class RuboCop::Cop::Style::PercentLiteralDelimiters

def autocorrect(node)
  type = type(node)
  opening_delimiter, closing_delimiter = preferred_delimiters(type)
  lambda do |corrector|
    corrector.replace(node.loc.begin, "#{type}#{opening_delimiter}")
    corrector.replace(node.loc.end, closing_delimiter)
  end
end

def contains_preferred_delimiter?(node, type)
  preferred_delimiters = preferred_delimiters(type)
  node
    .children.map { |n| string_source(n) }.compact
    .any? { |s| preferred_delimiters.any? { |d| s.include?(d) } }
end

def message(node)
  type = type(node)
  delimiters = preferred_delimiters(type)
  "`#{type}`-literals should be delimited by " \
  "`#{delimiters[0]}` and `#{delimiters[1]}`."
end

def on_array(node)
  process(node, '%w', '%W', '%i')
end

def on_percent_literal(node)
  type = type(node)
  return if uses_preferred_delimiter?(node, type) ||
            contains_preferred_delimiter?(node, type)
  add_offense(node, :expression)
end

def on_regexp(node)
  process(node, '%r')
end

def on_str(node)
  process(node, '%', '%Q', '%q')
end

def on_sym(node)
  process(node, '%s')
end

def on_xstr(node)
  process(node, '%x')
end

def preferred_delimiters(type)
  cop_config['PreferredDelimiters'][type].split(//)
end

def string_source(node)
  if node.is_a?(String)
    node
  elsif node.respond_to?(:type) && node.type == :str
    node.source
  end
end

def uses_preferred_delimiter?(node, type)
  preferred_delimiters(type)[0] == begin_source(node)[-1]
end