chore: refactor frontend url parts handling

server/vbv_lernwelt/learnpath/models.py

@@ -1,5 +1,6 @@
 import re
 from enum import Enum
+from typing import Tuple
 
 from django.db import models
 from django.utils.text import slugify
@@ -219,21 +220,29 @@ class LearningUnit(CourseBasePage):
             )
         super(LearningUnit, self).save(clean, user, log_action, **kwargs)
 
-    def get_frontend_url(self):
+    def get_frontend_url_parts(self) -> Tuple[str, str, str]:
+        """
+        Extracts the course, circle and learning unit part from the slug.
+        :return: Tuple of course, circle and learning unit part
+        """
+
         r = re.compile(
             r"^(?P<coursePart>.+?)-lp-circle-(?P<circlePart>.+?)-lu-(?P<luPart>.+?)$"
         )
         m = r.match(self.slug)
+
         if m is None:
-            return "ERROR: could not parse slug"
-        return f"/course/{m.group('coursePart')}/learn/{m.group('circlePart')}#lu-{m.group('luPart')}"
+            ValueError(f"Could not parse slug: {self.slug}")
+
+        return m.group("coursePart"), m.group("circlePart"), m.group("luPart")
+
+    def get_frontend_url(self):
+        course, circle, learning_unit = self.get_frontend_url_parts()
+        return f"/course/{course}/learn/{circle}#lu-{learning_unit}"
 
     def get_evaluate_url(self):
-        r = re.compile(
-            r"^(?P<coursePart>.+?)-lp-circle-(?P<circlePart>.+?)-lu-(?P<luPart>.+?)$"
-        )
-        m = r.match(self.slug)
-        return f"/course/{m.group('coursePart')}/learn/{m.group('circlePart')}/evaluate/{m.group('luPart')}"
+        course, circle, learning_unit = self.get_frontend_url_parts()
+        return f"/course/{course}/learn/{circle}/evaluate/{learning_unit}"
 
     def get_admin_display_title(self):
         return f"LE: {self.draft_title}"