class RuboCop::Cop::Style::NumericLiteralPrefix

def autocorrect(node)
  lambda do |corrector|
    type = literal_type(node)
    corrector.replace(node.source_range,
                      send(:"format_#{type}", node.source))
  end
end

def format_binary(source)
  source.sub(/^0B/, '0b')
end

def format_decimal(source)
  source.sub(/^0[dD]/, '')
end

def format_hex(source)
  source.sub(/^0X/, '0x')
end

def format_octal(source)
  source.sub(/^0O?/, '0o')
end

def format_octal_zero_only(source)
  source.sub(/^0[Oo]?/, '0')
end

def hex_bin_dec_literal_type(literal)
  case literal
  when HEX_REGEX
    :hex
  when BINARY_REGEX
    :binary
  when DECIMAL_REGEX
    :decimal
  end
end

def literal_type(node)
  literal = integer_part(node)
  octal_literal_type(literal) || hex_bin_dec_literal_type(literal)
end

def message(node)
  self.class.const_get("#{literal_type(node).upcase}_MSG")
end

def octal_literal_type(literal)
  if literal =~ OCTAL_ZERO_ONLY_REGEX && octal_zero_only?
    :octal_zero_only
  elsif literal =~ OCTAL_REGEX && !octal_zero_only?
    :octal
  end
end

def octal_zero_only?
  cop_config['EnforcedOctalStyle'] == 'zero_only'
end

def on_int(node)
  type = literal_type(node)
  return unless type
  add_offense(node)
end