/*	$OpenBSD: worm.c,v 1.27 2014/11/03 22:14:54 deraadt Exp $	*/

/*
 * Copyright (c) 1980, 1993
 *	The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

/*
 * Worm.  Written by Michael Toy
 * UCSC
 */

#include <sys/types.h>
#include <ctype.h>
#include <curses.h>
#include <err.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <poll.h>

#define HEAD '@'
#define BODY 'o'
#define LENGTH 7
#define RUNLEN 8
#define CNTRL(p) (p-'A'+1)

WINDOW *tv;
WINDOW *stw;
struct body {
	int x;
	int y;
	struct body *prev;
	struct body *next;
} *head, *tail, goody;
int growing = 0;
int running = 0;
int slow = 0;
int score = 0;
int start_len = LENGTH;
int visible_len;
int lastch;
char outbuf[BUFSIZ];

volatile sig_atomic_t wantleave = 0;
volatile sig_atomic_t wantsuspend = 0;

void	crash(void);
void	display(struct body *, char);
void	leave(int);
void	life(void);
void	newpos(struct body *);
struct body 	*newlink(void);
void	process(int);
void	prize(void);
int	rnd(int);
void	setup(void);
void	suspend(int);

int
main(int argc, char **argv)
{
	int retval;
	struct timeval t, tod;
	struct timezone tz;
	struct pollfd pfd[1];
	const char *errstr;

	setbuf(stdout, outbuf);
	signal(SIGINT, leave);
	signal(SIGQUIT, leave);
	signal(SIGTSTP, suspend);	/* process control signal */
	initscr();
	cbreak();
	noecho();
	keypad(stdscr, TRUE);
	slow = (baudrate() <= 1200);
	clear();
	if (COLS < 18 || LINES < 5) {
		endwin();
		errx(1, "screen too small");
	}
	if (argc >= 2) {
		start_len = strtonum(argv[1], 1, ((LINES-3) * (COLS-2)) / 3,
		    &errstr);
		if (errstr) {
			endwin();
			errx(1, "length argument is %s.", errstr);
		}
	}
	stw = newwin(1, COLS-1, 0, 0);
	tv = newwin(LINES-1, COLS-1, 1, 0);
	box(tv, '*', '*');
	scrollok(tv, FALSE);
	scrollok(stw, FALSE);
	wmove(stw, 0, 0);
	wprintw(stw, " Worm");
	refresh();
	wrefresh(stw);
	wrefresh(tv);
	life();			/* Create the worm */
	prize();		/* Put up a goal */
	wmove(tv, head->y, head->x);    /* Leave cursor on worm */
	wrefresh(tv);
	while(1)
	{
		if (wantleave) {
			endwin();		/* XXX signal race */
			exit(0);
		}
		if (wantsuspend) {
			move(LINES-1, 0);
			refresh();
			endwin();
			fflush(stdout);
			kill(getpid(), SIGSTOP);
			signal(SIGTSTP, suspend);
			cbreak();
			noecho();
			setup();
			wantsuspend = 0;
		}

		if (running)
		{
			running--;
			process(lastch);
		}
		else
		{
			/* fflush(stdout); */
			/* Delay could be a command line option */
			t.tv_sec = 1;
			t.tv_usec = 0;
			(void)gettimeofday(&tod, &tz);
			pfd[0].fd = STDIN_FILENO;
			pfd[0].events = POLLIN;
			retval = poll(pfd, 1, t.tv_sec * 1000 + t.tv_usec / 1000);
			if (retval > 0)
				process(getch());
			else
				process(lastch);
		}
	}
}

void
life(void)
{
	struct body *bp, *np;
	int i,j = 1;

	head = newlink();
	head->x = start_len % (COLS-5) + 2;
	head->y = LINES / 2;
	head->next = NULL;
	display(head, HEAD);
	for (i = 0, bp = head; i < start_len; i++, bp = np) {
		np = newlink();
		np->next = bp;
		bp->prev = np;
		if (((bp->x <= 2) && (j == 1)) || ((bp->x >= COLS-4) && (j == -1))) {
			j *= -1;
			np->x = bp->x;
			np->y = bp->y + 1;
		} else {
			np->x = bp->x - j;
			np->y = bp->y;
		}
		display(np, BODY);
	}
	tail = np;
	tail->prev = NULL;
	visible_len = start_len + 1;
}

void
display(struct body *pos, char chr)
{
	wmove(tv, pos->y, pos->x);
	waddch(tv, chr);
}

void
leave(int dummy)
{
	wantleave = 1;
}

int
rnd(int range)
{
	return arc4random_uniform(range);
}

void
newpos(struct body *bp)
{
	if (visible_len == (LINES-3) * (COLS-3) - 1) {
		endwin();
		printf("\nYou won!\nYour final score was %d\n\n", score);
		exit(0);
	}
	do {
		bp->y = rnd(LINES-3)+ 1;
		bp->x = rnd(COLS-3) + 1;
		wmove(tv, bp->y, bp->x);
	} while(winch(tv) != ' ');
}

void
prize(void)
{
	int value;

	value = rnd(9) + 1;
	newpos(&goody);
	waddch(tv, value+'0');
	wrefresh(tv);
}

void
process(int ch)
{
	int x,y;
	struct body *nh;

	x = head->x;
	y = head->y;
	switch(ch)
	{
#ifdef KEY_LEFT
		case KEY_LEFT:
#endif
		case 'h':
			x--; break;
#ifdef KEY_DOWN
		case KEY_DOWN:
#endif
		case 'j':
			y++; break;
#ifdef KEY_UP
		case KEY_UP:
#endif
		case 'k':
			y--; break;
#ifdef KEY_RIGHT
		case KEY_RIGHT:
#endif
		case 'l':
			x++; break;
		case 'H': x--; running = RUNLEN; ch = tolower(ch); break;
		case 'J': y++; running = RUNLEN/2; ch = tolower(ch); break;
		case 'K': y--; running = RUNLEN/2; ch = tolower(ch); break;
		case 'L': x++; running = RUNLEN; ch = tolower(ch); break;
		case '\f': setup(); return;
		case CNTRL('Z'): suspend(0); return;
		case CNTRL('C'): crash(); return;
		case CNTRL('D'): crash(); return;
		case ERR: leave(0); return;
		default: return;
	}
	lastch = ch;
	if (growing == 0)
	{
		display(tail, ' ');
		tail->next->prev = NULL;
		nh = tail->next;
		free(tail);
		tail = nh;
		visible_len--;
	}
	else growing--;
	display(head, BODY);
	wmove(tv, y, x);
	if (isdigit(ch = winch(tv)))
	{
		growing += ch-'0';
		prize();
		score += growing;
		running = 0;
		wmove(stw, 0, COLS - 12);
		wprintw(stw, "Score: %3d", score);
		wrefresh(stw);
	}
	else if(ch != ' ') crash();
	nh = newlink();
	nh->next = NULL;
	nh->prev = head;
	head->next = nh;
	nh->y = y;
	nh->x = x;
	display(nh, HEAD);
	head = nh;
	visible_len++;
	if (!(slow && running)) {
		wmove(tv, head->y, head->x);
		wrefresh(tv);
	}
}

struct body *
newlink(void)
{
	struct body *tmp;

	if ((tmp = (struct body *) malloc(sizeof (struct body))) == NULL) {
		endwin();
		errx(1, "out of memory");
	}
	return (tmp);
}

void
crash(void)
{
	sleep(2);
	clear();
	endwin();
	printf("Well, you ran into something and the game is over.\n");
	printf("Your final score was %d\n", score);
	exit(0);  /* leave() calls endwin(), which would hose the printf()'s */
}

void
suspend(int dummy)
{
	wantsuspend = 1;
}

void
setup(void)
{
	clear();
	refresh();
	touchwin(stw);
	wrefresh(stw);
	touchwin(tv);
	wrefresh(tv);
}