added first implementation of the patients-without-episodes server side APIs

Author: paolo7

tmh_registry/registry/api/serializers.py

@@ -670,3 +670,45 @@ def get_discharge(self, obj):
         # Return the discharge date if available, otherwise None
         discharge = getattr(obj, 'discharge', None)
         return discharge.date if discharge else None
+
+
+class UnlinkedPatientSerializer(ModelSerializer):
+    full_name = CharField()
+    id = CharField()
+    hospital_id = SerializerMethodField()
+    patient_hospital_id = SerializerMethodField()
+
+    class Meta:
+        model = Patient
+        fields = ['id', 'full_name', 'hospital_id', 'patient_hospital_id']
+
+    def get_hospital_id(self, obj):
+        request = self.context.get('request')
+        if not request:
+            return None
+
+        try:
+            medical_personnel = request.user.medical_personnel
+            preferred_hospital = medical_personnel.preferred_hospital.hospital
+        except Exception:
+            return None
+
+        return preferred_hospital.id
+
+    def get_patient_hospital_id(self, obj):
+        request = self.context.get('request')
+        if not request:
+            return None
+
+        try:
+            medical_personnel = request.user.medical_personnel
+            preferred_hospital = medical_personnel.preferred_hospital.hospital
+        except Exception:
+            return None
+
+        mapping = PatientHospitalMapping.objects.filter(
+            patient=obj,
+            hospital=preferred_hospital
+        ).first()
+
+        return mapping.patient_hospital_id if mapping else None

tmh_registry/registry/api/viewsets.py

@@ -1,5 +1,5 @@
 from django.core.exceptions import ObjectDoesNotExist
-from django.db.models import CharField, Q, Count, Max
+from django.db.models import CharField, Q, Count, Max, OuterRef, Exists
 from django.db.models.functions import Cast
 from django.utils.decorators import method_decorator
 from django_filters import (  # pylint: disable=E0401
@@ -41,7 +41,7 @@
     PatientHospitalMappingWriteSerializer,
     PreferredHospitalReadSerializer,
     ReadPatientSerializer,
-    SurgeonEpisodeSummarySerializer, OwnedEpisodeSerializer,
+    SurgeonEpisodeSummarySerializer, OwnedEpisodeSerializer, UnlinkedPatientSerializer,
 )
 from ...users.models import MedicalPersonnel
 
@@ -365,3 +365,39 @@ def get_serializer_class(self):
             return FollowUpWriteSerializer
 
         raise NotImplementedError
+
+
+class UnlinkedPatientsViewSet(viewsets.ReadOnlyModelViewSet):
+    serializer_class = UnlinkedPatientSerializer
+    permission_classes = [IsAuthenticated]
+    pagination_class = None
+
+    def get_queryset(self):
+        user = self.request.user
+
+        try:
+            medical_personnel = user.medical_personnel
+            preferred_hospital = medical_personnel.preferred_hospital.hospital
+        except (MedicalPersonnel.DoesNotExist, PreferredHospital.DoesNotExist):
+            return Patient.objects.none()
+
+        # Subquery: check if any Episode exists for a given patient in the preferred hospital
+        has_episode_subquery = Episode.objects.filter(
+            patient_hospital_mapping__patient=OuterRef('pk'),
+            patient_hospital_mapping__hospital=preferred_hospital
+        )
+
+        patients = Patient.objects.filter(
+            hospital_mappings__hospital=preferred_hospital
+        ).annotate(
+            has_episode=Exists(has_episode_subquery)
+        ).filter(
+            has_episode=False
+        ).distinct().prefetch_related('hospital_mappings')
+
+        return patients
+
+    def get_serializer_context(self):
+        context = super().get_serializer_context()
+        context['request'] = self.request
+        return context

tmh_registry/registry/urls.py

@@ -10,7 +10,7 @@
     PatientViewSet,
     PreferredHospitalViewSet,
     SurgeonEpisodeSummaryViewSet,
-    OwnedEpisodesViewSet,
+    OwnedEpisodesViewSet, UnlinkedPatientsViewSet,
 )
 
 router = DefaultRouter()
@@ -23,6 +23,7 @@
 router.register(r"preferred-hospital", PreferredHospitalViewSet, basename='preferred-hospital')
 router.register(r'surgeon-episode-summary', SurgeonEpisodeSummaryViewSet, basename='surgeon-episode-summary')
 router.register(r"owned-episodes", OwnedEpisodesViewSet, basename='owned-episodes')
+router.register(r'unlinked-patients', UnlinkedPatientsViewSet, basename='unlinked-patients')
 
 
 urlpatterns = [