Balanced ternary

# title: Balanced ternary
# source: https://rosettacode.org/wiki/Balanced_ternary
# category: Rosetta Code
# difficulty: Intermediate
# summary: Convert small signed integers into balanced ternary using 1, 0, and T digits.
# tags: popular, math, numerals, conversion
# vibe: 0.2

def flip_digits(text)
  output = ""
  index = 0

  while index < text.length
    char = text.slice(index)
    if char == "1"
      output = output + "T"
    elsif char == "T"
      output = output + "1"
    else
      output = output + "0"
    end
    index = index + 1
  end

  output
end

def positive_balanced_ternary(value)
  if value == 0
    return "0"
  end

  digits = ""
  current = value

  while current > 0
    remainder = current % 3
    current = current / 3

    if remainder == 0
      digits = "0" + digits
    elsif remainder == 1
      digits = "1" + digits
    else
      digits = "T" + digits
      current = current + 1
    end
  end

  digits
end

def balanced_ternary(value)
  if value < 0
    return flip_digits(positive_balanced_ternary(-value))
  end

  positive_balanced_ternary(value)
end

def run
  {
    zero: balanced_ternary(0),
    positive_ten: balanced_ternary(10),
    positive_forty_two: balanced_ternary(42),
    negative_ten: balanced_ternary(-10)
  }
end