path: root/backgammon/backgammon/main.c

/*	$NetBSD: main.c,v 1.34 2021/05/02 12:50:43 rillig 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.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1980, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)main.c	8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: main.c,v 1.34 2021/05/02 12:50:43 rillig Exp $");
#endif
#endif				/* not lint */

#include <time.h>

#include "back.h"
#include "backlocal.h"

#define MVPAUSE	5		/* time to sleep when stuck */

extern const char   *const instr[];		/* text of instructions */
extern const char   *const message[];		/* update message */

static const char *const helpm[] = {		/* help message */
	"Enter a space or newline to roll, or",
	"     R   to reprint the board\tD   to double",
	"     S   to save the game\tQ   to quit",
	0
};

static const char *const contin[] = {		/* pause message */
	"(Type a newline to continue.)",
	"",
	0
};
static const char rules[] = "\nDo you want the rules of the game?";
static const char noteach[] = "Teachgammon not available!\n\a";
static const char need[] = "Do you need instructions for this program?";
static const char askcol[] =
"Enter 'r' to play red, 'w' to play white, 'b' to play both:";
static const char rollr[] = "Red rolls a ";
static const char rollw[] = ".  White rolls a ";
static const char rstart[] = ".  Red starts.\n";
static const char wstart[] = ".  White starts.\n";
static const char toobad1[] = "Too bad, ";
static const char unable[] = " is unable to use that roll.\n";
static const char toobad2[] = ".  Too bad, ";
static const char cantmv[] = " can't move.\n";
static const char bgammon[] = "Backgammon!  ";
static const char gammon[] = "Gammon!  ";
static const char again[] = ".\nWould you like to play again?";
static const char svpromt[] = "Would you like to save this game?";

static const char password[] = "losfurng";
static char pbuf[10];

int
main(int argc __unused, char **argv)
{
	int     i;		/* non-descript index */
	int     l;		/* non-descript index */
	char    c;		/* non-descript character storage */
	time_t  t;		/* time for random num generator */
	struct move mmstore, *mm;

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

	/* initialization */
	bflag = 2;		/* default no board */
	signal(SIGINT, getout);	/* trap interrupts */
	if (tcgetattr(0, &old) == -1)	/* get old tty mode */
		errexit("backgammon(gtty)");
	noech = old;
	noech.c_lflag &= ~ECHO;
	raw = noech;
	raw.c_lflag &= ~ICANON;	/* set up modes */
	ospeed = cfgetospeed(&old);	/* for termlib */

	/* get terminal capabilities, and decide if it can cursor address */
	tflag = getcaps(getenv("TERM"));
	/* use whole screen for text */
	if (tflag)
		begscr = 0;
	t = time(NULL);
	srandom(t);		/* 'random' seed */

	/* need this now beceause getarg() may try to load a game */
	mm = &mmstore;
	move_init(mm);
	while (*++argv != 0)	/* process arguments */
		getarg(mm, &argv);
	args[acnt] = '\0';
	if (tflag) {		/* clear screen */
		noech.c_oflag &= ~(ONLCR | OXTABS);
		raw.c_oflag &= ~(ONLCR | OXTABS);
		clear();
	}
	fixtty(&raw);		/* go into raw mode */

	/* check if restored game and save flag for later */
	if ((rfl = rflag) != 0) {
		wrtext(message);	/* print message */
		wrtext(contin);
		wrboard();	/* print board */
		/* if new game, pretend to be a non-restored game */
		if (cturn == 0)
			rflag = 0;
	} else {
		rscore = wscore = 0;	/* zero score */
		wrtext(message);	/* update message without pausing */

		if (aflag) {	/* print rules */
			writel(rules);
			if (yorn(0)) {

				fixtty(&old);	/* restore tty */
				execl(TEACH, "teachgammon", args[0]?args:0,
				      (char *) 0);

				tflag = 0;	/* error! */
				writel(noteach);
				exit(1);
			} else {/* if not rules, then instructions */
				writel(need);
				if (yorn(0)) {	/* print instructions */
					clear();
					wrtext(instr);
				}
			}
		}
		init();		/* initialize board */

		if (pnum == 2) {/* ask for color(s) */
			writec('\n');
			writel(askcol);
			while (pnum == 2) {
				c = readc();
				switch (c) {

				case 'R':	/* red */
					pnum = -1;
					break;

				case 'W':	/* white */
					pnum = 1;
					break;

				case 'B':	/* both */
					pnum = 0;
					break;

				case 'P':
					if (iroll)
						break;
					if (tflag)
						curmove(curr, 0);
					else
						writec('\n');
					writel("Password:");
					signal(SIGALRM, getout);
					cflag = 1;
					alarm(10);
					for (i = 0; i < 10; i++) {
						pbuf[i] = readc();
						if (pbuf[i] == '\n')
							break;
					}
					if (i == 10)
						while (readc() != '\n');
					alarm(0);
					cflag = 0;
					if (i < 10)
						pbuf[i] = '\0';
					for (i = 0; i < 9; i++)
						if (pbuf[i] != password[i])
							getout(0);
					iroll = 1;
					if (tflag)
						curmove(curr, 0);
					else
						writec('\n');
					writel(askcol);
					break;

				default:	/* error */
					writec('\007');
				}
			}
		} else
			if (!aflag)
				/* pause to read message */
				wrtext(contin);

		wrboard();	/* print board */

		if (tflag)
			curmove(18, 0);
		else
			writec('\n');
	}
	/* limit text to bottom of screen */
	if (tflag)
		begscr = 17;

	for (;;) {		/* begin game! */
		/* initial roll if needed */
		if ((!rflag) || raflag)
			roll(mm);

		/* perform ritual of first roll */
		if (!rflag) {
			if (tflag)
				curmove(17, 0);
			while (mm->D0 == mm->D1)	/* no doubles */
				roll(mm);

			/* print rolls */
			writel(rollr);
			writec(mm->D0 + '0');
			writel(rollw);
			writec(mm->D1 + '0');

			/* winner goes first */
			if (mm->D0 > mm->D1) {
				writel(rstart);
				cturn = 1;
			} else {
				writel(wstart);
				cturn = -1;
			}
		}
		/* initialize variables according to whose turn it is */

		if (cturn == 1) {	/* red */
			home = 25;
			bar = 0;
			inptr = &in[1];
			inopp = &in[0];
			offptr = &off[1];
			offopp = &off[0];
			Colorptr = &color[1];
			colorptr = &color[3];
			colen = 3;
		} else {	/* white */
			home = 0;
			bar = 25;
			inptr = &in[0];
			inopp = &in[1];
			offptr = &off[0];
			offopp = &off[1];
			Colorptr = &color[0];
			colorptr = &color[2];
			colen = 5;
		}

		/* do first move (special case) */
		if (!(rflag && raflag)) {
			if (cturn == pnum)	/* computer's move */
				move(mm, 0);
			else {	/* player's move */
				mm->mvlim = movallow(mm);
				/* reprint roll */
				if (tflag)
					curmove(cturn == -1 ? 18 : 19, 0);
				proll(mm);
				getmove(mm);	/* get player's move */
			}
		}
		if (tflag) {
			curmove(17, 0);
			cline();
			begscr = 18;
		}
		/* no longer any diff- erence between normal game and
		 * recovered game. */
		rflag = 0;

		/* move as long as it's someone's turn */
		while (cturn == 1 || cturn == -1) {

			/* board maintainence */
			if (tflag)
				refresh();	/* fix board */
			else
				/* redo board if -p */
				if (cturn == bflag || bflag == 0)
					wrboard();

			/* do computer's move */
			if (cturn == pnum) {
				move(mm, 1);

				/* see if double refused */
				if (cturn == -2 || cturn == 2)
					break;

				/* check for winning move */
				if (*offopp == 15) {
					cturn *= -2;
					break;
				}
				continue;

			}
			/* (player's move) */

			/* clean screen if safe */
			if (tflag && hflag) {
				curmove(20, 0);
				clend();
				hflag = 1;
			}
			/* if allowed, give him a chance to double */
			if (dlast != cturn && gvalue < 64) {
				if (tflag)
					curmove(cturn == -1 ? 18 : 19, 0);
				writel(*Colorptr);
				c = readc();

				/* character cases */
				switch (c) {

					/* reprint board */
				case 'R':
					wrboard();
					break;

					/* save game */
				case 'S':
					raflag = 1;
					save(mm, 1);
					break;

					/* quit */
				case 'Q':
					quit(mm);
					break;

					/* double */
				case 'D':
					dble();
					break;

					/* roll */
				case ' ':
				case '\n':
					roll(mm);
					writel(" rolls ");
					writec(mm->D0 + '0');
					writec(' ');
					writec(mm->D1 + '0');
					writel(".  ");

					/* see if he can move */
					if ((mm->mvlim = movallow(mm)) == 0) {

						/* can't move */
						writel(toobad1);
						writel(*colorptr);
						writel(unable);
						if (tflag) {
							if (pnum) {
								buflush();
								sleep(MVPAUSE);
							}
						}
						nexturn();
						break;
					}
					/* get move */
					getmove(mm);

					/* okay to clean screen */
					hflag = 1;
					break;

					/* invalid character */
				default:

					/* print help message */
					if (tflag)
						curmove(20, 0);
					else
						writec('\n');
					wrtext(helpm);
					if (tflag)
						curmove(cturn == -1 ?
						    18 : 19, 0);
					else
						writec('\n');

					/* don't erase */
					hflag = 0;
				}
			} else {/* couldn't double */

				/* print roll */
				roll(mm);
				if (tflag)
					curmove(cturn == -1 ? 18 : 19, 0);
				proll(mm);

				/* can he move? */
				if ((mm->mvlim = movallow(mm)) == 0) {

					/* he can't */
					writel(toobad2);
					writel(*colorptr);
					writel(cantmv);
					buflush();
					sleep(MVPAUSE);
					nexturn();
					continue;
				}
				/* get move */
				getmove(mm);
			}
		}

		/* don't worry about who won if quit */
		if (cturn == 0)
			break;

		/* fix cturn = winner */
		cturn /= -2;

		/* final board pos. */
		if (tflag)
			refresh();

		/* backgammon? */
		mflag = 0;
		l = bar + 7 * cturn;
		for (i = bar; i != l; i += cturn)
			if (board[i] && cturn)
				mflag++;

		/* compute game value */
		if (tflag)
			curmove(20, 0);
		if (*offopp == 15 && (*offptr == 0 || *offptr == -15)) {
			if (mflag) {
				writel(bgammon);
				gvalue *= 3;
			} else {
				writel(gammon);
				gvalue *= 2;
			}
		}
		/* report situation */
		if (cturn == -1) {
			writel("Red wins ");
			rscore += gvalue;
		} else {
			writel("White wins ");
			wscore += gvalue;
		}
		wrint(gvalue);
		writel(" point");
		if (gvalue > 1)
			writec('s');
		writel(".\n");

		/* write score */
		wrscore();

		/* see if he wants another game */
		writel(again);
		if ((i = yorn('S')) == 0)
			break;

		init();
		if (i == 2) {
			writel("  Save.\n");
			cturn = 0;
			save(mm, 0);
		}
		/* yes, reset game */
		wrboard();
	}

	/* give him a chance to save if game was recovered */
	if (rfl && cturn) {
		writel(svpromt);
		if (yorn(0)) {
			/* re-initialize for recovery */
			init();
			cturn = 0;
			save(mm, 0);
		}
	}
	/* leave peacefully */
	getout(0);
	/* NOTREACHED */
	return (0);
}