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

namespace WindowHider
{
    /// <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];
            }
        }
    }
}