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

namespace MsdnMag
{
	// *****************************************************************
	// Buttons combination
	public enum MyMessageBoxButtons 
	{
		OK = 0,
		OKCancel = 1,
		AbortRetryIgnore = 2,
		YesNoCancel = 3,
		YesNo = 4,
		RetryCancel = 5,
		YesNoAllCancel = 6		// NEW
	}
	// *****************************************************************

	public class MessageBox  
	{
		// *****************************************************************
		// Properties
		protected LocalCbtHook m_cbt;
		protected IntPtr m_handle = IntPtr.Zero;
		protected bool m_alreadySetup = false;
		// *****************************************************************

		// *****************************************************************
		public MessageBox()
		{
			m_cbt = new LocalCbtHook();
			m_cbt.WindowCreated += new LocalCbtHook.CbtEventHandler(WndCreated);
			m_cbt.WindowDestroyed += new LocalCbtHook.CbtEventHandler(WndDestroyed);
			m_cbt.WindowActivated += new LocalCbtHook.CbtEventHandler(WndActivated);
		}
		// *****************************************************************

		// *****************************************************************
		// PROPERTY IconFile
		private string m_iconFile = "";
		public string IconFile
		{
			get {return m_iconFile;}
			set {m_iconFile=value; m_iconIndex=0;}
		}
		// *****************************************************************

		// *****************************************************************
		// PROPERTY YesAllNoCancel
		public bool YesAllNoCancel = false;
		private const int IDALL = 9;			// same as IDHELP in the Win32 API
		private const int MB_HELP = 0x00004000;
		// *****************************************************************

		// *****************************************************************
		// PROPERTY IconIndex
		private int m_iconIndex = 0;
		public int IconIndex
		{
			get {return m_iconIndex;}
			set {m_iconIndex=value;}
		}
		// *****************************************************************

		// *****************************************************************
		// Show  
		public DialogResult Show(string text, string title, MessageBoxButtons buttons, MessageBoxIcon icon)
		{
			// If a custom icon is requested, ensure the window leaves room for 
			// the icon... Add a fake icon
			if (IconFile.Length > 0 && icon == MessageBoxIcon.None)
				icon = MessageBoxIcon.Information;
			else
				IconFile = "";


			// Apply the changes needed if 4 buttons are required
			if (YesAllNoCancel)
			{
				m_cbt.Install();
				buttons = MessageBoxButtons.YesNoCancel;
				// Must use MessageBox API because of the 4th button
				int res = _MessageBox(GetActiveWindow(), text, title, 
					(int) (buttons + (int) icon + MB_HELP));
				m_cbt.Uninstall();
				return (DialogResult) res;
			}

			// Go the default way
			m_cbt.Install();
			DialogResult dr = System.Windows.Forms.MessageBox.Show(text, title, buttons, icon);
			m_cbt.Uninstall();
			return dr;
		}
		public DialogResult Show(string text, string title, MessageBoxButtons buttons)
		{
			return Show(text, title, buttons, MessageBoxIcon.None);
		}
		public DialogResult Show(string text, string title)
		{
			return Show(text, title, MessageBoxButtons.OK, MessageBoxIcon.None);
		}
		public DialogResult Show(string text)
		{
			return Show(text, "", MessageBoxButtons.OK, MessageBoxIcon.None);
		}
		// *****************************************************************

		// *****************************************************************
		// WndCreated event handler
		private void WndCreated(object sender, CbtEventArgs e)
		{
			if (e.IsDialogWindow)
			{
				m_alreadySetup = false;
				Console.WriteLine("MessageBox created"); 
				m_handle = e.Handle;
			}
		}
		// *****************************************************************

		// *****************************************************************
		// WndDestroyed event handler
		private void WndDestroyed(object sender, CbtEventArgs e)
		{
			if (e.Handle == m_handle)
			{
				m_alreadySetup = false;
				m_handle = IntPtr.Zero;
			}
		}
		// *****************************************************************

		// *****************************************************************
		// WndActivated event handler
		private void WndActivated(object sender, CbtEventArgs e)
		{
			if (m_handle != e.Handle)
				return;

			// Not the first time
			if (m_alreadySetup)
			{
				Console.WriteLine("(Already configured. Not the first time it is activated!)");
				return;
			}
			else
				m_alreadySetup = true;


			//
			// Modify the MessageBox window
			//
			Console.WriteLine("MessageBox activated"); 

	
			// Replace the icon (0x0014 is the ID of the icon window)
			if (m_iconFile.Length >0)
			{
				IntPtr hwndIcon = GetDlgItem(m_handle, 0x0014);
				IntPtr hIcon = ExtractIcon(IntPtr.Zero, m_iconFile, m_iconIndex);
				SendMessage(hwndIcon, STM_SETICON, hIcon, IntPtr.Zero); 
			}

			// Get the static window with the text and the text
			IntPtr hwndText = GetDlgItem(m_handle, 0xFFFF);
			StringBuilder sb = new StringBuilder();
			sb.Capacity = 256;
			GetWindowText(hwndText, sb, 256);
			string text = sb.ToString();

			// Get the window position
			RECT rc = new RECT();
			GetWindowRect(hwndText, rc);
			POINT pt = new POINT();
			pt.x = rc.left;
			pt.y = rc.top;
			ScreenToClient(m_handle, pt);
			
			// Create the alternate EDIT window
			IntPtr m_edit = CreateWindowEx(0, "edit", "", ES_READONLY|ES_MULTILINE|WS_CHILD|WS_VISIBLE, 
				pt.x, pt.y, rc.right-rc.left, rc.bottom-rc.top,
				m_handle, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);

			// Set font and text
			IntPtr hFont = SendMessage(hwndText, WM_GETFONT, IntPtr.Zero, IntPtr.Zero);			
			SendMessage(m_edit, WM_SETFONT, hFont, new IntPtr(1));			
			SetWindowText(m_edit, text); 

			// Copy the displayed text to the clipboard
			Clipboard.SetDataObject(text);

			// Finalizing...
			DestroyWindow(hwndText);



			// Yes-All-No-Cancel setup
			// Map the YES-NO-CANCEL-HELP sequence to YES-OK-NO-CANCEL 
			// The mapping has two steps: button text and button ID
			// No need to change the Yes button

			// Map button text
			SetWindowText(GetDlgItem(m_handle,(int) DialogResult.No), "OK to All");
			SetWindowText(GetDlgItem(m_handle,(int) DialogResult.Cancel), DialogResult.No.ToString());
			SetWindowText(GetDlgItem(m_handle,IDALL), DialogResult.Cancel.ToString());
			
			// Map button IDs
			SetWindowLong(GetDlgItem(m_handle,(int) DialogResult.No), GWL_ID, (int)DialogResult.OK);
			SetWindowLong(GetDlgItem(m_handle,(int) DialogResult.Cancel), GWL_ID, (int) DialogResult.No);
			SetWindowLong(GetDlgItem(m_handle,IDALL), GWL_ID, (int) DialogResult.Cancel);
		}
		// *****************************************************************

		#region Win32 Imports
		private const int ES_READONLY  = 0x00000800;
		private const int ES_MULTILINE = 0x00000004;
		private const int WS_VISIBLE   = 0x10000000;
		private const int WS_CHILD     = 0x40000000;
		private const int WM_SETFONT   = 0x00000030;
		private const int WM_GETFONT   = 0x00000031;
		private const int STM_SETICON  = 0x00000170;

		// ************************************************************************
		// Win32: GetClassName
		[DllImport("user32.dll")]
		protected static extern int GetClassName(IntPtr hwnd,
			StringBuilder lpClassName, int nMaxCount);
		// ************************************************************************

		// ************************************************************************
		// Win32: GetDlgItem
		[DllImport("user32.dll")]
		protected static extern IntPtr GetDlgItem(IntPtr hwnd, int id);
		// ************************************************************************

		// ************************************************************************
		// Win32: GetWindowText
		[DllImport("user32.dll")]
		protected static extern int GetWindowText(IntPtr hwnd,
			StringBuilder lpString, int nMaxCount);
		// ************************************************************************

		// ************************************************************************
		// Win32: SetWindowText
		[DllImport("user32.dll")]
		protected static extern bool SetWindowText(IntPtr hwnd, string text); 
		// ************************************************************************

		// ************************************************************************
		// Win32: GetWindowRect
		[DllImport("user32.dll")]
		protected static extern int GetWindowRect(IntPtr hwnd, RECT rc);
		// ************************************************************************

		// ************************************************************************
		// Win32: ScreenToClient
		[DllImport("user32.dll")]
		protected static extern int ScreenToClient(IntPtr hwnd, POINT pt);
		// ************************************************************************

		// ************************************************************************
		// Win32: SetWindowLong
		protected const int GWL_ID = -12;
		[DllImport("user32.dll")]
		protected static extern int SetWindowLong(IntPtr hwnd,
			int index, int newValue);
		// ************************************************************************

		// ************************************************************************
		// Win32: ExtractIcon
		[DllImport("shell32.dll")]
		protected static extern IntPtr ExtractIcon(
			IntPtr hInst,          // instance handle
			string lpszExeFileName,  // file name
			int nIconIndex           // icon index
			);
		// ************************************************************************

		// ************************************************************************
		// Win32: DestroyWindow
		[DllImport("user32.dll")]
		protected static extern void DestroyWindow(IntPtr hwnd);
		// ************************************************************************

		// ************************************************************************
		// Win32: MessageBox
		[DllImport("user32.dll", EntryPoint="MessageBox")]
		protected static extern int _MessageBox(IntPtr hwnd, string text, string caption,
			int options);
		// ************************************************************************

		// ************************************************************************
		// Win32: SendMessage
		[DllImport("user32.dll")]
		protected static extern IntPtr SendMessage(IntPtr hwnd, 
			int msg, IntPtr wParam, IntPtr lParam);
		// ************************************************************************

		// ************************************************************************
		// Win32: GetActiveWindow
		[DllImport("user32.dll")]
		protected static extern IntPtr GetActiveWindow();
		// ************************************************************************

		// ************************************************************************
		// Win32: CreateWindowEx
		[DllImport("user32.dll")]
		protected static extern IntPtr CreateWindowEx(
			int dwExStyle,			// extended window style
			string lpClassName,		// registered class name
			string lpWindowName,	// window name
			int dwStyle,			// window style
			int x,					// horizontal position of window
			int y,					// vertical position of window
			int nWidth,				// window width
			int nHeight,			// window height
			IntPtr hWndParent,      // handle to parent or owner window
			IntPtr hMenu,			// menu handle or child identifier
			IntPtr hInstance,		// handle to application instance
			IntPtr lpParam			// window-creation data
		);
		// ************************************************************************

		// ************************************************************************
		// POINT
		[StructLayout(LayoutKind.Sequential)]
		public class POINT
		{ 
			public int x;
			public int y;
		}
		// ************************************************************************

		// ************************************************************************
		// RECT
		[StructLayout(LayoutKind.Sequential)]
		public class RECT
		{ 
			public int left; 
			public int top; 
			public int right; 
			public int bottom; 
		}
		// ************************************************************************

		#endregion
	}
}