Fix graphql amend lesson mutation

aleksis/apps/chronos/frontend/components/amendLesson.graphql

-mutation createAmendLesson($input: LessonEventInput!) {
+mutation createAmendLesson($input: CreateLessonEventInput!) {
   amendLesson(input: $input) {
     lessonEvent {
       id
-      amends
+      amends {
+        id
+      }
       datetimeStart
       datetimeEnd
-      subject
-      teachers
-      groups
-      rooms
+      subject {
+        id
+      }
+      teachers {
+        id
+      }
+      groups {
+        id
+      }
+      rooms {
+        id
+      }
       cancelled
       comment
     }

aleksis/apps/chronos/frontend/components/calendar_feeds/details/LessonDetails.vue

@@ -99,16 +99,24 @@
         <edit-button
           i18n-key="chronos.event.amend.title"
           @click="amendEvent.open = true"
-      />
-      <dialog-object-form
-        v-model="amendEvent.open"
-        :fields="amendEvent.fields"
-        :default-item="amendEvent.default"
-        :is-create="true"
-        createItemI18nKey="chronos.event.amend.title"
-        :gql-create-mutation="amendEvent.gqlCreateMutation"
-        @cancel="amendEvent.open = false"
-      />
+        />
+        <dialog-object-form
+          v-model="amendEvent.open"
+          :fields="amendEvent.fields"
+          :default-item="amendEvent.default"
+          :is-create="true"
+          createItemI18nKey="chronos.event.amend.title"
+          :gql-create-mutation="amendEvent.gqlCreateMutation"
+          :get-create-data="transformCreateData"
+          @cancel="amendEvent.open = false"
+        >
+          <template #cancelled.field="{ on, attrs }">
+            <v-checkbox
+              v-bind="attrs"
+              v-on="on"
+            />
+          </template>
+        </dialog-object-form>
       </v-card-actions>
     </template>
   </base-calendar-feed-details>
@@ -167,9 +175,6 @@ export default {
           },
         ],
         default: {
-          subject: "",
-          teachers: [],
-          rooms: [],
           cancelled: false,
           comment: ""
         },
@@ -177,5 +182,32 @@ export default {
       },
     };
   },
+  methods: {
+    toISODateTime(date) {
+      // Yes js date does not do timezone...
+      // -> Roll our own
+      const tzOffset = date.getTimezoneOffset(); // minutes
+      const tzSign = tzOffset < 0 ? '+' : '-';
+      const pad = n => `${Math.floor(Math.abs(n))}`.padStart(2, '0');
+      //      const tzString = tzSign + pad(tzOffset / 60) + ':' + pad(tzOffset % 60);
+      const tzString = '';
+      return date.toISOString().replace('Z', tzString);
+    },
+    transformCreateData(item) {
+      console.log("in transformCreateData", item);
+      console.log("selectedEvent", this.selectedEvent);
+      console.log("start", this.selectedEvent.start);
+      console.log("startISO", this.toISODateTime(this.selectedEvent.start));
+      let next = {
+        ...item,
+        // FIXME: Pass id directly & do not parse a string here.
+        amends: parseInt(this.selectedEvent.uid.split('-')[1]),
+        datetimeStart: this.toISODateTime(this.selectedEvent.start),
+        datetimeEnd: this.toISODateTime(this.selectedEvent.end),
+      };
+      console.log("in transformCreateData", next);
+      return next;
+    },
+  },
 };
 </script>

aleksis/apps/chronos/schema/__init__.py

@@ -2,7 +2,7 @@ import graphene
 from graphene_django import DjangoObjectType
 from graphene_django_cud.mutations import DjangoCreateMutation
 
-from aleksis.core.models import Group, Person, Room
+from aleksis.core.models import Group, Person, Room, CalendarEvent
 from ..models import LessonEvent
 
 from ..util.chronos_helpers import get_classes, get_rooms, get_teachers
@@ -28,6 +28,19 @@ class TimetableRoomType(DjangoObjectType):
         fields = ("id", "name", "short_name")
         skip_registry = True
 
+
+# There is another unrelated CalendarEventType in aleksis/core/schema/calendar
+# This CalendarEventType is needed for the inherited amends field of LessonEvent
+# to work in the graphql query.
+class CalendarEventForLessonEventType(DjangoObjectType):
+    class Meta:
+        model = CalendarEvent
+        fields = ("id",
+                  "amends",
+                  "datetime_start",
+                  "datetime_end")
+
+
 class LessonEventType(DjangoObjectType):
     class Meta:
         model = LessonEvent