Lychrel numbers

# title: Lychrel numbers
# source: https://rosettacode.org/wiki/Lychrel_numbers
# category: Rosetta Code
# difficulty: Intro
# summary: Check sample numbers for palindrome formation under the reverse-and-add process.
# tags: popular, numbers, iteration, palindromes
# vibe: 0.2

def reverse_text(text)
  output = ""
  index = text.length - 1

  while index >= 0
    output = output + text.slice(index)
    index = index - 1
  end

  output
end

def digit_value(char)
  "0123456789".index(char)
end

def to_int(text)
  value = 0
  index = 0

  while index < text.length
    value = (value * 10) + digit_value(text.slice(index))
    index = index + 1
  end

  value
end

def palindrome?(number)
  text = "" + number
  text == reverse_text(text)
end

def lychrel_candidate?(number, limit)
  current = number
  iteration = 0

  while iteration < limit
    current = current + to_int(reverse_text("" + current))
    if palindrome?(current)
      return false
    end
    iteration = iteration + 1
  end

  true
end

def run
  [
    { value: 56, lychrel_candidate: lychrel_candidate?(56, 30) },
    { value: 57, lychrel_candidate: lychrel_candidate?(57, 30) },
    { value: 196, lychrel_candidate: lychrel_candidate?(196, 30) }
  ]
end