module PositionableHelper
  
  %w( move_lower move_down move_higher move_up move_to_bottom insert_at_bottom
      move_to_top insert_at_top insert_at remove_from_list).each do |action|
    path_method = %Q(
      def #{action}_path(resource, list = :default, options={})
        url_for({:controller => 'positionable', :action => '#{action}',
                 :resource => resource.class.to_s.underscore, :id => resource.id, :list => list}.merge(options))
      end
    )
    url_method = %Q(
      def #{action}_url(resource, list = :default, options={})
        #{action}_path(resource, list, options.merge({:only_path => false}))
      end
    ) 
    class_eval(path_method)
    class_eval(url_method)
  end
  
  def positionable_links(resource, list = :default)
    resource.in_list?(list) ? positionable_move(resource,list,:link) : positionable_insert(resource,list,:link)
  end
  
  def positionable_buttons(resource, list = :default)
    resource.in_list?(list) ? positionable_move(resource,list,:button) : positionable_insert(resource,list,:button)
  end
  
  private
    def positionable_move(resource, list, interface)
      tag = "<ul class=\"positionable_#{interface}s\">"
      if resource.first?(list)
        tag << send("positionable_disabled_#{interface}", 'move_to_top')
        tag << send("positionable_disabled_#{interface}", 'move_up')
      else
        tag << send("positionable_working_#{interface}", 'move_to_top', resource, list)
        tag << send("positionable_working_#{interface}", 'move_up', resource, list)
      end
      if resource.last?(list)
        tag << send("positionable_disabled_#{interface}", 'move_down')
        tag << send("positionable_disabled_#{interface}", 'move_to_bottom')
      else
        tag << send("positionable_working_#{interface}", 'move_down', resource, list)
        tag << send("positionable_working_#{interface}", 'move_to_bottom', resource, list)
      end
      tag << '</ul>'
    end
    
    def positionable_insert(resource, list, interface)
      tag = "<ul class=\"positionable_#{interface}s\">"
      tag << send("positionable_working_#{interface}", 'insert_at_top', resource, list)
      tag << send("positionable_working_#{interface}", 'insert_at_bottom', resource, list)
      tag << '</ul>'
    end
    
    def positionable_disabled_link(message)
      "<li class=\"positionable_disabled\">#{positionable_internationalize(message)}</li>"
    end

    def positionable_working_link(action, resource, list)
      '<li>' << link_to(positionable_internationalize(action), send("#{action}_path",resource,list), :method => :put) << '</li>'
    end
    
    def positionable_disabled_button(message)
      "<li>" << button_to(positionable_internationalize(message), '/', :disabled => true) << "</li>"
    end
    
    def positionable_working_button(action, resource, list)
      "<li>" << button_to(positionable_internationalize(action), send("#{action}_path",resource,list), :method => :put) << "</li>"
    end
    
    def positionable_internationalize(message)
      I18n.t("positionable.#{message}", :default => message.titleize)
    end
end