module InvoiceHelper

  SEPA_SEQUENCE_TYPES = {
    FRST: "Erst-Lastschrift",
    RCUR: "Folge-Lastschrift",
    OOFF: "Einmalige Lastschrift",
    FNAL: "Letztmalige Lastschrift"
  }.freeze

  def generate_invoice_number(instance, count)
    trailing_number = count.to_s.rjust(4, '0')
    if GroupOrderInvoice.find_by(invoice_number: instance.invoice_date.strftime("%Y%m%d") + trailing_number) || OrdergroupInvoice.find_by(invoice_number: instance.invoice_date.strftime("%Y%m%d") + trailing_number)
      generate_invoice_number(instance, count.to_i + 1)
    else
      instance.invoice_date.strftime("%Y%m%d") + trailing_number
    end
  end
end