payrollhero / dispatch-rider / #3015

require "active_record"

module DispatchRider

  class ScheduledJob < ActiveRecord::Base

    class << self

      def publisher

        @publisher ||= Publisher.new

      end

      def publish_due_jobs(every: nil)

        loop {

          claim_stub = get_new_claim_stub

          due.unclaimed.update_all claim_stub

          due.claimed_by(claim_stub[:claim_id]).find_each(&:publish)

          every ? sleep(every) : break # until the next loop

        }

      end

      private

      def get_new_claim_stub

        { claim_id: SecureRandom.uuid, claim_expires_at: 30.minutes.from_now }

      end

    end

    serialize :destinations

    serialize :message

    validates :scheduled_at,

              :destinations,

              :message,

              presence: true

    scope :due, -> (time = Time.now) { where "scheduled_at <= ?", time }

    scope :claimed_by, -> (claim_id) { where(claim_id: claim_id).where "claim_expires_at > ?", Time.now }

    scope :unclaimed, -> { where "claim_expires_at IS NULL OR claim_expires_at <= ?", Time.now }

    def publish

      publisher.publish(destinations: destinations, message: message)

      destroy # once published

    end

    private

    delegate :publisher, to: :"self.class"

  end

end

require_relative "scheduled_job/migration"