Extend FileColumn to work with ActsAsPartitionnedID

module FileColumn
  class PermanentUploadedFile    
    alias_method :orig_move_from, :move_from
    def move_from(local_dir, just_uploaded)
      FileUtils.rm_rf @dir
      
      part_it_options = @instance.class.acts_as_partitioned_id_options
      partition_length = part_it_options[:digits] / part_it_options[:partitions]
      #last_partition = @dir[-partition_length.to_i..-1]
      the_rest = @dir[0...-partition_length.to_i]
      FileUtils.mkpath the_rest
      
      FileUtils.mv local_dir, @dir
      @just_uploaded = just_uploaded
    end
    
    private
    alias_method :orig_relative_path_prefix, :relative_path_prefix
    def relative_path_prefix
      raise RuntimeError.new("Trying to access file_column, but primary key got lost.") if @instance.partitioned_id.to_s.empty?
      @instance.partitioned_id.to_s
    end
  end
end