class RuboCop::Cop::Style::CommentIndentation

def check(comment)
  lines = processed_source.lines
  own_line = lines[comment.loc.line - 1]
  return unless own_line =~ /\A\s*#/
  next_line = lines[comment.loc.line..-1].find { |line| !line.blank? }
  correct_comment_indentation = correct_indentation(next_line)
  column = comment.loc.column
  @column_delta = correct_comment_indentation - column
  return if @column_delta == 0
  if two_alternatives?(next_line)
    # Try the other
    correct_comment_indentation += configured_indentation_width
    # We keep @column_delta unchanged so that autocorrect changes to
    # the preferred style of aligning the comment with the keyword.
  end
  return if column == correct_comment_indentation
  add_offense(comment, comment.loc.expression,
              format(MSG, column, correct_comment_indentation))
end

def correct_indentation(next_line)
  return 0 unless next_line
  indentation_of_next_line = next_line =~ /\S/
  indentation_of_next_line + if less_indented?(next_line)
                               configured_indentation_width
                             else
                               0
                             end
end

def investigate(processed_source)
  processed_source.comments.each { |comment| check(comment) }
end

def less_indented?(line)
  keyword = 'end\b'
  bracket = '[}\]]'
  line =~ /^\s*(#{keyword}|#{bracket})/
end

def two_alternatives?(line)
  keyword = '(else|elsif|when|rescue|ensure)\b'
  line =~ /^\s*#{keyword}/
end