using System;
using System.Text;
using System.Collections;
using System.Runtime.InteropServices;

namespace MinimiseWindow
{
	/// <summary>
	/// Object used to control a Windows Form.
	/// </summary>
	public class Window
	{
		/// <summary>
		/// Win32 API Imports
		/// </summary>
		[DllImport("user32.dll")] private static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
		[DllImport("user32.dll")] private static extern bool SetForegroundWindow(IntPtr hWnd);
		[DllImport("user32.dll")] private static extern bool IsIconic(IntPtr hWnd);
		[DllImport("user32.dll")] private static extern bool IsZoomed(IntPtr hWnd);
		[DllImport("user32.dll")] private static extern IntPtr GetForegroundWindow();
		[DllImport("user32.dll")] private static extern IntPtr GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId);
		[DllImport("user32.dll")] private static extern IntPtr AttachThreadInput(IntPtr idAttach, IntPtr idAttachTo, int fAttach);

		/// <summary>
		/// Win32 API Constants for ShowWindowAsync()
		/// </summary>
		private const int SW_HIDE = 0;
		private const int SW_SHOWNORMAL = 1;
		private const int SW_SHOWMINIMIZED = 2;
		private const int SW_SHOWMAXIMIZED = 3;
		private const int SW_SHOWNOACTIVATE = 4;
		private const int SW_RESTORE = 9;
		private const int SW_SHOWDEFAULT = 10;

		/// <summary>
		/// Private Fields
		/// </summary>
		private IntPtr m_hWnd;
		private string m_Title;
		private bool m_Visible = true;
		private string m_Process;
		private bool m_WasMax = false;

		/// <summary>
		/// Window Object's Public Properties
		/// </summary>
		public IntPtr hWnd
		{
			get{return m_hWnd;}
		}
		public string Title
		{
			get{return m_Title;}
		}
		public string Process
		{
			get{return m_Process;}
		}

		/// <summary>
		/// Sets this Window Object's visibility
		/// </summary>
		public bool Visible
		{
			get{return m_Visible;}
			set
			{
				//show the window
				if(value == true)
				{
					if(m_WasMax)
					{
						if(ShowWindowAsync(m_hWnd,SW_SHOWMAXIMIZED))
							m_Visible = true;
					}
					else
					{
						if(ShowWindowAsync(m_hWnd,SW_SHOWNORMAL))
							m_Visible = true;
					}
				}
				//hide the window
				if(value == false)
				{
					m_WasMax = IsZoomed(m_hWnd);
					if(ShowWindowAsync(m_hWnd,SW_HIDE))
						m_Visible = false;
				}
			}
		}

		/// <summary>
		/// Constructs a Window Object
		/// </summary>
		/// <param name="Title">Title Caption</param>
		/// <param name="hWnd">Handle</param>
		/// <param name="Process">Owning Process</param>
		public Window(string Title, IntPtr hWnd, string Process)
		{
			m_Title = Title;
			m_hWnd = hWnd;
			m_Process = Process;
		}

		//Override ToString() 
		public override string ToString()
		{
			//return the title if it has one, if not return the process name
			if (m_Title.Length > 0)
			{
				return m_Title;
			}
			else
			{
				return m_Process;
			}
		}

		/// <summary>
		/// Sets focus to this Window Object
		/// </summary>
		public void Activate()
		{
			if(m_hWnd == GetForegroundWindow())
				return;

			IntPtr ThreadID1 = GetWindowThreadProcessId(GetForegroundWindow(),IntPtr.Zero);
			IntPtr ThreadID2 = GetWindowThreadProcessId(m_hWnd,IntPtr.Zero);
			
			if (ThreadID1 != ThreadID2)
			{
				AttachThreadInput(ThreadID1,ThreadID2,1);
				SetForegroundWindow(m_hWnd);
				AttachThreadInput(ThreadID1,ThreadID2,0);
			}
			else
			{
				SetForegroundWindow(m_hWnd);
			}

			if (IsIconic(m_hWnd))
			{
				ShowWindowAsync(m_hWnd,SW_RESTORE);
			}
			else
			{
				ShowWindowAsync(m_hWnd,SW_SHOWNORMAL);
			}
		}
	}

	/// <summary>
	/// Collection used to enumerate Window Objects
	/// </summary>
	public class Windows : IEnumerable, IEnumerator
	{
		/// <summary>
		/// Win32 API Imports
		/// </summary>
		[DllImport("user32.dll")] private static extern int GetWindowText(int hWnd, StringBuilder title, int size);
		[DllImport("user32.dll")] private static extern int GetWindowModuleFileName(int hWnd, StringBuilder title, int size);
		[DllImport("user32.dll")] private static extern int EnumWindows(EnumWindowsProc ewp, int lParam); 
		[DllImport("user32.dll")] private static extern bool IsWindowVisible(int hWnd);

		//delegate used for EnumWindows() callback function
		public delegate bool EnumWindowsProc(int hWnd, int lParam);

		private int m_Position = -1; //holds current index of wndArray, necessary for IEnumerable
		
		ArrayList wndArray = new ArrayList(); //array of windows
		
		//Object's private fields
		private bool m_invisible = false;
		private bool m_notitle = false;

		/// <summary>
		/// Collection Constructor with additional options
		/// </summary>
		/// <param name="Invisible">Include invisible Windows</param>
		/// <param name="Untitled">Include untitled Windows</param>
		public Windows(bool Invisible, bool Untitled)
		{
			m_invisible = Invisible;
			m_notitle = Untitled;

			//Declare a callback delegate for EnumWindows() API call
			EnumWindowsProc ewp = new EnumWindowsProc(EvalWindow);
			//Enumerate all Windows
			EnumWindows(ewp, 0);
		}
		/// <summary>
		/// Collection Constructor
		/// </summary>
		public Windows()
		{
			//Declare a callback delegate for EnumWindows() API call
			EnumWindowsProc ewp = new EnumWindowsProc(EvalWindow);
			//Enumerate all Windows
			EnumWindows(ewp, 0);
		}
		//EnumWindows CALLBACK function
		private bool EvalWindow(int hWnd, int lParam)
		{
			if (m_invisible == false && !IsWindowVisible(hWnd))
				return(true);

			StringBuilder title = new StringBuilder(256);
			StringBuilder module = new StringBuilder(256);

			GetWindowModuleFileName(hWnd, module, 256);
			GetWindowText(hWnd, title, 256);

			if (m_notitle == false && title.Length == 0)
				return(true);

			wndArray.Add(new Window(title.ToString(), (IntPtr)hWnd, module.ToString()));

			return(true);
		}
		
		//implement IEnumerable
		public IEnumerator GetEnumerator()
		{
			return (IEnumerator)this;
		}
		//implement IEnumerator
		public bool MoveNext()
		{
			m_Position++;
			if (m_Position < wndArray.Count)
			{
				return true;
			}
			else
			{
				return false;
			}
		}
		public void Reset()
		{
			m_Position = -1;
		}
		public object Current
		{
			get
			{
				return wndArray[m_Position];
			}
		}
	}
}