yMin > coordinates[i, 1]) yMin = coordinates[i, 1];
        if (xMax < coordinates[i, 0]) xMax = coordinates[i, 0];
        if (yMax < coordinates[i, 1]) yMax = coordinates[i, 1];
      }
      double xRange = xMax - xMin;
      double yRange = yMax - yMin;
      double scaling = Math.Min((TourWidth-TourBorder*2)/xRange, (TourHeight-TourBorder*2)/yRange);
      Bitmap bitmap = new Bitmap((int)Math.Ceiling(xRange*scaling+TourBorder*2), (int)Math.Ceiling(yRange*scaling+TourBorder*2));
      var pens = TourColors.Select(c => new Pen(c, 2)).ToList();
      using (Graphics g = Graphics.FromImage(bitmap)) {
        using (var brush = new SolidBrush(Color.FromArgb(100, 0, 0, 0))) {
          g.FillRectangle(Brushes.White, 0, 0, bitmap.Width, bitmap.Height);

          int currentTour = 0;
          foreach (List<int> tour in solution.Routes) {
            Point[] tourPoints = new Point[tour.Count + 2];
            int[] customerSizes = new int[tour.Count];

            for (int i = -1; i <= tour.Count; i++) {
              int location = (i == -1 || i == tour.Count) ? 0 : tour[i];
              Point locationPoint = new Point(TourBorder + ((int) ((coordinates[location, 0] - xMin)*scaling)),
                                              bitmap.Height -
                                              (TourBorder + ((int) ((coordinates[location, 1] - yMin)*scaling))));
              tourPoints[i + 1] = locationPoint;
              if (i != -1 && i != tour.Count) {
                customerSizes[i] =
                  (int)
                  Math.Round(MinDemandSize +
                             problemInstance.Demands[location]/problemInstance.Capacity*(MaxDemandSize - MinDemandSize));
              }
            }
            g.DrawPolygon(pens[((currentTour >= pens.Count) ? (pens.Count - 1) : (currentTour))], tourPoints);
            for (int i = 0; i < tour.Count; i++) {
              int size = customerSizes[i];
              g.FillEllipse(brush, tourPoints[i + 1].X - size, tourPoints[i + 1].Y - size, size*2, size*2);
            }
            g.FillRectangle(Brushes.Blue, tourPoints[0].X - 5, tourPoints[0].Y - 5, 10, 10);
            currentTour++;
          }
        }
      }
      foreach (var p in pens) p.Dispose();
      return bitmap;
    }

    private static List<Tuple<double, int>> GetDemandDistribution(TSPLIBParser problemInstance) {
      var result = new List<Tuple<double, int>>();

      double step = problemInstance.Capacity / (double)DemandSegments;
      double current = 0;

      while(current < problemInstance.Capacity) {
        int count = problemInstance.Demands.Where(d => d > current && d <= current + step).Count(); 
        result.Add(new Tuple<double, int>(current + step / 2, count));
        current += step;           
      }
     
      return result;
    }

    private static Image GenerateDemandDistribution(TSPLIBParser problemInstance) {     
      Chart chart = new Chart();
      chart.Size = new Size(ChartWidth, ChartHeight);

      chart.ChartAreas.Add("");
      ConfigureChartAppearance(chart);
      chart.ChartAreas[0].AxisX.Title = "Demands";
      chart.ChartAreas[0].AxisX.Minimum = 0;
      chart.ChartAreas[0].AxisX.Maximum = problemInstance.Capacity;
      chart.ChartAreas[0].AxisX.Interval = problemInstance.Capacity/DemandSegments;
      chart.ChartAreas[0].AxisX.LabelStyle.Interval = problemInstance.Capacity/DemandSegments*4;
      chart.ChartAreas[0].AxisY.Title = "Customers";
      chart.ChartAreas[0].AxisY.Minimum = 0;
      chart.ChartAreas[0].AxisY.Maximum = problemInstance.Vertices.GetLength(0);

      chart.Series.Add("");
      chart.Series[0].ChartType = SeriesChartType.Column;

      foreach (Tuple<double, int> entry in GetDemandDistribution(problemInstance)) {
        chart.Series[0].Points.AddXY(entry.Item1, entry.Item2);
      }

      Image image;
      using (var chartimage = new MemoryStream()) {
        chart.SaveImage(chartimage, ChartImageFormat.Png);
        image = Image.FromStream(chartimage);
      }
      return image;
    }

    private static void ConfigureChartAppearance(Chart chart) {
      chart.ChartAreas[0].BackColor = Color.White;
      chart.ChartAreas[0].AxisX.TitleFont = new Font("Helvetica", 16);
      chart.ChartAreas[0].AxisX.MajorGrid.Enabled = false;
      chart.ChartAreas[0].AxisY.TitleFont = new Font("Helvetica", 16);
      chart.ChartAreas[0].AxisY.MajorGrid.Enabled = true;
      chart.ChartAreas[0].AxisY.MajorGrid.LineColor = Color.FromArgb(100, Color.LightBlue);
    }

    private static double GetAverageDistance(int customer, double[,] vertices) {
      double dist = 0;
      int count = 0;

      for (int i = 0; i < vertices.GetLength(0); i++) {
        if (i != customer) {
          dist += Utils.GetDistance(vertices, customer, i);
          count++;
        }
      }

      return dist / count;
    }

    private static List<Tuple<double, int>> GetDistanceDistribution(TSPLIBParser problemInstance) {
      var result = new List<Tuple<double, int>>();

      double step = 1.0 / (double)DistanceSegments;
      double current = 0;

      List<double> averageDistances = new List<double>();
      for (int i = 0; i < problemInstance.Vertices.GetLength(0); i++) {
        averageDistances.Add(GetAverageDistance(i, problemInstance.Vertices));
      }

        while (current < 1.0) {
          int count = averageDistances.Where(d => d > current && d <= current + step).Count();
          result.Add(new Tuple<double, int>(current + step / 2, count));
          current += step;
        }

      return result;
    }

    private static Image GenerateDistanceDistribution(TSPLIBParser problemInstance) {
      Chart chart = new Chart();
      chart.Size = new Size(ChartWidth, ChartHeight);

      chart.ChartAreas.Add("");
      ConfigureChartAppearance(chart);
      chart.ChartAreas[0].AxisX.Title = "Distances";
      chart.ChartAreas[0].AxisX.Minimum = 0;
      chart.ChartAreas[0].AxisX.Maximum = 1;
      chart.ChartAreas[0].AxisX.Interval = 1.0/DistanceSegments;
      chart.ChartAreas[0].AxisX.LabelStyle.Interval = 1.0/DistanceSegments*4;
      chart.ChartAreas[0].AxisY.Title = "Customers";
      chart.ChartAreas[0].AxisY.Minimum = 0;
      chart.ChartAreas[0].AxisY.Maximum = problemInstance.Vertices.GetLength(0);

      chart.Series.Add("");
      chart.Series[0].ChartType = SeriesChartType.Column;

      foreach (Tuple<double, int> entry in GetDistanceDistribution(problemInstance)) {
        chart.Series[0].Points.AddXY(entry.Item1, entry.Item2);
      }

      Image image;
      using (var chartimage = new MemoryStream()) {
        chart.SaveImage(chartimage, ChartImageFormat.Png);
        image = Image.FromStream(chartimage);
      }
      return image;
    }
  }
}