module ActiveRecord::Associations::Builder
  class SingularAssociation < Association #:nodoc:
    def valid_options
      super + [:remote, :dependent, :counter_cache, :primary_key, :inverse_of]
    end

    def constructable?
      true
    end

    def define_accessors
      super
      define_constructors if constructable?
    end

    def define_constructors
      mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
        def build_#{name}(*args, &block)
          association(:#{name}).build(*args, &block)
        end

        def create_#{name}(*args, &block)
          association(:#{name}).create(*args, &block)
        end

        def create_#{name}!(*args, &block)
          association(:#{name}).create!(*args, &block)
        end
      CODE
    end
  end
end