using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;

namespace Volian.Svg.Library
{
	public class SvgScale
	{
		private float _XLowerLimit;
		public float XLowerLimit
		{
			get { return _XLowerLimit; }
			set { _XLowerLimit = value; }
		}
		private float _YLowerLimit;
		public float YLowerLimit
		{ 
			get { return _YLowerLimit; }
			set { _YLowerLimit = value; }
		}
		private float _Scale; // Scale from Logical to Physical
		public float Scale
		{ get { return _Scale; } }
		private float _Width; // Physical Width
		public float Width
		{ get { return _Width; } }
		private float _Height; // Physical Height
		public float Height
		{ get { return _Height; } }
		public float XUpperLimit
		{ get { return _Width * _Scale + _XLowerLimit; } }
		public float YUpperLimit
		{ get { return _Height * _Scale + _YLowerLimit; } }
		private float _DPI;
		public float DPI
		{	get { return _DPI; } }
		private SvgScale(SvgScale tmp,SvgMeasurement newX, SvgMeasurement newY)
		{
			_DPI = tmp.DPI;
			_Scale = tmp.Scale;
			_Width = tmp.Width;
			_Height = tmp.Height;
			_XLowerLimit = tmp.XLowerLimit - newX.GetSizeInPixels(DPI);
			_YLowerLimit = tmp.YLowerLimit - newY.GetSizeInPixels(DPI);
		}
		public SvgScale(float myDPI, RectangleF bounds,SvgMeasurement width, SvgMeasurement height, SvgViewBox myViewBox)
		{
			// TODO: Should I convert to pixels or something fixed (Inches, Points, Picas, CMs, MMs, Twips)
			_DPI = myDPI;
			float outputWidth = width.GetSizeInPixels(100);
			if(outputWidth == 0) outputWidth = bounds.Width;
			float outputHeight = height.GetSizeInPixels(100);
			if (outputHeight == 0) outputHeight = bounds.Height;
			float inputWidth = myViewBox.Width;
			if (inputWidth == 0) inputWidth = outputWidth;
			float scalex = outputWidth / inputWidth;
			float inputHeight = myViewBox.Height;
			if (inputHeight == 0) inputHeight = outputHeight;
			float scaley = outputHeight / inputHeight;
			_Scale = (scalex < scaley) ? scaley : scalex;
			//Console.WriteLine("'Scale',{0}",_Scale);
			_Width = outputWidth / _Scale;
			_Height = outputHeight / _Scale;
			_XLowerLimit = myViewBox.X + (inputWidth - _Width) / 2;
			_YLowerLimit = myViewBox.Y + (inputHeight - _Height) / 2;
			//if (myDPI != 96) Console.WriteLine("DPI {0}", myDPI);
			//Console.WriteLine("Scale,{0},{1},{2},{3},{4},{5},{6}", Scale, Width, Height, XLowerLimit, XUpperLimit, YLowerLimit, YUpperLimit);
		}
		public SvgScale AdjustOrigin(SvgMeasurement newX, SvgMeasurement newY)
		{
			return new SvgScale(this, newX, newY);
		}
		public float X(float x)
		{
			return _Scale * (x - XLowerLimit);
		}
		public float Y(float y)
		{
			return _Scale * (y - YLowerLimit);
		}
		public float AbsX(SvgMeasurement x)
		{
			return x.GetSizeInPixels(DPI) + Svg.AbsoluteOffset.X;
		}
		public float AbsY(iTextSharp.text.pdf.PdfContentByte cb, SvgMeasurement y)
		{
			// the following line of code is 'taken' from the 16bit code: \promsnt\exe\wined\togdi.cpp
			// whenever doing an 'Absolute' macro.
			float yOffset = 54 * 4.8f + 0.5f;	// yOffset starts in 'twips'  (twip = 1/20 point)
			yOffset = yOffset / 20;				// convert from twips to points  (point = 1/72 inch)
			return cb.PdfDocument.PageSize.Height - y.GetSizeInPixels(DPI) + yOffset + Svg.AbsoluteOffset.Y;
		}
		public float Y(iTextSharp.text.pdf.PdfContentByte cb, float y)
		{
			return cb.PdfDocument.PageSize.Height - _Scale * (y - YLowerLimit);
		}
		public float M(float m)
		{
			return _Scale * m;
		}
		public float X(SvgMeasurement x)
		{
			float retval = _Scale * (x.GetSizeInPixels(DPI)  - XLowerLimit);
			return retval;
		}
		public float Y(SvgMeasurement y)
		{
			return _Scale * (y.GetSizeInPixels(DPI) - YLowerLimit);
		}
		public float Y(iTextSharp.text.pdf.PdfContentByte cb, SvgMeasurement y)
		{
			float yOffset = 0; // = (cb.PdfWriter.CurrentPageNumber -1) * .8F * cb.PdfDocument.PageSize.Height;
			float myY = yOffset + cb.PdfDocument.PageSize.Height - _Scale * (y.GetSizeInPixels(DPI) - YLowerLimit);
			return myY;
		}
		public float YY(SvgMeasurement y)
		{
			return -_Scale * y.GetSizeInPixels(DPI);
		}
		public float M(SvgMeasurement m)
		{
			return _Scale * m.GetSizeInPixels(DPI);
		}
	}
}