# P-3 MCS 260 Monday 8 March : simulate slot game

# The goal of this project is to simulate a slot machine game.
# The slot machines we consider have a varying number of reels,
# between 2 and 6.  This implies that the slot machine spins
# numbers of 2, 3, 4, 5, or 6 digits.

# Numbers displayed to the player are padded by zeroes from the left.
# For example, if the number of reels equals 4 and the random number
# generator returns 93, then 0093 is shown to the user.

# The user of the program is first prompted to enter the number of reels.
# This number stays fixed during the whole duration of the game.

# At the start of the game, the player enters the number of tokens.
# Each spin costs the player one token.  The game ends when the user
# chooses not to continue, or when the balance of tokens equals zero.

# The player hits the jackpot if the same digit occurs exactly as many
# times as the number of reels.  We call the largest number of the same
# digits in one number the weight.  
# The payoff is the number of tokens given as a reward to the player.
# For number of reels r and weight w, the payoff is as follows:
# If w equals the number of same digits
# that occur in one spin, then the payoff (number of tokens given as
# reward to the player) is as follows:

#       w=1 w=2 w=3 w=4  w=5 w=6
#  r=2   0   10  --  --   --  --
#  r=3   0    2  46  --   --  --
#  r=4   0    1   8 253   --  --
#  r=5   0    1   3  10 1000  --
#  r=6   0    0   1  11 1002 18037

# At each spin, the player is shown the generated number,
# the weight of the number, and the corresponding payoff,
# all on the same line.  In the next line, the program shows
# the player the accumulated balance of tokens, and asks if
# the player wants to continue the game.

from random import randint

def generate_number(R):
   """
   Generates a number of R digits.
   Returns a string of length R,
   padding the number from the left with zeroes.
   """
   n = randint(0,10**R-1)
   f = '%0' + ('%d' % R) + 'd'
   s = f % n
   return s

def equal_digits(s):
   """
   Returns the maximum number of equal symbols in the string s.
   """
   L = [e for e in s]
   D = {}
   for c in L:
      if D.has_key(c):
         D[c] = D[c] + 1
      else:
         D[c] = 1
   return max(D.values())

def payout(R,e):
   """
   Returns the payout for the number e of equal digits,
   where R is the number of reels.
   """
   D = {2:{1:0,2:10},\
        3:{1:0,2:2,3:46},\
        4:{1:0,2:1,3:8,4:253},\
        5:{1:0,2:1,3:3,4:10,5:1000},\
        6:{1:0,2:0,3:1,4:11,5:1002,6:18037}}
   return D[R][e]

def show_spin(s,e,p):
   """
   Shows user result of a spin.
   On input is s a string with a number
   and e, the number of equal digits.
   """
   a = 'spin ' + s
   b = ' has weight %d' % e
   c = ' with award %d' % p
   print a + b + c

def main():
   """
   Simulates playing on a slot machine.
   """
   print 'welcome to our slot machine'
   R = input('-> how many reels (2, 3, 4, 5, or 6) ? ')
   t = input('-> give the number of tokens : ')
   while (t > 0):
      g = generate_number(R)
      e = equal_digits(g)
      p = payout(R,e)
      show_spin(g,e,p)
      t = t - 1 + p
      s = '-> your current balance : %d, ' % t
      if t == 0: break
      ans = raw_input(s + 'continue ? (y/n) ')
      if ans != 'y': break
   print 'ending balance :', t

main()