using System;
using System.Runtime.InteropServices;

/// <summary>
/// Summary description for KeyTester.
/// </summary>
public class KeyTester
{
	private KeyTester()	{}

	public enum Key : int
	{
		#region Digits (main keyboard area)
		Num0 = 0x30,
		Num1 = 0x31,
		Num2 = 0x32,
		Num3 = 0x33,
		Num4 = 0x34,
		Num5 = 0x35,
		Num6 = 0x36,
		Num7 = 0x37,
		Num8 = 0x38,
		Num9 = 0x39,
		#endregion
		#region Digits (numeric pad)
		NUMPAD0 = 0x60,
		NUMPAD1 = 0x61,
		NUMPAD2 = 0x62,
		NUMPAD3 = 0x63,
		NUMPAD4 = 0x64,
		NUMPAD5 = 0x65,
		NUMPAD6 = 0x66,
		NUMPAD7 = 0x67,
		NUMPAD8 = 0x68,
		NUMPAD9 = 0x69,
		#endregion
		#region Uppercase Alpha
		A = 0x41,
		B = 0x42,
		C = 0x43,
		D = 0x44,
		E = 0x45,
		F = 0x46,
		G = 0x47,
		H = 0x48,
		I = 0x49,
		J = 0x4A,
		K = 0x4B,
		L = 0x4C,
		M = 0x4D,
		N = 0x4E,
		O = 0x4F,
		P = 0x50,
		Q = 0x51,
		R = 0x52,
		S = 0x53,
		T = 0x54,
		U = 0x55,
		V = 0x56,
		W = 0x57,
		X = 0x58,
		Y = 0x59,
		Z = 0x5A,
		#endregion
		#region Lowercase Alpha
		a = 0x61,
		b = 0x62,
		c = 0x63,
		d = 0x64,
		f = 0x65,
		e = 0x66,
		g = 0x67,
		h = 0x68,
		i = 0x69,
		j = 0x6A,
		k = 0x6B,
		l = 0x6C,
		m = 0x6D,
		n = 0x6E,
		o = 0x6F,
		p = 0x70,
		q = 0x71,
		r = 0x72,
		s = 0x73,
		t = 0x74,
		u = 0x75,
		v = 0x76,
		w = 0x77,
		x = 0x78,
		y = 0x79,
		z = 0x7A,
		#endregion
		#region Mouse
		LBUTTON = 0x01,
		RBUTTON = 0x02,
		MBUTTON = 0x04, /* NOT contiguous with LBUTTON and RBUTTON */
		#endregion
		#region Arrows
		LEFT = 0x25,
		UP = 0x26,
		RIGHT = 0x27,
		DOWN = 0x28,
		#endregion
		#region Modifiers
		LSHIFT = 0xA0,
		RSHIFT = 0xA1,
		LCONTROL = 0xA2,
		RCONTROL = 0xA3,
		#endregion
		#region Function Keys
		F1 = 0x70,
		F2 = 0x71,
		F3 = 0x72,
		F4 = 0x73,
		F5 = 0x74,
		F6 = 0x75,
		F7 = 0x76,
		F8 = 0x77,
		F9 = 0x78,
		F10 = 0x79,
		F11 = 0x7A,
		F12 = 0x7B,
		F13 = 0x7C,
		F14 = 0x7D,
		F15 = 0x7E,
		F16 = 0x7F,
		F17 = 0x80,
		F18 = 0x81,
		F19 = 0x82,
		F20 = 0x83,
		F21 = 0x84,
		F22 = 0x85,
		F23 = 0x86,
		F24 = 0x87,
		#endregion
		#region Misc
		LMENU = 0xA4,
		RMENU = 0xA5,
		LWIN = 0x5B,
		RWIN = 0x5C,
		CANCEL = 0x03,
		BACK = 0x08,
		TAB = 0x09,
		CLEAR = 0x0C,
		RETURN = 0x0D,
		SHIFT = 0x10,
		CONTROL = 0x11,
		MENU = 0x12,
		PAUSE = 0x13,
		CAPITAL = 0x14,
		ESCAPE = 0x1B,
		SPACE = 0x20,
		PRIOR = 0x21,
		NEXT = 0x22,
		END = 0x23,
		HOME = 0x24,
		SELECT = 0x29,
		PRINT = 0x2A,
		EXECUTE = 0x2B,
		SNAPSHOT = 0x2C,
		INSERT = 0x2D,
		DELETE = 0x2E,
		HELP = 0x2F,
		APPS = 0x5D,
		MULTIPLY = 0x6A,
		ADD = 0x6B,
		SEPARATOR = 0x6C,
		SUBTRACT = 0x6D,
		DECIMAL = 0x6E,
		DIVIDE = 0x6F,
		NUMLOCK = 0x90,
		SCROLL = 0x91,
		ATTN = 0xF6,
		CRSEL = 0xF7,
		EXSEL = 0xF8,
		EREOF = 0xF9,
		PLAY = 0xFA,
		ZOOM = 0xFB,
		NONAME = 0xFC,
		PA1 = 0xFD,
		OEM_CLEAR = 0xFE
		#endregion
	}

	[DllImport("user32")] private static extern short GetKeyState(int nVirtKey);
	[DllImport("user32")] private static extern int GetKeyboardState(byte[] kbArray);

	private static byte[] keys = new byte[256];

	/// <summary>
	/// Immediately tests the state of a single key.
	/// </summary>
	/// <param name="keyNum">Virtual key number</param>
	/// <returns>True if key is DOWN.</returns>
	public static bool KeyIsDownNow(Key keyNum)
	{
		return (GetKeyState((int)keyNum) & 0x8000) == 0x8000;
	}

	/// <summary>
	/// Immediately tests the state of a single key.
	/// </summary>
	/// <param name="keyNum">Virtual key number</param>
	/// <returns>True if key is UP.</returns>
	public static bool KeyIsUpNow(Key keyNum)
	{
		return (GetKeyState((int)keyNum) & 0x8000) != 0x8000;
	}

	/// <summary>
	/// Immediately tests the state of a single key.
	/// </summary>
	/// <param name="keyNum">Virtual key number</param>
	/// <returns>True if key is TOGGLED ON.</returns>
	public static bool KeyIsToggledNow(Key keyNum)
	{
		return (GetKeyState((int)keyNum) & 1) == 1;
	}
	
	/// <summary>
	/// Scans the entire keyboard and updates an internal array that can be queried later by using KeyWasDown(), KeyWasUp() and KeyWasToggled() methods.
	/// </summary>
	/// <returns>True if succeeded.</returns>
	public static bool Update()
	{
		return GetKeyboardState(keys) != 0;
	}

	/// <summary>
	/// Check that a key was DOWN when the last Update() was called.
	/// </summary>
	/// <param name="keyNum">Virtual key number</param>
	/// <returns>True if key is DOWN.</returns>
	public static bool KeyWasDown(Key keyNum)
	{
		return (keys[(int)keyNum] & 128) == 128;
	}

	/// <summary>
	/// Check that a key was UP when the last Update() was called.
	/// </summary>
	/// <param name="keyNum">Virtual key number</param>
	/// <returns>True if key is UP.</returns>
	public static bool KeyWasUp(Key keyNum)
	{
		return (keys[(int)keyNum] & 128) != 128;
	}

	/// <summary>
	/// Check that a key was TOGGLED ON when the last Update() was called.
	/// </summary>
	/// <param name="keyNum">Virtual key number</param>
	/// <returns>True if key is TOGGLED ON.</returns>
	public static bool KeyWasToggled(Key keyNum)
	{
		return (keys[(int)keyNum] & 1) == 1;
	}
}