Django Admin - populate other fields after changing foreignkey

Question

I have this model:

class Order(models.Model):
    client = models.ForeignKey(
        Client,
        on_delete=models.CASCADE,
        related_name='orders',
        related_query_name='order',
    )

    delivery_country = CountryField('Kraj wysyłki', null=True, blank=True)
    delivery_city = models.CharField('Miasto wysyłki', max_length=255, null=True, blank=True)
    delivery_street = models.CharField('Ulica wysyłki', max_length=255, null=True, blank=True)

    billing_country = CountryField('Kraj dla faktury', null=True, blank=True)
    billing_city = models.CharField('Miasto dla faktury', max_length=255, null=True, blank=True)
    billing_street = models.CharField('Ulica dla faktury', max_length=255, null=True, blank=True)

    products = models.ManyToManyField(Product, through='OrderProduct')

class Client(models.Model):
    name = models.CharField('Imię', max_length=255)
    surname = models.CharField('Nazwisko', max_length=255)
    country = CountryField('Kraj', null=True, blank=True)
    city = models.CharField('Miasto', max_length=255, null=True, blank=True)
    street = models.CharField('Ulica', max_length=255, null=True, blank=True)

And I would like to achieve this behaviour in Django Admin: After every change of Order.client I want to prepopulate other fields like this:

• Order.delivery_country = client.country
• Order.delivery_city = client.city
• Order.delivery_street = client.street
• Order.billing_country = client.country
• Order.billing_city = client.city
• Order.billing_street = client.street

Is there any package/plugin to achieve this? Or maybe you have some ideas how I could do it myself?

Answer 1

Ok I achieved this:

JS:

(function ($) {
    $(document).ready(function(){
        $("select[name='client']").on("change", function(){
            $.ajax({
                url: "/admin/clients/"+$(this).val(),
                type: "GET",
            }).done(function(data){
                client_data = $.parseJSON(data);
                client_data = client_data[0];

                $("select[name='delivery_country']").val(client_data.fields.country);
                $("input[name='delivery_city']").val(client_data.fields.city);
                $("input[name='delivery_street']").val(client_data.fields.street);

                $("select[name='billing_country']").val(client_data.fields.country);
                $("input[name='billing_city']").val(client_data.fields.city);
                $("input[name='billing_street']").val(client_data.fields.street);
            });
        });
    });
})(django.jQuery);

And View:

def get_client_ajax(request, id):
    return JsonResponse(serializers.serialize('json', Client.objects.filter(id=id)), safe=False)