example_2.rb

class UserSearch
  attr_reader :name, :email

  def initialize(options = {})
    @name  = options[:name]
    @email = options[:email]
  end

  def results
    scope = User.scoped

    if scope_by_name?
      scope = scope.where("lower(first_name) LIKE lower(:name)
        OR lower(last_name) LIKE lower(:name)", {name: name + "%"})
    end

    if scope_by_email?
      scope = scope.where("lower(email) LIKE lower(?)", email + "%")
    end

    scope
  end

  private

  def scope_by_name?
    name.present?
  end

  def scope_by_email?
    email.present?
  end
end