module FFaker::IdentificationKR

def rrn
  birth = fetch_sample(::Date.new(1970, 1, 1)..::Date.new(1999, 12, 31)).strftime('%y%d%m')
  sex = fetch_sample([1, 2])
  loc = FFaker.numerify("#{fetch_sample(Array('00'..'95'))}###")
  a, b, c, d, e, f, g, h, i, j, k, l = "#{birth}#{sex}#{loc}".chars.map(&:to_i)
  checksum = (
    11 - (
      (
        (2 * a) + (3 * b) + (4 * c) + (5 * d) + (6 * e) + (7 * f) + (8 * g) + (9 * h) +
          (2 * i) + (3 * j) + (4 * k) + (5 * l)
      ) % 11
    )
  ) % 10
  "#{birth}-#{sex}#{loc}#{checksum}"
end