/****************************************************************************
*
*                   SciTech OS Portability Manager Library
*
*  ========================================================================
*
*    The contents of this file are subject to the SciTech MGL Public
*    License Version 1.0 (the "License"); you may not use this file
*    except in compliance with the License. You may obtain a copy of
*    the License at http://www.scitechsoft.com/mgl-license.txt
*
*    Software distributed under the License is distributed on an
*    "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
*    implied. See the License for the specific language governing
*    rights and limitations under the License.
*
*    The Original Code is Copyright (C) 1991-1998 SciTech Software, Inc.
*
*    The Initial Developer of the Original Code is SciTech Software, Inc.
*    All Rights Reserved.
*
*  ========================================================================
*
* Language:     ANSI C
* Environment:  32-bit DOS
*
* Description:  32-bit DOS implementation for the SciTech cross platform
*               event library.
*
****************************************************************************/

/*--------------------------- Global variables ----------------------------*/

ibool _VARAPI   _EVT_useEvents = true;  /* True to use event handling   */
ibool _VARAPI   _EVT_installed = 0;     /* Event handers installed?     */
uchar _VARAPI   *_EVT_biosPtr = NULL;   /* Pointer to the BIOS data area */
static ibool    haveMouse = false;      /* True if we have a mouse      */

/*---------------------------- Implementation -----------------------------*/

/* External assembler functions */

void    EVTAPI _EVT_pollJoystick(void);
uint    EVTAPI _EVT_disableInt(void);
uint    EVTAPI _EVT_restoreInt(uint flags);
void    EVTAPI _EVT_codeStart(void);
void    EVTAPI _EVT_codeEnd(void);
void    EVTAPI _EVT_cCodeStart(void);
void    EVTAPI _EVT_cCodeEnd(void);
int     EVTAPI _EVT_getKeyCode(void);
void    EVTAPI _EVT_pumpMessages(void);
int     EVTAPI EVT_rdinx(int port,int index);
void    EVTAPI EVT_wrinx(int port,int index,int value);

#ifdef NO_KEYBOARD_INTERRUPT
/****************************************************************************
REMARKS:
This function is used to pump all keyboard messages from the BIOS keyboard
handler into our event queue. This can be used to avoid using the
installable keyboard handler if this is causing problems.
****************************************************************************/
static void EVTAPI _EVT_pumpMessages(void)
{
    RMREGS  regs;
	uint    key,ps;

	/* Since the keyboard ISR has not been installed if NO_IDE_BUG has
	 * been defined, we first check for any pending keyboard events
	 * here, and if there are some insert them into the event queue to
	 * be picked up later - what a kludge.
	 */
	while ((key = _EVT_getKeyCode()) != 0) {
		ps = _EVT_disableInt();
		addKeyEvent(EVT_KEYDOWN, key);
		_EVT_restoreInt(ps);
		}

    regs.x.ax = 0x0B;           /* Reset Move Mouse */
    PM_int86(0x33,&regs,&regs);
}
#endif

/****************************************************************************
REMARKS:
This function is used to return the number of ticks since system
startup in milliseconds. This should be the same value that is placed into
the time stamp fields of events, and is used to implement auto mouse down
events.
****************************************************************************/
ulong _EVT_getTicks(void)
{
    return (ulong)PM_getLong(_EVT_biosPtr+0x6C) * 55UL;
}

/****************************************************************************
REMARKS:
Reboots the machine from DOS (warm boot)
****************************************************************************/
static void Reboot(void)
{
    PMREGS  regs;
    PMSREGS sregs;

    ushort *rebootType = PM_mapRealPointer(0x40,0x72);
    *rebootType = 0x1234;
    PM_callRealMode(0xFFFF,0x0000,&regs,&sregs);
}

/****************************************************************************
REMARKS:
Include generic raw scancode keyboard module.
****************************************************************************/
#define SUPPORT_CTRL_ALT_DEL
#include "common/keyboard.c"

/****************************************************************************
REMARKS:
This function fools the DOS mouse driver into thinking that it is running
in graphics mode, rather than text mode so we always get virtual coordinates
correctly rather than character coordinates.
****************************************************************************/
int _EVT_foolMouse(void)
{
    int oldmode = PM_getByte(_EVT_biosPtr+0x49);
    PM_setByte(_EVT_biosPtr+0x49,0x10);
    oldmode |= (EVT_rdinx(0x3C4,0x2) << 8);
    return oldmode;
}

/****************************************************************************
REMARKS:
This function unfools the DOS mouse driver after we have finished calling it.
****************************************************************************/
void _EVT_unfoolMouse(
    int oldmode)
{
    PM_setByte(_EVT_biosPtr+0x49,oldmode);

    /* Some mouse drivers reset the plane mask register for VGA plane 4
     * modes, which screws up the display on some VGA compatible controllers
     * in SuperVGA modes. We reset the value back again in here to solve
     * the problem.
     */
    EVT_wrinx(0x3C4,0x2,oldmode >> 8);
}

/****************************************************************************
REMARKS:
Determines if we have a mouse attached and functioning.
****************************************************************************/
static ibool detectMouse(void)
{
    RMREGS  regs;
    RMSREGS sregs;
    uchar   *p;
    ibool   retval;

    regs.x.ax = 0x3533;                 /* Get interrupt vector 0x33    */
    PM_int86x(0x21,&regs,&regs,&sregs);

    /* Check that interrupt vector 0x33 is not a zero, and that the first
     * instruction in the interrupt vector is not an IRET instruction
     */
    p = PM_mapRealPointer(sregs.es, regs.x.bx);
    retval = ((sregs.es != 0) || (regs.x.bx != 0)) && (PM_getByte(p) != 207);
    return retval;
}

/****************************************************************************
PARAMETERS:
what        - Event code
message     - Event message
x,y         - Mouse position at time of event
but_stat    - Mouse button status at time of event

REMARKS:
Adds a new mouse event to the event queue. This routine is called from within
the mouse interrupt subroutine, so it must be efficient.

NOTE:   Interrupts MUST be OFF while this routine is called to ensure we have
	mutually exclusive access to our internal data structures for
	interrupt driven systems (like under DOS).
****************************************************************************/
static void addMouseEvent(
    uint what,
    uint message,
    int x,
    int y,
    int mickeyX,
    int mickeyY,
    uint but_stat)
{
    event_t evt;

    if (EVT.count < EVENTQSIZE) {
	/* Save information in event record. */
	evt.when = _EVT_getTicks();
	evt.what = what;
	evt.message = message;
	evt.modifiers = but_stat;
	evt.where_x = x;                /* Save mouse event position    */
	evt.where_y = y;
	evt.relative_x = mickeyX;
	evt.relative_y = mickeyY;
	evt.modifiers |= EVT.keyModifiers;
	addEvent(&evt);                 /* Add to tail of event queue   */
	}
}

/****************************************************************************
PARAMETERS:
mask        - Event mask
butstate    - Button state
x           - Mouse x coordinate
y           - Mouse y coordinate

REMARKS:
Mouse event handling routine. This gets called when a mouse event occurs,
and we call the addMouseEvent() routine to add the appropriate mouse event
to the event queue.

Note: Interrupts are ON when this routine is called by the mouse driver code.
****************************************************************************/
static void EVTAPI mouseISR(
    uint mask,
    uint butstate,
    int x,
    int y,
    int mickeyX,
    int mickeyY)
{
    uint    ps;
    uint    buttonMask;

    if (mask & 1) {
	/* Save the current mouse coordinates */
	EVT.mx = x; EVT.my = y;

	/* If the last event was a movement event, then modify the last
	 * event rather than post a new one, so that the queue will not
	 * become saturated. Before we modify the data structures, we
	 * MUST ensure that interrupts are off.
	 */
	ps = _EVT_disableInt();
	if (EVT.oldMove != -1) {
	    EVT.evtq[EVT.oldMove].where_x = x;  /* Modify existing one  */
	    EVT.evtq[EVT.oldMove].where_y = y;
	    EVT.evtq[EVT.oldMove].relative_x += mickeyX;
	    EVT.evtq[EVT.oldMove].relative_y += mickeyY;
	    }
	else {
	    EVT.oldMove = EVT.freeHead;         /* Save id of this move event   */
	    addMouseEvent(EVT_MOUSEMOVE,0,x,y,mickeyX,mickeyY,butstate);
	    }
	_EVT_restoreInt(ps);
	}
    if (mask & 0x2A) {
	ps = _EVT_disableInt();
	buttonMask = 0;
	if (mask & 2)  buttonMask |= EVT_LEFTBMASK;
	if (mask & 8)  buttonMask |= EVT_RIGHTBMASK;
	if (mask & 32) buttonMask |= EVT_MIDDLEBMASK;
	addMouseEvent(EVT_MOUSEDOWN,buttonMask,x,y,0,0,butstate);
	EVT.oldMove = -1;
	_EVT_restoreInt(ps);
	}
    if (mask & 0x54) {
	ps = _EVT_disableInt();
	buttonMask = 0;
	if (mask & 2)  buttonMask |= EVT_LEFTBMASK;
	if (mask & 8)  buttonMask |= EVT_RIGHTBMASK;
	if (mask & 32) buttonMask |= EVT_MIDDLEBMASK;
	addMouseEvent(EVT_MOUSEUP,buttonMask,x,y,0,0,butstate);
	EVT.oldMove = -1;
	_EVT_restoreInt(ps);
	}
    EVT.oldKey = -1;
}

/****************************************************************************
REMARKS:
Keyboard interrupt handler function.

NOTE:   Interrupts are OFF when this routine is called by the keyboard ISR,
	and we leave them OFF the entire time.
****************************************************************************/
static void EVTAPI keyboardISR(void)
{
    processRawScanCode(PM_inpb(0x60));
    PM_outpb(0x20,0x20);
}

/****************************************************************************
REMARKS:
Safely abort the event module upon catching a fatal error.
****************************************************************************/
void _EVT_abort()
{
    EVT_exit();
    PM_fatalError("Unhandled exception!");
}

/****************************************************************************
PARAMETERS:
mouseMove   - Callback function to call wheneve the mouse needs to be moved

REMARKS:
Initiliase the event handling module. Here we install our mouse handling ISR
to be called whenever any button's are pressed or released. We also build
the free list of events in the event queue.

We use handler number 2 of the mouse libraries interrupt handlers for our
event handling routines.
****************************************************************************/
void EVTAPI EVT_init(
    _EVT_mouseMoveHandler mouseMove)
{
    int     i;

    PM_init();
    EVT.mouseMove = mouseMove;
    _EVT_biosPtr = PM_getBIOSPointer();
    EVT_resume();

    /* Grab all characters pending in the keyboard buffer and stuff
     * them into our event buffer. This allows us to pick up any keypresses
     * while the program is initialising.
     */
    while ((i = _EVT_getKeyCode()) != 0)
	addKeyEvent(EVT_KEYDOWN,i);
}

/****************************************************************************
REMARKS:
Initiailises the internal event handling modules. The EVT_suspend function
can be called to suspend event handling (such as when shelling out to DOS),
and this function can be used to resume it again later.
****************************************************************************/
void EVTAPI EVT_resume(void)
{
    static int      locked = 0;
    int             stat;
    uchar           mods;
    PM_lockHandle   lh; /* Unused in DOS */

    if (_EVT_useEvents) {
	/* Initialise the event queue and enable our interrupt handlers */
	initEventQueue();
#ifndef NO_KEYBOARD_INTERRUPT
	PM_setKeyHandler(keyboardISR);
#endif
#ifndef NO_MOUSE_INTERRUPT
	if ((haveMouse = detectMouse()) != 0) {
	    int oldmode = _EVT_foolMouse();
	    PM_setMouseHandler(0xFFFF,mouseISR);
	    _EVT_unfoolMouse(oldmode);
	    }
#endif

	/* Read the keyboard modifier flags from the BIOS to get the
	 * correct initialisation state. The only state we care about is
	 * the correct toggle state flags such as SCROLLLOCK, NUMLOCK and
	 * CAPSLOCK.
	 */
	EVT.keyModifiers = 0;
	mods = PM_getByte(_EVT_biosPtr+0x17);
	if (mods & 0x10)
	    EVT.keyModifiers |= EVT_SCROLLLOCK;
	if (mods & 0x20)
	    EVT.keyModifiers |= EVT_NUMLOCK;
	if (mods & 0x40)
	    EVT.keyModifiers |= EVT_CAPSLOCK;

	/* Lock all of the code and data used by our protected mode interrupt
	 * handling routines, so that it will continue to work correctly
	 * under real mode.
	 */
	if (!locked) {
	    /* It is difficult to ensure that we lock our global data, so we
	     * do this by taking the address of a variable locking all data
	     * 2Kb on either side. This should properly cover the global data
	     * used by the module (the other alternative is to declare the
	     * variables in assembler, in which case we know it will be
	     * correct).
	     */
	    stat  = !PM_lockDataPages(&EVT,sizeof(EVT),&lh);
	    stat |= !PM_lockDataPages(&_EVT_biosPtr,sizeof(_EVT_biosPtr),&lh);
	    stat |= !PM_lockCodePages((__codePtr)_EVT_cCodeStart,(int)_EVT_cCodeEnd-(int)_EVT_cCodeStart,&lh);
	    stat |= !PM_lockCodePages((__codePtr)_EVT_codeStart,(int)_EVT_codeEnd-(int)_EVT_codeStart,&lh);
	    if (stat) {
		PM_fatalError("Page locking services failed - interrupt handling not safe!");
		exit(1);
		}
	    locked = 1;
	    }

	/* Catch program termination signals so we can clean up properly */
	signal(SIGABRT, _EVT_abort);
	signal(SIGFPE, _EVT_abort);
	signal(SIGINT, _EVT_abort);
	_EVT_installed = true;
	}
}

/****************************************************************************
REMARKS
Changes the range of coordinates returned by the mouse functions to the
specified range of values. This is used when changing between graphics
modes set the range of mouse coordinates for the new display mode.
****************************************************************************/
void EVTAPI EVT_setMouseRange(
    int xRes,
    int yRes)
{
    RMREGS  regs;

    if (haveMouse) {
	int oldmode = _EVT_foolMouse();
	PM_resetMouseDriver(1);
	regs.x.ax = 7;  /* Mouse function 7 - Set horizontal min and max */
	regs.x.cx = 0;
	regs.x.dx = xRes;
	PM_int86(0x33,&regs,&regs);
	regs.x.ax = 8;  /* Mouse function 8 - Set vertical min and max   */
	regs.x.cx = 0;
	regs.x.dx = yRes;
	PM_int86(0x33,&regs,&regs);
	_EVT_unfoolMouse(oldmode);
	}
}

/****************************************************************************
REMARKS
Modifes the mouse coordinates as necessary if scaling to OS coordinates,
and sets the OS mouse cursor position.
****************************************************************************/
void _EVT_setMousePos(
    int *x,
    int *y)
{
    RMREGS  regs;

    if (haveMouse) {
	int oldmode = _EVT_foolMouse();
	regs.x.ax = 4;      /* Mouse function 4 - Set mouse position    */
	regs.x.cx = *x;     /* New horizontal coordinate                */
	regs.x.dx = *y;     /* New vertical coordinate                  */
	PM_int86(0x33,&regs,&regs);
	_EVT_unfoolMouse(oldmode);
	}
}

/****************************************************************************
REMARKS
Suspends all of our event handling operations. This is also used to
de-install the event handling code.
****************************************************************************/
void EVTAPI EVT_suspend(void)
{
    uchar   mods;

    if (_EVT_installed) {
	/* Restore the interrupt handlers */
	PM_restoreKeyHandler();
	if (haveMouse)
	    PM_restoreMouseHandler();
	signal(SIGABRT, SIG_DFL);
	signal(SIGFPE, SIG_DFL);
	signal(SIGINT, SIG_DFL);

	/* Set the keyboard modifier flags in the BIOS to our values */
	EVT_allowLEDS(true);
	mods = PM_getByte(_EVT_biosPtr+0x17) & ~0x70;
	if (EVT.keyModifiers & EVT_SCROLLLOCK)
	    mods |= 0x10;
	if (EVT.keyModifiers & EVT_NUMLOCK)
	    mods |= 0x20;
	if (EVT.keyModifiers & EVT_CAPSLOCK)
	    mods |= 0x40;
	PM_setByte(_EVT_biosPtr+0x17,mods);

	/* Flag that we are no longer installed */
	_EVT_installed = false;
	}
}

/****************************************************************************
REMARKS
Exits the event module for program terminatation.
****************************************************************************/
void EVTAPI EVT_exit(void)
{
    EVT_suspend();
}