refactor timeslot API filters

This MR:

• removes default values for start and end filter (see #189 (closed))
• renames start to startsAfter and end to endsBefore
• adds datetime support to startsAfter and endsBefore
• adds new datetime filter startsBefore and endsAfter

program/filters.py

@@ -184,20 +184,20 @@ class TimeSlotFilterSet(filters.FilterSet):
             "If specified without a datetime value the current date and time is assumed."
         ),
     )
-    start = filters.DateFilter(
-        method="filter_start",
+    starts_after = filters.DateTimeFilter(
+        field_name="start",
+        lookup_expr="gte",
         help_text="Only returns timeslots that start at or after the specified datetime.",
     )
-    end = filters.DateFilter(
-        method="filter_end",
+    ends_before = filters.DateTimeFilter(
+        field_name="end",
+        lookup_expr="lt",
         help_text="Only returns timeslots that end before the specified datetime.",
     )
-
     schedule_ids = IntegerInFilter(
         field_name="schedule",
         help_text="Return only timeslots that belong to the specified schedule(s).",
     )
-
     show_ids = IntegerInFilter(
         field_name="schedule__show",
         help_text="Return only timeslots that belong to the specified show(s).",
@@ -217,14 +217,6 @@ class TimeSlotFilterSet(filters.FilterSet):
         relevant_timeslot_ids = list(nearest_timeslots_in_future) + list(nearest_timeslots_in_past)
         return queryset.filter(id__in=relevant_timeslot_ids)
 
-    def filter_start(self, queryset: QuerySet, name: str, value: datetime.date):
-        start = timezone.make_aware(datetime.datetime.combine(value, datetime.time.min))
-        return queryset.filter(start__gte=start)
-
-    def filter_end(self, queryset: QuerySet, name: str, value: datetime.date):
-        end = timezone.make_aware(datetime.datetime.combine(value, datetime.time.max))
-        return queryset.filter(end__lte=end)
-
     def filter_queryset(self, queryset):
         queryset = super().filter_queryset(queryset)
         # This is for backwards compatibility as the surrounding-filter was formerly implemented