using System;
using System.Collections;
using System.Drawing;
using System.Drawing.Drawing2D;

namespace Server.Engines.Reports
{
  // Modified from MS sample

  //*********************************************************************
  //
  // PieChart Class
  //
  // This class uses GDI+ to render Pie Chart.
  //
  //*********************************************************************

  public class PieChartRenderer : ChartRenderer
  {
    private const int _bufferSpace = 125;
    private Color _backgroundColor;
    private Color _borderColor;
    private ArrayList _chartItems;
    private int _legendFontHeight;
    private float _legendFontSize;
    private string _legendFontStyle;
    private int _legendHeight;
    private int _legendWidth;
    private int _perimeter;
    private float _total;

    public PieChartRenderer()
    {
      _chartItems = new ArrayList();
      _perimeter = 250;
      _backgroundColor = Color.White;
      _borderColor = Color.FromArgb(63, 63, 63);
      _legendFontSize = 8;
      _legendFontStyle = "Verdana";
    }

    public PieChartRenderer(Color bgColor)
    {
      _chartItems = new ArrayList();
      _perimeter = 250;
      _backgroundColor = bgColor;
      _borderColor = Color.FromArgb(63, 63, 63);
      _legendFontSize = 8;
      _legendFontStyle = "Verdana";
    }

    public bool ShowPercents{ get; set; }

    //*********************************************************************
    //
    // This method collects all data points and calculate all the necessary dimensions 
    // to draw the chart.  It is the first method called before invoking the Draw() method.
    //
    //*********************************************************************

    public void CollectDataPoints(string[] xValues, string[] yValues)
    {
      _total = 0.0f;

      for (int i = 0; i < xValues.Length; i++)
      {
        float ftemp = Convert.ToSingle(yValues[i]);
        _chartItems.Add(new DataItem(xValues[i], xValues.ToString(), ftemp, 0, 0, Color.AliceBlue));
        _total += ftemp;
      }

      float nextStartPos = 0.0f;
      int counter = 0;
      foreach (DataItem item in _chartItems)
      {
        item.StartPos = nextStartPos;
        item.SweepSize = item.Value / _total * 360;
        nextStartPos = item.StartPos + item.SweepSize;
        item.ItemColor = GetColor(counter++);
      }

      CalculateLegendWidthHeight();
    }

    //*********************************************************************
    //
    // This method returns a bitmap to the calling function.  This is the method
    // that actually draws the pie chart and the legend with it.
    //
    //*********************************************************************

    public override Bitmap Draw()
    {
      int perimeter = _perimeter;
      Rectangle pieRect = new Rectangle(0, 0, perimeter, perimeter - 1);
      Bitmap bmp = new Bitmap(perimeter + _legendWidth, perimeter);
      Font fnt = null;
      Pen pen = null;
      Graphics grp = null;
      StringFormat sf = null, sfp = null;

      try
      {
        grp = Graphics.FromImage(bmp);
        grp.CompositingQuality = CompositingQuality.HighQuality;
        grp.SmoothingMode = SmoothingMode.AntiAlias;
        sf = new StringFormat();

        //Paint Back ground
        using (SolidBrush brsh = new SolidBrush(_backgroundColor))
        {
          grp.FillRectangle(brsh, -1, -1, perimeter + _legendWidth + 1, perimeter + 1);
        }

        //Align text to the right
        sf.Alignment = StringAlignment.Far;

        //Draw all wedges and legends
        for (int i = 0; i < _chartItems.Count; i++)
        {
          DataItem item = (DataItem)_chartItems[i];
          SolidBrush brs = null;
          try
          {
            brs = new SolidBrush(item.ItemColor);
            grp.FillPie(brs, pieRect, item.StartPos, item.SweepSize);

            //grp.DrawPie(new Pen(_borderColor,1.2f),pieRect,item.StartPos,item.SweepSize);

            if (fnt == null)
              fnt = new Font(_legendFontStyle, _legendFontSize);

            if (ShowPercents && item.SweepSize > 10)
            {
              if (sfp == null)
              {
                sfp = new StringFormat();
                sfp.Alignment = StringAlignment.Center;
                sfp.LineAlignment = StringAlignment.Center;
              }

              float perc = item.SweepSize * 100.0f / 360.0f;
              string percString = $"{perc:F0}%";

              float px = pieRect.X + pieRect.Width / 2;
              float py = pieRect.Y + pieRect.Height / 2;

              double angle = item.StartPos + item.SweepSize / 2;
              double rads = angle / 180.0 * Math.PI;

              px += (float)(Math.Cos(rads) * perimeter / 3);
              py += (float)(Math.Sin(rads) * perimeter / 3);

              grp.DrawString(percString, fnt, Brushes.Gray,
                new RectangleF(px - 30 - 1, py - 20, 60, 40), sfp);

              grp.DrawString(percString, fnt, Brushes.Gray,
                new RectangleF(px - 30 + 1, py - 20, 60, 40), sfp);

              grp.DrawString(percString, fnt, Brushes.Gray,
                new RectangleF(px - 30, py - 20 - 1, 60, 40), sfp);

              grp.DrawString(percString, fnt, Brushes.Gray,
                new RectangleF(px - 30, py - 20 + 1, 60, 40), sfp);


              grp.DrawString(percString, fnt, Brushes.White,
                new RectangleF(px - 30, py - 20, 60, 40), sfp);
            }

            if (pen == null)
              pen = new Pen(_borderColor, 0.5f);

            grp.FillRectangle(brs, perimeter + _bufferSpace, i * _legendFontHeight + 15, 10, 10);
            grp.DrawRectangle(pen, perimeter + _bufferSpace, i * _legendFontHeight + 15, 10, 10);

            grp.DrawString(item.Label, fnt,
              Brushes.Black, perimeter + _bufferSpace + 20, i * _legendFontHeight + 13);

            grp.DrawString(item.Value.ToString("#,###.##"), fnt,
              Brushes.Black, perimeter + _bufferSpace + 200, i * _legendFontHeight + 13, sf);
          }
          finally
          {
            brs?.Dispose();
          }
        }

        for (int i = 0; i < _chartItems.Count; i++)
        {
          DataItem item = (DataItem)_chartItems[i];
          SolidBrush brs = null;
          try
          {
            grp.DrawPie(new Pen(_borderColor, 0.5f), pieRect, item.StartPos, item.SweepSize);
          }
          finally
          {
            brs?.Dispose();
          }
        }

        //draws the border around Pie
        using (Pen pen2 = new Pen(_borderColor, 2))
        {
          grp.DrawEllipse(pen2, pieRect);
        }

        //draw border around legend
        using (Pen pen1 = new Pen(_borderColor, 1))
        {
          grp.DrawRectangle(pen1, perimeter + _bufferSpace - 10, 10, 220,
            _chartItems.Count * _legendFontHeight + 25);
        }

        //Draw Total under legend
        using (Font fntb = new Font(_legendFontStyle, _legendFontSize, FontStyle.Bold))
        {
          grp.DrawString("Total", fntb,
            Brushes.Black, perimeter + _bufferSpace + 30, (_chartItems.Count + 1) * _legendFontHeight, sf);
          grp.DrawString(_total.ToString("#,###.##"), fntb,
            Brushes.Black, perimeter + _bufferSpace + 200, (_chartItems.Count + 1) * _legendFontHeight, sf);
        }

        grp.SmoothingMode = SmoothingMode.AntiAlias;
      }
      finally
      {
        sf?.Dispose();
        grp?.Dispose();
        sfp?.Dispose();
        fnt?.Dispose();
        pen?.Dispose();
      }

      return bmp;
    }

    //*********************************************************************
    //
    //	This method calculates the space required to draw the chart legend.
    //
    //*********************************************************************

    private void CalculateLegendWidthHeight()
    {
      Font fontLegend = new Font(_legendFontStyle, _legendFontSize);
      _legendFontHeight = fontLegend.Height + 3;
      _legendHeight = fontLegend.Height * (_chartItems.Count + 1);
      if (_legendHeight > _perimeter) _perimeter = _legendHeight;

      _legendWidth = _perimeter + _bufferSpace;
      fontLegend.Dispose();
    }
  }
}