/*      $NetBSD: extra.c,v 1.7 2009/08/12 05:17:57 dholland 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
#if 0
static char sccsid[] = "@(#)extra.c     8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: extra.c,v 1.7 2009/08/12 05:17:57 dholland Exp $");
#endif
#endif /* not lint */

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

#ifdef DEBUG
FILE   *trace;
#endif

static int eval(void);

/*
 * dble()
 *      Have the current player double and ask opponent to accept.
 */

void
dble(void)
{
        int     resp;           /* response to y/n */

        for (;;) {
                writel(" doubles.");    /* indicate double */

                if (cturn == -pnum) {   /* see if computer accepts */
                        if (dblgood()) {        /* guess not */
                                writel("  Declined.\n");
                                nexturn();
                                cturn *= -2;    /* indicate loss */
                                return;
                        } else {/* computer accepts */
                                writel("  Accepted.\n");
                                gvalue *= 2;    /* double game value */
                                dlast = cturn;
                                if (tflag)
                                        gwrite();
                                return;
                        }
                }
                /* ask if player accepts */
                writel("  Does ");
                writel(cturn == 1 ? color[2] : color[3]);
                writel(" accept?");

                /* get response from yorn, a "2" means he said "p" for print
                 * board. */
                if ((resp = yorn('R')) == 2) {
                        writel("  Reprint.\n");
                        buflush();
                        wrboard();
                        writel(*Colorptr);
                        continue;
                }
                /* check response */
                if (resp) {
                        /* accepted */
                        gvalue *= 2;
                        dlast = cturn;
                        if (tflag)
                                gwrite();
                        return;
                }
                nexturn();      /* declined */
                cturn *= -2;
                return;
        }
}
/*
 * dblgood ()
 *      Returns 1 if the computer would double in this position.  This
 * is not an exact science.  The computer will decline a double that he
 * would have made.  Accumulated judgments are kept in the variable n,
 * which is in "pips", i.e., the position of each man summed over all
 * men, with opponent's totals negative.  Thus, n should have a positive
 * value of 7 for each move ahead, or a negative value of 7 for each one
 * behind.
 */

int
dblgood(void)
{
        int     n;              /* accumulated judgment */
        int     OFFC = *offptr; /* no. of computer's men off */
        int     OFFO = *offopp; /* no. of player's men off */

#ifdef DEBUG
        int     i;
        if (trace == NULL)
                trace = fopen("bgtrace", "w");
#endif

        /* get real pip value */
        n = eval() * cturn;
#ifdef DEBUG
        fputs("\nDoubles:\nBoard: ", trace);
        for (i = 0; i < 26; i++)
                fprintf(trace, " %d", board[i]);
        fprintf(trace, "\n\tpip = %d, ", n);
#endif

        /* below adjusts pip value according to position judgments */

        /* check men moving off board */
        if (OFFC > -15 || OFFO > -15) {
                if (OFFC < 0 && OFFO < 0) {
                        OFFC += 15;
                        OFFO += 15;
                        n += ((OFFC - OFFO) * 7) / 2;
                } else
                        if (OFFC < 0) {
                                OFFC += 15;
                                n -= OFFO * 7 / 2;
                        } else
                                if (OFFO < 0) {
                                        OFFO += 15;
                                        n += OFFC * 7 / 2;
                                }
                if (OFFC < 8 && OFFO > 8)
                        n -= 7;
                if (OFFC < 10 && OFFO > 10)
                        n -= 7;
                if (OFFC < 12 && OFFO > 12)
                        n -= 7;
                if (OFFO < 8 && OFFC > 8)
                        n += 7;
                if (OFFO < 10 && OFFC > 10)
                        n += 7;
                if (OFFO < 12 && OFFC > 12)
                        n += 7;
                n += ((OFFC - OFFO) * 7) / 2;
        }
#ifdef DEBUG
        fprintf(trace, "off = %d, ", n);
#endif

        /* see if men are trapped */
        n -= freemen(bar);
        n += freemen(home);
        n += trapped(home, -cturn);
        n -= trapped(bar, cturn);

#ifdef DEBUG
        fprintf(trace, "free = %d\n", n);
        fprintf(trace, "\tOFFC = %d, OFFO = %d\n", OFFC, OFFO);
        fflush(trace);
#endif

        /* double if 2-3 moves ahead */
        if (n > 10 + rnum(7))
                return (1);
        return (0);
}

int
freemen(int b)
{
        int     i, inc, lim;

        odds(0, 0, 0);
        if (board[b] == 0)
                return (0);
        inc = (b == 0 ? 1 : -1);
        lim = (b == 0 ? 7 : 18);
        for (i = b + inc; i != lim; i += inc)
                if (board[i] * inc < -1)
                        odds(abs(b - i), 0, abs(board[b]));
        if (abs(board[b]) == 1)
                return ((36 - count()) / 5);
        return (count() / 5);
}

int
trapped(int n, int inc)
{
        int     i, j, k;
        int     c, l, ct;

        ct = 0;
        l = n + 7 * inc;
        for (i = n + inc; i != l; i += inc) {
                odds(0, 0, 0);
                c = abs(i - l);
                if (board[i] * inc > 0) {
                        for (j = c; j < 13; j++)
                                if (board[i + inc * j] * inc < -1) {
                                        if (j < 7)
                                                odds(j, 0, 1);
                                        for (k = 1; k < 7 && k < j; k++)
                                                if (j - k < 7)
                                                        odds(k, j - k, 1);
                                }
                        ct += abs(board[i]) * (36 - count());
                }
        }
        return (ct / 5);
}

static int
eval(void)
{
        int     i, j;

        for (j = i = 0; i < 26; i++)
                j += (board[i] >= 0 ? i * board[i] : (25 - i) * board[i]);

        if (off[1] >= 0)
                j += 25 * off[1];
        else
                j += 25 * (off[1] + 15);

        if (off[0] >= 0)
                j -= 25 * off[0];
        else
                j -= 25 * (off[0] + 15);
        return (j);
}