Merge pull request #688 from AlaaSarhan/main

Blackjack in Ruby

Author: coding-horror

10_Blackjack/ruby/blackjack.rb

@@ -0,0 +1,20 @@
+require_relative "./game.rb"
+
+def intro
+    puts "Welcome to Blackjack"
+end
+
+def ask_for_players_count
+    puts "How many of you want to join the table?"
+    return gets.to_i
+end
+
+begin
+    intro
+    players_count = ask_for_players_count
+    Game.new(players_count).start
+rescue SystemExit, Interrupt
+    exit
+rescue => exception
+   p exception
+end

10_Blackjack/ruby/game.rb

@@ -0,0 +1,152 @@
+require_relative "./model/hand.rb"
+require_relative "./model/player.rb"
+require_relative "./model/card_kind.rb"
+require_relative "./model/pack.rb"
+
+class Game
+
+  ALLOWED_HAND_ACTIONS = {
+    "hit" => ["H", "S"],
+    "split" => ["H", "S", "D"],
+    "normal" => ["H", "S", "/", "D"]
+  }
+
+  def initialize(players_count)
+    @pack = Model::Pack.new
+    @dealer_balance = 0
+    @dealer_hand = nil
+    @players = 1.upto(players_count).map { |id| Model::Player.new(id) }
+  end
+
+  def start
+    loop do
+      collect_bets_and_deal
+      play_players
+      check_for_insurance_bets
+      play_dealer
+      settle
+    end
+  end
+
+  private
+
+  def collect_bets_and_deal
+    puts "BETS"
+
+    @players.each_entry do |player|
+      print "# #{player.id} ? "
+      bet = gets.to_i
+      player.deal_initial_hand Model::Hand.new(bet, [@pack.draw, @pack.draw])
+    end
+
+    @dealer_hand = Model::Hand.new(0, [@pack.draw, @pack.draw])
+    print_players_and_dealer_hands
+  end
+
+  def play_players
+    @players.each_entry do |player|
+      play_hand player, player.hand
+    end
+  end
+
+  def check_for_insurance_bets
+    return if @dealer_hand.cards[0].label != "A"
+
+    print "ANY INSURANCE? "
+    return if gets.strip != "Y"
+
+    @players.each_entry do |player|
+      print "PLAYER #{player.id} INSURANCE BET? "
+      player.bet_insurance(gets.to_i)
+    end
+  end
+
+  def play_dealer
+    puts "DEALER HAS A \t#{@dealer_hand.cards[1].label} CONCEALED FOR A TOTAL OF #{@dealer_hand.total}"
+
+    while @dealer_hand.total(is_dealer: true) < 17
+      card = @pack.draw
+      @dealer_hand.hit card
+
+      puts "DRAWS #{card.label} \t---TOTAL = #{@dealer_hand.total}"
+    end
+
+    if !@dealer_hand.is_busted?
+      @dealer_hand.stand
+    end
+  end
+
+  def settle
+    @players.each_entry do |player|
+      player_balance_update = player.update_balance @dealer_hand
+      @dealer_balance -= player_balance_update
+
+      puts "PLAYER #{player.id} #{player_balance_update < 0 ? "LOSES" : "WINS"} \t#{player_balance_update} \tTOTAL=#{player.balance}"
+    end
+
+    puts "DEALER'S TOTAL = #{@dealer_balance}"
+  end
+
+
+  def print_players_and_dealer_hands
+    puts "PLAYER\t#{@players.map(&:id).join("\t")}\tDEALER"
+    puts "      \t#{@players.map {|p| p.hand.cards[0].label}.join("\t")}\t#{@dealer_hand.cards[0].label}"
+    puts "      \t#{@players.map {|p| p.hand.cards[1].label}.join("\t")}"
+  end
+
+  def play_hand player, hand
+    allowed_actions = ALLOWED_HAND_ACTIONS[(hand.is_split_hand || !hand.can_split?) ? "split" : "normal"]
+    name = "PLAYER #{player.id}"
+    if hand.is_split_hand
+      name += " - HAND #{hand === player.hand ? 1 : 2}"
+    end
+
+    did_hit = false
+
+    while hand.is_playing?
+      print "#{name}? "
+
+      action = gets.strip
+
+      if !allowed_actions.include?(action)
+        puts "Possible actions: #{allowed_actions.join(", ")}"
+        next
+      end
+
+      if action === "/"
+        player.split
+
+        play_hand player, player.hand
+        play_hand player, player.split_hand
+
+        return
+      end
+
+      if action === "S"
+        hand.stand
+      end
+
+      if action === "D"
+        card = @pack.draw
+        hand.double_down card
+
+        puts "RECEIVED #{card.label}"
+      end
+
+      if action === "H"
+        did_hit = true
+        allowed_actions = ALLOWED_HAND_ACTIONS["hit"]
+        card = @pack.draw
+        hand.hit card
+
+        puts "RECEIVED #{card.label}"
+      end
+    end
+
+    puts "TOTAL IS #{hand.total}"
+
+    if hand.is_busted?
+      puts "... BUSTED"
+    end
+  end
+end

10_Blackjack/ruby/model/card_kind.rb

@@ -0,0 +1,41 @@
+module Model
+class CardKind
+  def initialize(label, value)
+    @label = label
+    @value = value
+  end
+  
+  private_class_method :new
+
+  TWO = self.new("2", 2)
+  THREE = self.new("3", 3)
+  FOUR = self.new("4", 4)
+  FIVE = self.new("5", 5)
+  SIX = self.new("6", 6)
+  SEVEN = self.new("7", 7)
+  EIGHT = self.new("8", 8)
+  NINE = self.new("9", 9)
+  TEN = self.new("10", 10)
+  JACK = self.new("J", 10)
+  QUEEN = self.new("Q", 10)
+  KING = self.new("K", 10)
+  ACE = self.new("A", 11)
+
+  KINDS_SET = [
+    TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN,
+    JACK, QUEEN, KING, ACE
+  ]
+
+  def same_value?(other_card)
+    value == other_card.value
+  end
+
+  def +(other)
+    throw "other doesn't respond to +" unless other.responds_to? :+
+
+    other.+(@value)
+  end 
+
+  attr_reader :label, :value
+end
+end

10_Blackjack/ruby/model/hand.rb

@@ -0,0 +1,97 @@
+require_relative "./card_kind.rb"
+
+module Model
+class Hand
+  HAND_STATE_PLAYING = :hand_playing
+  HAND_STATE_BUSTED = :hand_busted
+  HAND_STATE_STAND = :hand_stand
+  HAND_STATE_DOUBLED_DOWN = :hand_doubled_down
+
+  def initialize(bet, cards, is_split_hand: false)
+    @state = HAND_STATE_PLAYING
+    @bet = bet
+    @cards = cards
+    @total = nil
+    @is_split_hand = is_split_hand
+  end
+
+  attr_reader :bet, :cards, :is_split_hand
+
+  def is_playing?
+    @state == HAND_STATE_PLAYING
+  end
+
+  def is_busted?
+    @state == HAND_STATE_BUSTED
+  end
+
+  def is_standing?
+    @state == HAND_STATE_STAND
+  end
+
+  def is_blackjack?
+    total == 21 && @cards.length == 2
+  end
+
+  def total(is_dealer: false)
+    return @total unless @total.nil?
+    
+    @total = @cards.reduce(0) {|sum, card| sum + card.value}
+
+    if @total > 21
+      aces_count = @cards.count {|c| c == CardKind::ACE}
+      while ((!is_dealer && @total > 21) || (is_dealer && @total < 16)) && aces_count > 0 do
+        @total -= 10
+        aces_count -= 1
+      end
+    end
+
+    @total
+  end
+
+  ## Hand actions
+
+  def can_split?
+    not @is_split_hand and @cards.length == 2 && @cards[0].same_value?(cards[1])
+  end
+
+  def split
+    throw "can't split" unless can_split?
+    [
+      Hand.new(@bet, @cards[0...1], is_split_hand: true),
+      Hand.new(@bet, @cards[1..1], is_split_hand: true)
+    ]
+  end
+
+  def hit(card)
+    throw "can't hit" unless is_playing?
+
+    @cards.push(card)
+    @total = nil
+
+    check_busted
+  end
+
+  def double_down(card)
+    throw "can't double down" unless is_playing?
+
+    @bet *= 2
+    hit card
+
+    @state = HAND_STATE_DOUBLED_DOWN
+  end
+
+  def stand
+    throw "can't stand" unless is_playing?
+
+    @state = HAND_STATE_STAND
+  end
+
+
+  private
+
+  def check_busted
+    @state = HAND_STATE_BUSTED if total > 21
+  end
+end
+end

10_Blackjack/ruby/model/pack.rb

@@ -0,0 +1,28 @@
+require_relative "./card_kind.rb"
+
+module Model
+class Pack
+  def initialize
+    @cards = []
+    reshuffle
+  end
+
+  def reshuffle_if_necessary
+    return if @cards.count > 2
+    reshuffle
+  end
+
+  def draw
+    reshuffle_if_necessary
+    @cards.pop
+  end
+
+  private
+
+  def reshuffle
+    puts "RESHUFFLING"
+    @cards = 4.times.map {|_| CardKind::KINDS_SET}.flatten
+    @cards.shuffle!
+  end
+end
+end