Fix design for cancelled lessons and don't allow participation status with cancelled lessons

aleksis/apps/alsijil/frontend/components/coursebook/absences/ManageStudentsTrigger.vue

@@ -58,6 +58,7 @@ export default {
     v-bind="documentationPartProps"
     @update="() => null"
     :loading-indicator="loading"
+    v-if="!documentation.amends?.cancelled"
   >
     <template #activator="{ attrs, on }">
       <v-chip

aleksis/apps/alsijil/frontend/components/coursebook/documentation/LessonInformation.vue

@@ -38,6 +38,10 @@ import PersonChip from "aleksis.core/components/person/PersonChip.vue";
         :subject="documentation.subject"
         v-bind="compact ? dialogActivator.attrs : {}"
         v-on="compact ? dialogActivator.on : {}"
+        :class="{
+          'text-decoration-line-through': documentation.amends?.cancelled,
+        }"
+        :disabled="documentation.amends?.cancelled"
       />
       <subject-chip
         v-if="

aleksis/apps/alsijil/models.py

@@ -695,6 +695,7 @@ class Documentation(CalendarEvent):
             self.participation_touched_at
             or not self.amends
             or self.value_start_datetime(self) > now()
+            or self.amends.cancelled
         ):
             # There is no source to update from or it's too early
             return

aleksis/apps/alsijil/util/predicates.py

@@ -450,6 +450,8 @@ def can_edit_documentation(user: User, obj: Documentation):
 def can_view_participation_status(user: User, obj: Documentation):
     """Predicate which checks if the user is allowed to view participation for a documentation."""
     if obj:
+        if obj.amends and obj.amends.cancelled:
+            return False
         if is_documentation_teacher(user, obj):
             return True
         if obj.amends:
@@ -465,6 +467,8 @@ def can_view_participation_status(user: User, obj: Documentation):
 def can_edit_participation_status(user: User, obj: Documentation):
     """Predicate which checks if the user is allowed to edit participation for a documentation."""
     if obj:
+        if obj.amends and obj.amends.cancelled:
+            return False
         if is_documentation_teacher(user, obj):
             return True
         if obj.amends: