/*
 * holdodds.c  --  Show hold'em odds.
 * Copyright (c) 2006 by James Dow Allen
 *
 *  This program can be distributed or modified subject to
 *  the terms of the GNU General Public License (version 2
 *  or, at your option, any later version) as published by
 *  the Free Software Foundation.
 *
 * Joker is "jo" (code 0xff)
 * Code assumes 32-bit int's -- sorry.
 */
#include	<stdlib.h>
#include	<stdio.h>

/* Following can be 1, higher values not well supported */
/* (Frankly, don't recall testing single joker thoroughly) */
#define	NUMJOKER	0

typedef	int	Card;

#define	NUMSUIT		4
#define	NUMRANK		13
#define	XRANK(x)	((x) & 0xf)
#define	XSUIT(x)	((x) >> 4)
#define	DECKSIZE	(NUMSUIT*NUMRANK + NUMJOKER)

char	name_rank[] =	"--23456789TJQKAj";
char	name_suit[] =	"-SH-D---C------o";
#define	DEUCE		2
#define	JOKER		15

Card	Deck[DECKSIZE];

char *name_card(char *out, Card x)
{
	out[0] = name_rank[XRANK(x)];
	out[1] = name_suit[XSUIT(x)];
	out[2] = '\0';
	return out;
}

int s2i(char *inp)
{
	char	*index();
	char	*s, *r;

	r = index(name_rank, inp[0]);
	s = index(name_suit, inp[1]);
	if (s && r)
		return (((s - name_suit) << 4) + r - name_rank);
	fprintf(stderr, "Unrecognized card *%s*\n", inp);
	exit(1);
}

void initdeck()
{
	int	i, j;
	Card	*dp = Deck;

	for (i = 0; i < NUMRANK; i++)
	for (j = 0; j < NUMSUIT; j++)
		*dp++ = i + DEUCE + (1 << j + 4);
	for (i = 0; i < NUMJOKER; i++)
		*dp++ = 0xf0 | JOKER;
}

/* The "sample application" herein doesn't call shuffle() */
void shuffle()
{
	int	i, j, t;

	for (i = 0; i < DECKSIZE; i++) {
		j = random() % (DECKSIZE - i) + i;
		t = Deck[j];
		Deck[j] = Deck[i];
		Deck[i] = t;
	}
}

char	*valnames[] = {
	/* Codes for hand types */
	/* 0 */		"no pair",
	/* 1 */		"1 pair",
	/* 2 */		"2 pair",
	/* 3 */		"triplets",
	/* 4 */		"straight",
	/* 5 */		"flush",
	/* 6 */		"full house",
	/* 7 */		"4-of-a-kind",
	/* 8 */		"str flush",
	/* 9 */		"5-of-a-kind",
};

/* Poker hand ranking.
 * Return TBccccc with T type, B tiebreaker (e.g. pair rank)
 *  and ccccc usually the sorted cards (except for 2-pair
 *  where they are needed for tie-breaking on second-pair.)
 */
int pokval(Card c0, Card c1, Card c2, Card c3, Card c4)
{
	register int	ghand;
	register int t, h0, h1, h2, h3, h4;
	int	isflush;
	int	numpair, numtrip;
	int	i;

	/* Detect flush and clear suit bits */
	isflush = c0 & c1 & c2 & c3 & c4 & 0xf0;
	h0 = c0 & 15;
	h1 = c1 & 15;
	h2 = c2 & 15;
	h3 = c3 & 15;
	h4 = c4 & 15;
#define	CSWAP(a, b)	if (a < b) t = a, a = b, b = t
	CSWAP(h0, h1);
	CSWAP(h1, h2);
	CSWAP(h2, h3);
	CSWAP(h3, h4);
	CSWAP(h0, h1);
	CSWAP(h1, h2);
	CSWAP(h2, h3);
	CSWAP(h0, h1);
	CSWAP(h1, h2);
	CSWAP(h0, h1);

	/* Check adjacent cards for pairs */
	numpair = (h0 == h1) + (h1 == h2) + (h2 == h3) + (h3 == h4);
	/* Check near-adjacent cards for triplets */
	numtrip = (h0 == h2) + (h1 == h3) + (h2 == h4);

	if (h0 == JOKER) {
		if (numpair == 0) {
			i = h1 - h4;
			if (i == 3) {
				ghand = (isflush ? 8 : 4) << 24
					| (h1 == DEUCE + 12 ? h1 : h1 + 1);
				goto finished;
			} else if (i == 4) {
				ghand = (isflush ? 8 : 4) << 24 | h1;
				goto finished;
			} else if (h1 == DEUCE + 12 && h2 <= DEUCE + 3) {
				goto fivestr;
			} else if (isflush) {
				h0 = DEUCE + 12;
				if (h1 == DEUCE + 12)
					if (h2 == --h1)
						if (h3 == --h2)
							if (h4 == --h3)
								--h4;
				goto doflush;
			}
		}
		h0 = DEUCE + 12;
		numpair += h1 == DEUCE + 12;
		numtrip += h2 == DEUCE + 12;
	} else if (numpair == 0) {
		i = h0 - h4;
		if (i == 4) {
			ghand = (isflush ? 8 : 4) << 24 | h0;
			goto finished;
		} else if (i == 12 && h1 == DEUCE + 3) {
		fivestr:
			ghand = (isflush ? 8 : 4) << 24 | (DEUCE + 3);
			goto finished;
		} else if (isflush) {
		doflush:
			ghand = (5) << 24;
			ghand |= h0 << 16 | h1 << 12 | h2 << 8 | h3 << 4 | h4;
			goto finished;
		}
	}

	/* Switch on hand type */
	switch (numpair + numtrip) {
	case 0:
	/* No pair */
		ghand = (0) << 24;
		ghand |= h0 << 16 | h1 << 12 | h2 << 8 | h3 << 4 | h4;
		break;
	case 1:
	/* One pair */
		ghand = (1) << 24;
		ghand |= h0 << 16 | h1 << 12 | h2 << 8 | h3 << 4 | h4;
		/* Forgot where the pair is; find it again for tiebreaker */
		if (h0 == h1 || h1 == h2)
			ghand |= h1 << 20;
		else
			ghand |= h3 << 20;
		break;
	case 2:
	/* Two pair */
		ghand = (2) << 24;
		ghand |= h1 << 16 | h3 << 12 | h0 << 8 | h2 << 4 | h4;
		break;
	case 3:
	/* Triplets */
		ghand = (3) << 24;
	tiebreak:
		ghand |= h2 << 20 | h0 << 16 | h1 << 12 | h2 << 8 | h3 << 4 | h4;
		break;
	case 4:
	/* Full house */
		ghand = (6) << 24;
		goto tiebreak;
	case 5:
	/* Four-of-kind */
		ghand = (7) << 24;
		goto tiebreak;
	case 7:
	/* Five-of-kind */
		ghand = (9) << 24;
		goto tiebreak;
	default:
		printf("numpair = %d numtrip = %d\n", numpair, numtrip);
		exit(1);
	}
	finished:
	return ghand;
}

/* The "sample application" herein doesn't call pcards() */
void pcards(Card *han, int cnt)
{
	int	i;
 
	for (i = 0; i < cnt; i++) {
		char    cardname[3];
		name_card(cardname, han[i]);
		printf("%s ", cardname);
	}
}

/* The "sample application" herein doesn't call phand() */
void phand(char *msg, Card *han)
{
	int	val;

	pcards(han, 5);
	val = pokval(han[0], han[1], han[2], han[3], han[4]);
	printf(" ( %08x %s ) -- %s\n", val, valnames[val >> 24], msg);
}

/* Find best 5-hand from set of 7.
 * Do it the brute-force obvious way.
 */
int eval7(Card c0, Card c1, Card *rest)
{
	int	best, i;

	best = pokval(rest[0], rest[1], rest[2], rest[3], rest[4]);
	if ((i = pokval(c0, c1, rest[0], rest[1], rest[2])) > best) best = i;
	if ((i = pokval(c0, c1, rest[0], rest[1], rest[3])) > best) best = i;
	if ((i = pokval(c0, c1, rest[0], rest[1], rest[4])) > best) best = i;
	if ((i = pokval(c0, c1, rest[0], rest[2], rest[3])) > best) best = i;
	if ((i = pokval(c0, c1, rest[0], rest[2], rest[4])) > best) best = i;
	if ((i = pokval(c0, c1, rest[0], rest[3], rest[4])) > best) best = i;
	if ((i = pokval(c0, c1, rest[1], rest[2], rest[3])) > best) best = i;
	if ((i = pokval(c0, c1, rest[1], rest[2], rest[4])) > best) best = i;
	if ((i = pokval(c0, c1, rest[1], rest[3], rest[4])) > best) best = i;
	if ((i = pokval(c0, c1, rest[2], rest[3], rest[4])) > best) best = i;
	if ((i = pokval(c0, rest[0], rest[1], rest[2], rest[3])) > best)best=i;
	if ((i = pokval(c0, rest[0], rest[1], rest[2], rest[4])) > best)best=i;
	if ((i = pokval(c0, rest[0], rest[1], rest[3], rest[4])) > best)best=i;
	if ((i = pokval(c0, rest[0], rest[2], rest[3], rest[4])) > best)best=i;
	if ((i = pokval(c0, rest[1], rest[2], rest[3], rest[4])) > best)best=i;
	if ((i = pokval(c1, rest[0], rest[1], rest[2], rest[3])) > best)best=i;
	if ((i = pokval(c1, rest[0], rest[1], rest[2], rest[4])) > best)best=i;
	if ((i = pokval(c1, rest[0], rest[1], rest[3], rest[4])) > best)best=i;
	if ((i = pokval(c1, rest[0], rest[2], rest[3], rest[4])) > best)best=i;
	if ((i = pokval(c1, rest[1], rest[2], rest[3], rest[4])) > best)best=i;
	return best;
}

int excluded(int i, Card *a, Card *b)
{
	i = Deck[i];
	if (i != a[0] && i != a[1] && i != b[0] &&i != b[1])
		return i;
	else
		return 0;
}

long thisto[2][10];

int main(int argc, char **argv)
{
	Card	handa[2], handb[2], rest[5];
	int	i1, i2, i3, i4, i5;
	long	awin, bwin, draw;
	unsigned int	aval, bval;

	setlinebuf(stdout);
	initdeck();
	if (argc != 5) {
		printf("Usage: holdodds #A1 #A2 #B1 #B2 -- compare two hold'em hands\n");
		printf("\tCards are '9S', 'KD', etc.\n");
		exit(1);
	}
	awin = bwin = draw = 0;
	handa[0] = s2i(argv[1]);
	handa[1] = s2i(argv[2]);
	handb[0] = s2i(argv[3]);
	handb[1] = s2i(argv[4]);
	for (i1 = 0; i1 < DECKSIZE; i1++)
	if (rest[0] = excluded(i1, handa, handb))
	for (i2 = i1+1; i2 < DECKSIZE; i2++)
	if (rest[1] = excluded(i2, handa, handb))
	for (i3 = i2+1; i3 < DECKSIZE; i3++)
	if (rest[2] = excluded(i3, handa, handb))
	for (i4 = i3+1; i4 < DECKSIZE; i4++)
	if (rest[3] = excluded(i4, handa, handb))
	for (i5 = i4+1; i5 < DECKSIZE; i5++)
	if (rest[4] = excluded(i5, handa, handb)) {
		aval = eval7(handa[0], handa[1], rest);
		bval = eval7(handb[0], handb[1], rest);
		++thisto[0][aval >> 24];
		++thisto[1][bval >> 24];
		if (aval > bval) {
			++awin;
		} else if (aval < bval) {
			++bwin;
		} else {
			++draw;
		}
	}
	printf("A wins = %f%%\n", awin * 100.0 / (awin + bwin + draw));
	printf("B wins = %f%%\n", bwin * 100.0 / (awin + bwin + draw));
	printf("Drawn = %f%%\n", draw * 100.0 / (awin + bwin + draw));
	for (i1 = 0; i1 < 2; i1++)
	for (i2 = 0; i2 < 10; i2++)
	if (i3 = thisto[i1][i2])
		printf("Player %c gets %s with prob %f%%\n",
				"AB"[i1], valnames[i2],
				i3 * 100.0 / (awin + bwin + draw));
	exit(0);
}