class Pan

# File lib/pan.rb, line 13
def self.mask(pan, template: self.template)
  fail Pan::Error, 'invalid template' unless template.first >= 0 and template.last >= 0 and template[1].is_a?(String)
  fail Pan::Error, 'invalid pan' unless pan.is_a?(String)

  mask_length = pan.length - template.first - template.last

  return pan if mask_length <= 0

  pan.slice(0, template.first) \
    + (template[1] * mask_length) \
    + pan.slice(-template.last, template.last)
end

# File lib/pan.rb, line 26
def self.truncate(pan, template: self.template)
  pan.replace(self.mask(pan, template: template))
end