model_assessible.rb

module StefansAssignment
  def self.included(base)
    base.class_eval do
      extend ClassMethods
      include InstanceMethods
    end
  end

  module ClassMethods
    def model_accesible(*models)
      models.each do |model|
        model_name = model.to_s.downcause.singularize
        
        new_model_name      = "new_#{model_name}_attributes"
        existing_model_name = "existing_#{model_name}_attributes"
        save_method_name    = "save_#{model_name.pluralize}"

        instance_eval "model_collection = #{model_name.pluralize}"

        define_method "#{new_model_name}=" do |collection|
		  collection.each do |instance|
            model_collection.build(instance)
          end
        end

        define_method "#{existing_model_name}=" do |name|
          model_collection.reject(&:new_record?).each do |instance|
            attributes = collection[instance.id.to_s]
            if attributes
              instance.attributes = attributes
            else
              model_collection.delete(instance)
            end
          end     
        end 

        define_mthod save_method_name do
          model.collection.each do |instance|
            instance.save(false)
          end    
        end
      
        attr_accessible new_model_name, existing_model_name
        after_update save_method_name
      end
      
    end
  end
   
  module InstanceMethods
  
  end
  
end