/*-
 * Copyright (c) 2007 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "cons.h"
#include "emul.h"
#include "vars.h"

#include <errno.h>
#include <signal.h>

/*
 * Register variables used by WWIV when interfacing with the BIOS.
 */
unsigned int	_AX;
unsigned short	_AH;
unsigned short	_AL;
unsigned int	_BX;
unsigned short	_BH;
unsigned short	_BL;
unsigned int	_CX;
unsigned short	_CH;
unsigned short	_CL;
unsigned int	_DX;
unsigned short	_DH;
unsigned short	_DL;
unsigned int	_DS;
unsigned int	_SS;
unsigned int	_SP;

/*
 * Interrupt 16 operations: keyboard.
 */
#define	INT16_KEYCHECK	0x01

/*
 * Simulated interrupt vector table.
 */
// static void (*intr)(void)[256];

void
geninterrupt(int intr_num)
{
	struct timeval tv;
	struct tm tm;
	time_t t;

	if (intr_num == 0x21 && _AH == 0x2a) {
		/*
		 * Retrieve system date.
		 */
		if (gettimeofday(&tv, NULL) < 0)
			panic("geninterrupt: gettimeofday: %s",
			    strerror(errno));

		t = tv.tv_sec;
		localtime_r(&t, &tm);

		_CX = tm.tm_year - 80;
		_DH = tm.tm_mon;
		_DL = tm.tm_mday;
		_AL = tm.tm_wday;
		return;
	}
	panic("geninterrupt(0x%02x): %s", intr_num, strerror(ENOSYS));
}

void
setvect(int intr_num, void (*intr)(void))
{

}

void *
getvect(int intr_num)
{

	return (NULL);
}

/*
 * my_video_int() is a wrapper for int10, the BIOS video interrupt.
 */
void
_VideoInt(void)
{

	switch (_AH) {
	case 0x02:
		cons_setxy(_DL, _DH);
		return;

	case 0x03:
		_DL = cons_getx();
		_DH = cons_gety();
		_AX = 0x0000;
		return;

	case 0x06:
		//printf("0x06 %d (%d, %d) (%d %d)\n", _AL, _CH, _CL, _DH, _DL);
		/*
		 * Scroll up window.
		 */
		if (_AL == 0)
			cons_winclear(_CL, _CH, _DL, _DH);
		else
			cons_winscrollup(_CL, _CH, _DL, _DH, _AL);
		return;

	case 0x07:
		if (_AL == 0)
			cons_winclear(_CL, _CH, _DL, _DH);
		else
			cons_winscrolldown(_CL, _CH, _DL, _DH, _AL);
		return;

	case 0x09:
		cons_putchar(_AL);
		return;

	case 0x0f:
		_AH = cons_getwidth();
		_AL = 3;
		_BH = 0;
		return;
	}

	panic("my_video_int(%d): %s", _AH, strerror(ENOSYS));
}

static int
video_int(union REGS *regs)
{

	switch (regs->h.ah) {
	case 0x0f:
		/*
		 * Return video mode information.
		 */
		regs->h.ah = 80;	/* Columns. */
		regs->h.al = 3;		/* Video mode. */
		return (regs->w.ax);
	}
	panic("video_int(0x%02x): %s", regs->h.ah, strerror(ENOSYS));
}

static int
keyboard_int(union REGS *regs)
{

	switch (regs->h.ah) {
	case 0x01:
		/*
		 * Has a key been hit?
		 */
		if (cons_keycheck() == 0)
			regs->x.flags |= 64;
		else
			regs->x.flags &= ~64;
		return (regs->w.ax);
	}
	panic("keyboard_int(0x%02x): %s", regs->h.ah, strerror(ENOSYS));
}

static int
dos_int(union REGS *regs)
{

	switch (regs->h.ah) {
	case 0x06:
		/*
		 * Direct console input.
		 */
		if (regs->h.dl == 0xff) {
			if (cons_keycheck() == 0) {
				regs->h.al = 0x00;
				regs->x.flags |= 64;
			} else {
				regs->h.al = cons_keyget();
				regs->x.flags &= ~64;
			}
		} else {
			regs->h.al = cons_keyget();
			regs->x.flags &= ~64;
		}
		return (regs->w.ax);

	case 0x33:
		/*
		 * Disable Ctrl-Break handling.
		 *
		 * XXXRW: Currently not implemented.  Should disable
		 * SIGINT?
		 */
		if (regs->h.al != 0x01)
			break;
		//signal(SIGINT, SIG_IGN);
		return (regs->w.ax);
	}
	panic("dos_int(0x%02x): %s", regs->h.ah, strerror(ENOSYS));
}

int
int86(int ivec, union REGS *in, union REGS *out)
{

	*out = *in;

	switch (ivec) {
	case 0x10:
		return (video_int(out));

	case 0x16:
		return (keyboard_int(out));

	case 0:
	case 0x21:
		return (dos_int(out));
	}

	panic("int86 (ivec 0x%02x ah 0x%02x): %s", ivec, in->h.ah,
	    strerror(ENOSYS));
}

int
int86x(int ivec, union REGS *in, union REGS *out, struct SREGS *seg)
{

	/*
	 * XXXRW: This may not work.
	 */
#if 0
	errno = ENOSYS;
	errx(-1, "int86x");
#else
	return (int86(ivec, in, out));
#endif
}

unsigned char
inportb(unsigned short port)
{

	panic("inportb: %s", strerror(ENOSYS));
}

unsigned char
outportb(unsigned short port, unsigned char data)
{

	panic("outportb: %s", strerror(ENOSYS));
}

void
disable(void)
{

}

void
enable(void)
{

}

/*
 * setbeep() turns on or off the system speaker.
 */
void
setbeep(int i)
{

	if (i)
		cons_beep();
}

void
bios_init(void)
{

}