/* Discrete-event simulation of a simple casino poker game */
/* to demonstrate simulation approach and random numbers.  */
/*                                                         */
/* Usage: cc -o poker poker.c                              */
/*        ./poker                                          */
/*                                                         */
/* Written by Carey Williamson              March 12, 2013 */

#include <stdio.h>

#define NUM_ROUNDS 8
#define NUM_PLAYERS 4
#define NUM_CARDS 1
#define BANK_ROLL 10
#define MIN_WAGER 1
#define MAX_WAGER 5
#define DECK_SIZE 10
#define AVAILABLE -1

#define DEBUG 1

/***********************************************************************/
/*                 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 );
  }

int main()
  {
    int round;
    int money[NUM_PLAYERS];
    int bet[NUM_PLAYERS];
    int handvalue[NUM_PLAYERS];
    int deckofcards[DECK_SIZE];
    int i, j, card;
    float prob;
    int best, winner, pot;

    /* set random number seed based on time of day */
    srandom(time(NULL));

    /* Give each player some money to start with */
    for( i = 0; i < NUM_PLAYERS; i++ )
      {
	money[i] = BANK_ROLL;
      }

    /* Main loop: repeat once for each round of poker being simulated */

    for( round = 1; round <= NUM_ROUNDS; round++ )
      {
	printf("Starting round %d of poker simulation...\n", round);

	/* Report bank balance for each player */
	for( i = 0; i < NUM_PLAYERS; i++ )
	  {
	    printf("    Player %d has %d to spend\n", i, money[i]);
	  }

	/* Shuffle the deck to make all cards available */
	for( i = 0; i < DECK_SIZE; i++ )
	  {
	    deckofcards[i] = AVAILABLE;
	  }

	/* Deal cards to each player */
	for( i = 0; i < NUM_PLAYERS; i++ )
	  {
	    /* Don't let bankrupt players play any more rounds */
	    if( money[i] <= 0 )
	      {
		printf("  Player %d is BROKE, and gets no cards!\n", i);
		handvalue[i] = 0;
		continue;
	      }

	    handvalue[i] = 0;
	    for( j = 0; j < NUM_CARDS; j++ )
	      {
		/* Generate a card (at random) for this player's hand */
		card = Uniform01() * DECK_SIZE;
		while( deckofcards[card] != AVAILABLE )
		  {
		    card = Uniform01() * DECK_SIZE;
		  }
#ifdef DEBUG
		printf("  Giving card %d to player %d\n", card, i);
#endif
		deckofcards[card] = i;
		handvalue[i] += card;
	      }
	  }

	/* Collect wagers from each player */
	pot = 0;
	for( i = 0; i < NUM_PLAYERS; i++ )
	  {
	    bet[i] = MIN_WAGER + (Uniform01() * (MAX_WAGER - MIN_WAGER));
	    if( bet[i] > money[i] )
	      bet[i] = money[i];
#ifdef DEBUG
	    printf("  Player %d is wagering %d\n", i, bet[i]);
#endif
	    pot += bet[i];
	    money[i] -= bet[i];
	  }
#ifdef DEBUG
	printf("  Total pot for round %d is %d\n", round, pot);
#endif

	/* Determine winner */
	winner = -1;
	best = -1;
	for( i = 0; i < NUM_PLAYERS; i++ )
	  {
	    if( handvalue[i] > best )
	      {
		best = handvalue[i];
		winner = i;
	      }
	  }
	money[winner] += pot;
	printf("Player %d wins the round %d pot of %d with a hand value of %d!!\n\n",
	       winner, round, pot, best);
      }

  }