require 'sneakers'

module Sneakers
  module DelayedJobSupport
    def enqueue_at(job, timestamp)
      delay = timestamp - Time.current.to_f
      # Just enqueue job if delay is zero or negative
      return enqueue(job) if delay < 0

      # Ensure queue is bound to the delayed message exchange
      self.class.ensure_delayed_exchange_bound(job.queue_name)

      # Publish on the delayed message exchange
      self.class.delayed_publisher.publish(
          ActiveSupport::JSON.encode(job.serialize),
          headers: { 'x-delay' => (delay.to_f * 1000).to_i },
          routing_key: job.queue_name)
    end

    module ClassMethods
      def delayed_publisher
        @delayed_publisher ||= Sneakers::Publisher.new({
                                                           exchange: 'backend.delayed',
                                                           exchange_options: {
                                                               type: 'x-delayed-message',
                                                               arguments: { 'x-delayed-type' => 'direct' },
                                                               durable: true,
                                                               auto_delete: false
                                                           }
                                                       })
      end

      # The first time a queue receives a delayed job, make sure
      # that the queue is bound to the delayed message exchange
      def ensure_delayed_exchange_bound(queue_name)
        @bound_to_delayed_exchange ||= {}
        return nil if @bound_to_delayed_exchange[queue_name].present?
        delayed_publisher.ensure_connection!
        queue = delayed_publisher.channel.queue(queue_name, Sneakers::CONFIG[:queue_options].merge( {arguments: { 'x-dead-letter-exchange' => 'nobi.dlx' } }))
        queue.bind(delayed_publisher.exchange, routing_key: queue_name)
        @bound_to_delayed_exchange[queue_name] = true
      end
    end
  end
end

module ActiveJob
  module QueueAdapters
    class SneakersAdapter
      # Add support for delayed jobs to SneakersAdapter
      extend Sneakers::DelayedJobSupport::ClassMethods
      prepend Sneakers::DelayedJobSupport
    end
  end
end