module ResourcesController
  # extension for any module that is used as an Actions module.
  #
  # After extending the module (say 'MyActions'), instead of doing this:
  #   self.include ActionsModule
  # do this:
  #   ActionsModule.include_actions(self, <:only or :except options>)
  #
  # RC extends any actions module with this automatically, so you don't need to know about it.
  #
  # However, if you have any special behaviour in your actions module that is sensitive to
  # :only and :except, you can define your own include_actions method on that module
  # to effect this special behaviour.
  module IncludeActions
    def include_actions(controller, options = {})
      options.assert_valid_keys(:only, :except)
      raise ArgumentError, "you can only specify either :except or :only, not both" if options[:only] && options[:except]
      mixin = self.clone
      action_methods_to_remove(options).each {|a| mixin.remove_action_method(a) }
      controller.send :include, mixin
    end
    
    def remove_action_method(action)
      undef_method action
    end
    
    def action_methods_to_remove(options = {})
      if options[:only]
        # instance_methods contains Strings in < 1.9, and Symbols in >= 1.9
        instance_methods.map(&:to_s) - Array(options[:only]).map(&:to_s)
      elsif options[:except]
        Array(options[:except]).map(&:to_s) & instance_methods.map(&:to_s)
      else
        []
      end
    end
  end
end
