Add metrics related to fallback assignments

shiftregister/metrics/views.py

@@ -2,6 +2,8 @@ from django.db import models
 from django.db.models import Count, Case, F, When, Sum
 from django.http import HttpResponse
 from shiftregister.app.models import Helper, Room, Shift, ShiftRegistration, Message
+from shiftregister.fallback.models import FallbackAssignment
+from shiftregister.importer.models import Event
 
 
 def metrics(request):
@@ -14,6 +16,37 @@ def metrics(request):
             (
                 f"shiftregister_{name} {value}"
                 for name, value in (
+                    (
+                        "fallback_shifts",
+                        Event.objects.filter(
+                            deleted=False, calendar__needs_fallback=True
+                        ).count(),
+                    ),
+                    (
+                        "fallback_shifts_assigned",
+                        FallbackAssignment.objects.aggregate(
+                            count=Count("shift", distinct=True)
+                        )["count"],
+                    ),
+                    (
+                        "fallback_shifts_full",
+                        Shift.with_reg_count()
+                        .annotate(
+                            real_required_helpers=Case(
+                                When(
+                                    required_helpers=0, then=F("room__required_helpers")
+                                ),
+                                default=F("required_helpers"),
+                            ),
+                            fallbackassignment_count=Count("fallbackassignment"),
+                        )
+                        .filter(
+                            deleted=False,
+                            reg_count__gte=F("real_required_helpers"),
+                            fallbackassignment_count__gt=0,
+                        )
+                        .count(),
+                    ),
                     ("helpers_total", Helper.objects.count()),
                     (
                         "helpers_confirmed_total",