/*-
 * 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.
 *
 * @(#) Copyright (c) 1980, 1993 The Regents of the University of California.  All rights reserved.
 * @(#)worm.c   8.1 (Berkeley) 5/31/93
 * $FreeBSD: src/games/worm/worm.c,v 1.9 1999/12/07 02:01:27 billf Exp $
 */

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

#include <ctype.h>
#include <curses.h>
#include <signal.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>

#define newlink() malloc(sizeof(struct body));
#define HEAD '@'
#define BODY 'o'
#define LENGTH 7
#define RUNLEN 8
#define CNTRL(p) (p-'A'+1)

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

static void crash(void) __dead2;
static void display(struct body *, char);
static void leave(int) __dead2;
static void life(void);
static void newpos(struct body *);
static void prize(void);
static void process(char);
static long rnd(int);
static void setup(void);
static void suspend(int);
static void wake(int);

int
main(int argc, char **argv)
{
        char ch;

        /* Revoke setgid privileges */
        setgid(getgid());

        if (argc == 2)
                start_len = atoi(argv[1]);
        if ((start_len <= 0) || (start_len > 500))
                start_len = LENGTH;
        setbuf(stdout, outbuf);
        srandomdev();
        signal(SIGALRM, wake);
        signal(SIGINT, leave);
        signal(SIGQUIT, leave);
        signal(SIGTSTP, suspend);       /* process control signal */
        initscr();
        cbreak();
        noecho();
        slow = (baudrate() <= B1200);
        clear();
        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 */
        while(1)
        {
                if (running)
                {
                        running--;
                        process(lastch);
                }
                else
                {
                    fflush(stdout);
                    if (read(0, &ch, 1) >= 0)
                        process(ch);
                }
        }
}

static void
life(void)
{
        struct body *bp, *np;
        int i;

        np = NULL;
        head = newlink();
        head->x = start_len+2;
        head->y = 12;
        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;
                np->x = bp->x - 1;
                np->y = bp->y;
                display(np, BODY);
        }
        tail = np;
        tail->prev = NULL;
}

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

static void
leave(int sig __unused)
{
        endwin();
        exit(0);
}

static void
wake(int sig __unused)
{
        signal(SIGALRM, wake);
        fflush(stdout);
        process(lastch);
}

static long
rnd(int range)
{
        return (random() % range);
}

static void
newpos(struct body *bp)
{
        do {
                bp->y = rnd(LINES-3)+ 2;
                bp->x = rnd(COLS-3) + 1;
                wmove(tv, bp->y, bp->x);
        } while(winch(tv) != ' ');
}

static void
prize(void)
{
        int value;

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

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

        alarm(0);
        x = head->x;
        y = head->y;
        switch(ch)
        {
                case 'h': x--; break;
                case 'j': y++; break;
                case 'k': y--; break;
                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();
                case CNTRL('D'): crash();
                default: if (! running) alarm(1);
                           return;
        }
        lastch = ch;
        if (growing == 0)
        {
                display(tail, ' ');
                tail->next->prev = NULL;
                nh = tail->next;
                free(tail);
                tail = nh;
        }
        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, 68);
                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;
        if (!(slow && running))
                wrefresh(tv);
        if (!running)
                alarm(1);
}

static void
crash(void)
{
        sleep(2);
        clear();
        move(23, 0);
        refresh();
        printf("Well, you ran into something and the game is over.\n");
        printf("Your final score was %d\n", score);
        leave(0);
}

static void
suspend(int sig __unused)
{
        move(LINES-1, 0);
        refresh();
        endwin();
        fflush(stdout);
        kill(getpid(), SIGTSTP);
        signal(SIGTSTP, suspend);
        cbreak();
        noecho();
        setup();
}

static void
setup(void)
{
        clear();
        refresh();
        touchwin(stw);
        wrefresh(stw);
        touchwin(tv);
        wrefresh(tv);
        alarm(1);
}