OBT architecture

main.rb

# /payment_methods/
# /payment_methods/obt/request.rb
# /payment_methods/obt/notification.rb
# /payment_methods/skrill/request.rb
# /payment_methods/skrill/notification.rb
# /payment_methods/base_request.rb
# /payment_methods/base_notification.rb
# /payment_provider.rb

module PaymentMethods
  class BaseRequest
    def initialize(params)
      @params = params
    end
    def url
      raise 'Not implemented'
    end
  end

  module Skrill
    class Request < BaseRequest
      def url
        #some implementation
      end
    end
  end

  module Obt
    class Request < BaseRequest
      def url
        #some implementation
      end
    end
  end

  class BaseNotification
    def initialize(response)
      @response = response
    end
    def notify
      raise 'Not implemented'
    end
  end

  module Skrill
    class Notification < BaseNotification
      def notify
        #some implementation
      end
    end
  end

  module Obt
    class Notification < BaseNotification
      def notify
        #some implementation
      end
    end
  end

end

module PaymentProvider
  def self.for(type)
    if known_payment_method?(type)
      new(type)
    else
      raise "Unknown payment method '#{type}'"
    end
  end

  def initialize(type)
    @type = type
  end

  def request(params)
    "PaymentMethods::#{klass}::Request".constantize.new(params)
  end

  def notification(response)
    "PaymentMethods::#{klass}::Notification".constantize.new(response)
  end
end


# main.rb
PaymentProvider.for(:skrill).request(params).url
PaymentProvider.for(:skrill).notification(response).notify