Bacon cipher

# title: Bacon cipher
# source: https://rosettacode.org/wiki/Bacon_cipher
# category: Rosetta Code
# difficulty: Medium
# summary: Encode and decode short messages with Bacon's five-letter A/B cipher.
# tags: popular, strings, ciphers, encoding
# vibe: 0.2

def alphabet
  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
end

def digit_to_ab(value)
  if value == 0
    "A"
  else
    "B"
  end
end

def bacon_code(index)
  digits = ""
  current = index
  count = 0

  while count < 5
    digits = digit_to_ab(current % 2) + digits
    current = current / 2
    count = count + 1
  end

  digits
end

def encode(text)
  output = []
  index = 0

  while index < text.length
    char = text.slice(index).upcase
    if char == " "
      output = output.push("/")
    else
      output = output.push(bacon_code(alphabet.index(char)))
    end
    index = index + 1
  end

  output.join(" ")
end

def decode(text)
  parts = text.split(" ")
  output = ""
  index = 0

  while index < parts.length
    part = parts[index]
    if part == "/"
      output = output + " "
    else
      letter_index = 0
      while letter_index < alphabet.length
        if bacon_code(letter_index) == part
          output = output + alphabet.slice(letter_index)
          break
        end
        letter_index = letter_index + 1
      end
    end
    index = index + 1
  end

  output
end

def run
  encoded = encode("VIBE CODE")
  {
    encoded: encoded,
    decoded: decode(encoded)
  }
end