using System;
using System.Collections.Generic;
#if DEBUG
using System.Diagnostics;
#endif // #if DEBUG
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices; 
using System.Text;
using System.Windows.Controls;
using System.Windows;
using System.Windows.Interop;

namespace BroccoliProducts
{

	/// <summary>
	/// Declaration of TrayIcon class
	/// </summary>
	public class TrayIcon : IDisposable
	{

		/////////////////////////////////////////////////////////////
		#region Imports - Constants, Structures and Functions

		const int NIM_ADD = 0x00;
		const int NIM_MODIFY = 0x01;
		const int NIM_DELETE = 0x02;

		const int NIF_MESSAGE = 0x01;
		const int NIF_ICON = 0x02;
		const int NIF_TIP = 0x04;

		const int ID_TRAY_APP_ICON = 5000;
		const int ID_TRAY_EXIT_CONTEXT_MENU_ITEM = 3000;
		const int WM_USER = 0x0400;
		const int WM_TRAYICON = (WM_USER + 1);

		const int WM_LBUTTONDOWN = 0x0201;
		const int WM_LBUTTONUP = 0x0202;
		const int WM_LBUTTONDBLCLK = 0x0203;

		[StructLayout(LayoutKind.Sequential)]
		public struct NOTIFYICONDATA
		{
			public System.Int32 cbSize; // DWORD
			public System.IntPtr hWnd; // HWND
			public System.Int32 uID; // UINT
			public UInt32 uFlags; // UINT
			public System.Int32 uCallbackMessage; // UINT
			public System.IntPtr hIcon; // HICON
			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
			public System.String szTip; // char[128]
			public System.Int32 dwState; // DWORD
			public System.Int32 dwStateMask; // DWORD
			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
			public System.String szInfo; // char[256]
			public System.Int32 uTimeoutOrVersion; // UINT
			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)]
			public System.String szInfoTitle; // char[64]
			public System.Int32 dwInfoFlags; // DWORD
		}

		[DllImport("shell32.dll")]
		static extern bool Shell_NotifyIcon( uint dwMessage, [In] ref NOTIFYICONDATA pnid );

		#endregion Imports - Constants, Structures and Functions

		/////////////////////////////////////////////////////////////
		// Events and Delegates

		public event EventHandler LeftDoubleClick;

		/////////////////////////////////////////////////////////////
		// Attributes

		// The system-level notify-icon structure
		private NOTIFYICONDATA m_notifyIconData;

		// Retain the last icon that was set
		private Icon m_currentTrayIcon;

		// The main window of the application
		private Window m_mainWindow;

		// A hook into the main window so
		// we can find out when the icon was clicked
		private HookWrapper m_hook;

		// Is the icon visible, or not
		private bool m_bIsIconVisible = false;
		public bool IsIconVisible
		{
			get { return m_bIsIconVisible; }
		}

		// Is this item disposed?
		private bool m_bDisposed = false;

		/////////////////////////////////////////////////////////////
		// Construction

		public TrayIcon( Window mainWindow )
		{

			// Initialize member variables
			m_mainWindow = mainWindow;

			// Get handle of application window
			WindowInteropHelper helper = new WindowInteropHelper(mainWindow);
#if DEBUG
			Debug.Assert(helper != null);
#endif // #if DEBUG
			IntPtr hMainWindow = helper.Handle;
#if DEBUG
			Debug.Assert(hMainWindow != IntPtr.Zero);
#endif // #if DEBUG

			// Construct the notify icon data structure
			m_notifyIconData = new NOTIFYICONDATA();
			m_notifyIconData.cbSize = Marshal.SizeOf(m_notifyIconData);
			m_notifyIconData.hWnd = hMainWindow;
			m_notifyIconData.uID = ID_TRAY_APP_ICON;
			m_notifyIconData.uFlags = NIF_MESSAGE;
			m_notifyIconData.uCallbackMessage = WM_TRAYICON;

		}

		~TrayIcon()
		{
			Dispose(false);
		}

		/////////////////////////////////////////////////////////////
		// Implementation of IDisposable interface

		public void Dispose()
		{
			Dispose(true);
			GC.SuppressFinalize(this);
		}

		protected virtual void Dispose(bool disposing)
		{

			// Check to see if Dispose has already been called
			if (!this.m_bDisposed)
			{

				// Update member flag
				m_bDisposed = true;

				// If disposing equals true, dispose all managed and unmanaged resources.
				if (disposing)
				{

					// Dispose of managed resources
					m_hook.Dispose();

				}

				// Dispose of un-managed resources
				if (m_bIsIconVisible)
					this.Hide();

			}

		}

		/////////////////////////////////////////////////////////////
		// Operations

		public void Show( Icon trayIcon, string strTip )
		{

			// SHOW THE TRAY ICON

			// Shortcuts
			if (m_bIsIconVisible)
			{
#if DEBUG
				Debug.Assert(false);
#endif // #if DEBUG
				return;
			}

			// Retain the current icon
			m_currentTrayIcon = trayIcon;

			// Prep the notify-icon structure
			_prepStructure_Icon(trayIcon);
			_prepStructure_Tip(strTip);

			// Add the icon to the tray with a system-level call
			if (Shell_NotifyIcon(NIM_ADD, ref m_notifyIconData))
			{

				// Track the visiblity
				m_bIsIconVisible = true;

				// Hook the window for icon
				// Set filter so only find out about WM_TRAYICON messages
				m_hook = new HookWrapper( m_mainWindow, _fnHookCallback, WM_TRAYICON );

			}
#if DEBUG
			else
				Debug.Assert(false);
#endif // #if DEBUG

		}

		public void SetTip(string strTip)
		{

			// UPDATE THE TOOLTIP FOR THE ICON

			// shortcuts
			if (!m_bIsIconVisible)
			{
#if DEBUG
				Debug.Assert(false);
#endif // #if DEBUG
				return;
			}

			// Prep the structure (keep the current icon)
			_prepStructure_Icon(m_currentTrayIcon);
			_prepStructure_Tip(strTip);

			// Modify the icon with a system call
			if (!Shell_NotifyIcon(NIM_MODIFY, ref m_notifyIconData))
			{
#if DEBUG
			Debug.Assert(false);
#endif // #if DEBUG
			}

		}

		public void Hide()
		{

			// HIDE THE TRAY ICON BY REMOVING IT

			// shortcuts
			if (!m_bIsIconVisible)
			{
#if DEBUG
				Debug.Assert(false);
#endif // #if DEBUG
				return;
			}

			// Prep structure for delete
			_prepStructure_Icon(null);
			_prepStructure_Tip(null);

			// Remove the icon with a system-level call
			if (Shell_NotifyIcon(NIM_DELETE, ref m_notifyIconData))
			{

				// Update flag
				m_bIsIconVisible = false;

				// Loose the hook
				if (m_hook != null)
				{
					m_hook.Dispose();
					m_hook = null;
				}

			}
#if DEBUG
			else
				Debug.Assert(false);
#endif // #if DEBUG

		}

		private void _prepStructure_Icon(Icon trayIcon)
		{

			// UPDATE THE NOTIFY_ICON STRUCTURE FOR AN ICON

			// If there is an icon...
			if (trayIcon != null)
			{
				m_notifyIconData.uFlags |= NIF_ICON;
				m_notifyIconData.hIcon = trayIcon.Handle;
			}
			else
			{
				if ((m_notifyIconData.uFlags & NIF_ICON) == NIF_ICON)
					m_notifyIconData.uFlags ^= NIF_ICON;
				m_notifyIconData.hIcon = IntPtr.Zero;
			}

		}

		private void _prepStructure_Tip(string strTip)
		{

			// UPDATE THE NOTIFY_ICON STRUCTURE FOR A TOOLTIP

			// If there is a top...
			if (!string.IsNullOrEmpty(strTip))
			{
				m_notifyIconData.uFlags |= NIF_TIP;
				m_notifyIconData.szTip = strTip.Substring(0, Math.Min(127, strTip.Length));
			}
			else
			{
				if ((m_notifyIconData.uFlags & NIF_TIP) == NIF_TIP)
					m_notifyIconData.uFlags ^= NIF_TIP;
				m_notifyIconData.szTip = null;
			}

		}

		private void _fnHookCallback(int msg, IntPtr wParam, IntPtr lParam)
		{
#if DEBUG
			Debug.Assert(msg == WM_TRAYICON);
#endif // #if DEBUG

			// CALLBACK FUNCTION FOR WINDOW HOOK			

			// Get the notification event
			int iEvent = lParam.ToInt32() & 0xFFFF;
			if(iEvent == WM_LBUTTONDBLCLK)
			{

				// Fire an event
				if (LeftDoubleClick != null)
					LeftDoubleClick(this, new EventArgs());

			}

		}

	}

}