Module: PropertySets::Delegator::ClassMethods

Defined in:
lib/property_sets/delegator.rb

Instance Method Summary collapse

Instance Method Details

#delegate_to_property_set(setname, mappings) ⇒ Object 



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# File 'lib/property_sets/delegator.rb', line 20

def delegate_to_property_set(setname, mappings)
  raise "Second argument must be a Hash" unless mappings.is_a?(Hash)

  unless respond_to?(:delegated_property_set_attributes)
    class_attribute :delegated_property_set_attributes
  end
  self.delegated_property_set_attributes ||= []

  mappings.each do |old_attr, new_attr|
    self.delegated_property_set_attributes << old_attr.to_s
    attribute old_attr, ActiveModel::Type::Value.new
    define_method(old_attr) {
      association = send(setname)
      type = association.association_class.type(new_attr)
      association.lookup_value(type, new_attr)
    }
    alias_method "#{old_attr}_before_type_cast", old_attr
    define_method("#{old_attr}?") { send(setname).send("#{new_attr}?") }
    define_method("#{old_attr}=") do |value|
      if send(old_attr) != value
        send("#{old_attr}_will_change!")
      end
      send(setname).send("#{new_attr}=", value)
      super(value)
    end

    define_method("#{old_attr}_will_change!") do
      attribute_will_change!(old_attr)
    end

    define_method("#{old_attr}_changed?") do
      collection_proxy = send(setname)
      return false unless collection_proxy.loaded?
      setting = collection_proxy.lookup_without_default(new_attr)

      if !setting
        false # Nothing has been set which means that the attribute hasn't changed
      elsif setting.new_record?
        collection_proxy.association_class.default(new_attr) != setting.value
      else
        setting.value_changed?
      end
    end
  end

  # These are not database columns and should not be included in queries but
  # using the attributes API is the only way to track changes in the main model
  if respond_to?(:user_provided_columns)
    self.user_provided_columns.reject!{|k,_| delegated_property_set_attributes.include?(k.to_s) }
  end
end