Blackjack

blackjack.py

from collections import namedtuple
from enum import Enum

import random

compose = lambda f: lambda g: lambda *a, **k: f(g(*a, **k))

class Face(Enum):
    ACE   = 'A'
    TWO   = '2'
    THREE = '3'
    FOUR  = '4'
    FIVE  = '5'
    SIX   = '6'
    SEVEN = '7'
    EIGHT = '8'
    NINE  = '9'
    TEN   = 'X'
    JACK  = 'J'
    QUEEN = 'Q'
    KING  = 'K'

class Suit(Enum):
    SPADE   = '♠'
    HEART   = '♥'
    DIAMOND = '♦'
    CLUB    = '♣'

class Card(namedtuple('Card', 'face suit')):
    def __str__(self):
        return self.face.value + self.suit.value

    @property
    def score(self):
        if self.face == Face.ACE:
            return 11
        elif self.face in (Face.TEN, Face.JACK, Face.QUEEN, Face.KING):
            return 10
        else:
            return int(self.face.value)

full_deck = {f.name.lower() + '_of_' + s.name.lower() + 's' : Card(f, s)
             for f in Face for s in Suit}

class Move(Enum):
    HIT  = 'hit'
    STAY = 'stay'

class Result(Enum):
    BLACKJACK = 'blackjack'
    PUSH      = 'push'
    BUST      = 'bust'
    WIN       = 'win'
    LOSE      = 'lose'

class Gamestate(namedtuple('Gamestate', 'dealer player')):
    @compose(''.join)
    def __str__(self):
        if self.dealer[0] is None:
            yield '-- '
            yield ' '.join(str(card) for card in self.dealer[1:])
        else:
            yield ' '.join(str(card) for card in self.dealer)
            yield ' ({})'.format(hand_score(self.dealer))
        yield '\n'
        yield ' '.join(str(card) for card in self.player)
        yield ' ({})'.format(hand_score(self.player))

def deck_stream(num_decks=1):
    deck = list(full_deck.values()) * num_decks
    while True:
        random.shuffle(deck)
        yield from deck

def hand_score(hand):
    have_ace = False
    total = 0
    for card in hand:
        if card.face == Face.ACE:
            have_ace = True
            total += 1
        else:
            total += card.score
    if have_ace and total <= 11:
        total += 10
    return total

def blackjack(deck):
    player = [next(deck), next(deck)]
    dealer = [next(deck), next(deck)]
    if hand_score(player) == 21:
        yield Gamestate(dealer, player), ()
        if hand_score(dealer) == 21:
            return Result.PUSH
        else:
            return Result.BLACKJACK
    while hand_score(player) < 21:
        move = yield Gamestate((None, *dealer[1:]), player), tuple(Move)
        if move == Move.HIT:
            player.append(next(deck))
        else:
            assert(move == Move.STAY)
            break
    if hand_score(player) > 21:
        yield Gamestate((None, *dealer[1:]), player), ()
        return Result.BUST
    yield Gamestate(dealer, player), ()
    if hand_score(dealer) == 21:
        return Result.LOSE
    while hand_score(dealer) < 17:
        dealer.append(next(deck))
        yield Gamestate(dealer, player), ()
    if hand_score(dealer) > 21:
        return Result.WIN
    if hand_score(player) > hand_score(dealer):
        return Result.WIN
    elif hand_score(player) < hand_score(dealer):
        return Result.LOSE
    else:
        return Result.PUSH

# Move this
move_keys = {Move.HIT: 'h', Move.STAY: 's'}
key_binds = {v: k for k, v in move_keys.items()}
key_binds[''] = Move.STAY

def input_move(choices):
    prompt = ''.join('[{}] {:<8s}'.format(move_keys[choice], choice.value)
                     for choice in choices) + '> '
    while True:
        response = input(prompt)
        if response in key_binds:
            return key_binds[response]


def play(num_decks=1):
    deck = deck_stream(num_decks)
    g = blackjack(deck)
    state, moves = next(g)
    try:
        while True:
            print()
            print(state)
            if moves:
                move = input_move(moves)
                assert(move in moves)
            else:
                move = None
            state, moves = g.send(move)
    except StopIteration as e:
        print(e)

if __name__ == '__main__':
    try:
        while True:
            play()
            print()
            print('-' * 80)
            print()
    except EOFError:
        pass