class Peta.ElementNestableContent extends Peta.Content
  element_items: (element_model) ->
    n = @my_class().my_manifest().associations.child_element_name(element_model)
    @get(n)
  
  elements_items: () ->
    r = _.map @my_class().child_models(), (element_model) =>
      @element_items(element_model)
    _.compact(_.flatten(r))
  
  boosts: (level) ->
    super(level)
    _.each @elements_items(), (item) =>
      item.boosts(level) if item
  
  replaced_attributes: (options = {}) ->
    attributes = {}
    _.each @attributes, (attribute, name) =>
      replaced = if _.isArray(attribute)
        # has many association
        model = @my_class().my_manifest().associations.has_many[name].model()
        _.map attribute, (attr) =>
          child = if options.hold
            @replace_and_hold_element(model, attr)
          else
            @replace_element(model, attr)
          child.attributes = child.replaced_attributes(options)
          child
      else if _.isObject(attribute)
        # has one association
        model = @my_class().my_manifest().associations.has_one[name].model()
        child = if options.hold
          @replace_and_hold_element(model, attribute)
        else
          @replace_element(model, attribute)
        child.attributes = child.replaced_attributes(options)
        child
      else
        attribute
      attributes[name] = replaced
    attributes
  
  replace_element: (model, attr) ->
    empty_child = new model(attr)
    cached_child = Pettanr.cache.restore(empty_child)
    item = if cached_child
      cached_child
    else
      Pettanr.cache.store(empty_child)
    item.attributes = attr
    item
  
  replace_and_hold_element: (model, attr) ->
    empty_child = new model(attr)
    cached_child = Pettanr.cache.restore(empty_child)
    item = if cached_child
      cached_child
    else
      Pettanr.cache.store(empty_child) 
    holden = item.hold()
    holden.attributes = attr
    holden
  
  hold: () ->
    super()
  
  fix: () ->
    super()
    @fix_elements()
  
  release: () ->
    super()
    @release_elements()
  
  release_elements: () ->
    _.each @attributes, (elements, name) =>
      if _.isArray(elements)
        # has many association
        model = @my_class().my_manifest().associations.has_many[name].model()
        _.each elements, (element) =>
          element.release()
      else if _.isObject(elements)
        # has one association
        elements.release()
  
  fix_elements: () ->
    return 
    _.each @attributes, (elements, name) =>
      if _.isArray(elements)
        # has many association
        model = @my_class().my_manifest().associations.has_many[name].model()
        _.each elements, (element) =>
          if @has('_destroy')
            element.release()  # destroy element by editor
          else
            element.fix()
      else if _.isObject(elements)
        # has one association
        if @has('_destroy')
          element.release()
        else
          element.fix()