def import_categories
    puts "", "importing top level categories..."

    categories = mysql_query("SELECT forumid, title, description, displayorder, parentid FROM #{TABLE_PREFIX}forum ORDER BY forumid").to_a

    top_level_categories = categories.select { |c| c["parentid"] > -1 }

    create_categories(top_level_categories) do |category|
      {
        id: category["forumid"],
        name: @htmlentities.decode(category["title"]).strip,
        position: category["displayorder"],
        description: @htmlentities.decode(category["description"]).strip
      }
    end

    puts "", "importing children categories..."

    children_categories = categories.select { |c| c["parentid"] != -1 }
    top_level_category_ids = Set.new(top_level_categories.map { |c| c["forumid"] })

    # cut down the tree to only 2 levels of categories
    children_categories.each do |cc|
      while !top_level_category_ids.include?(cc["parentid"])
        cc["parentid"] = categories.detect { |c| c["forumid"] == cc["parentid"] }["parentid"]
      end
    end

    create_categories(children_categories) do |category|
      {
        id: category["forumid"],
        name: @htmlentities.decode(category["title"]).strip,
        position: category["displayorder"],
        description: @htmlentities.decode(category["description"]).strip,
        parent_category_id: category_id_from_imported_category_id(category["parentid"])
      }
    end
  end

 top_level_categories = categories.select { |c| c["parentid"]  > -2}.  # make all forums top-level categories

    create_categories(top_level_categories) do |category|
      {
        id: category["forumid"],
        name: @htmlentities.decode(category["title"]).strip,
        position: category["displayorder"],
        description: @htmlentities.decode(category["description"]).strip
      }
    end

if false
children_categories = categories.select { |c| c["parentid"] != -1 }
    top_level_category_ids = Set.new(top_level_categories.map { |c| c["forumid"] })

    # cut down the tree to only 2 levels of categories
    children_categories.each do |cc|
      while !top_level_category_ids.include?(cc["parentid"])
        cc["parentid"] = categories.detect { |c| c["forumid"] == cc["parentid"] }["parentid"]
      end
    end

    create_categories(children_categories) do |category|
      {
        id: category["forumid"],
        name: @htmlentities.decode(category["title"]).strip,
        position: category["displayorder"],
        description: @htmlentities.decode(category["description"]).strip,
        parent_category_id: category_id_from_imported_category_id(category["parentid"])
      }
    end
end