using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;


namespace Marker
{
	public partial class FormMain : Form
	{
		static readonly string progver = "0.10 beta";


		static bool helprequested = false;
		static Color ringcolor = Color.Red;
		static int ringthickness = 10;
		static int rotation = 0;
		static int windowheight;
		static int windowwidth;
		static int initialheight;
		static int initialwidth;


		public FormMain( )
		{
			InitializeComponent( );
			this.FormBorderStyle = FormBorderStyle.None;
			this.DoubleBuffered = true;
			this.SetStyle( ControlStyles.ResizeRedraw, true );
		}


		private void DrawEllipse( )
		{
			Application.DoEvents( );
			Pen pen = new Pen( ringcolor, (float)ringthickness );
			Graphics graphics = this.CreateGraphics( );
			if ( rotation == 0 )
			{
				graphics.DrawEllipse( pen, new Rectangle( ringthickness, ringthickness, windowwidth - 2 * ringthickness, windowheight - 2 * ringthickness ) );
			}
			else
			{
				// Though the following code DOES produce a rotated ellipse,
				// I haven't managed to make it fit within the window yet.

				// Set world transform of graphics object to translate.
				graphics.TranslateTransform( 100.0F, 0.0F );
				// Then to rotate, prepending rotation matrix.
				graphics.RotateTransform( (float)rotation );
				this.Size = new Size( Math.Max( initialwidth, initialheight ), Math.Max( initialwidth, initialheight ) );
				graphics.DrawEllipse( pen, new Rectangle( ringthickness, ringthickness, initialwidth - 2 * ringthickness, initialheight - 2 * ringthickness ) );
			}
			pen.Dispose( );
			graphics.Dispose( );
		}


		private void FormMain_FormClosing( object sender, FormClosingEventArgs e )
		{
			if ( helprequested )
			{
				ShowHelp( true );
			}
		}


		private void FormMain_KeyUp( object sender, KeyEventArgs e )
		{
			if ( e.KeyCode == Keys.Escape )
			{
				Application.Exit( );
			}
			if ( e.KeyCode == Keys.F1 )
			{
				ShowHelp( );
			}
		}


		private void FormMain_Load( object sender, EventArgs e )
		{
			windowwidth = this.ClientRectangle.Width;
			windowheight = this.ClientRectangle.Height;
			initialheight = windowheight;
			initialwidth = windowwidth;
			string commandline = Environment.CommandLine;
			if ( commandline.Contains( "/?" ) )
			{
				ShowHelp( true );
				Application.Exit( );
			}
			if ( commandline.ToUpper( ).Contains( "/C:" ) )
			{
				string test = commandline.Substring( commandline.IndexOf( "/C:", StringComparison.OrdinalIgnoreCase ) + 3 );
				test = test.Split( ' ' )[0];
				ringcolor = Color.FromName( test );
			}
			if ( commandline.ToUpper( ).Contains( "/H:" ) )
			{
				string test = commandline.Substring( commandline.IndexOf( "/H:", StringComparison.OrdinalIgnoreCase ) + 3 );
				test = test.Split( ' ' )[0];
				if ( !int.TryParse( test, out windowheight ) )
				{
					windowheight = this.ClientRectangle.Height;
				}
			}
			/*
			if ( commandline.ToUpper( ).Contains( "/R:" ) )
			{
				string test = commandline.Substring( commandline.IndexOf( "/R:", StringComparison.OrdinalIgnoreCase ) + 3 );
				test = test.Split( ' ' )[0];
				if ( !int.TryParse( test, out rotation ) )
				{
					rotation = 0;
				}
			}
			*/
			if ( commandline.ToUpper( ).Contains( "/T:" ) )
			{
				string test = commandline.Substring( commandline.IndexOf( "/T:", StringComparison.OrdinalIgnoreCase ) + 3 );
				test = test.Split( ' ' )[0];
				if ( !int.TryParse( test, out ringthickness ) )
				{
					ringthickness = 10;
				}
			}
			if ( commandline.ToUpper( ).Contains( "/W:" ) )
			{
				string test = commandline.Substring( commandline.IndexOf( "/W:", StringComparison.OrdinalIgnoreCase ) + 3 );
				test = test.Split( ' ' )[0];
				if ( !int.TryParse( test, out windowwidth ) )
				{
					windowwidth = this.ClientRectangle.Width;
				}
			}
		}


		private void FormMain_Resize( object sender, EventArgs e )
		{
			windowheight = this.ClientRectangle.Height;
			windowwidth = this.ClientRectangle.Width;
			DrawEllipse( );
		}


		private void FormMain_Shown( object sender, EventArgs e )
		{
			DrawEllipse( );
		}


		private void FormMain_SizeChanged( object sender, EventArgs e )
		{
			windowheight = this.ClientRectangle.Height;
			windowwidth = this.ClientRectangle.Width;
			DrawEllipse( );
		}


		private static int ShowHelp( bool cli = false )
		{
			string message = string.Format( "Marker.exe,  Version {0}\n", progver );
			message += "Show a resizable elliptic ring with transparent background on screen\n\n";
			message += "Usage:  \tMarker\t[ options ]\n\n";
			message += "Options:\t      \t/?\t\tdisplay this help and exit\n";
			message += "        \t      \t/C:color    \tdefault Red\n";
			message += "        \t      \t/H:height   \tdefault 450\n";
			//message += "        \t      \t/R:rotation \tdefault 0\n";
			message += "        \t      \t/T:thickness\tdefault 10\n";
			message += "        \t      \t/W:width    \tdefault 800\n\n";
			message += "The ellipse can be resized bij \"grabbing\" its border at top center,\n";
			message += "bottom center, middle left or middle right.\n";
			message += "The ellipse can be moved by \"grabbing\" its border anywhere else.\n\n";
			message += "Keys:   \tPress F1 to display this help text, or Escape to exit.\n\n";
			message += "Credits:\tMake transparent window resizable by\n";
			message += "        \tuser1306322 on StackOverflow.com:\n";
			message += "        \thttps://stackoverflow.com/a/32261547\n";
			message += "        \tMake transparent window moveable by\n";
			message += "        \tFreewareFire on CodeProject.com\n";
			message += "        \thttps://www.codeproject.com/KB/cs/csharpmovewindow.aspx\n";
			message += "        \tOutput to parent console by Timm:\n";
			message += "        \tcsharp411.com/console-output-from-winforms-application/\n\n";
			message += "Written by Rob van der Woude\n";
			message += "https://www.robvanderwoude.com\n";
			if ( cli )
			{
				Console.Error.WriteLine( message );
				Environment.Exit( -1 );
				Application.Exit( );
			}
			else
			{
				helprequested = true;
				MessageBox.Show( message, "Help for Marker.exe, \u00A0 Version " + progver );
			}
			return -1;
		}


		#region Make Window Moveable

		// Code to allow dragging the window
		// by FreewareFire on CodeProject.com
		// https://www.codeproject.com/KB/cs/csharpmovewindow.aspx
		public const int WM_NCLBUTTONDOWN = 0xA1;
		public const int HT_CAPTION = 0x2;

		[DllImport( "user32.dll" )]
		public static extern int SendMessage( IntPtr hWnd, int Msg, int wParam, int lParam );

		[DllImport( "user32.dll" )]
		public static extern bool ReleaseCapture( );

		private void FormMain_MouseDown( object sender, MouseEventArgs e )
		{
			if ( e.Button == MouseButtons.Left )
			{
				ReleaseCapture( );
				SendMessage( Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0 );
			}
		}

		#endregion Make Window Moveable


		#region Make Window Resizable

		// Code to make borderless window resizable
		// by user1306322 on StackOverflow.com
		// https://stackoverflow.com/a/32261547
		private const int
			HTLEFT = 10,
			HTRIGHT = 11,
			HTTOP = 12,
			HTTOPLEFT = 13,
			HTTOPRIGHT = 14,
			HTBOTTOM = 15,
			HTBOTTOMLEFT = 16,
			HTBOTTOMRIGHT = 17;

		const int _ = 10; // you can rename this variable if you like

		Rectangle Top
		{
			get
			{
				return new Rectangle( 0, 0, this.ClientSize.Width, _ );
			}
		}

		Rectangle Left
		{
			get
			{
				return new Rectangle( 0, 0, _, this.ClientSize.Height );
			}
		}

		Rectangle Bottom
		{
			get
			{
				return new Rectangle( 0, this.ClientSize.Height - _, this.ClientSize.Width, _ );
			}
		}

		Rectangle Right
		{
			get
			{
				return new Rectangle( this.ClientSize.Width - _, 0, _, this.ClientSize.Height );
			}
		}

		Rectangle TopLeft
		{
			get
			{
				return new Rectangle( 0, 0, _, _ );
			}
		}

		Rectangle TopRight
		{
			get
			{
				return new Rectangle( this.ClientSize.Width - _, 0, _, _ );
			}
		}

		Rectangle BottomLeft
		{
			get
			{
				return new Rectangle( 0, this.ClientSize.Height - _, _, _ );
			}
		}

		Rectangle BottomRight
		{
			get
			{
				return new Rectangle( this.ClientSize.Width - _, this.ClientSize.Height - _, _, _ );
			}
		}


		protected override void WndProc( ref Message message )
		{
			base.WndProc( ref message );

			if ( message.Msg == 0x84 ) // WM_NCHITTEST
			{
				var cursor = this.PointToClient( Cursor.Position );

				if ( TopLeft.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTTOPLEFT;
				}
				else if ( TopRight.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTTOPRIGHT;
				}
				else if ( BottomLeft.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTBOTTOMLEFT;
				}
				else if ( BottomRight.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTBOTTOMRIGHT;
				}
				else if ( Top.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTTOP;
				}
				else if ( Left.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTLEFT;
				}
				else if ( Right.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTRIGHT;
				}
				else if ( Bottom.Contains( cursor ) )
				{
					message.Result = (IntPtr)HTBOTTOM;
				}
			}
		}

		#endregion Make Window Resizable
	}
}