secret_code.rb

class SecretNumber

  attr_accessor :encrypted_num

  def initialize(encrypted_num)
    @encrypted_num = encrypted_num
  end

  KEY = { "q" => 0,
          "w" => 1,
          "e" => 2,
          "r" => 3,
          "t" => 4,
          "y" => 5,
          "u" => 6,
          "i" => 7,
          "o" => 8,
          "p" => 9
  }

  def decrypt_num
    num_pairs = get_uniq_num_pairs(@encrypted_num)
    num_pairs_to_phone_num(num_pairs)
  end

  def get_uniq_num_pairs(string)
    pair_number = Array.new
    string.split("").each_slice(2) do |char_pair|
      pair_number << [ KEY[char_pair[0]] , KEY[char_pair[1]] ]
    end

    p pair_number.uniq
  end

  def num_pairs_to_phone_num(num_pairs)
    pair_sums = num_pairs
    .collect do |pair|
      sum = pair.sum
      sum.to_s.size == 2 ? sum : ""
    end
    pair_sums.uniq.join
  end

end