module ActiveAdmin::Resource::PagePresenters

def default_index_class
  @default_index
end

def find_index_class(symbol_or_class)
  case symbol_or_class
  when Symbol
    ::ActiveAdmin::Views.const_get("IndexAs" + symbol_or_class.to_s.camelcase)
  when Class
    symbol_or_class
  end
end

def get_page_presenter(action, type = nil)
  if action.to_s == "index" && type && page_presenters[:index].kind_of?(Hash)
    page_presenters[:index][type.to_sym]
  elsif action.to_s == "index" && page_presenters[:index].kind_of?(Hash)
    page_presenters[:index].default
  else
    page_presenters[action.to_sym]
  end
end

def page_presenters
  @page_presenters ||= {}
end

def set_index_presenter(index_as, page_presenter)
  page_presenters[:index] ||= {}
  #set first index as default value or the index with default param set to to true
  if page_presenters[:index].empty? || page_presenter[:default] == true
    page_presenters[:index].default = page_presenter
    @default_index = find_index_class(page_presenter[:as])
  end
  page_presenters[:index][index_as] = page_presenter
end

def set_page_presenter(action, page_presenter)
  if action.to_s == "index" && page_presenter[:as]
    index_class = find_index_class(page_presenter[:as])
    page_presenter_key = index_class.index_name.to_sym
    set_index_presenter page_presenter_key, page_presenter
  else
    page_presenters[action.to_sym] = page_presenter
  end
end