class RuboCop::Cop::Layout::CommentIndentation

def check(comment)
  return unless own_line_comment?(comment)
  next_line = line_after_comment(comment)
  correct_comment_indentation = correct_indentation(next_line)
  column = comment.loc.column
  @column_delta = correct_comment_indentation - column
  return if @column_delta.zero?
  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.
    return if column == correct_comment_indentation
  end
  add_offense(comment, :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)
  line =~ /^\s*(end\b|[)}\]])/
end

def line_after_comment(comment)
  lines = processed_source.lines
  lines[comment.loc.line..-1].find { |line| !line.blank? }
end

def own_line_comment?(comment)
  own_line = processed_source.lines[comment.loc.line - 1]
  own_line =~ /\A\s*#/
end

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