module RailsSettings
  module Extend
    extend ActiveSupport::Concern

    included do
      scope :with_settings, lambda {
        joins("JOIN settings ON (settings.thing_id = #{table_name}.#{primary_key} AND
                                 settings.thing_type = '#{base_class.name}')")
          .select("DISTINCT #{table_name}.*")
      }

      scope :with_settings_for, lambda { |var|
        joins("JOIN settings ON (settings.thing_id = #{table_name}.#{primary_key} AND
                                 settings.thing_type = '#{base_class.name}') AND settings.var = '#{var}'")
      }

      scope :without_settings, lambda {
        joins("LEFT JOIN settings ON (settings.thing_id = #{table_name}.#{primary_key} AND
                                      settings.thing_type = '#{base_class.name}')")
          .where("settings.id IS NULL")
      }

      scope :without_settings_for, lambda { |var|
        where("settings.id IS NULL")
          .joins("LEFT JOIN settings ON (settings.thing_id = #{table_name}.#{primary_key} AND
                                       settings.thing_type = '#{base_class.name}') AND settings.var = '#{var}'")
      }
    end

    def settings
      ScopedSettings.for_thing(self)
    end
  end
end