using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

// Simple screen saver, using code from Computer Shopper April 07 pp186-189

namespace BasicScreenSaver
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		private System.ComponentModel.IContainer components;
		private System.Windows.Forms.Timer timer1;
		private string[] m_args;

		private Point m_textPos = new Point( 0, 0 );
		private Point m_textVelocity = new Point( 1, 1 );
		private Point m_mousePos;
		private IntPtr m_hwnd;

		// This is all so we can use Windows API calls... but seems an immensely ugly way to do it?
		public struct RECT
		{
			public int Left;
			public int Top;
			public int Right;
			public int Bottom;
		}

		[DllImport("user32.dll")]
			static extern bool GetClientRect( IntPtr hWnd, out RECT lpRect );

		[DllImport("user32.dll", SetLastError = true )]
			static extern int GetWindowLong( IntPtr hWnd, int nIndex );

		const int GWL_style = (-16);
		const int WS_CHILD = 0x40000000;

		[DllImport("user32.dll")]
			static extern IntPtr SetWindowLong( IntPtr hWnd, int nIndex, int dwNewLong );

		[DllImport("user32.dll")]
			static extern IntPtr SetParent( IntPtr hWndChild, IntPtr hwndNewParent );

		const int GWL_HWNDPARENT = (-8);

		[DllImport("user32.dll")]
			static extern bool SetWindowPos( IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags );

		static readonly IntPtr HWND_TOP = new IntPtr(0);

		const UInt32 SWP_NOZORDER = 0x0004;
		const UInt32 SWP_NOACTIVATE = 0x0010;
		const UInt32 SWP_SHOWWINDOW = 0x0040;

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.components = new System.ComponentModel.Container();
			this.timer1 = new System.Windows.Forms.Timer(this.components);
			// 
			// timer1
			// 
			this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(292, 266);
			this.Name = "Form1";
			this.Text = "Form1";
			this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.OnMouseEvent);
			this.Load += new System.EventHandler(this.Form1_Load);
			this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.OnMouseEvent);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main( string[] args ) 
		{
			Application.Run( new Form1( args ) );
		}

		// Parameterized constructor, to receive command line parameters from Main
		public Form1( string[] args )
		{
			InitializeComponent();
			m_args = args;
			this.TopLevel = false;	// Set invisible (can't use Hide or Visible = False)
		}

		private void Form1_Load( object sender, EventArgs e )
		{
			if ( m_args.Length > 0 )
			{
				string arg = m_args[0].ToLower().Trim().Substring( 0, 2 );

				switch ( arg )
				{
					case "/c":
						// TODO configure screen saver
						break;

					case "/s":
						ShowScreenSaver();
						break;

					case "/p":
						if ( m_args.Length > 1 )
						{
							this.TopLevel = false;
							m_hwnd = (IntPtr)Int32.Parse( m_args[1] );
							ShowScreenSaver();
						}
						break;
				}
			}
			else
			{
				ShowScreenSaver();
			}
		}

		void ShowScreenSaver()
		{
			// Are we previewing or running for real?
			if ( this.m_hwnd == IntPtr.Zero )
			{
				//this.DoubleBuffered = true;	// ???
				this.timer1.Interval = 20;
				this.timer1.Enabled = true;

				this.FormBorderstyle = FormBorderstyle.None;
				this.TopLevel = true;
				this.WindowState = FormWindowState.Maximized;
				this.Capture = true;
				Cursor.Hide();
			}
			else
			{
				// This is a child window
				int style = GetWindowLong( this.Handle, GWL_style );
				style = style | WS_CHILD;
				SetWindowLong( this.Handle, GWL_style, style );

				// Its parent is the preview window
				SetParent( this.Handle, m_hwnd );
				SetWindowLong( this.Handle, GWL_HWNDPARENT, (int)m_hwnd );

				// Draw within the parent window
				this.FormBorderstyle = FormBorderstyle.None;
				RECT r = new RECT();
				GetClientRect( m_hwnd, out r );

				SetWindowPos( this.Handle, HWND_TOP, 0, 0, r.Right, r.Bottom, SWP_NOZORDER | SWP_NOACTIVATE | SWP_SHOWWINDOW );
			}
		}

		private void timer1_Tick( object sender, EventArgs e )
		{
			Graphics g = this.CreateGraphics();
			RectangleF bounds = this.ClientRectangle;

			//string displayMessage = "Some String";
			int fontSize = (int)bounds.Height / 20;

			FontFamily fontFamily = new FontFamily( "Arial" );
			Font font = new Font( fontFamily, fontSize, Fontstyle.Regular, GraphicsUnit.Pixel );

			// TODO determine text size - not sure how to do this in .NET 1.1

			m_textPos.X += m_textVelocity.X;
			m_textPos.Y += m_textVelocity.Y;

			if ( m_textPos.X > bounds.Width || m_textPos.X <= 0 )	// XXX slightly different
			{
				m_textVelocity.X *= -1;
			}
			
			if ( m_textPos.Y > bounds.Height || m_textPos.Y <= 0 )	// XXX slightly different
			{
				m_textVelocity.Y *= -1;
			}

			// TODO draw the text - not sure how to do this in .NET 1.1
		}

		private void OnMouseEvent( object sender, System.Windows.Forms.MouseEventArgs e )
		{
			if ( !m_mousePos.IsEmpty )
			{
				if ( m_mousePos != new Point( e.X, e.Y ) )
				{
					this.Close();
				}

				if ( e.Clicks > 0 )
				{
					this.Close();
				}
			}

			m_mousePos = new Point( e.X, e.Y );

			// TODO trap keyboard events as well
		}

	}
}