Port default LiveDocument.update() from Chronos

CHANGELOG.rst

@@ -13,6 +13,8 @@ Added
 ~~~~~
 
 * Open poster group menu entries in new tab.
+* [Dev] LiveDocument.update() now has a default implementaiton, rendering
+  ``self.template`` using ``self.get_context_data()``
 
 Fixed
 ~~~~~

aleksis/apps/resint/models.py

 from datetime import datetime
-from typing import Optional
+from typing import Any, Optional
 
 from django.core.files import File
 from django.core.validators import FileExtensionValidator, MaxValueValidator, MinValueValidator
@@ -10,9 +10,12 @@ from django.utils.translation import gettext_lazy as _
 import reversion
 from calendarweek import CalendarWeek
 from calendarweek.django import i18n_day_name_choices_lazy
+from celery.result import allow_join_result
+from celery.states import SUCCESS
 from reversion.models import Revision, Version
 
 from aleksis.core.mixins import ExtensibleModel, ExtensiblePolymorphicModel
+from aleksis.core.util.pdf import generate_pdf_from_template
 
 
 class PosterGroup(ExtensibleModel):
@@ -151,6 +154,8 @@ class LiveDocument(ExtensiblePolymorphicModel):
 
     SCOPE_PREFIX = "live_document_pdf"
 
+    template = None
+
     slug = models.SlugField(
         verbose_name=_("Slug"),
         help_text=_("This will be used for the name of the current PDF file."),
@@ -203,12 +208,26 @@ class LiveDocument(ExtensiblePolymorphicModel):
         with reversion.create_revision():
             super().save(*args, **kwargs)
 
+    def get_context_data(self) -> dict[str, Any]:
+        """Get context to pass to the PDF template."""
+        return {}
+
     def update(self, triggered_manually: bool = True):
         """Update the file with a new version.
 
         Has to be implemented by subclasses.
         """
-        raise NotImplementedError("Subclasses of LiveDocument must implement update()")
+        if not self.template:
+            raise NotImplementedError("Subclasses of LiveDocument must implement update()")
+
+        file_object, result = generate_pdf_from_template(self.template, self.get_context_data())
+        with allow_join_result():
+            result.wait()
+            file_object.refresh_from_db()
+            if result.status == SUCCESS and file_object.file:
+                self.last_update_triggered_manually = triggered_manually
+                self.current_file.save(self.filename, file_object.file.file)
+                self.save()
 
     def __str__(self) -> str:
         return self.name