/*	SCCS Id: @(#)nhraykey.c	3.4	$Date: 2003/11/01 23:57:00 $   */
/* Copyright (c) NetHack PC Development Team 2003                      */
/* NetHack may be freely redistributed.  See license for details.      */

/*
 * Keystroke handling contributed by Ray Chason.
 * The following text was written by Ray Chason.
 *  
 * The problem
 * ===========
 * 
 * The console-mode Nethack wants both keyboard and mouse input.  The
 * problem is that the Windows API provides no easy way to get mouse input
 * and also keyboard input properly translated according to the user's
 * chosen keyboard layout.
 * 
 * The ReadConsoleInput function returns a stream of keyboard and mouse
 * events.  Nethack is interested in those events that represent a key
 * pressed, or a click on a mouse button.  The keyboard events from
 * ReadConsoleInput are not translated according to the keyboard layout,
 * and do not take into account the shift, control, or alt keys.
 * 
 * The PeekConsoleInput function works similarly to ReadConsoleInput,
 * except that it does not remove an event from the queue and it returns
 * instead of blocking when the queue is empty.
 * 
 * A program can also use ReadConsole to get a properly translated stream
 * of characters.  Unfortunately, ReadConsole does not return mouse events,
 * does not distinguish the keypad from the main keyboard, does not return
 * keys shifted with Alt, and does not even return the ESC key when
 * pressed.  
 * 
 * We want both the functionality of ReadConsole and the functionality of
 * ReadConsoleInput.  But Microsoft didn't seem to think of that.
 * 
 * 
 * The solution, in the original code
 * ==================================
 * 
 * The original 3.4.1 distribution tries to get proper keyboard translation
 * by passing keyboard events to the ToAscii function.  This works, to some
 * extent -- it takes the shift key into account, and it processes dead
 * keys properly.  But it doesn't take non-US keyboards into account.  It
 * appears that ToAscii is meant for windowed applications, and does not
 * have enough information to do its job properly in a console application.
 * 
 * 
 * The Finnish keyboard patch
 * ==========================
 * 
 * This patch adds the "subkeyvalue" option to the defaults.nh file.  The
 * user can then add OPTIONS=sukeyvalue:171/92, for instance, to replace
 * the 171 character with 92, which is \.  This works, once properly
 * configured, but places too much burden on the user.  It also bars the
 * use of the substituted characters in naming objects or monsters.
 * 
 * 
 * The solution presented here
 * ===========================
 * 
 * The best way I could find to combine the functionality of ReadConsole
 * with that of ReadConsoleInput is simple in concept.  First, call
 * PeekConsoleInput to get the first event.  If it represents a key press,
 * call ReadConsole to retrieve the key.  Otherwise, pop it off the queue
 * with ReadConsoleInput and, if it's a mouse click, return it as such.
 * 
 * But the Devil, as they say, is in the details.  The problem is in
 * recognizing an event that ReadConsole will return as a key.  We don't
 * want to call ReadConsole unless we know that it will immediately return:
 * if it blocks, the mouse and the Alt sequences will cease to function
 * until it returns.
 * 
 * Separating process_keystroke into two functions, one for commands and a
 * new one, process_keystroke2, for answering prompts, makes the job a lot
 * easier.  process_keystroke2 doesn't have to worry about mouse events or
 * Alt sequences, and so the consequences are minor if ReadConsole blocks. 
 * process_keystroke, OTOH, never needs to return a non-ASCII character
 * that was read from ReadConsole; it returns bytes with the high bit set
 * only in response to an Alt sequence.
 * 
 * So in process_keystroke, before calling ReadConsole, a bogus key event
 * is pushed on the queue.  This event causes ReadConsole to return, even
 * if there was no other character available.  Because the bogus key has
 * the eighth bit set, it is filtered out.  This is not done in
 * process_keystroke2, because that would render dead keys unusable.
 * 
 * A separate process_keystroke2 can also process the numeric keypad in a
 * way that makes sense for prompts:  just return the corresponding symbol,
 * and pay no mind to number_pad or the num lock key.
 * 
 * The recognition of Alt sequences is modified, to support the use of
 * characters generated with the AltGr key.  A keystroke is an Alt sequence
 * if an Alt key is seen that can't be an AltGr (since an AltGr sequence
 * could be a character, and in some layouts it could even be an ASCII
 * character).  This recognition is different on NT-based and 95-based
 * Windows:
 * 
 *    * On NT-based Windows, AltGr signals as right Alt and left Ctrl
 *      together.  So an Alt sequence is recognized if either Alt key is
 *      pressed and if right Alt and left Ctrl are not both present.  This
 *      is true even if the keyboard in use does not have an AltGr key, and
 *      uses right Alt for AltGr.
 * 
 *    * On 95-based Windows, with a keyboard that lacks the AltGr key, the
 *      right Alt key is used instead.  But it still signals as right Alt,
 *      without left Ctrl.  There is no way for the application to know
 *      whether right Alt is Alt or AltGr, and so it is always assumed
 *      to be AltGr.  This means that Alt sequences must be formed with
 *      left Alt.
 * 
 * So the patch processes keystrokes as follows:
 * 
 *     * If the scan and virtual key codes are both 0, it's the bogus key,
 *       and we ignore it.
 * 
 *     * Keys on the numeric keypad are processed for commands as in the
 *       unpatched Nethack, and for prompts by returning the ASCII
 *       character, even if the num lock is off.
 *        
 *     * Alt sequences are processed for commands as in the unpatched
 *       Nethack, and ignored for prompts.
 *        
 *     * Control codes are returned as received, because ReadConsole will
 *       not return the ESC key.
 *        
 *     * Other key-down events are passed to ReadConsole.  The use of
 *       ReadConsole is different for commands than for prompts:
 * 
 *       o For commands, the bogus key is pushed onto the queue before
 *         ReadConsole is called.  On return, non-ASCII characters are
 *         filtered, so they are not mistaken for Alt sequences; this also
 *         filters the bogus key.
 * 
 *       o For prompts, the bogus key is not used, because that would
 *         interfere with dead keys.  Eight bit characters may be returned,
 *         and are coded in the configured code page.
 * 
 * 
 * Possible improvements
 * =====================
 * 
 * Some possible improvements remain:
 * 
 *     * Integrate the existing Finnish keyboard patch, for use with non-
 *       QWERTY layouts such as the German QWERTZ keyboard or Dvorak.
 *        
 *     * Fix the keyboard glitches in the graphical version.  Namely, dead
 *       keys don't work, and input comes in as ISO-8859-1 but is displayed
 *       as code page 437 if IBMgraphics is set on startup.
 * 
 *     * Transform incoming text to ISO-8859-1, for full compatibility with
 *       the graphical version.
 * 
 *     * After pushing the bogus key and calling ReadConsole, check to see
 *       if we got the bogus key; if so, and an Alt is pressed, process the
 *       event as an Alt sequence.
 * 
 */

static char where_to_get_source[] = "http://www.nethack.org/";
static char author[] = "Ray Chason";

#include "hack.h"
#include "wintty.h"
#include "win32api.h"

extern HANDLE hConIn;
extern INPUT_RECORD ir;
char dllname[512];
char *shortdllname;

int FDECL(__declspec(dllexport) __stdcall
ProcessKeystroke, (HANDLE hConIn, INPUT_RECORD *ir, 
    boolean *valid, BOOLEAN_P numberpad, int portdebug));

static INPUT_RECORD bogus_key;

int WINAPI DllMain(HINSTANCE hInstance, DWORD fdwReason, PVOID pvReserved)
{
	char dlltmpname[512];
	char *tmp = dlltmpname, *tmp2;
	*(tmp + GetModuleFileName(hInstance, tmp, 511)) = '\0';
	(void)strcpy(dllname, tmp);
	tmp2 = strrchr(dllname, '\\');
	if (tmp2) {
		tmp2++;
		shortdllname = tmp2;
	}
	/* A bogus key that will be filtered when received, to keep ReadConsole
	 * from blocking */
	bogus_key.EventType = KEY_EVENT;
	bogus_key.Event.KeyEvent.bKeyDown = 1;
	bogus_key.Event.KeyEvent.wRepeatCount = 1;
	bogus_key.Event.KeyEvent.wVirtualKeyCode = 0;
	bogus_key.Event.KeyEvent.wVirtualScanCode = 0;
	bogus_key.Event.KeyEvent.uChar.AsciiChar = (uchar)0x80;
	bogus_key.Event.KeyEvent.dwControlKeyState = 0;
	return TRUE;
}

/*
 *  Keyboard translation tables.
 *  (Adopted from the MSDOS port)
 */

#define KEYPADLO	0x47
#define KEYPADHI	0x53

#define PADKEYS 	(KEYPADHI - KEYPADLO + 1)
#define iskeypad(x)	(KEYPADLO <= (x) && (x) <= KEYPADHI)
#define isnumkeypad(x)	(KEYPADLO <= (x) && (x) <= 0x51 && (x) != 0x4A && (x) != 0x4E)

/*
 * Keypad keys are translated to the normal values below.
 * Shifted keypad keys are translated to the
 *    shift values below.
 */

static const struct pad {
	uchar normal, shift, cntrl;
} keypad[PADKEYS] = {
			{'y', 'Y', C('y')},		/* 7 */
			{'k', 'K', C('k')},		/* 8 */
			{'u', 'U', C('u')},		/* 9 */
			{'m', C('p'), C('p')},		/* - */
			{'h', 'H', C('h')},		/* 4 */
			{'g', 'G', 'g'},		/* 5 */
			{'l', 'L', C('l')},		/* 6 */
			{'+', 'P', C('p')},		/* + */
			{'b', 'B', C('b')},		/* 1 */
			{'j', 'J', C('j')},		/* 2 */
			{'n', 'N', C('n')},		/* 3 */
			{'i', 'I', C('i')},		/* Ins */
			{'.', ':', ':'}			/* Del */
}, numpad[PADKEYS] = {
			{'7', M('7'), '7'},		/* 7 */
			{'8', M('8'), '8'},		/* 8 */
			{'9', M('9'), '9'},		/* 9 */
			{'m', C('p'), C('p')},		/* - */
			{'4', M('4'), '4'},		/* 4 */
			{'g', 'G', 'g'},		/* 5 */
			{'6', M('6'), '6'},		/* 6 */
			{'+', 'P', C('p')},		/* + */
			{'1', M('1'), '1'},		/* 1 */
			{'2', M('2'), '2'},		/* 2 */
			{'3', M('3'), '3'},		/* 3 */
			{'i', 'I', C('i')},		/* Ins */
			{'.', ':', ':'}			/* Del */
};

#define inmap(x,vk)	(((x) > 'A' && (x) < 'Z') || (vk) == 0xBF || (x) == '2')

/* Use process_keystroke for key commands, process_keystroke2 for prompts */
/* int FDECL(process_keystroke, (INPUT_RECORD *ir, boolean *valid, int portdebug)); */
int FDECL(process_keystroke2, (HANDLE,INPUT_RECORD *ir, boolean *valid));
static int FDECL(is_altseq, (unsigned long shiftstate));

static int
is_altseq(shiftstate)
unsigned long shiftstate;
{
    /* We need to distinguish the Alt keys from the AltGr key.
     * On NT-based Windows, AltGr signals as right Alt and left Ctrl together;
     * on 95-based Windows, AltGr signals as right Alt only.
     * So on NT, we signal Alt if either Alt is pressed and left Ctrl is not,
     * and on 95, we signal Alt for left Alt only. */
    switch (shiftstate & (RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED | LEFT_CTRL_PRESSED)) {
	case LEFT_ALT_PRESSED:
	case LEFT_ALT_PRESSED | LEFT_CTRL_PRESSED:
	    return 1;

	case RIGHT_ALT_PRESSED:
	case RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED:
	    return (GetVersion() & 0x80000000) == 0;

        default:
            return 0;
    }
}

int __declspec(dllexport) __stdcall
ProcessKeystroke(hConIn, ir, valid, numberpad, portdebug)
HANDLE hConIn;
INPUT_RECORD *ir;
boolean *valid;
boolean numberpad;
int portdebug;
{
	int metaflags = 0, k = 0;
	int keycode, vk;
	unsigned char ch, pre_ch, mk = 0;
	unsigned short int scan;
	unsigned long shiftstate;
	int altseq = 0;
	const struct pad *kpad;
	DWORD count;

	shiftstate = 0L;
	ch = pre_ch = ir->Event.KeyEvent.uChar.AsciiChar;
	scan  = ir->Event.KeyEvent.wVirtualScanCode;
	vk    = ir->Event.KeyEvent.wVirtualKeyCode;
	keycode = MapVirtualKey(vk, 2);
	shiftstate = ir->Event.KeyEvent.dwControlKeyState;
	if (scan == 0 && vk == 0) {
	    /* It's the bogus_key */
	    ReadConsoleInput(hConIn,ir,1,&count);
	    *valid = FALSE;
	    return 0;
	}

	if (is_altseq(shiftstate)) {
		if (ch || inmap(keycode,vk)) altseq = 1;
		else altseq = -1;	/* invalid altseq */
	}
	if (ch || (iskeypad(scan)) || (altseq > 0))
		*valid = TRUE;
	/* if (!valid) return 0; */
    	/*
	 * shiftstate can be checked to see if various special
         * keys were pressed at the same time as the key.
         * Currently we are using the ALT & SHIFT & CONTROLS.
         *
         *           RIGHT_ALT_PRESSED, LEFT_ALT_PRESSED,
         *           RIGHT_CTRL_PRESSED, LEFT_CTRL_PRESSED,
         *           SHIFT_PRESSED,NUMLOCK_ON, SCROLLLOCK_ON,
         *           CAPSLOCK_ON, ENHANCED_KEY
         *
         * are all valid bit masks to use on shiftstate.
         * eg. (shiftstate & LEFT_CTRL_PRESSED) is true if the
         *      left control key was pressed with the keystroke.
         */
        if (iskeypad(scan)) {
	    ReadConsoleInput(hConIn,ir,1,&count);
            kpad = numberpad ? numpad : keypad;
            if (shiftstate & SHIFT_PRESSED) {
                ch = kpad[scan - KEYPADLO].shift;
            }
            else if (shiftstate & (LEFT_CTRL_PRESSED | RIGHT_CTRL_PRESSED)) {
                ch = kpad[scan - KEYPADLO].cntrl;
            }
            else {
                ch = kpad[scan - KEYPADLO].normal;
            }
        }
        else if (altseq > 0) { /* ALT sequence */
		ReadConsoleInput(hConIn,ir,1,&count);
		if (vk == 0xBF) ch = M('?');
		else ch = M(tolower(keycode));
        }
	else if (ch < 32 && !isnumkeypad(scan)) {
		/* Control code; ReadConsole seems to filter some of these,
		 * including ESC */
		ReadConsoleInput(hConIn,ir,1,&count);
	}
	/* Attempt to work better with international keyboards. */
	else {
		CHAR ch2;
		DWORD written;
		/* The bogus_key guarantees that ReadConsole will return,
		 * and does not itself do anything */
		WriteConsoleInput(hConIn, &bogus_key, 1, &written);
		ReadConsole(hConIn,&ch2,1,&count,NULL);
		/* Prevent high characters from being interpreted as alt
		 * sequences; also filter the bogus_key */
		if (ch2 & 0x80)
		    *valid = FALSE;
		else
		    ch = ch2;
                if (ch == 0) *valid = FALSE;
	}
	if (ch == '\r') ch = '\n';
#ifdef PORT_DEBUG
	if (portdebug) {
		char buf[BUFSZ];
		Sprintf(buf,
	"PORTDEBUG: ch=%u, scan=%u, vk=%d, pre=%d, shiftstate=0x%X (ESC to end)\n",
			ch, scan, vk, pre_ch, shiftstate);
		fprintf(stdout, "\n%s", buf);
	}
#endif
	return ch;
}

int process_keystroke2(hConIn, ir, valid)
HANDLE hConIn;
INPUT_RECORD *ir;
boolean *valid;
{
	/* Use these values for the numeric keypad */
	static const char keypad_nums[] = "789-456+1230.";

	unsigned char ch;
	int vk;
	unsigned short int scan;
	unsigned long shiftstate;
	int altseq;
	DWORD count;

	ch    = ir->Event.KeyEvent.uChar.AsciiChar;
	vk    = ir->Event.KeyEvent.wVirtualKeyCode;
	scan  = ir->Event.KeyEvent.wVirtualScanCode;
	shiftstate = ir->Event.KeyEvent.dwControlKeyState;

	if (scan == 0 && vk == 0) {
	    /* It's the bogus_key */
	    ReadConsoleInput(hConIn,ir,1,&count);
	    *valid = FALSE;
	    return 0;
	}

	altseq = is_altseq(shiftstate);
	if (ch || (iskeypad(scan)) || altseq)
		*valid = TRUE;
	/* if (!valid) return 0; */
    	/*
	 * shiftstate can be checked to see if various special
         * keys were pressed at the same time as the key.
         * Currently we are using the ALT & SHIFT & CONTROLS.
         *
         *           RIGHT_ALT_PRESSED, LEFT_ALT_PRESSED,
         *           RIGHT_CTRL_PRESSED, LEFT_CTRL_PRESSED,
         *           SHIFT_PRESSED,NUMLOCK_ON, SCROLLLOCK_ON,
         *           CAPSLOCK_ON, ENHANCED_KEY
         *
         * are all valid bit masks to use on shiftstate.
         * eg. (shiftstate & LEFT_CTRL_PRESSED) is true if the
         *      left control key was pressed with the keystroke.
         */
        if (iskeypad(scan) && !altseq) {
	    ReadConsoleInput(hConIn,ir,1,&count);
            ch = keypad_nums[scan - KEYPADLO];
        }
	else if (ch < 32 && !isnumkeypad(scan)) {
	    	/* Control code; ReadConsole seems to filter some of these,
		 * including ESC */
		ReadConsoleInput(hConIn,ir,1,&count);
	}
	/* Attempt to work better with international keyboards. */
	else {
		CHAR ch2;
		ReadConsole(hConIn,&ch2,1,&count,NULL);
		ch = ch2 & 0xFF;
                if (ch == 0) *valid = FALSE;
	}
	if (ch == '\r') ch = '\n';
	return ch;
}

int __declspec(dllexport) __stdcall
CheckInput(hConIn, ir, count, numpad, mode, mod, cc)
HANDLE hConIn;
INPUT_RECORD *ir;
DWORD *count;
int *mod;
boolean numpad;
coord *cc;
{
	int ch;
	boolean valid = 0, done = 0;
	while (!done) {
    	   *count = 0;
	   WaitForSingleObject(hConIn, INFINITE);
	   PeekConsoleInput(hConIn,ir,1,count);
	   if (mode == 0) {
		if ((ir->EventType == KEY_EVENT) && ir->Event.KeyEvent.bKeyDown) {
			ch = process_keystroke2(hConIn, ir, &valid);
			done = valid;
		} else
			ReadConsoleInput(hConIn,ir,1,count);
	   } else {
	   	ch = 0;
	        if (count > 0) {
		    if (ir->EventType == KEY_EVENT && ir->Event.KeyEvent.bKeyDown) {
			ch = ProcessKeystroke(hConIn, ir, &valid, numpad,
#ifdef PORTDEBUG
						1);
#else
						0);
#endif
			if (valid) return ch;
		    } else {
			ReadConsoleInput(hConIn,ir,1,count);
			if (ir->EventType == MOUSE_EVENT) {
			    if ((ir->Event.MouseEvent.dwEventFlags == 0) &&
		   	        (ir->Event.MouseEvent.dwButtonState & MOUSEMASK)) {
			  	cc->x = ir->Event.MouseEvent.dwMousePosition.X + 1;
			  	cc->y = ir->Event.MouseEvent.dwMousePosition.Y - 1;

			  	if (ir->Event.MouseEvent.dwButtonState & LEFTBUTTON)
		  	       		*mod = CLICK_1;
			  	else if (ir->Event.MouseEvent.dwButtonState & RIGHTBUTTON)
					*mod = CLICK_2;
#if 0	/* middle button */			       
				else if (ir->Event.MouseEvent.dwButtonState & MIDBUTTON)
			      		*mod = CLICK_3;
#endif 
			       return 0;
			    }
		        }
#if 0
			/* We ignore these types of console events */
		        else if (ir->EventType == FOCUS_EVENT) {
		        }
		        else if (ir->EventType == MENU_EVENT) {
		        }
#endif
		    }
	        } else 
		    done = 1;
	   }
	}
	*mod = 0;
	return ch;
}

int __declspec(dllexport) __stdcall
NHkbhit(hConIn, ir)
HANDLE hConIn;
INPUT_RECORD *ir;
{
	int done = 0;	/* true =  "stop searching"        */
	int retval;	/* true =  "we had a match"        */
	DWORD count;
	unsigned short int scan;
	unsigned char ch;
	unsigned long shiftstate;
	int altseq = 0, keycode, vk;
	done = 0;
	retval = 0;
	while (!done)
	{
	    count = 0;
	    PeekConsoleInput(hConIn,ir,1,&count);
	    if (count > 0) {
		if (ir->EventType == KEY_EVENT && ir->Event.KeyEvent.bKeyDown) {
			ch    = ir->Event.KeyEvent.uChar.AsciiChar;
			scan  = ir->Event.KeyEvent.wVirtualScanCode;
			shiftstate = ir->Event.KeyEvent.dwControlKeyState;
			vk = ir->Event.KeyEvent.wVirtualKeyCode;
			keycode = MapVirtualKey(vk, 2);
			if (is_altseq(shiftstate)) {
				if  (ch || inmap(keycode,vk)) altseq = 1;
				else altseq = -1;	/* invalid altseq */
			}
			if (ch || iskeypad(scan) || altseq) {
				done = 1;	    /* Stop looking         */
				retval = 1;         /* Found what we sought */
			} else {
				/* Strange Key event; let's purge it to avoid trouble */
				ReadConsoleInput(hConIn,ir,1,&count);
			}

		}
		else if ((ir->EventType == MOUSE_EVENT &&
		  (ir->Event.MouseEvent.dwButtonState & MOUSEMASK))) {
			done = 1;
			retval = 1;
		}

		else /* Discard it, it's an insignificant event */
			ReadConsoleInput(hConIn,ir,1,&count);
		} else  /* There are no events in console event queue */ {
		done = 1;	  /* Stop looking               */
		retval = 0;
	    }
	}
	return retval;
}


int __declspec(dllexport) __stdcall
SourceWhere(buf)
char **buf;
{
	if (!buf) return 0;
	*buf = where_to_get_source;
	return 1;
}

int __declspec(dllexport) __stdcall
SourceAuthor(buf)
char **buf;
{
	if (!buf) return 0;
	*buf = author;
	return 1;
}

int __declspec(dllexport) __stdcall
KeyHandlerName(buf, full)
char **buf;
int full;
{
	if (!buf) return 0;
	if (full) *buf = dllname;
	else *buf = shortdllname;
	return 1;
}