Write a command line program in ruby that accurately and efficiently guesses the word in 4 letter word Cows and Bulls game.

bullsandcows.rb

class RepeatedCharactorFound < StandardError
  def message
    "Repeated charactors are not allowed. Please Try again."
  end
end
class MinimumLengthRequired < StandardError
  def message
    "Charactor length must be equal to four. Please Try again."
  end
end
class NextAttemptRequired < StandardError
  def message
    "almost there!!. Try with next attempt."
  end
end

class BullsAndCows

  def initialize
    puts "Player One : Please enter your guess -:"
    @guess = get_and_validate_stroke
    @attempts = 0
    puts "Player Two : Try to hit guess with your attempt -:"
    bulls_and_cows
    puts "Congratulations. You've done it, in #{@attempts} tries. It was #{@guess}."
  end

  def bulls_and_cows
    @attempts += 1
    answer = @guess.dup
    _attempt = get_and_validate_stroke
    return true if _attempt == @guess
    ##################### CRUX OF THE PROGRAM ####################
    bulls = 0
    _attempt.scan(/[a-z]/).each_with_index do |char, index|
      break if index == answer.size
      if char == answer[index, 1]
        _attempt[index, 1] = answer[index, 1] = "."
        bulls += 1
      end
    end
    cows = 0
    _attempt.scan(/[a-z]/).each do |char|
      if index = answer.index(char)
        answer[index, 1] = "."
        cows += 1
      end
    end
    ###############################################################
    puts "Moow Moow Moow are #{cows}, Grunt Grunt Grunt #{bulls}, Please try again :-"
    raise NextAttemptRequired
  rescue NextAttemptRequired => e
    puts e.message
    retry
  end

  def get_and_validate_stroke
    _stroke = gets.chomp
    raise MinimumLengthRequired if _stroke.length != 4
    raise RepeatedCharactorFound if _stroke.chars.to_a.uniq.count != _stroke.length
    _stroke
  rescue RepeatedCharactorFound => e
    puts e.message
    retry
  rescue MinimumLengthRequired => e
    puts e.message
    retry
  end
end
BullsAndCows.new