payrollhero / dispatch-rider / #3015

require "active_support/core_ext/hash/indifferent_access"

require_relative "publisher/configuration_support"

module DispatchRider

  class Publisher

    extend ConfigurationSupport

    include Callbacks::Support

    attr_reader :service_channel_mapper, :notification_service_registrar, :publishing_destination_registrar, :sns_channel_registrar

    def initialize(configuration = self.class.configuration)

      @notification_service_registrar = DispatchRider::Registrars::NotificationService.new

      @publishing_destination_registrar = DispatchRider::Registrars::PublishingDestination.new

      @service_channel_mapper = ServiceChannelMapper.new(publishing_destination_registrar)

      ConfigurationReader.load_config(configuration, self)

    end

    def register_notification_service(name, options = {})

      notification_service_registrar.register(name, options)

      self

    end

    def register_destination(name, service, channel, options = {})

      register_channel(service, channel, options)

      publishing_destination_registrar.register(name, :service => service, :channel => channel)

      self

    end

    def register_channel(service, name, options = {})

      notification_service = notification_service_registrar.fetch(service)

      notification_service.register(name, options)

      self

    end

    def publish(original_options = {})

      options = build_publish_options(original_options)

      callbacks.invoke(:publish, options) do

        service_channel_mapper.map(options.delete(:destinations)).each do |(service, channels)|

          notification_service_registrar.fetch(service).publish(options.merge to: channels)

        end

      end

    end

    private

    def build_publish_options(message:, destinations:)

      { message: build_message(message), destinations: destinations }

    end

    def build_message(attributes)

      DispatchRider::Message.new(attributes).tap do |message|

        message.body[:guid] ||= generate_new_message_id

      end

    end

    def generate_new_message_id

      if DispatchRider.config.debug

        DispatchRider::Debug::PUBLISHER_MESSAGE_GUID

      else

        SecureRandom.uuid

      end

    end

    class ServiceChannelMapper

      attr_reader :destination_registrar

      def initialize(destination_registrar)

        @destination_registrar = destination_registrar

      end

      def map(names)

        services_and_channels_map(publishing_destinations(names))

      end

      private

      def publishing_destinations(names)

        Array(names).map { |name| destination_registrar.fetch(name) }

      end

      def services_and_channels_map(destinations)

        destinations.reduce({}) do |result, destination|

          if result.has_key?(destination.service)

            result[destination.service] << destination.channel

          else

            result[destination.service] = [destination.channel]

          end

          result

        end

      end

    end

  end

end

require_relative "publisher/configuration"

require_relative "publisher/configuration_reader"

require_relative "publisher/base"