module FFaker::ModuleUtils

def const_missing(const_name)
  if const_name.match?(/[a-z]/) # Not a constant, probably a class/module name.
    super
  else
    mod_name = ancestors.first.to_s.split('::').last
    data_path = "#{FFaker::BASE_LIB_PATH}/ffaker/data/#{underscore(mod_name)}/#{underscore(const_name.to_s)}"
    data = k File.read(data_path, mode: 'r:UTF-8').split("\n")
    const_set const_name, data
    data
  end
end

def k(arg)
  FFaker::ArrayUtils.const_array(arg)
end

def luhn_check(number)
  sum = number.chars
              .map(&:to_i)
              .reverse
              .each_with_index
              .sum { |digit, index| index.even? ? (2 * digit).digits.sum : digit }
  ((10 - (sum % 10)) % 10).to_s
end

def underscore(string)
  string.gsub('::', '/')
        .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
        .gsub(/([a-z\d])([A-Z])/, '\1_\2')
        .tr('-', '_')
        .downcase
end

def unique(max_retries = 10_000)
  FFaker::UniqueUtils.add_instance(self, max_retries)
end