/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

/*
 * This code is based on original Soltys source code
 * Copyright (c) 1994-1995 Janus B. Wisniewski and L.K. Avalon
 */

#include	"cge/keybd.h"
#include	"cge/mouse.h"
#include	<dos.h>

namespace CGE {

SPRITE * KEYBOARD::Client = NULL;
uint8  KEYBOARD::Key[0x60] = { 0 };
uint16  KEYBOARD::Current = 0;
uint16  KEYBOARD::Code[0x60] = { 0,Esc,'1','2','3','4','5','6','7','8','9','0',
			       '-','+',BSp,Tab,'Q','W','E','R','T','Y','U',
			       'I','O','P','[',']',Enter,0/*Ctrl*/,'A','S',
			       'D','F','G','H','J','K','L',';','\'','`',
			       0/*LShift*/,'\\','Z','X','C','V','B','N','M',
			       ',','.','/',0/*RShift*/,'*',0/*Alt*/,' ',
			       0/*Caps*/,F1,F2,F3,F4,F5,F6,F7,F8,F9,F10,
			       0/*NumLock*/,0/*ScrollLock*/,Home,Up,PgUp,
			       '-',Left,Ctr,Right,'+',End,Down,PgDn,Ins,Del,
			       0*0x54,0*0x55,0*0x56,F11,F12,0*0x59,0*0x5A,
			       0*0x5B,0*0x5C,0*0x5D,0*0x5E,0*0x5F
			     };
void interrupt	(* KEYBOARD::OldKeyboard) (...);



KEYBOARD::KEYBOARD (void)
{
  // steal keyboard interrupt
  OldKeyboard = getvect(KEYBD_INT);
  setvect(KEYBD_INT, NewKeyboard);
}




KEYBOARD::~KEYBOARD (void)
{
  // bring back keyboard interrupt
  setvect(KEYBD_INT, OldKeyboard);
}




SPRITE * KEYBOARD::SetClient (SPRITE * spr)
{
  Swap(Client, spr);
  return spr;
}





void interrupt KEYBOARD::NewKeyboard (...)
{
  // table address
  _SI = (uint16) Key;

  // take keyboard code
  asm	in	al,60h
  asm	mov	bl,al
  asm	and	bx,007Fh
  asm	cmp	bl,60h
  asm	jae	xit
  asm	cmp	al,bl
  asm	je	ok		// key pressed

  // key released...
  asm	cmp	[si+bx],bh	// BH == 0
  asm	jne	ok
  // ...but not pressed: call the original service
  OldKeyboard();
  return;

  ok:
  asm	shl	ax,1
  asm	and	ah,1
  asm	xor	ah,1
  asm	mov	[si+bx],ah
  asm	jz	xit		// released: exit

  // pressed: lock ASCII code
  _SI = (uint16) Code;
  asm	add	bx,bx		// uint16 size
  asm	mov	ax,[si+bx]
  asm	or	ax,ax
  asm	jz	xit		// zero means NO KEY
  Current = _AX;

  _SI = (uint16) Client;
  asm	or	si,si
  asm	jz	xit				// if (Client) ...
//--- fill current event entry with mask, key code and sprite
  asm	mov	bx,EvtHead			// take queue head pointer
  asm	inc	byte ptr EvtHead		// update queue head pointer
  asm	shl	bx,3				// * 8
  _AX = Current;
  asm	mov	Evt[bx].(struct EVENT)X,ax	// key code
  asm	mov	ax,KEYB				// event mask
  asm	mov	Evt[bx].(struct EVENT)Msk,ax	// event mask
  //asm	mov	Evt[bx].(struct EVENT)Y,dx	// row
  asm	mov	Evt[bx].(struct EVENT)Ptr,si	// SPRITE pointer

  xit:

  asm	in	al,61h		// kbd control lines
  asm	push	ax		// save it
  asm	or	al,80h		// set the "enable kbd" bit
  asm	out	61h,al		// and write it out
  asm	pop	ax		// original control port value
  asm	out	61h,al		// write it back
  asm	mov	al,20h		// send End-Of-Interrupt
  asm	out	20h,al		// to the 8259 IC
}

} // End of namespace CGE