using System;
using System.Drawing;

namespace Netron.Diagramming.Core {
  static class Measurements {
    [ThreadStaticAttribute()]
    private static float screenDpiX = 96.0F;

    [ThreadStaticAttribute()]
    private static float screenDpiY = 96.0F;

    private static float[,] conversionRatios = new float[,]{
	    {1.0F, 4.0F, 1.3333334e-002F, 0.33866665F, 0.95999998F}, 
	    {0.25F, 1.0F, 3.3333334e-003F, 8.4666662e-002F, 0.23999999F}, 
	    {75.0F, 300.0F, 1.0F, 25.4F, 72.0F}, 
	    {2.9527559F, 11.811024F, 3.9370079e-002F, 1.0F, 2.8346457F}, 
	    {1.0416666F, 4.1666665F, 1.3888889e-002F, 0.35277778F, 1.0F}, 
	    };

    private static MeasurementsUnit[] englishUnits;

    private static MeasurementsUnit[] metricUnits;


    private static int GraphicsUnitIndex(GraphicsUnit graphicsUnit) {
      int i = -1;
      switch (graphicsUnit) {
        case GraphicsUnit.Display:
          i = 0;
          break;

        case GraphicsUnit.Document:
          i = 1;
          break;

        case GraphicsUnit.Inch:
          i = 2;
          break;

        case GraphicsUnit.Millimeter:
          i = 3;
          break;

        case GraphicsUnit.Point:
          i = 4;
          break;
      }
      return i;
    }

    public static void InitScreenDPI() {
      Graphics graphics = Graphics.FromHwnd((IntPtr)0);
      if (graphics != null) {
        screenDpiX = graphics.DpiX;
        screenDpiY = graphics.DpiY;
      }
    }

    public static float UnitsPerInch(GraphicsUnit unit) {
      float f = 1.0F;
      switch (unit) {
        case GraphicsUnit.Inch:
          return 1.0F;

        case GraphicsUnit.Millimeter:
          return 25.4F;

        case GraphicsUnit.Point:
          return 72.0F;

        case GraphicsUnit.Document:
          return 300.0F;

        case GraphicsUnit.Display:
          return 75.0F;

        default:
          return f;
      }
    }

    public static float Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, float dpi, float value) {
      float f1 = value;
      if (fromUnits != toUnits) {
        float f2;

        GraphicsUnit graphicsUnit;

        if (fromUnits == GraphicsUnit.Pixel) {
          graphicsUnit = GraphicsUnit.Inch;
          f2 = value / dpi;
        } else {
          f2 = value;
          graphicsUnit = fromUnits;
        }
        if (graphicsUnit == toUnits) {
          f1 = f2;
        } else if (toUnits == GraphicsUnit.Pixel) {
          if (graphicsUnit != GraphicsUnit.Inch) {
            int i = GraphicsUnitIndex(graphicsUnit);
            int j = GraphicsUnitIndex(GraphicsUnit.Inch);
            f2 *= conversionRatios[i, j];
          }
          f1 = f2 * dpi;
        } else {
          int i = GraphicsUnitIndex(graphicsUnit);
          int j = GraphicsUnitIndex(toUnits);
          f1 = f2 * conversionRatios[i, j];
        }
      }
      return f1;
    }

    public static float Convert(GraphicsUnit fromUnits, float fromScale, GraphicsUnit toUnits, float toScale, float dpi, float value) {
      float f1 = value;
      if (fromUnits != toUnits || fromScale != toScale) {
        float f2;

        GraphicsUnit graphicsUnit;

        if (fromUnits == GraphicsUnit.Pixel) {
          graphicsUnit = GraphicsUnit.Inch;
          f2 = value / dpi;
        } else {
          f2 = value;
          graphicsUnit = fromUnits;
        }
        f2 *= fromScale;
        if (graphicsUnit == toUnits) {
          f1 = f2;
        } else if (toUnits == GraphicsUnit.Pixel) {
          if (graphicsUnit != GraphicsUnit.Inch) {
            int i = GraphicsUnitIndex(graphicsUnit);
            int j = GraphicsUnitIndex(GraphicsUnit.Inch);
            f2 *= conversionRatios[i, j];
          }
          f1 = f2 * dpi;
        } else {
          int i = GraphicsUnitIndex(graphicsUnit);
          int j = GraphicsUnitIndex(toUnits);
          f1 = f2 * conversionRatios[i, j];
        }
        f1 /= toScale;
      }
      return f1;
    }

    public static float Convert(MeasurementsUnit fromUnits, GraphicsUnit toUnits, float toScale, float dpi, float value) {
      GraphicsUnit graphicsUnit;
      float f;
      MeasurementsUnitToGraphicsUnit(fromUnits, out graphicsUnit, out f);
      return Convert(graphicsUnit, f, toUnits, toScale, dpi, value);
    }

    public static float Convert(GraphicsUnit fromUnits, float fromScale, MeasurementsUnit toUnits, float dpi, float value) {
      GraphicsUnit graphicsUnit;
      float f;
      MeasurementsUnitToGraphicsUnit(toUnits, out graphicsUnit, out f);
      return Convert(fromUnits, fromScale, graphicsUnit, f, dpi, value);
    }

    public static float Convert(MeasurementsUnit fromUnits, MeasurementsUnit toUnits, float dpi, float value) {
      GraphicsUnit graphicsUnit1, graphicsUnit2;
      float f1, f2;
      MeasurementsUnitToGraphicsUnit(fromUnits, out graphicsUnit1, out f1);
      MeasurementsUnitToGraphicsUnit(toUnits, out graphicsUnit2, out f2);
      return Convert(graphicsUnit1, f1, graphicsUnit2, f2, dpi, value);
    }

    public static float Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, float value) {
      return Convert(fromUnits, toUnits, screenDpiX, value);
    }

    public static float Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, Graphics grfx, float value) {
      float f = screenDpiX;
      if (grfx != null) {
        f = grfx.DpiX;
      }
      return Convert(fromUnits, toUnits, f, value);
    }

    public static PointF Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, PointF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      float f3 = Convert(fromUnits, toUnits, f1, value.X);
      float f4 = Convert(fromUnits, toUnits, f2, value.Y);
      return new PointF(f3, f4);
    }

    public static PointF Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, Graphics grfx, PointF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, toUnits, f1, value.X);
      float f4 = Convert(fromUnits, toUnits, f2, value.Y);
      return new PointF(f3, f4);
    }

    public static PointF Convert(GraphicsUnit fromUnits, float fromScale, GraphicsUnit toUnits, float toScale, Graphics grfx, PointF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, fromScale, toUnits, toScale, f1, value.X);
      float f4 = Convert(fromUnits, fromScale, toUnits, toScale, f2, value.Y);
      return new PointF(f3, f4);
    }

    public static PointF Convert(MeasurementsUnit fromUnits, MeasurementsUnit toUnits, Graphics grfx, PointF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, toUnits, f1, value.X);
      float f4 = Convert(fromUnits, toUnits, f2, value.Y);
      return new PointF(f3, f4);
    }

    public static PointF Convert(GraphicsUnit fromUnits, float fromScale, MeasurementsUnit toUnits, Graphics grfx, PointF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, fromScale, toUnits, f1, value.X);
      float f4 = Convert(fromUnits, fromScale, toUnits, f2, value.Y);
      return new PointF(f3, f4);
    }

    public static PointF Convert(MeasurementsUnit fromUnits, GraphicsUnit toUnits, float toScale, Graphics grfx, PointF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, toUnits, toScale, f1, value.X);
      float f4 = Convert(fromUnits, toUnits, toScale, f2, value.Y);
      return new PointF(f3, f4);
    }

    public static SizeF Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, SizeF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      float f3 = Convert(fromUnits, toUnits, f1, value.Width);
      float f4 = Convert(fromUnits, toUnits, f2, value.Height);
      return new SizeF(f3, f4);
    }

    public static SizeF Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, Graphics grfx, SizeF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, toUnits, f1, value.Width);
      float f4 = Convert(fromUnits, toUnits, f2, value.Height);
      return new SizeF(f3, f4);
    }

    public static SizeF Convert(GraphicsUnit fromUnits, float fromScale, GraphicsUnit toUnits, float toScale, Graphics grfx, SizeF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, fromScale, toUnits, toScale, f1, value.Width);
      float f4 = Convert(fromUnits, fromScale, toUnits, toScale, f2, value.Height);
      return new SizeF(f3, f4);
    }

    public static RectangleF Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, RectangleF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      float f3 = Convert(fromUnits, toUnits, f1, value.X);
      float f4 = Convert(fromUnits, toUnits, f2, value.Y);
      float f5 = Convert(fromUnits, toUnits, f1, value.Width);
      float f6 = Convert(fromUnits, toUnits, f2, value.Height);
      return new RectangleF(f3, f4, f5, f6);
    }

    public static RectangleF Convert(GraphicsUnit fromUnits, GraphicsUnit toUnits, Graphics grfx, RectangleF value) {
      float f1 = screenDpiX;
      float f2 = screenDpiY;
      if (grfx != null) {
        f1 = grfx.DpiX;
        f2 = grfx.DpiY;
      }
      float f3 = Convert(fromUnits, toUnits, f1, value.X);
      float f4 = Convert(fromUnits, toUnits, f2, value.Y);
      float f5 = Convert(fromUnits, toUnits, f1, value.Width);
      float f6 = Convert(fromUnits, toUnits, f2, value.Height);
      return new RectangleF(f3, f4, f5, f6);
    }

    public static void MeasurementsUnitToGraphicsUnit(MeasurementsUnit unitMeasure, out GraphicsUnit grfxUnit, out float grfxScale) {
      switch (unitMeasure) {
        case MeasurementsUnit.SixteenthInches:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 6.25e-002F;
          return;

        case MeasurementsUnit.EighthInches:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 0.125F;
          return;

        case MeasurementsUnit.QuarterInches:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 0.25F;
          return;

        case MeasurementsUnit.HalfInches:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 0.5F;
          return;

        case MeasurementsUnit.Inches:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 1.0F;
          return;

        case MeasurementsUnit.Feet:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 12.0F;
          return;

        case MeasurementsUnit.Yards:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 36.0F;
          return;

        case MeasurementsUnit.Miles:
          grfxUnit = GraphicsUnit.Inch;
          grfxScale = 63360.0F;
          return;

        case MeasurementsUnit.Millimeters:
          grfxUnit = GraphicsUnit.Millimeter;
          grfxScale = 1.0F;
          return;

        case MeasurementsUnit.Centimeters:
          grfxUnit = GraphicsUnit.Millimeter;
          grfxScale = 10.0F;
          return;

        case MeasurementsUnit.Meters:
          grfxUnit = GraphicsUnit.Millimeter;
          grfxScale = 1000.0F;
          return;

        case MeasurementsUnit.Kilometers:
          grfxUnit = GraphicsUnit.Millimeter;
          grfxScale = 1000000.0F;
          return;

        case MeasurementsUnit.Points:
          grfxUnit = GraphicsUnit.Point;
          grfxScale = 1.0F;
          return;

        default:
          grfxUnit = GraphicsUnit.Pixel;
          grfxScale = 1.0F;
          return;
      }
    }

    public static MeasurementSystem GetUnitsSystem(MeasurementsUnit units) {
      MeasurementSystem measurementSystem = MeasurementSystem.English;
      MeasurementsUnit[] measurementsUnits = metricUnits;
      for (int i = 0; i < (int)measurementsUnits.Length; i++) {
        if (measurementsUnits[i] == units) {
          measurementSystem = MeasurementSystem.Metric;
          break;
        }
      }
      return measurementSystem;
    }

    public static bool GetLargerUnits(MeasurementsUnit units, out MeasurementsUnit largerUnits) {
      bool flag = false;
      largerUnits = units;
      for (int i = 0; !flag && i < (int)englishUnits.Length - 1; i++) {
        if (englishUnits[i] == units) {
          largerUnits = englishUnits[i + 1];
          flag = true;
        }
      }
      for (int j = 0; !flag && j < (int)metricUnits.Length - 1; j++) {
        if (metricUnits[j] == units) {
          largerUnits = englishUnits[j + 1];
        }
      }
      return flag;
    }

    public static bool GetSmallerUnits(MeasurementsUnit units, out MeasurementsUnit smallerUnits) {
      bool flag = false;
      smallerUnits = units;
      for (int i = (int)englishUnits.Length - 1; !flag && i > 0; i--) {
        if (englishUnits[i] == units) {
          smallerUnits = englishUnits[i - 1];
          flag = true;
        }
      }
      for (int j = (int)metricUnits.Length - 1; !flag && j > 0; j--) {
        if (metricUnits[j] == units) {
          smallerUnits = metricUnits[j - 1];
          flag = true;
        }
      }
      return flag;
    }

    public static MeasurementsUnit GetSystemUnits(MeasurementSystem measureSys, int unitOrdinal) {
      MeasurementsUnit measurementsUnit;

      //if (measureSys == null)
      //{
      //  if (unitOrdinal < 0 || unitOrdinal >= (int)englishUnits.Length)
      //  {
      //      throw new InconsistencyException("Oops");
      //  }
      //  measurementsUnit = englishUnits[unitOrdinal];
      //}
      //else
      {
        if (measureSys != MeasurementSystem.Metric) {
          throw new InconsistencyException("Oops");
        }
        if (unitOrdinal < 0 || unitOrdinal >= (int)metricUnits.Length) {
          throw new InconsistencyException("Oops");
        }
        measurementsUnit = metricUnits[unitOrdinal];
      }
      return measurementsUnit;
    }

    static Measurements() {
      MeasurementsUnit[] measurementsUnits = new MeasurementsUnit[8];
      measurementsUnits[1] = MeasurementsUnit.EighthInches;
      measurementsUnits[2] = MeasurementsUnit.QuarterInches;
      measurementsUnits[3] = MeasurementsUnit.HalfInches;
      measurementsUnits[4] = MeasurementsUnit.Inches;
      measurementsUnits[5] = MeasurementsUnit.Feet;
      measurementsUnits[6] = MeasurementsUnit.Yards;
      measurementsUnits[7] = MeasurementsUnit.Miles;
      englishUnits = measurementsUnits;
      measurementsUnits = new MeasurementsUnit[] { MeasurementsUnit.Millimeters, MeasurementsUnit.Centimeters, MeasurementsUnit.Meters, MeasurementsUnit.Kilometers };
      metricUnits = measurementsUnits;
    }
  }

}