JourneyJoker/payment/demo/models.py

from payment.models import InvoicePayment, Invoice
from payment.signals import initiate_payment

from django.db import models
from django.urls import reverse_lazy
from django.dispatch import receiver

import uuid

class DemoInvoicePayment(InvoicePayment):
    @property
    def gateway(self):
        return "Demo"

    @classmethod
    def initiate(cls, invoice):
        payment = cls.objects.create(invoice=invoice, amount=invoice.balance * -1, gateway_id=uuid.uuid4())
        invoice.finalize()
        return reverse_lazy("payment:status", args=[payment.uuid])

    @property
    def status(self):
        return 0

@receiver(initiate_payment)
def from_signal(sender, **kwargs):
    if kwargs["gateway"] == "demo":
        return {"redirect": DemoInvoicePayment.initiate(kwargs["invoice"])}
    else:
        return {}