Automatic allergens and expiry_date update

apps/food/models.py

@@ -1,6 +1,8 @@
 # Copyright (C) 2018-2024 by BDE ENS Paris-Saclay
 # SPDX-License-Identifier: GPL-3.0-or-later
 
+from datetime import timedelta
+
 from django.db import models, transaction
 from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
@@ -120,6 +122,23 @@ class BasicFood(Food):
     #     upload_to='label/',
     # )
 
+    @transaction.atomic
+    def update_allergens(self):
+        # update parents
+        for parent in self.transformed_ingredient_inv.iterator():
+            parent.update_allergens()
+
+    @transaction.atomic
+    def update_expiry_date(self):
+        # update parents
+        for parent in self.transformed_ingredient_inv.iterator():
+            parent.update_expiry_date()
+
+    @transaction.atomic
+    def update(self):
+        self.update_allergens()
+        self.update_expiry_date()
+
     class Meta:
         verbose_name = _('Basic food')
         verbose_name_plural = _('Basic foods')
@@ -146,6 +165,47 @@ class TransformedFood(Food):
         verbose_name=_('is active'),
     )
 
+    @transaction.atomic
+    def update_allergens(self):
+        # When allergens are changed, simply update the parents' allergens
+        old_allergens = list(self.allergens.all())
+        self.allergens.clear()
+        for ingredient in self.ingredient.iterator():
+            self.allergens.set(self.allergens.union(ingredient.allergens.all()))
+
+        if old_allergens == list(self.allergens.all()):
+            return
+        super().save()
+
+        # update parents
+        for parent in self.transformed_ingredient_inv.iterator():
+            parent.update_allergens()
+
+    @transaction.atomic
+    def update_expiry_date(self):
+        # When expiry_date is changed, simply update the parents' expiry_date
+        old_expiry_date = self.expiry_date
+        self.expiry_date = self.creation_date + timedelta(days=3)
+        for ingredient in self.ingredient.iterator():
+            self.expiry_date = min(self.expiry_date, ingredient.expiry_date)
+
+        if old_expiry_date == self.expiry_date:
+            return
+        super().save()
+
+        # update parents
+        for parent in self.transformed_ingredient_inv.iterator():
+            parent.update_expiry_date()
+
+    @transaction.atomic
+    def update(self):
+        self.update_allergens()
+        self.update_expiry_date()
+
+    @transaction.atomic
+    def save(self, *args, **kwargs):
+        super().save(*args, **kwargs)
+
     class Meta:
         verbose_name = _('Transformed food')
         verbose_name_plural = _('Transformed foods')