/*
 * Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
 *
 * Copy permission is hereby granted provided that this notice is
 * retained on all partial or complete copies.
 *
 * For more info on this and all of my stuff, mail edjames@berkeley.edu.
 */

#ifndef lint
static char sccsid[] = "@(#)input.c	1.2 (Berkeley) 10/22/87";
#endif not lint

#include "include.h"

#define MAXRULES	6
#define MAXDEPTH	15

#define RETTOKEN	'\n'
#ifdef SYSV
#define CRTOKEN		'\r'
#endif
#define REDRAWTOKEN	'\014'	/* CTRL(L) */
#define	SHELLTOKEN	'!'
#define HELPTOKEN	'?'
#define ALPHATOKEN	256
#define NUMTOKEN	257

typedef struct {
	int	token;
	int	to_state;
	char	*str;
	char	*(*func)();
} RULE;

typedef struct {
	int	num_rules;
	RULE	*rule;
} STATE;

typedef struct {
	char	str[20];
	int	state;
	int	rule;
	int	ch;
	int	pos;
} STACK;

#define T_RULE		stack[level].rule
#define T_STATE		stack[level].state
#define T_STR		stack[level].str
#define T_POS		stack[level].pos
#define	T_CH		stack[level].ch

#define NUMELS(a)	(sizeof (a) / sizeof (*(a)))

#define NUMSTATES	NUMELS(st)

char	*setplane(), *circle(), *left(), *right(), *Left(), *Right(), 
	*beacon(), *ex_it(), *climb(), *descend(), *setalt(), *setrelalt(), 
	*benum(), *to_dir(), *rel_dir(), *delayb(), *mark(), *unmark(),
	*airport(), *turn(), *ignore();

RULE	state0[] = {	{ ALPHATOKEN,	1,	"%c:",		setplane},
			{ RETTOKEN,	-1,	"",		NULL	},
#ifdef SYSV
			{ CRTOKEN,	-1,	"",		NULL	},
#endif
			{ HELPTOKEN,	12,	" [a-z]<ret>",	NULL	}},
	state1[] = {	{ 't',		2,	" turn",	turn	},	
			{ 'a',		3,	" altitude:",	NULL	},	
			{ 'c',		4,	" circle",	circle	},
			{ 'm',		7,	" mark",	mark	},
			{ 'u',		7,	" unmark",	unmark	},
			{ 'i',		7,	" ignore",	ignore	},
			{ HELPTOKEN,	12,	" tacmui",	NULL	}},
	state2[] = {	{ 'l',		6,	" left",	left	},	
			{ 'r',		6,	" right",	right	},	
			{ 'L',		4,	" left 90",	Left	},
			{ 'R',		4,	" right 90",	Right	},	
			{ 't',		11,	" towards",	NULL	},
			{ 'w',		4,	" to 0",	to_dir	},
			{ 'e',		4,	" to 45",	to_dir	},
			{ 'd',		4,	" to 90",	to_dir	},
			{ 'c',		4,	" to 135",	to_dir	},
			{ 'x',		4,	" to 180",	to_dir	},
			{ 'z',		4,	" to 225",	to_dir	},
			{ 'a',		4,	" to 270",	to_dir	},
			{ 'q',		4,	" to 315",	to_dir	},
			{ HELPTOKEN,	12,	" lrLRt<dir>",	NULL	}},
	state3[] = {	{ '+',		10,	" climb",	climb	},	
			{ 'c',		10,	" climb",	climb	},	
			{ '-',		10,	" descend",	descend	},	
			{ 'd',		10,	" descend",	descend	},	
			{ NUMTOKEN,	7,	" %c000 feet",	setalt	},
			{ HELPTOKEN,	12,	" +-cd[0-9]",	NULL	}},
	state4[] = {	{ '@',		9,	" at",		NULL	},	
			{ 'a',		9,	" at",		NULL	},	
			{ RETTOKEN,	-1,	"",		NULL	},
#ifdef SYSV
			{ CRTOKEN,	-1,	"",		NULL	},
#endif
			{ HELPTOKEN,	12,	" @a<ret>",	NULL	}},
	state5[] = {	{ NUMTOKEN,	7,	"%c",		delayb	},
			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
	state6[] = {	{ '@',		9,	" at",		NULL	},
			{ 'a',		9,	" at",		NULL	},
			{ 'w',		4,	" 0",		rel_dir	},
			{ 'e',		4,	" 45",		rel_dir	},
			{ 'd',		4,	" 90",		rel_dir	},
			{ 'c',		4,	" 135",		rel_dir	},
			{ 'x',		4,	" 180",		rel_dir	},
			{ 'z',		4,	" 225",		rel_dir	},
			{ 'a',		4,	" 270",		rel_dir	},
			{ 'q',		4,	" 315",		rel_dir	},
			{ RETTOKEN,	-1,	"",		NULL	},	
#ifdef SYSV
			{ CRTOKEN,	-1,	"",		NULL	},	
#endif
			{ HELPTOKEN,	12,	" @a<dir><ret>",NULL	}},
	state7[] = {	{ RETTOKEN,	-1,	"",		NULL	},
#ifdef SYSV
	            	{ CRTOKEN,	-1,	"",		NULL	},
#endif
			{ HELPTOKEN,	12,	" <ret>",	NULL	}},
	state8[] = {	{ NUMTOKEN,	4,	"%c",		benum	},
			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
	state9[] = {	{ 'b',		5,	" beacon #",	NULL	},
			{ '*',		5,	" beacon #",	NULL	},
			{ HELPTOKEN,	12,	" b*",		NULL	}},
	state10[] = {	{ NUMTOKEN,	7,	" %c000 ft",	setrelalt},
			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
	state11[] = {	{ 'b',		8,	" beacon #",	beacon	},	
			{ '*',		8,	" beacon #",	beacon	},
			{ 'e',		8,	" exit #",	ex_it	},
			{ 'a',		8,	" airport #",	airport	},
			{ HELPTOKEN,	12,	" b*ea",	NULL	}},
	state12[] = {	{ -1,		-1,	"",		NULL	}};

#define DEF_STATE(s)	{ NUMELS(s),	(s)	}

STATE	st[] = {
	DEF_STATE(state0), DEF_STATE(state1), DEF_STATE(state2),
	DEF_STATE(state3), DEF_STATE(state4), DEF_STATE(state5),
	DEF_STATE(state6), DEF_STATE(state7), DEF_STATE(state8),
	DEF_STATE(state9), DEF_STATE(state10), DEF_STATE(state11),
	DEF_STATE(state12)
};

PLANE	p;
STACK	stack[MAXDEPTH];
int	level;
int	tval;
int	dest_type, dest_no, dir;

pop()
{
	if (level == 0)
		return (-1);
	level--;

	ioclrtoeol(T_POS);

	strcpy(T_STR, "");
	T_RULE = -1;
	T_CH = -1;
	return (0);
}

rezero()
{
	iomove(0);

	level = 0;
	T_STATE = 0;
	T_RULE = -1;
	T_CH = -1;
	T_POS = 0;
	strcpy(T_STR, "");
}

push(ruleno, ch)
{
	int	newstate, newpos;

	(void)sprintf(T_STR, st[T_STATE].rule[ruleno].str, tval);
	T_RULE = ruleno;
	T_CH = ch;
	newstate = st[T_STATE].rule[ruleno].to_state;
	newpos = T_POS + strlen(T_STR);

	ioaddstr(T_POS, T_STR);

	if (level == 0)
		ioclrtobot();
	level++;
	T_STATE = newstate;
	T_POS = newpos;
	T_RULE = -1;
	strcpy(T_STR, "");
}

getcommand()
{
	int	c, i, done;
	char	*s, *(*func)();
	PLANE	*pp;

	rezero();

	do {
		c = gettoken();
		if (c == tty_new.sg_erase) {
			if (pop() < 0)
				noise();
		} else if (c == tty_new.sg_kill) {
			while (pop() >= 0)
				;
		} else {
			done = 0;
			for (i = 0; i < st[T_STATE].num_rules; i++) {
				if (st[T_STATE].rule[i].token == c ||
				    st[T_STATE].rule[i].token == tval) {
					push(i, (c >= ALPHATOKEN) ? tval : c);
					done = 1;
					break;
				}
			}
			if (!done)
				noise();
		}
	} while (T_STATE != -1);

	if (level == 1)
		return (1);	/* forced update */

	dest_type = T_NODEST;
	
	for (i = 0; i < level; i++) {
		func = st[stack[i].state].rule[stack[i].rule].func;
		if (func != NULL)
			if ((s = (*func)(stack[i].ch)) != NULL) {
				ioerror(stack[i].pos, strlen(stack[i].str), s);
				return (-1);
			}
	}

	pp = findplane(p.plane_no);
	if (pp->new_altitude != p.new_altitude)
		pp->new_altitude = p.new_altitude;
	else if (pp->status != p.status)
		pp->status = p.status;
	else {
		pp->new_dir = p.new_dir;
		pp->delayd = p.delayd;
		pp->delayd_no = p.delayd_no;
	}
	return (0);
}

noise()
{
	putchar('\07');
	fflush(stdout);
}

gettoken()
{
	while ((tval = getAChar()) == REDRAWTOKEN || tval == SHELLTOKEN)
	{
		if (tval == SHELLTOKEN)
		{
#ifdef BSD
			struct itimerval	itv;
			itv.it_value.tv_sec = 0;
			itv.it_value.tv_usec = 0;
			setitimer(ITIMER_REAL, &itv, NULL);
#endif
#ifdef SYSV
			int aval;
			aval = alarm(0);
#endif
			if (fork() == 0)	/* child */
			{
				char *shell, *base, *getenv(), *strrchr();

				setuid(getuid()); /* turn off setuid bit */
				done_screen();

						 /* run user's favorite shell */
				if ((shell = getenv("SHELL")) != NULL)
				{
					base = strrchr(shell, '/');
					if (base == NULL)
						base = shell;
					else
						base++;
					execl(shell, base, 0);
				}
				else
					execl("/bin/sh", "sh", 0);

				exit(0);	/* oops */
			}

			wait(0);
#ifdef BSD
			ioctl(fileno(stdin), TIOCSETP, &tty_new);
			itv.it_value.tv_sec = 0;
			itv.it_value.tv_usec = 1;
			itv.it_interval.tv_sec = sp->update_secs;
			itv.it_interval.tv_usec = 0;
			setitimer(ITIMER_REAL, &itv, NULL);
#endif
#ifdef SYSV
			ioctl(fileno(stdin), TCSETAW, &tty_new);
			alarm(aval);
#endif
		}
		redraw();
	}

	if (isdigit(tval))
		return (NUMTOKEN);
	else if (isalpha(tval))
		return (ALPHATOKEN);
	else
		return (tval);
}

char	*
setplane(c)
{
	PLANE	*pp;

	pp = findplane(number(c));
	if (pp == NULL)
		return ("Unknown Plane");
	bcopy(pp, &p, sizeof (p));
	p.delayd = 0;
	return (NULL);
}

char	*
turn(c)
{
	if (p.altitude == 0)
		return ("Planes at airports may not change direction");
	return (NULL);
}

char	*
circle(c)
{
	if (p.altitude == 0)
		return ("Planes cannot circle on the ground");
	p.new_dir = MAXDIR;
	return (NULL);
}

char	*
left(c)
{
	dir = D_LEFT;
	p.new_dir = p.dir - 1;
	if (p.new_dir < 0)
		p.new_dir += MAXDIR;
	return (NULL);
}

char	*
right(c)
{
	dir = D_RIGHT;
	p.new_dir = p.dir + 1;
	if (p.new_dir > MAXDIR)
		p.new_dir -= MAXDIR;
	return (NULL);
}

char	*
Left(c)
{
	p.new_dir = p.dir - 2;
	if (p.new_dir < 0)
		p.new_dir += MAXDIR;
	return (NULL);
}

char	*
Right(c)
{
	p.new_dir = p.dir + 2;
	if (p.new_dir > MAXDIR)
		p.new_dir -= MAXDIR;
	return (NULL);
}

char	*
delayb(c)
{
	int	xdiff, ydiff;

	c -= '0';

	if (c >= sp->num_beacons)
		return ("Unknown beacon");
	xdiff = sp->beacon[c].x - p.xpos;
	xdiff = SGN(xdiff);
	ydiff = sp->beacon[c].y - p.ypos;
	ydiff = SGN(ydiff);
	if (xdiff != displacement[p.dir].dx || ydiff != displacement[p.dir].dy)
		return ("Beacon is not in flight path");
	p.delayd = 1;
	p.delayd_no = c;

	if (dest_type != T_NODEST) {
		switch (dest_type) {
		case T_BEACON:
			xdiff = sp->beacon[dest_no].x - sp->beacon[c].x;
			ydiff = sp->beacon[dest_no].y - sp->beacon[c].y;
			break;
		case T_EXIT:
			xdiff = sp->exit[dest_no].x - sp->beacon[c].x;
			ydiff = sp->exit[dest_no].y - sp->beacon[c].y;
			break;
		case T_AIRPORT:
			xdiff = sp->airport[dest_no].x - sp->beacon[c].x;
			ydiff = sp->airport[dest_no].y - sp->beacon[c].y;
			break;
		default:
			return ("Bad case in delayb!  Get help!");
			break;
		}
		if (xdiff == 0 && ydiff == 0)
			return ("Would already be there");
		p.new_dir = DIR_FROM_DXDY(xdiff, ydiff);
		if (p.new_dir == p.dir)
			return ("Already going in that direction");
	}
	return (NULL);
}

char	*
beacon(c)
{
	dest_type = T_BEACON;
	return (NULL);
}

char	*
ex_it(c)
{
	dest_type = T_EXIT;
	return (NULL);
}

char	*
airport(c)
{
	dest_type = T_AIRPORT;
	return (NULL);
}

char	*
climb(c)
{
	dir = D_UP;
	return (NULL);
}

char	*
descend(c)
{
	dir = D_DOWN;
	return (NULL);
}

char	*
setalt(c)
{
	if ((p.altitude == c - '0') && (p.new_altitude == p.altitude))
		return ("Already at that altitude");
	p.new_altitude = c - '0';
	return (NULL);
}

char	*
setrelalt(c)
{
	if (c == 0)
		return ("altitude not changed");

	switch (dir) {
	case D_UP:
		p.new_altitude = p.altitude + c - '0';
		break;
	case D_DOWN:
		p.new_altitude = p.altitude - (c - '0');
		break;
	default:
		return ("Unknown case in setrelalt!  Get help!");
		break;
	}
	if (p.new_altitude < 0)
		return ("Altitude would be too low");
	else if (p.new_altitude > 9)
		return ("Altitude would be too high");
	return (NULL);
}

char	*
benum(c)
{
	dest_no = c -= '0';

	switch (dest_type) {
	case T_BEACON:
		if (c >= sp->num_beacons)
			return ("Unknown beacon");
		p.new_dir = DIR_FROM_DXDY(sp->beacon[c].x - p.xpos,
			sp->beacon[c].y - p.ypos);
		break;
	case T_EXIT:
		if (c >= sp->num_exits)
			return ("Unknown exit");
		p.new_dir = DIR_FROM_DXDY(sp->exit[c].x - p.xpos,
			sp->exit[c].y - p.ypos);
		break;
	case T_AIRPORT:
		if (c >= sp->num_airports)
			return ("Unknown airport");
		p.new_dir = DIR_FROM_DXDY(sp->airport[c].x - p.xpos,
			sp->airport[c].y - p.ypos);
		break;
	default:
		return ("Unknown case in benum!  Get help!");
		break;
	}
	return (NULL);
}

char	*
to_dir(c)
{
	p.new_dir = dir_no(c);
	return (NULL);
}

char	*
rel_dir(c)
{
	int	angle;

	angle = dir_no(c);
	switch (dir) {
	case D_LEFT:
		p.new_dir = p.dir - angle;
		if (p.new_dir < 0)
			p.new_dir += MAXDIR;
		break;
	case D_RIGHT:
		p.new_dir = p.dir + angle;
		if (p.new_dir >= MAXDIR)
			p.new_dir -= MAXDIR;
		break;
	default:
		return ("Bizarre direction in rel_dir!  Get help!");
		break;
	}
	return (NULL);
}

char	*
mark(c)
{
	if (p.altitude == 0)
		return ("Cannot mark planes on the ground");
	if (p.status == S_MARKED)
		return ("Already marked");
	p.status = S_MARKED;
	return (NULL);
}

char	*
unmark(c)
{
	if (p.altitude == 0)
		return ("Cannot unmark planes on the ground");
	if (p.status == S_UNMARKED)
		return ("Already unmarked");
	p.status = S_UNMARKED;
	return (NULL);
}

char	*
ignore(c)
{
	if (p.altitude == 0)
		return ("Cannot ignore planes on the ground");
	if (p.status == S_IGNORED)
		return ("Already ignored");
	p.status = S_IGNORED;
	return (NULL);
}

dir_no(ch)
	char	ch;
{
	int	dir;

	switch (ch) {
	case 'w':	dir = 0;	break;
	case 'e':	dir = 1;	break;
	case 'd':	dir = 2;	break;
	case 'c':	dir = 3;	break;
	case 'x':	dir = 4;	break;
	case 'z':	dir = 5;	break;
	case 'a':	dir = 6;	break;
	case 'q':	dir = 7;	break;
	default:
		fprintf(stderr, "bad character in dir_no\n");
		break;
	}
	return (dir);
}