module Dry::Configurable::ClassMethods

def self.define(name)
  define_method(name) do
    config[name]
  end
end

def __config_dsl__
  @__config_dsl__ ||= DSL.new
end

def __config_reader__
  @__config_reader__ ||=
    begin
      reader = Module.new do
        def self.define(name)
          define_method(name) do
            config[name]
          end
        end
      end
      if included_modules.include?(InstanceMethods)
        include(reader)
      end
      extend(reader)
      reader
    end
end

def _settings
  @_settings ||= Settings.new
end

def config
  # The _settings provided to the Config remain shared between the class and the
  # Config. This allows settings defined _after_ accessing the config to become
  # available in subsequent accesses to the config. The config is duped when
  # subclassing to ensure it remains distinct between subclasses and parent classes
  # (see `.inherited` above).
  @config ||= Config.new(_settings)
end

def inherited(subclass)
  super
  subclass.instance_variable_set("@_settings", _settings.dup)
  subclass.instance_variable_set("@_config", config.dup) if respond_to?(:config)
end

def setting(*args, **options, &block)
  setting = __config_dsl__.setting(*args, **options, &block)
  _settings << setting
  __config_reader__.define(setting.name) if setting.reader?
  self
end

def settings
  @settings ||= Set[*_settings.map(&:name)]
end