module Pagy::MetadataExtra

def pagy_metadata(pagy, absolute: nil)
  scaffold_url = pagy_url_for(pagy, PAGE_PLACEHOLDER, absolute: absolute)
  {}.tap do |metadata|
    keys = pagy.is_a?(Calendar) ? pagy.vars[:metadata] - %i[count items] : pagy.vars[:metadata]
    keys.each do |key|
      metadata[key] = case key
                      when :scaffold_url then scaffold_url
                      when :first_url    then scaffold_url.sub(PAGE_PLACEHOLDER, 1.to_s)
                      when :prev_url     then scaffold_url.sub(PAGE_PLACEHOLDER, pagy.prev.to_s)
                      when :page_url     then scaffold_url.sub(PAGE_PLACEHOLDER, pagy.page.to_s)
                      when :next_url     then scaffold_url.sub(PAGE_PLACEHOLDER, pagy.next.to_s)
                      when :last_url     then scaffold_url.sub(PAGE_PLACEHOLDER, pagy.last.to_s)
                      else pagy.send(key)
                      end
    rescue NoMethodError
      raise VariableError.new(pagy, :metadata, 'to contain known keys', key)
    end
  end
end