using System;
using System.Drawing;

namespace DevComponents.Tree
{
    /// <summary>
    /// Represents the class that provides color support to ColorScheme object.
    /// </summary>
    internal class ColorFunctions
    {
		#region Private Variables
		private static Color m_HoverBackColor;
		private static Color m_HoverBackColor2;
		private static Color m_HoverBackColor3;
		private static Color m_CheckBoxBackColor;
		private static Color m_MenuBackColor;
		private static Color m_MenuFocusBorderColor;
		private static Color m_PressedBackColor;
		private static Color m_ToolMenuFocusBackColor;
		private static Color m_SideRecentlyBackColor;
		private static Color m_RecentlyUsedOfficeBackColor;
		private static bool m_ThemedOS=false;
		private static Bitmap m_PushedBrushBmp=null;
		#endregion

		#region Win32 Interop
		[System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
			public struct OSVERSIONINFO 
		{
			public int dwOSVersionInfoSize;
			public int dwMajorVersion;
			public int dwMinorVersion;
			public int dwBuildNumber;
			public int dwPlatformId;
			[System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst=128)]
			public string szCSDVersion;
		}
		[System.Runtime.InteropServices.DllImport("kernel32.Dll")] private static extern short GetVersionEx(ref OSVERSIONINFO o);
		[System.Runtime.InteropServices.DllImport("gdi32")]
		private static extern int CreateDC(string lpszDriver, int lpszDevice, int lpszOutput, int lpInitData);
		[System.Runtime.InteropServices.DllImport("gdi32")]
		private static extern bool DeleteDC(int hDC);
		[System.Runtime.InteropServices.DllImport("gdi32",SetLastError=true, CharSet=System.Runtime.InteropServices.CharSet.Auto)]
		private static extern int GetDeviceCaps(int hdc, int nIndex);
		private const int BITSPIXEL = 12; // Number of bits per pixel

		#endregion

		public static void Initialize()
		{
			OnDisplayChange();
			OSVERSIONINFO os = new OSVERSIONINFO();
			os.dwOSVersionInfoSize=System.Runtime.InteropServices.Marshal.SizeOf(typeof(OSVERSIONINFO)); 
			GetVersionEx(ref os);
			if(os.dwMajorVersion>=5 && os.dwMinorVersion>=1 && os.dwPlatformId==2)
				m_ThemedOS=System.Windows.Forms.OSFeature.Feature.IsPresent(System.Windows.Forms.OSFeature.Themes);

			RefreshColors();
		}

		public static void RefreshColors()
		{
			if(ColorDepth>=16)
			{
				int red=(int)((System.Drawing.SystemColors.Highlight.R-System.Drawing.SystemColors.Window.R)*.30+System.Drawing.SystemColors.Window.R);
				int green=(int)((System.Drawing.SystemColors.Highlight.G-System.Drawing.SystemColors.Window.G)*.30+System.Drawing.SystemColors.Window.G);
				int blue=(int)((System.Drawing.SystemColors.Highlight.B-System.Drawing.SystemColors.Window.B)*.30+System.Drawing.SystemColors.Window.B);
				m_HoverBackColor=Color.FromArgb(red,green,blue);

				red=(int)((System.Drawing.SystemColors.Highlight.R-System.Drawing.SystemColors.Window.R)*.45+System.Drawing.SystemColors.Window.R);
				green=(int)((System.Drawing.SystemColors.Highlight.G-System.Drawing.SystemColors.Window.G)*.45+System.Drawing.SystemColors.Window.G);
				blue=(int)((System.Drawing.SystemColors.Highlight.B-System.Drawing.SystemColors.Window.B)*.45+System.Drawing.SystemColors.Window.B);
				m_HoverBackColor2=Color.FromArgb(red,green,blue);

				red=(int)((System.Drawing.SystemColors.Highlight.R-System.Drawing.SystemColors.Window.R)*.10+System.Drawing.SystemColors.Window.R);
				green=(int)((System.Drawing.SystemColors.Highlight.G-System.Drawing.SystemColors.Window.G)*.10+System.Drawing.SystemColors.Window.G);
				blue=(int)((System.Drawing.SystemColors.Highlight.B-System.Drawing.SystemColors.Window.B)*.10+System.Drawing.SystemColors.Window.B);
				m_HoverBackColor3=Color.FromArgb(red,green,blue);

				red=(int)((System.Drawing.SystemColors.Highlight.R-System.Drawing.SystemColors.Window.R)*.25+System.Drawing.SystemColors.Window.R);
				green=(int)((System.Drawing.SystemColors.Highlight.G-System.Drawing.SystemColors.Window.G)*.25+System.Drawing.SystemColors.Window.G);
				blue=(int)((System.Drawing.SystemColors.Highlight.B-System.Drawing.SystemColors.Window.B)*.25+System.Drawing.SystemColors.Window.B);
				m_CheckBoxBackColor=Color.FromArgb(red,green,blue);

				if(ColorDepth<=16)
				{
					m_MenuBackColor=System.Drawing.SystemColors.ControlLightLight;
				}
				else
				{
					red=(int)((System.Drawing.SystemColors.Control.R-System.Drawing.Color.White.R)*.20+System.Drawing.Color.White.R);
					green=(int)((System.Drawing.SystemColors.Control.G-System.Drawing.Color.White.G)*.20+System.Drawing.Color.White.G);
					blue=(int)((System.Drawing.SystemColors.Control.B-System.Drawing.Color.White.B)*.20+System.Drawing.Color.White.B);
					m_MenuBackColor=Color.FromArgb(red,green,blue);
				}

				red=(int)(System.Drawing.SystemColors.ControlDark.R*.80);
				green=(int)(System.Drawing.SystemColors.ControlDark.G*.80);
				blue=(int)(System.Drawing.SystemColors.ControlDark.B*.80);
				m_MenuFocusBorderColor=Color.FromArgb(red,green,blue);

				// and Highlight color
				red=(int)((System.Drawing.SystemColors.Highlight.R-System.Drawing.SystemColors.Window.R)*.25+System.Drawing.SystemColors.Window.R);
				green=(int)((System.Drawing.SystemColors.Highlight.G-System.Drawing.SystemColors.Window.G)*.25+System.Drawing.SystemColors.Window.G);
				blue=(int)((System.Drawing.SystemColors.Highlight.B-System.Drawing.SystemColors.Window.B)*.25+System.Drawing.SystemColors.Window.B);
				m_PressedBackColor=Color.FromArgb(red,green,blue);

				red=(int)((System.Drawing.SystemColors.Control.R-System.Drawing.Color.White.R)*.80+System.Drawing.Color.White.R);
				green=(int)((System.Drawing.SystemColors.Control.G-System.Drawing.Color.White.G)*.80+System.Drawing.Color.White.G);
				blue=(int)((System.Drawing.SystemColors.Control.B-System.Drawing.Color.White.B)*.80+System.Drawing.Color.White.B);
				m_ToolMenuFocusBackColor=Color.FromArgb(red,green,blue);

				red=(int)((System.Drawing.SystemColors.Control.R-System.Drawing.Color.White.R)*.50+System.Drawing.Color.White.R);
				green=(int)((System.Drawing.SystemColors.Control.G-System.Drawing.Color.White.G)*.50+System.Drawing.Color.White.G);
				blue=(int)((System.Drawing.SystemColors.Control.B-System.Drawing.Color.White.B)*.50+System.Drawing.Color.White.B);
				m_RecentlyUsedOfficeBackColor=Color.FromArgb(red,green,blue);

				m_SideRecentlyBackColor=System.Drawing.SystemColors.Control;
			}
			else
			{
                m_HoverBackColor=System.Drawing.SystemColors.ControlLightLight;
				m_HoverBackColor2=m_HoverBackColor;
				m_HoverBackColor3=m_HoverBackColor;
                m_CheckBoxBackColor=System.Drawing.SystemColors.ControlLight;
				m_MenuBackColor=System.Drawing.SystemColors.ControlLightLight;
                m_MenuFocusBorderColor=System.Drawing.SystemColors.ControlDark;
				m_PressedBackColor=System.Drawing.SystemColors.ControlLight;
                m_ToolMenuFocusBackColor=System.Drawing.SystemColors.ControlLight;
				m_RecentlyUsedOfficeBackColor=System.Drawing.SystemColors.ControlLight;
                m_SideRecentlyBackColor=System.Drawing.SystemColors.Control;
			}

			if(m_PushedBrushBmp!=null)
			{
				m_PushedBrushBmp.Dispose();
				m_PushedBrushBmp=new System.Drawing.Bitmap(2,2);
				m_PushedBrushBmp.SetPixel(0,0,System.Drawing.SystemColors.Control);
				m_PushedBrushBmp.SetPixel(1,0,System.Drawing.SystemColors.ControlLightLight);
				m_PushedBrushBmp.SetPixel(0,1,System.Drawing.SystemColors.ControlLightLight);
				m_PushedBrushBmp.SetPixel(1,1,System.Drawing.SystemColors.Control);
			}
		}

		public struct HLSColor
		{
			public double Hue;
			public double Lightness;
			public double Saturation;
		}
		public struct RGBColor
		{
			public int Red;
			public int Green;
			public int Blue;
		}
		public static HLSColor RGBToHSL(int Red, int Green, int Blue)
		{
			double Max, Min, delta;
			double rR, rG, rB;
			HLSColor ret=new HLSColor();

			rR = (double)Red / 255;
			rG = (double)Green / 255;
			rB = (double)Blue / 255;

			// Given: rgb each in [0,1].
			// Desired: h in [0,360] and s in [0,1], except if s=0, then h=UNDEFINED.}
			Max = Maximum(rR, rG, rB);
			Min = Minimum(rR, rG, rB);
			ret.Lightness = (Max + Min) / 2;    // {This is the lightness}
			// {Next calculate saturation}
			
			if(Max == Min)
			{
				// begin {Acrhomatic case}
			    ret.Saturation = 0;
			    ret.Hue = 0;
			    // end {Acrhomatic case}	
			}
			else
			{
                // begin {Chromatic case}
			    // {First calculate the saturation.}
                if(ret.Lightness <= 0.5)
			         ret.Saturation = (Max - Min) / (Max + Min);
			    else
			         ret.Saturation = (Max - Min) / (2 - Max - Min);
			    // {Next calculate the hue.}
			    delta = Max - Min;
			    if(rR == Max)
					ret.Hue = (rG - rB) / delta;		//{Resulting color is between yellow and magenta}
			    else if(rG == Max)
					ret.Hue = 2 + (rB - rR) / delta;	// {Resulting color is between cyan and yellow}
				else if(rB == Max)
					ret.Hue = 4 + (rR - rG) / delta;	// {Resulting color is between magenta and cyan}
			}
			return ret;
		}

		public static HLSColor RGBToHSL(RGBColor clr)
		{
			return RGBToHSL(clr.Red,clr.Green,clr.Blue);
		}

		private static double Maximum(double rR, double rG, double rB)
		{
			double ret=0;
			if(rR > rG)
			{			
			   if(rR > rB)
			      ret = rR;
			   else
			      ret = rB;
			}
			else
			{
			   if(rB > rG)
			      ret = rB;
			   else
			      ret = rG;
			}
			return ret;
		}

		private static double Minimum(double rR, double rG, double rB)
		{
			double ret=0;
			if(rR < rG)
			{
			   if(rR < rB)
			      ret = rR;
			   else
			      ret = rB;
			}
			else
			{
			   if(rB < rG)
			      ret = rB;
			   else
			      ret = rG;
			}
			return ret;
		}

		public static RGBColor HLSToRGB(double Hue, double Lightness, double Saturation)
		{
			double rR, rG, rB;
			double Min, Max;
			RGBColor ret=new RGBColor();

			if(Saturation == 0)
			{
				// Achromatic case:
				rR = Lightness;
                rG = Lightness;
				rB = Lightness;	
			}
			else
			{
                // Chromatic case:
                // delta = Max-Min
				if(Lightness <= 0.5)
				{
					Min = Lightness * (1 - Saturation);
				}
				else
				{
					Min = Lightness - Saturation * (1 - Lightness);
				}
				// Get the Max value:
				Max = 2 * Lightness - Min;
		      
				// Now depending on sector we can evaluate the h,l,s:
				if(Hue < 1)
				{
                    rR = Max;
					if(Hue < 0)
					{
						rG = Min;
						rB = rG - Hue * (Max - Min);
					}
					else
					{
						rB = Min;
						rG = Hue * (Max - Min) + rB;
					}
				}
				else if (Hue < 3)
				{
					rG = Max;
					if(Hue < 2)
					{
						rB = Min;
						rR = rB - (Hue - 2) * (Max - Min);
					}
					else
					{
						rR = Min;
						rB = (Hue - 2) * (Max - Min) + rR;
					}
				}
				else
				{
					rB = Max;
					if(Hue < 4)
					{
						rR = Min;
						rG = rR - (Hue - 4) * (Max - Min);
					}
					else
					{
					   rG = Min;
					   rR = (Hue - 4) * (Max - Min) + rG;
					}
				}
			}
			ret.Red = (int)(rR * 255);
			ret.Green = (int)(rG * 255);
			ret.Blue = (int)(rB * 255);
			if(ret.Red>255)
				ret.Red=255;
			if(ret.Green>255)
				ret.Green=255;
			if(ret.Blue>255)
				ret.Blue=255;
			return ret;
		}

		public static RGBColor HLSToRGB(HLSColor clr)
		{
			return HLSToRGB(clr.Hue,clr.Lightness,clr.Saturation);
		}

		public static System.Drawing.Color HoverBackColor()
		{
			return m_HoverBackColor;
		}

		public static System.Drawing.Color HoverBackColor2()
		{
			return m_HoverBackColor2;
		}

		public static System.Drawing.Color HoverBackColor3()
		{
			return m_HoverBackColor3;
		}

		public static System.Drawing.Color HoverBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(HoverBackColor());
		}

		public static System.Drawing.Color PressedBackColor()
		{
			return m_PressedBackColor;
		}

		public static System.Drawing.Color PressedBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(PressedBackColor());
		}

		public static System.Drawing.Color CheckBoxBackColor()
		{
			return m_CheckBoxBackColor;
		}

		public static System.Drawing.Color CheckBoxBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(CheckBoxBackColor());
		}

		public static System.Drawing.Color ToolMenuFocusBackColor()
		{
			return m_ToolMenuFocusBackColor;
		}

		public static System.Drawing.Color RecentlyUsedOfficeBackColor()
		{
			return m_RecentlyUsedOfficeBackColor;
		}

		public static System.Drawing.Color RecentlyUsedOfficeBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(RecentlyUsedOfficeBackColor());
		}

		public static System.Drawing.Color SideRecentlyBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(SideRecentlyBackColor());
		}

		public static System.Drawing.Color SideRecentlyBackColor()
		{
			return m_SideRecentlyBackColor;
		}

		public static System.Drawing.Color ToolMenuFocusBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(ToolMenuFocusBackColor());
		}

		public static System.Drawing.Color MenuFocusBorderColor()
		{
			return m_MenuFocusBorderColor;
		}

		public static System.Drawing.Color MenuFocusBorderColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(MenuFocusBorderColor());
		}

		public static System.Drawing.Color MenuBackColor()
		{
			return m_MenuBackColor;
		}

		public static System.Drawing.Color MenuBackColor(System.Drawing.Graphics g)
		{
			return g.GetNearestColor(MenuBackColor());
		}

		public static System.Drawing.TextureBrush GetPushedBrush()
		{
			if(m_PushedBrushBmp==null)
			{
				m_PushedBrushBmp=new System.Drawing.Bitmap(2,2);
				m_PushedBrushBmp.SetPixel(0,0,System.Drawing.SystemColors.Control);
				m_PushedBrushBmp.SetPixel(1,0,System.Drawing.SystemColors.ControlLightLight);
				m_PushedBrushBmp.SetPixel(0,1,System.Drawing.SystemColors.ControlLightLight);
				m_PushedBrushBmp.SetPixel(1,1,System.Drawing.SystemColors.Control);
			}
			return (new System.Drawing.TextureBrush(m_PushedBrushBmp));
		}

		public static bool ThemedOS
		{
			get{return m_ThemedOS;}
			set{m_ThemedOS=value;}
		}

		public static eWinXPColorScheme WinXPColorScheme
		{
			get
			{
				eWinXPColorScheme c=eWinXPColorScheme.Undetermined;
				if(ThemedOS && ColorDepth>=16)
				{
					if(SystemColors.Control.ToArgb()==Color.FromArgb(236,233,216).ToArgb() && SystemColors.Highlight.ToArgb()==Color.FromArgb(49,106,197).ToArgb())
						c=eWinXPColorScheme.Blue;
					else if(SystemColors.Control.ToArgb()==Color.FromArgb(224,223,227).ToArgb() && SystemColors.Highlight.ToArgb()==Color.FromArgb(178,180,191).ToArgb())
						c=eWinXPColorScheme.Silver;
					else if(SystemColors.Control.ToArgb()==Color.FromArgb(236,233,216).ToArgb() && SystemColors.Highlight.ToArgb()==Color.FromArgb(147,160,112).ToArgb())
						c=eWinXPColorScheme.OliveGreen;
				}

				return c;
			}
		}

		public static int ColorDepth=0;

		internal static void OnDisplayChange()
		{
			int hdc = CreateDC("DISPLAY", 0, 0, 0);
			ColorDepth = GetDeviceCaps(hdc, BITSPIXEL);
			DeleteDC(hdc);
		}
    }
}