Payment.payable_object property to get payable (#3737)

* Split Entry.payment into separate fields on Renewal and Registration

This is needed to be able to easily use the reverse relation from Payment to distinguish between registrations and renewals.

* Make Payable an ABC

This should make it a bit more readable, and improves linting.

* Add prefetch-based Payment.payable_object property

* Fix typo in migration

* Add field and filter to admin

* Add hyperlink to MoneybirdExternalInvoice admin's payable_object

* Fix tests

* Add tests

website/events/payables.py

@@ -6,7 +6,7 @@
 from payments.payables import Payable, payables
 
 
-class EventRegistrationPayable(Payable):
+class EventRegistrationPayable(Payable[EventRegistration]):
     @property
     def payment_amount(self):
         return self.model.payment_amount

website/moneybirdsynchronization/admin.py

@@ -1,5 +1,7 @@
 from django.contrib import admin
 from django.contrib.admin import RelatedOnlyFieldListFilter
+from django.urls import reverse
+from django.utils.html import format_html
 
 from .models import (
     MoneybirdContact,
@@ -81,6 +83,19 @@ class MoneybirdExternalInvoiceAdmin(admin.ModelAdmin):
         ("payable_model", RelatedOnlyFieldListFilter),
     )
 
+    def payable_object(self, obj: MoneybirdExternalInvoice) -> str:
+        payable_object = obj.payable_object
+        if payable_object:
+            return format_html(
+                "<a href='{}'>{}</a>",
+                reverse(
+                    f"admin:{payable_object._meta.app_label}_{payable_object._meta.model_name}_change",
+                    args=[payable_object.pk],
+                ),
+                payable_object,
+            )
+        return "None"
+
 
 @admin.register(MoneybirdPayment)
 class MoneybirdPaymentAdmin(admin.ModelAdmin):

website/payments/admin.py

@@ -4,6 +4,7 @@
 
 from django.contrib import admin, messages
 from django.contrib.admin import ModelAdmin
+from django.contrib.admin.options import IncorrectLookupParameters
 from django.contrib.admin.utils import model_ngettext
 from django.db.models import QuerySet
 from django.db.models.query_utils import Q
@@ -14,7 +15,7 @@
 from django.utils.text import capfirst
 from django.utils.translation import gettext_lazy as _
 
-from payments import admin_views, services
+from payments import admin_views, payables, services
 from payments.forms import BankAccountAdminForm, BatchPaymentInlineAdminForm
 
 from .models import BankAccount, Batch, Payment, PaymentUser
@@ -33,6 +34,38 @@ def _show_message(
         )
 
 
+class PayableModelListFilter(admin.SimpleListFilter):
+    title = _("payable model")
+    parameter_name = "payable_model"
+
+    def lookups(self, request, model_admin):
+        return [
+            (
+                model._meta.get_field("payment").related_query_name(),
+                f"{model._meta.app_label} | {model._meta.verbose_name}",
+            )
+            for model in payables.payables.get_payable_models()
+        ] + [("none", _("None"))]
+
+    def queryset(self, request, queryset):
+        value = self.value()
+        if not value:
+            return queryset
+        if value == "none":
+            return queryset.filter(
+                **{
+                    model._meta.get_field("payment").related_query_name(): None
+                    for model in payables.payables.get_payable_models()
+                }
+            )
+        if value not in (
+            model._meta.get_field("payment").related_query_name()
+            for model in payables.payables.get_payable_models()
+        ):
+            raise IncorrectLookupParameters(_("Invalid payable model"))
+        return queryset.filter(**{value + "__isnull": False})
+
+
 @admin.register(Payment)
 class PaymentAdmin(admin.ModelAdmin):
     """Manage the payments."""
@@ -46,7 +79,7 @@ class PaymentAdmin(admin.ModelAdmin):
         "batch_link",
         "topic",
     )
-    list_filter = ("type", "batch")
+    list_filter = ("type", "batch", PayableModelListFilter)
     list_select_related = ("paid_by", "processed_by", "batch")
     date_hierarchy = "created_at"
     fields = (
@@ -58,17 +91,9 @@ class PaymentAdmin(admin.ModelAdmin):
         "topic",
         "notes",
         "batch",
+        "payable_object",
     )
-    readonly_fields = (
-        "created_at",
-        "amount",
-        "paid_by",
-        "processed_by",
-        "type",
-        "topic",
-        "notes",
-        "batch",
-    )
+
     search_fields = (
         "topic",
         "notes",
@@ -88,6 +113,20 @@ class PaymentAdmin(admin.ModelAdmin):
         "export_csv",
     ]
 
+    @admin.display(description=_("payable object"))
+    def payable_object(self, obj: Payment) -> str:
+        payable_object = obj.payable_object
+        if payable_object:
+            return format_html(
+                "<a href='{}'>{}</a>",
+                reverse(
+                    f"admin:{payable_object._meta.app_label}_{payable_object._meta.model_name}_change",
+                    args=[payable_object.pk],
+                ),
+                payable_object,
+            )
+        return "None"
+
     @staticmethod
     def _member_link(member: PaymentUser) -> str:
         return (
@@ -148,19 +187,25 @@ def get_field_queryset(self, db, db_field, request):
         return super().get_field_queryset(db, db_field, request)
 
     def get_readonly_fields(self, request: HttpRequest, obj: Payment = None):
+        readonly_fields = "created_at", "processed_by", "payable_object"
         if not obj:
-            return "created_at", "processed_by", "batch"
+            return readonly_fields + ("batch",)
         if obj.type == Payment.TPAY and not (obj.batch and obj.batch.processed):
-            return (
-                "created_at",
+            return readonly_fields + (
                 "amount",
-                "type",
                 "paid_by",
-                "processed_by",
-                "notes",
+                "type",
                 "topic",
+                "notes",
             )
-        return super().get_readonly_fields(request, obj)
+        return readonly_fields + (
+            "amount",
+            "paid_by",
+            "type",
+            "topic",
+            "notes",
+            "batch",
+        )
 
     def get_actions(self, request: HttpRequest) -> OrderedDict:
         """Get the actions for the payments.

website/payments/models.py

@@ -21,6 +21,8 @@
 
 from members.models import Member
 
+from . import payables
+
 
 def validate_not_zero(value):
     if value == 0:
@@ -180,6 +182,40 @@ class Payment(models.Model):
     notes = models.TextField(verbose_name=_("notes"), blank=True, null=True)
     topic = models.CharField(verbose_name=_("topic"), max_length=255, default="Unknown")
 
+    @classmethod
+    def get_payable_prefetches(cls):
+        """Return all (OneToOneField reverse relation) fields from payables to `Payment`.
+
+        This can be used to prefetch all payable models related to a payment, which makes
+        the `Payment.payable_object` property much faster when called on multiple payments.
+
+        Usage:
+        >>> Payment.objects.prefetch_related(*Payment.get_payable_prefetches())
+        """
+        return [
+            model._meta.get_field("payment").related_query_name()
+            for model in payables.payables.get_payable_models()
+        ]
+
+    @property
+    def payable_object(self) -> models.Model | None:
+        """Return the payable model instance associated with this payment.
+
+        This is based on the reverse relations of the OneToOneFields from all
+        payable models to `Payment`.
+
+        This property will perform many queries if the related payable models
+        have not been prefetched. Prefetch them with:
+
+        >>> Payment.objects.prefetch_related(*Payment.get_payable_prefetches())
+        """
+        for model in payables.payables.get_payable_models():
+            if hasattr(self, model._meta.get_field("payment").related_query_name()):
+                return getattr(
+                    self, model._meta.get_field("payment").related_query_name()
+                )
+        return None
+
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)