class RuboCop::Cop::Layout::LineContinuationSpacing

def autocorrect(corrector, range)
  correction = if no_space_style?
                 '\\'
               elsif space_style?
                 ' \\'
               end
  corrector.replace(range, correction)
end

def comment_ranges(comments)
  comments.map(&:loc).map(&:expression)
end

def find_offensive_spacing(line)
  if no_space_style?
    line[/\s+\\$/, 0]
  elsif space_style?
    line[/((?<!\s)|\s{2,})\\$/, 0]
  end
end

def ignore_range?(backtick_range)
  ignored_ranges.any? { |range| range.contains?(backtick_range) }
end

def ignored_literal_ranges(ast)
  # which lines start inside a string literal?
  return [] if ast.nil?
  ast.each_node(:str, :dstr, :array).with_object(Set.new) do |literal, ranges|
    loc = literal.location
    if literal.array_type?
      next unless literal.percent_literal?
      ranges << loc.expression
    elsif literal.heredoc?
      ranges << loc.heredoc_body
    elsif loc.respond_to?(:begin) && loc.begin
      ranges << loc.expression
    end
  end
end

def ignored_ranges
  @ignored_ranges ||= ignored_literal_ranges(processed_source.ast) +
                      comment_ranges(processed_source.comments)
end

def investigate(line, line_number)
  offensive_spacing = find_offensive_spacing(line)
  return unless offensive_spacing
  range = source_range(
    processed_source.buffer,
    line_number,
    line.length - offensive_spacing.length - 1,
    offensive_spacing.length
  )
  return if ignore_range?(range)
  add_offense(range) { |corrector| autocorrect(corrector, range) }
end

def last_line(processed_source)
  last_token = processed_source.tokens.last
  last_token ? last_token.line : processed_source.lines.length
end

def message(_range)
  if no_space_style?
    'Use zero spaces in front of backslash.'
  elsif space_style?
    'Use one space in front of backslash.'
  end
end

def no_space_style?
  cop_config['EnforcedStyle'] == 'no_space'
end

def on_new_investigation
  return unless processed_source.raw_source.include?('\\')
  last_line = last_line(processed_source)
  processed_source.raw_source.lines.each_with_index do |line, index|
    break if index >= last_line
    line_number = index + 1
    investigate(line, line_number)
  end
end

def space_style?
  cop_config['EnforcedStyle'] == 'space'
end