feat(conflicts): added conflicts business and presentation logic

src/backend/apps/decision/services.py

@@ -8,6 +8,7 @@ from django.core.cache import cache
 from django.utils import timezone
 from prometheus_client import Counter
 
+from apps.conflicts.services import resolve_domain_conflict
 from apps.events.models import Decision
 from apps.events.services import decision_create
 from apps.experiments.models import Experiment, ExperimentStatus, Variant
@@ -143,6 +144,23 @@ def _check_participation_limits(
     return not recent_completed
 
 
+def _check_domain_conflicts(experiment: Experiment) -> bool:
+    from apps.conflicts.models import ExperimentConflictDomain
+
+    memberships = ExperimentConflictDomain.objects.filter(
+        experiment=experiment,
+    ).select_related("conflict_domain")
+
+    for membership in memberships:
+        if not resolve_domain_conflict(
+            experiment_id=experiment.pk,
+            domain_id=membership.conflict_domain_id,
+            subject_id="",
+        ):
+            return False
+    return True
+
+
 def decide_for_flag(
     flag_key: str,
     subject_id: str,
@@ -202,6 +220,19 @@ def decide_for_flag(
         _persist_decision(result, subject_id)
         return result
 
+    if not _check_domain_conflicts(experiment):
+        DECIDE_REQUESTS.labels(reason="domain_conflict").inc()
+        result = {
+            "flag": flag_key,
+            "value": flag.default_value,
+            "decision_id": str(uuid.uuid4()),
+            "experiment_id": str(experiment.pk),
+            "variant_id": None,
+            "reason": "domain_conflict",
+        }
+        _persist_decision(result, subject_id)
+        return result
+
     allocation_hash = _hash_subject(
         subject_id,
         str(experiment.pk),