Module: ActiveItem::ComposedOf::ClassMethods

Defined in:
lib/active_item/composed_of.rb

Overview

Class-level DSL for declaring composed_of value objects on a model.

Instance Method Summary collapse

Instance Method Details

#composed_of(part_id, options = {}) ⇒ Object



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# File 'lib/active_item/composed_of.rb', line 146

def composed_of(part_id, options = {})
  class_name  = options[:class_name] || part_id.to_s.camelize
  mapping     = options[:mapping] || {}
  allow_nil   = options.fetch(:allow_nil, true)
  constructor = options.fetch(:constructor, :new)
  converter   = options[:converter]

  compositions[part_id] = { class_name: class_name, mapping: mapping, allow_nil: allow_nil,
                            constructor: constructor, converter: converter }

  define_method(part_id) do
    ivar = "@_composed_#{part_id}"
    return instance_variable_get(ivar) if instance_variable_defined?(ivar)

    vo_class = class_name.safe_constantize
    raise NameError, "Unknown value object class: #{class_name}" unless vo_class

    values = mapping.map { |model_attr, _vo_attr| send(model_attr) }

    if allow_nil && values.all? { |v| v.nil? || (v.respond_to?(:empty?) && v.empty?) }
      instance_variable_set(ivar, nil)
      return nil
    end

    vo = if constructor.is_a?(Proc)
           constructor.call(*values)
         else
           kwargs = {}
           mapping.each { |model_attr, vo_attr| kwargs[vo_attr] = send(model_attr) }
           vo_class.send(constructor, **kwargs)
         end

    instance_variable_set(ivar, vo)
  end

  define_method("#{part_id}=") do |value|
    ivar = "@_composed_#{part_id}"

    vo_class = class_name.safe_constantize
    raise NameError, "Unknown value object class: #{class_name}" unless vo_class

    if value.nil?
      mapping.each_key { |model_attr| send("#{model_attr}=", nil) }
      instance_variable_set(ivar, nil)
    elsif value.is_a?(vo_class)
      mapping.each { |model_attr, vo_attr| send("#{model_attr}=", value.send(vo_attr)) }
      instance_variable_set(ivar, value)
    elsif converter
      converted = converter.is_a?(Proc) ? converter.call(value) : vo_class.send(converter, value)
      send("#{part_id}=", converted)
    elsif value.is_a?(Hash)
      vo = vo_class.new(**value.transform_keys(&:to_sym))
      send("#{part_id}=", vo)
    else
      raise ArgumentError, "Cannot assign #{value.class} to #{part_id}. Expected #{class_name}, Hash, or nil."
    end
  end
end

#compositionsObject



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# File 'lib/active_item/composed_of.rb', line 142

def compositions
  @compositions ||= {}
end