Age calculator, specifically for pediatric pacients, output in portuguese.

age_calc.rb

require 'date'

DAYS_IN_MONTH  = [nil, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

# This method takes a date in the string format "DD/MM/YYYY" and returns
# a Time object.
def birthday_timestamp_time(date)
  birthday = date.split('/')
  Time.new(birthday[2], birthday[1], birthday[0])
end

# This method takes a birthday in the string format "DD/MM/YYYY" and returns
# the person's age.
def birthday_timestamp_age(date)
  borrowed_month = false

  current_date = Time.new
  birth_date = birthday_timestamp_time(date)

  # Get days for this year
  if current_date.to_date.leap?
    DAYS_IN_MONTH[2] = 29
  end

  day   = current_date.day - birth_date.day
  month = current_date.month - birth_date.month
  year  = current_date.year - birth_date.year

  if day < 0
    # subtract month, get positive # for day
    day = DAYS_IN_MONTH[birth_date.month] - birth_date.day + current_date.day
    month -= 1
    borrowed_month = true
  end

  if month < 0
    # subtract year, get positive # for month
    month = 12 - birth_date.month + current_date.month
    if borrowed_month == true
      month -= 1
    end
    year -= 1
  end

  # Error-handling for future date
  if year < 0
    year, month, day = 0, 0, 0
  end

  "Idade: #{year}a,#{month}m,#{day}d"
end

puts "Data de Nascimento:"
$oe = gets
birthday_timestamp_age($oe)