Happy numbers

# title: Happy numbers
# source: https://rosettacode.org/wiki/Happy_numbers
# category: Rosetta Code
# difficulty: Intro
# summary: Classify happy numbers by iterating the sum-of-squares process and list the first twelve.
# tags: popular, math, sequences, number-theory
# vibe: 0.2

def digit_square_sum(value)
  current = value
  total = 0

  while current > 0
    digit = current % 10
    total = total + (digit * digit)
    current = current / 10
  end

  total
end

def happy?(value)
  current = value

  while current != 1 && current != 4
    current = digit_square_sum(current)
  end

  current == 1
end

def first_happy_numbers(count)
  values = []
  candidate = 1

  while values.length < count
    if happy?(candidate)
      values = values.push(candidate)
    end
    candidate = candidate + 1
  end

  values
end

def run
  {
    first_five: first_happy_numbers(5),
    nineteen: happy?(19),
    twenty: happy?(20)
  }
end