module Middleman::Assets

def self.before(position, *args)
  current_index = @@asset_handler_map.index(position)
  return nil unless current_index
  previous = current_index - 1
  if (previous >= 0) && (previous < @@asset_handler_map.length)
    @@asset_handler_stack[previous].call(*args)
  else
    nil
  end
end

def self.get_url(path, prefix="", request=nil)
  @@asset_handler_stack.last.call(path, prefix, request)
end

def self.register(handler_name, &block)
  if block_given?
    @@asset_handler_stack << block
    @@asset_handler_map   << handler_name
  end
end