/* Monte Carlo simulation of Baby Blackjack for CPSC 641 */
/*                                                       */
/* Written by Carey Williamson, University of Calgary    */
/*                                                       */
/* Usage: cc -o baby baby.c                              */
/*        ./baby                                         */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define NUMGAMES 10 /* Number of games to simulate */
#define WAGER 1          /* Fixed wager amount on each play */
#define WIN_VALUE 2      /* Amount you win if successful */
   
/* #define SINGLE 1         /* Single deck dealer */

/* Set the Blackjack parameters */
#define TARGET 7
#define THRESHOLD 5

/* Constrain the deck size */
#define LOW_RANK 1
#define HIGH_RANK 3
#define RANKS (HIGH_RANK - LOW_RANK + 1)

/* Debugging output */
#define DEBUG 1

/* Global variable */
static int dealt[RANKS*4];

/***********************************************************************/
/*                 RANDOM NUMBER GENERATION STUFF                      */
/***********************************************************************/

/* Parameters for random number generation. */
#define MAX_INT 2147483647       /* Maximum positive integer 2^31 - 1 */

/* Generate a random floating point value uniformly distributed in [0,1] */
float Uniform01()
  {
    float randnum;

    /* get a random positive integer from random() */
    randnum = (float) 1.0 * random();

    /* divide by max int to get something in 0..1  */
    randnum = (float) randnum / (1.0 * MAX_INT); 

    return( randnum );
  }

/* Generate a random integer uniformly distributed in [low,high] */
int EquiLikely(low, high)
     int low, high;
  {
    float randnum;
    int answer;

    randnum = Uniform01();
    answer = low + randnum*(high-low+1);

#ifdef DEBUG
    printf("EquiLikely(%d,%d) uses %8.6f to return %d\n",
	   low, high, randnum, answer);
#endif

    return( answer );
  }

/* Deal a card at random from an infinite set of shuffled decks */
int DrawCardFromInfiniteDeckDealer()
  {
    int card, suit, rank;
    char rankchar;
    char suitstring[10];

    card = EquiLikely(0,RANKS*4-1);
    suit = card / RANKS;
    if( suit == 0 )
      strcpy(suitstring, "Clubs");
    else if( suit == 1 )
      strcpy(suitstring, "Diamonds");
    else if( suit == 2 )
      strcpy(suitstring, "Hearts");
    else if( suit == 3 )
      strcpy(suitstring, "Spades");
    else strcpy(suitstring, "Unknown?");
    rank = card % RANKS;
    if( rank == 0 )
      rankchar = 'A';
    else if( rank == 10 )
      rankchar = 'J';
    else if( rank == 11 )
      rankchar = 'Q';
    else if( rank == 12 )
      rankchar = 'K';
    else rankchar = '1' + rank;

#ifdef DEBUG
    if( rank == 9 )
      printf("Card from dealer is the 10 of %s\n", suitstring);
    else printf("Card from dealer is the %c of %s\n", rankchar, suitstring);
#endif

    return( card );
  }

/* Deal a card at random from a single shuffled deck */
int DrawCardFromSingleDeckDealer()
  {
    int card, suit, rank;
    char rankchar;
    char suitstring[10];

    card = EquiLikely(0,RANKS*4-1);
    while( dealt[card] > 0 )
      {
#ifdef DEBUG
	printf("Sorry, but I can't use that one. Drawing another card...\n");
#endif
	card = EquiLikely(0,RANKS*4-1);
      }
    dealt[card]++;
    suit = card / RANKS;
    if( suit == 0 )
      strcpy(suitstring, "Clubs");
    else if( suit == 1 )
      strcpy(suitstring, "Diamonds");
    else if( suit == 2 )
      strcpy(suitstring, "Hearts");
    else if( suit == 3 )
      strcpy(suitstring, "Spades");
    else strcpy(suitstring, "Unknown?");
    rank = card % RANKS;
    if( rank == 0 )
      rankchar = 'A';
    else if( rank == 10 )
      rankchar = 'J';
    else if( rank == 11 )
      rankchar = 'Q';
    else if( rank == 12 )
      rankchar = 'K';
    else rankchar = '1' + rank;

#ifdef DEBUG
    if( rank == 9 )
      printf("Card from dealer is the 10 of %s\n", suitstring);
    else printf("Card from dealer is the %c of %s\n", rankchar, suitstring);
#endif

    return( card );
  }

/***********************************************************************/
/*                 MAIN PROGRAM                                        */
/***********************************************************************/

int main()
  {
    int i, games, wins, ties, losses, card, winnings;
    int mysum, dealersum;
    int myhist[THRESHOLD+RANKS+1], dhist[THRESHOLD+RANKS+1];

    /* Initialization */
    srandom(1234567);
    games = 0;
    wins = 0;
    ties = 0;
    losses = 0;
    winnings = 0;
    for( i = 0; i <= THRESHOLD+RANKS; i++ )
      {
	myhist[i] = 0;
	dhist[i] = 0;
      }

    while( games < NUMGAMES )
      {
#ifdef SINGLE
	for( i = 0; i < RANKS*4; i++ )
	  dealt[i] = 0;
#endif
	mysum = 0;
	while( mysum <= THRESHOLD )
	  {
#ifdef SINGLE
	    card = DrawCardFromSingleDeckDealer();
#else
	    card = DrawCardFromInfiniteDeckDealer();
#endif
	    if( (card % RANKS) > 9 )
	      card = 9;
	    mysum += (card % RANKS) + 1;
	  }
#ifdef DEBUG
	printf("My hand: %d\n", mysum);
#endif
	myhist[mysum]++;
	dealersum = 0;
	while( dealersum <= THRESHOLD )
	  {
#ifdef SINGLE
	    card = DrawCardFromSingleDeckDealer();
#else
	    card = DrawCardFromInfiniteDeckDealer();
#endif
	    if( (card % RANKS) > 9 )
	      card = 9;
	    dealersum += (card % RANKS) + 1;
	  }
	dhist[dealersum]++;
#ifdef DEBUG
	printf("Dealer hand: %d\n", dealersum);
#endif
	/* check outcome of game */
	if( mysum > TARGET )
	  {
#ifdef DEBUG
	    printf("Loser!\n");
#endif
	    losses++;
	  }
	else if( dealersum > TARGET )
	  {
#ifdef DEBUG
	    printf("Winner!\n");
#endif
	    wins++;
	    winnings += WIN_VALUE;
	  }
	else if( mysum > dealersum )
	  {
#ifdef DEBUG
	    printf("Winner!\n");
#endif
	    wins++;
	    winnings += WIN_VALUE;
	  }
	else if( mysum == dealersum )
	  {
#ifdef DEBUG
	    printf("TIE!\n");
#endif
	    ties++;
	    winnings += WIN_VALUE/2;
	  }
	else
	  {
#ifdef DEBUG
	    printf("Loser!\n");
#endif
	    losses++;
	  }
	games++;
      }

    printf("\n");
    printf("Casino Card Game: Baby Blackjack\n");
    printf("Number of trials: %d\n", NUMGAMES);
    printf("Number of wins: %d\n", wins);
    printf("Number of ties: %d\n", ties);
    printf("Number of losses: %d\n", losses);
    printf("Estimated probability of winning: %8.6f\n", 1.0*wins/games);
    printf("Amount wagered: %d\n", games*WAGER);
    printf("Amount won: %d\n", winnings);
    printf("Estimated winnings per play: %8.6f\n", (1.0*winnings - games)/games);
    printf("Statistical summary of hands:\nSum Player Dealer\n");
    for( i = 0; i <= THRESHOLD+RANKS; i++ )
      printf(" %d :  %d   %d\n", i, myhist[i], dhist[i]);
  }