postal/app/lib/message_dequeuer/single_message_processor.rb

# frozen_string_literal: true

module MessageDequeuer
  class SingleMessageProcessor < Base

    def process
      catch_stops do
        check_message_exists
        check_server_suspension
        check_delivery_attempts
        check_raw_message_exists

        processor = nil
        case queued_message.message.scope
        when "incoming"
          processor = IncomingMessageProcessor
        when "outgoing"
          processor = OutgoingMessageProcessor
        else
          create_delivery "HardFail", details: "Scope #{queued_message.message.scope} is not valid"
          remove_from_queue
          stop_processing
        end

        processor.process(queued_message, logger: @logger, state: @state)
      end
    rescue StandardError => e
      handle_exception(e)
    end

    private

    def check_message_exists
      queued_message.message
    rescue Postal::MessageDB::Message::NotFound
      log "unqueueing because backend message has been removed"
      remove_from_queue
      stop_processing
    end

    def check_server_suspension
      return unless queued_message.server.suspended?

      log "server is suspended, holding message"
      create_delivery "Held", details: "Mail server has been suspended. No e-mails can be processed at present. Contact support for assistance."
      remove_from_queue
      stop_processing
    end

    def check_delivery_attempts
      return if queued_message.attempts < Postal::Config.postal.default_maximum_delivery_attempts

      details = "Maximum number of delivery attempts (#{queued_message.attempts}) has been reached."
      if queued_message.message.scope == "incoming"
        # Send bounces to incoming e-mails when they are hard failed
        if bounce_id = queued_message.send_bounce
          details += " Bounce sent to sender (see message <msg:#{bounce_id}>)"
        end
      elsif queued_message.message.scope == "outgoing"
        # Add the recipient to the suppression list
        if queued_message.server.message_db.suppression_list.add(:recipient, queued_message.message.rcpt_to, reason: "too many soft fails")
          log "added #{queued_message.message.rcpt_to} to suppression list because maximum attempts has been reached"
          details += " Added #{queued_message.message.rcpt_to} to suppression list because delivery has failed #{queued_message.attempts} times."
        end
      end

      log "message has reached maximum number of attempts, hard failing"
      create_delivery "HardFail", details: details
      remove_from_queue
      stop_processing
    end

    def check_raw_message_exists
      return if queued_message.message.raw_message?

      log "raw message has been removed, not sending"
      create_delivery "HardFail", details: "Raw message has been removed. Cannot send message."
      remove_from_queue
      stop_processing
    end

  end
end