feat(rates): record hourly rate history

apps/projects/services/rates.py

@@ -1,6 +1,35 @@
 from django.utils import timezone
 
 from apps.projects.models import ProjectUserRate
+from apps.workspaces.models import HourlyRateHistory
+
+
+def record_project_rate_history(*, project, user, hourly_rate, currency, effective_from=None):
+    currency = currency.upper()
+    effective_from = effective_from or timezone.now()
+    latest = (
+        HourlyRateHistory.objects.filter(
+            workspace=project.workspace,
+            project=project,
+            user=user,
+            scope=HourlyRateHistory.Scope.PROJECT,
+            is_deleted=False,
+        )
+        .order_by("-effective_from", "-created_at")
+        .first()
+    )
+    if latest and latest.hourly_rate == hourly_rate and latest.currency == currency:
+        return latest
+    return HourlyRateHistory.objects.create(
+        workspace=project.workspace,
+        project=project,
+        user=user,
+        scope=HourlyRateHistory.Scope.PROJECT,
+        hourly_rate=hourly_rate,
+        currency=currency,
+        effective_from=effective_from,
+        is_active=True,
+    )
 
 
 def get_current_project_user_rate(*, project, user):
@@ -27,6 +56,7 @@ def upsert_project_user_rate(*, project, user, hourly_rate, currency="USD"):
         .first()
     )
 
+    effective_from = timezone.now()
     if rate:
         update_fields = []
         if rate.is_deleted:
@@ -43,16 +73,31 @@ def upsert_project_user_rate(*, project, user, hourly_rate, currency="USD"):
         if update_fields:
             update_fields.append("updated_at")
             rate.save(update_fields=update_fields)
+            record_project_rate_history(
+                project=project,
+                user=user,
+                hourly_rate=rate.hourly_rate,
+                currency=rate.currency,
+                effective_from=effective_from,
+            )
         return rate
 
-    return ProjectUserRate.objects.create(
+    rate = ProjectUserRate.objects.create(
         project=project,
         user=user,
         hourly_rate=hourly_rate,
         currency=currency,
-        effective_from=timezone.now(),
+        effective_from=effective_from,
         is_active=True,
     )
+    record_project_rate_history(
+        project=project,
+        user=user,
+        hourly_rate=rate.hourly_rate,
+        currency=rate.currency,
+        effective_from=rate.effective_from,
+    )
+    return rate
 
 
 def remove_project_user_rate(*, project, user):