Simulation.cs

using System;
using System.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using System.Windows.Input;

///
///
/// The code yoinked from: https://gist.github.com/DrustZ/640912b9d5cb745a3a56971c9bd58ac7
///
/// All credit goes to: DrustZ, https://github.com/DrustZ
///
///

namespace Simulation
{
  /// <summary>
  /// Native methods
  /// </summary>
  internal static class NativeMethods
  {
    //User32 wrappers cover API's used for Mouse input
    #region User32
    // Two special bitmasks we define to be able to grab
    // shift and character information out of a VKey.
    internal const int VKeyShiftMask = 0x0100;
    internal const int VKeyCharMask = 0x00FF;

    // Various Win32 constants
    internal const int KeyeventfExtendedkey = 0x0001;
    internal const int KeyeventfKeyup = 0x0002;
    internal const int KeyeventfScancode = 0x0008;

    internal const int MouseeventfVirtualdesk = 0x4000;

    internal const int SMXvirtualscreen = 76;
    internal const int SMYvirtualscreen = 77;
    internal const int SMCxvirtualscreen = 78;
    internal const int SMCyvirtualscreen = 79;

    internal const int XButton1 = 0x0001;
    internal const int XButton2 = 0x0002;
    internal const int WheelDelta = 120;

    internal const int InputMouse = 0;
    internal const int InputKeyboard = 1;

    // Various Win32 data structures
    [StructLayout(LayoutKind.Sequential)]
    internal struct INPUT
    {
      internal int type;
      internal INPUTUNION union;
    };

    [StructLayout(LayoutKind.Explicit)]
    internal struct INPUTUNION
    {
      [FieldOffset(0)]
      internal MOUSEINPUT mouseInput;
      [FieldOffset(0)]
      internal KEYBDINPUT keyboardInput;
    };

    [StructLayout(LayoutKind.Sequential)]
    internal struct MOUSEINPUT
    {
      internal int dx;
      internal int dy;
      internal int mouseData;
      internal int dwFlags;
      internal int time;
      internal IntPtr dwExtraInfo;
    };

    [StructLayout(LayoutKind.Sequential)]
    internal struct KEYBDINPUT
    {
      internal short wVk;
      internal short wScan;
      internal int dwFlags;
      internal int time;
      internal IntPtr dwExtraInfo;
    };

    [Flags]
    internal enum SendMouseInputFlags
    {
      Move = 0x0001,
      LeftDown = 0x0002,
      LeftUp = 0x0004,
      RightDown = 0x0008,
      RightUp = 0x0010,
      MiddleDown = 0x0020,
      MiddleUp = 0x0040,
      XDown = 0x0080,
      XUp = 0x0100,
      Wheel = 0x0800,
      Absolute = 0x8000,
    };

    // Importing various Win32 APIs that we need for input
    [DllImport("user32.dll", ExactSpelling = true, CharSet = CharSet.Auto)]
    internal static extern int GetSystemMetrics(int nIndex);

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    internal static extern int MapVirtualKey(int nVirtKey, int nMapType);

    [DllImport("user32.dll", SetLastError = true)]
    internal static extern int SendInput(int nInputs, ref INPUT mi, int cbSize);

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    internal static extern short VkKeyScan(char ch);

    #endregion
  }


  /// <summary>
  /// Exposes a simple interface to common mouse operations, allowing the user to simulate mouse input.
  /// </summary>
  /// <example>The following code moves to screen coordinate 100,100 and left clicks.
  /// <code>
  /**
      Mouse.MoveTo(new Point(100, 100));
      Mouse.Click(MouseButton.Left);
  */
  /// </code>
  /// </example>
  public static class Mouse
  {
    /// <summary>
    /// Clicks a mouse button.
    /// </summary>
    /// <param name="mouseButton">The mouse button to click.</param>
    public static void Click(MouseButton mouseButton)
    {
      Down(mouseButton);
      Up(mouseButton);
    }

    /// <summary>
    /// Double-clicks a mouse button.
    /// </summary>
    /// <param name="mouseButton">The mouse button to click.</param>
    public static void DoubleClick(MouseButton mouseButton)
    {
      Click(mouseButton);
      Click(mouseButton);
    }

    /// <summary>
    /// Performs a mouse-down operation for a specified mouse button.
    /// </summary>
    /// <param name="mouseButton">The mouse button to use.</param>
    public static void Down(MouseButton mouseButton)
    {
      switch (mouseButton)
      {
        case MouseButton.Left:
          SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.LeftDown);
          break;
        case MouseButton.Right:
          SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.RightDown);
          break;
        case MouseButton.Middle:
          SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.MiddleDown);
          break;
        case MouseButton.XButton1:
          SendMouseInput(0, 0, NativeMethods.XButton1, NativeMethods.SendMouseInputFlags.XDown);
          break;
        case MouseButton.XButton2:
          SendMouseInput(0, 0, NativeMethods.XButton2, NativeMethods.SendMouseInputFlags.XDown);
          break;
        default:
          throw new InvalidOperationException("Unsupported MouseButton input.");
      }
    }

    /// <summary>
    /// Moves the mouse pointer to the specified screen coordinates.
    /// </summary>
    /// <param name="point">The screen coordinates to move to.</param>
    public static void MoveTo(Point point)
    {
      SendMouseInput(point.X, point.Y, 0, NativeMethods.SendMouseInputFlags.Move | NativeMethods.SendMouseInputFlags.Absolute);
    }

    /// <summary>
    /// Resets the system mouse to a clean state.
    /// </summary>
    public static void Reset()
    {
      MoveTo(new Point(0, 0));

      if (System.Windows.Input.Mouse.LeftButton == MouseButtonState.Pressed)
      {
        SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.LeftUp);
      }

      if (System.Windows.Input.Mouse.MiddleButton == MouseButtonState.Pressed)
      {
        SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.MiddleUp);
      }

      if (System.Windows.Input.Mouse.RightButton == MouseButtonState.Pressed)
      {
        SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.RightUp);
      }

      if (System.Windows.Input.Mouse.XButton1 == MouseButtonState.Pressed)
      {
        SendMouseInput(0, 0, NativeMethods.XButton1, NativeMethods.SendMouseInputFlags.XUp);
      }

      if (System.Windows.Input.Mouse.XButton2 == MouseButtonState.Pressed)
      {
        SendMouseInput(0, 0, NativeMethods.XButton2, NativeMethods.SendMouseInputFlags.XUp);
      }
    }

    /// <summary>
    /// Simulates scrolling of the mouse wheel up or down.
    /// </summary>
    /// <param name="lines">The number of lines to scroll. Use positive numbers to scroll up and negative numbers to scroll down.</param>
    public static void Scroll(double lines)
    {
      int amount = (int)(NativeMethods.WheelDelta * lines);

      SendMouseInput(0, 0, amount, NativeMethods.SendMouseInputFlags.Wheel);
    }

    /// <summary>
    /// Performs a mouse-up operation for a specified mouse button.
    /// </summary>
    /// <param name="mouseButton">The mouse button to use.</param>
    public static void Up(MouseButton mouseButton)
    {
      switch (mouseButton)
      {
        case MouseButton.Left:
          SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.LeftUp);
          break;
        case MouseButton.Right:
          SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.RightUp);
          break;
        case MouseButton.Middle:
          SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.MiddleUp);
          break;
        case MouseButton.XButton1:
          SendMouseInput(0, 0, NativeMethods.XButton1, NativeMethods.SendMouseInputFlags.XUp);
          break;
        case MouseButton.XButton2:
          SendMouseInput(0, 0, NativeMethods.XButton2, NativeMethods.SendMouseInputFlags.XUp);
          break;
        default:
          throw new InvalidOperationException("Unsupported MouseButton input.");
      }
    }

    /// <summary>
    /// Sends mouse input.
    /// </summary>
    /// <param name="x">x coordinate</param>
    /// <param name="y">y coordinate</param>
    /// <param name="data">scroll wheel amount</param>
    /// <param name="flags">SendMouseInputFlags flags</param>
    [PermissionSet(SecurityAction.Assert, Name = "FullTrust")]
    private static void SendMouseInput(int x, int y, int data, NativeMethods.SendMouseInputFlags flags)
    {
      PermissionSet permissions = new PermissionSet(PermissionState.Unrestricted);
      permissions.Demand();

      int intflags = (int)flags;

      if ((intflags & (int)NativeMethods.SendMouseInputFlags.Absolute) != 0)
      {
        // Absolute position requires normalized coordinates.
        NormalizeCoordinates(ref x, ref y);
        intflags |= NativeMethods.MouseeventfVirtualdesk;
      }

      NativeMethods.INPUT mi = new NativeMethods.INPUT();
      mi.type = NativeMethods.InputMouse;
      mi.union.mouseInput.dx = x;
      mi.union.mouseInput.dy = y;
      mi.union.mouseInput.mouseData = data;
      mi.union.mouseInput.dwFlags = intflags;
      mi.union.mouseInput.time = 0;
      mi.union.mouseInput.dwExtraInfo = new IntPtr(0);

      if (NativeMethods.SendInput(1, ref mi, Marshal.SizeOf(mi)) == 0)
      {
        throw new Win32Exception(Marshal.GetLastWin32Error());
      }
    }

    private static void NormalizeCoordinates(ref int x, ref int y)
    {
      int vScreenWidth = NativeMethods.GetSystemMetrics(NativeMethods.SMCxvirtualscreen);
      int vScreenHeight = NativeMethods.GetSystemMetrics(NativeMethods.SMCyvirtualscreen);
      int vScreenLeft = NativeMethods.GetSystemMetrics(NativeMethods.SMXvirtualscreen);
      int vScreenTop = NativeMethods.GetSystemMetrics(NativeMethods.SMYvirtualscreen);

      // Absolute input requires that input is in 'normalized' coords - with the entire
      // desktop being (0,0)...(65536,65536). Need to convert input x,y coords to this
      // first.
      //
      // In this normalized world, any pixel on the screen corresponds to a block of values
      // of normalized coords - eg. on a 1024x768 screen,
      // y pixel 0 corresponds to range 0 to 85.333,
      // y pixel 1 corresponds to range 85.333 to 170.666,
      // y pixel 2 correpsonds to range 170.666 to 256 - and so on.
      // Doing basic scaling math - (x-top)*65536/Width - gets us the start of the range.
      // However, because int math is used, this can end up being rounded into the wrong
      // pixel. For example, if we wanted pixel 1, we'd get 85.333, but that comes out as
      // 85 as an int, which falls into pixel 0's range - and that's where the pointer goes.
      // To avoid this, we add on half-a-"screen pixel"'s worth of normalized coords - to
      // push us into the middle of any given pixel's range - that's the 65536/(Width*2)
      // part of the formula. So now pixel 1 maps to 85+42 = 127 - which is comfortably
      // in the middle of that pixel's block.
      // The key ting here is that unlike points in coordinate geometry, pixels take up
      // space, so are often better treated like rectangles - and if you want to target
      // a particular pixel, target its rectangle's midpoint, not its edge.
      x = ((x - vScreenLeft) * 65536) / vScreenWidth + 65536 / (vScreenWidth * 2);
      y = ((y - vScreenTop) * 65536) / vScreenHeight + 65536 / (vScreenHeight * 2);
    }
  }

  /// <summary>
  /// Exposes a simple interface to common keyboard operations, allowing the user to simulate keyboard input.
  /// </summary>
  /// <example>
  /// The following code types "Hello world" with the specified casing,
  /// and then types "hello, capitalized world" which will be in all caps because
  /// the left shift key is being held down.
  /// <code>
  /**
          Keyboard.Type("Hello world");
          Keyboard.Press(Key.LeftShift);
          Keyboard.Type("hello, capitalized world");
          Keyboard.Release(Key.LeftShift);
  */
  /// </code>
  /// </example>
  public static class Keyboard
  {
    #region Public Members

    /// <summary>
    /// Presses down a key.
    /// </summary>
    /// <param name="key">The key to press.</param>
    public static void Press(Key key)
    {
      SendKeyboardInput(key, true);
    }

    /// <summary>
    /// Releases a key.
    /// </summary>
    /// <param name="key">The key to release.</param>
    public static void Release(Key key)
    {
      SendKeyboardInput(key, false);
    }

    /// <summary>
    /// Resets the system keyboard to a clean state.
    /// </summary>
    public static void Reset()
    {
      foreach (Key key in Enum.GetValues(typeof(Key)))
      {
        if (key != Key.None && (System.Windows.Input.Keyboard.GetKeyStates(key) & KeyStates.Down) > 0)
        {
          Release(key);
        }
      }
    }

    /// <summary>
    /// Performs a press-and-release operation for the specified key, which is effectively equivallent to typing.
    /// </summary>
    /// <param name="key">The key to press.</param>
    public static void Type(Key key)
    {
      Press(key);
      Release(key);
    }

    /// <summary>
    /// Types the specified text.
    /// </summary>
    /// <param name="text">The text to type.</param>
    public static void Type(string text)
    {
      foreach (char c in text)
      {
        // We get the vKey value for the character via a Win32 API. We then use bit masks to pull the
        // upper and lower bytes to get the shift state and key information. We then use WPF KeyInterop
        // to go from the vKey key info into a System.Windows.Input.Key data structure. This work is
        // necessary because Key doesn't distinguish between upper and lower case, so we have to wrap
        // the key type inside a shift press/release if necessary.
        int vKeyValue = NativeMethods.VkKeyScan(c);
        bool keyIsShifted = (vKeyValue & NativeMethods.VKeyShiftMask) == NativeMethods.VKeyShiftMask;
        Key key = KeyInterop.KeyFromVirtualKey(vKeyValue & NativeMethods.VKeyCharMask);

        if (keyIsShifted)
        {
          Type(key, new Key[] { Key.LeftShift });
        }
        else
        {
          Type(key);
        }
      }
    }

    #endregion

    #region Private Members

    /// <summary>
    /// Types a key while a set of modifier keys are being pressed. Modifer keys
    /// are pressed in the order specified and released in reverse order.
    /// </summary>
    /// <param name="key">Key to type.</param>
    /// <param name="modifierKeys">Set of keys to hold down with key is typed.</param>
    private static void Type(Key key, Key[] modifierKeys)
    {
      foreach (Key modiferKey in modifierKeys)
      {
        Press(modiferKey);
      }

      Type(key);

      foreach (Key modifierKey in modifierKeys.Reverse())
      {
        Release(modifierKey);
      }
    }

    /// <summary>
    /// Injects keyboard input into the system.
    /// </summary>
    /// <param name="key">Indicates the key pressed or released. Can be one of the constants defined in the Key enum.</param>
    /// <param name="press">True to inject a key press, false to inject a key release.</param>
    [PermissionSet(SecurityAction.Assert, Name = "FullTrust")]
    private static void SendKeyboardInput(Key key, bool press)
    {
      PermissionSet permissions = new PermissionSet(PermissionState.Unrestricted);
      permissions.Demand();

      NativeMethods.INPUT ki = new NativeMethods.INPUT();
      ki.type = NativeMethods.InputKeyboard;
      ki.union.keyboardInput.wVk = (short)KeyInterop.VirtualKeyFromKey(key);
      ki.union.keyboardInput.wScan = (short)NativeMethods.MapVirtualKey(ki.union.keyboardInput.wVk, 0);

      int dwFlags = 0;

      if (ki.union.keyboardInput.wScan > 0)
      {
        dwFlags |= NativeMethods.KeyeventfScancode;
      }

      if (!press)
      {
        dwFlags |= NativeMethods.KeyeventfKeyup;
      }

      ki.union.keyboardInput.dwFlags = dwFlags;

      if (ExtendedKeys.Contains(key))
      {
        ki.union.keyboardInput.dwFlags |= NativeMethods.KeyeventfExtendedkey;
      }

      ki.union.keyboardInput.time = 0;
      ki.union.keyboardInput.dwExtraInfo = new IntPtr(0);

      if (NativeMethods.SendInput(1, ref ki, Marshal.SizeOf(ki)) == 0)
      {
        throw new Win32Exception(Marshal.GetLastWin32Error());
      }
    }

    // From the SDK:
    // The extended-key flag indicates whether the keystroke message originated from one of
    // the additional keys on the enhanced keyboard. The extended keys consist of the ALT and
    // CTRL keys on the right-hand side of the keyboard; the INS, DEL, HOME, END, PAGE UP,
    // PAGE DOWN, and arrow keys in the clusters to the left of the numeric keypad; the NUM LOCK
    // key; the BREAK (CTRL+PAUSE) key; the PRINT SCRN key; and the divide (/) and ENTER keys in
    // the numeric keypad. The extended-key flag is set if the key is an extended key.
    //
    // - docs appear to be incorrect. Use of Spy++ indicates that break is not an extended key.
    // Also, menu key and windows keys also appear to be extended.
    private static readonly Key[] ExtendedKeys = new Key[] {
                                                                   Key.RightAlt,
                                                                   Key.RightCtrl,
                                                                   Key.NumLock,
                                                                   Key.Insert,
                                                                   Key.Delete,
                                                                   Key.Home,
                                                                   Key.End,
                                                                   Key.Prior,
                                                                   Key.Next,
                                                                   Key.Up,
                                                                   Key.Down,
                                                                   Key.Left,
                                                                   Key.Right,
                                                                   Key.Apps,
                                                                   Key.RWin,
                                                                   Key.LWin };
    // Note that there are no distinct values for the following keys:
    // numpad divide
    // numpad enter

    #endregion
  }
}