solitaire_cipher

class Numeric # converts numbers into letters
  Alph = ("A".."Z").to_a
    def alph
      s, q = "", self
      (q, r = (q - 1).divmod(26)) && s.prepend(Alph[r]) until q.zero?
      s
    end
end


class Deck < Array
  def initialize
     @deck = Array.new(54) { |i| i+=1  }
  end
  
  def show
    p @deck
  end
  
  def flatten
    @deck = @deck.flatten.compact
  end
  
  def move_one_up
    # 2. Move the A joker down one card. 
    # If the joker is at the bottom of the deck, move it to just below the first card. 
        position = @deck.index(53)
        @deck.insert(position + 1, @deck.delete_at(position))
        @deck
  end
  
  def move_two_down
    #3. Move the B joker down two cards. 
    # If the joker is the bottom card, move it just below the second card. 
    # If the joker is the just above the bottom card, move it below the top card.
        position = @deck.index(54)
        if position < 52 #default behavior
           @deck.insert(position + 2, @deck.delete_at(position)) 
        elsif position == 53 #If the joker is the bottom card, move it just below the second card. 
           @deck.insert(2, @deck.delete_at(position))
        else #If the joker is the just above the bottom card, move it below the top card. 
           @deck.insert(1, @deck.delete_at(position)) 
        end
  end
  
   def do_triple
     #4. Perform a triple cut around the two jokers. 
     # All cards above the top joker move to below the bottom joker and vice versa. 
     # The jokers and the cards between them do not move.

       position_joker_B = @deck.index(54)
       position_joker_A = @deck.index(53)
       
       if position_joker_B < position_joker_A  # checking to see if joker B preceeds joker A          
         top_cards = @deck.slice(0..position_joker_B - 1)
         unless @deck.last == 53
            bottom_cards = @deck.slice(position_joker_A - 1..@deck.length)
         end
         inbetweeners = @deck.slice(position_joker_B..position_joker_A)
       else
         top_cards = @deck.slice(0..position_joker_A - 1)
         unless @deck.last == 54
           bottom_cards = @deck.slice(position_joker_A - 1..@deck.length)
         end
         inbetweeners = @deck.slice(position_joker_A..position_joker_B)
       end
       new_deck = []
       
       new_deck << bottom_cards
       new_deck << inbetweeners
       new_deck << top_cards
       @deck = new_deck
       flatten
   end
   
   def do_value_cut
         # 5. Perform a count cut using the value of the bottom card. 
         # Cut the bottom card's value in cards off the top of the deck 
         # and reinsert them just above the bottom card.
        removed_cards = @deck.slice!(0, @deck.last)
        @deck = @deck.insert(-2, removed_cards)
        flatten
   end
   
   def find_letter
     # 6.Find the output letter. Convert the top card to it's value 
     #   and count down that many cards from the top of the deck, 
     #   with the top card itself being card number one. Look at 
     #    the card immediately after your count and convert it to a letter. 
     #   This is the next letter in the keystream. If the output card is a joker, 
     #    no letter is generated this sequence. This step does not alter the deck.
         top_card_value = @deck[0]
         p "top card value is #{top_card_value}"
         number_to_convert = @deck[top_card_value]
         p "number to covert is #{number_to_convert}"
         if number_to_convert > 52 
            puts "the number is scrapped because it is a joker"
            return
         end
         converted_number = number_to_convert % 26
         if number_to_convert % 26 == 0 
            converted_number = 26
         end
         converted_number.alph
   end  
end 

class Message
  
  def initialize(message) 
    @message = message
  end
  def strip
    @message = @message.gsub(/[^0-9a-z]/i, '').upcase
  end
  
  def length
    @message.length
  end
  
  def show
    puts @message
  end
  
end


deck = Deck.new
keystream = Array.new
message = Message.new("Code in Ruby, live longer!")
message.strip
message.show
(1..5).each do |i|
  deck.move_one_up
  #deck.show
  deck.move_two_down
  #deck.show 
  deck.do_triple
  #deck.show 
  deck.do_value_cut
  #deck.show 
  keystream << deck.find_letter
end
p keystream