invoice_job_op.rb

class InvoiceJobOp < ::Backend::Op
  include Mixins::AtomicOperation # all in same transaction

  field :hours
  field :job_id

  validates :job_id, presence: true
  validate  :validate_hour       # hours given
  validate  :validate_assignment # tasker is assigned
  # ... other checks

  def perform
    create_invoice!    # record hours and such
    generate_payment!  # pending payment transaction
    appointment_done!  # note that appointment completed

    if ongoing?
      schedule_next_appointment! # schedule next if more
    else
      complete_assignment!       # otherwise, no more
    end

    enqueue_background_workers!  # follow up later on stuff
  end
end