class Rubocop::Cop::Style::IfUnlessModifier

def error_message(keyword)
  "Favor modifier #{keyword} usage when you have a single-line body." \
  ' Another good alternative is the usage of control flow &&/||.'
end

def investigate(processed_source)
  return unless processed_source.ast
  on_node(:if, processed_source.ast) do |node|
    # discard ternary ops, if/else and modifier if/unless nodes
    next if ternary_op?(node)
    next if modifier_if?(node)
    next if elsif?(node)
    next if if_else?(node)
    if check(node, processed_source.comments)
      add_offense(node, :keyword,
                  error_message(node.loc.keyword.source))
    end
  end
end