fix: resolve architecture validation violations

- Add invoice exceptions module with proper exception hierarchy
- Replace HTTPException with service-layer exceptions in invoice API
- Add InvoicePDFGeneratedResponse and InvoiceStatsResponse Pydantic models
- Replace db.commit() with db.flush() in services for proper transaction control
- Update invoice service to use exceptions from app/exceptions/invoice.py

All 14 errors and 14 warnings are now resolved. Validation passes with
only INFO-level findings.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/services/invoice_pdf_service.py

@@ -97,7 +97,7 @@ class InvoicePDFService:
         # Update invoice record with PDF path and timestamp
         invoice.pdf_path = str(pdf_path)
         invoice.pdf_generated_at = datetime.now(UTC)
-        db.commit()
+        db.flush()
 
         return str(pdf_path)
 
@@ -151,7 +151,7 @@ class InvoicePDFService:
         # Clear PDF fields
         invoice.pdf_path = None
         invoice.pdf_generated_at = None
-        db.commit()
+        db.flush()
 
         return True
 

app/services/invoice_service.py

@@ -25,9 +25,17 @@ from sqlalchemy import and_, func
 from sqlalchemy.orm import Session
 
 from app.exceptions import (
-    OrderNotFoundException,
     ValidationException,
 )
+from app.exceptions.invoice import (
+    InvoiceNotFoundException,
+    InvoicePDFGenerationException,
+    InvoicePDFNotFoundException,
+    InvoiceSettingsAlreadyExistException,
+    InvoiceSettingsNotFoundException,
+    InvoiceValidationException,
+    OrderNotFoundException,
+)
 from models.database.invoice import (
     Invoice,
     InvoiceStatus,
@@ -89,18 +97,6 @@ LU_VAT_RATES = {
 }
 
 
-class InvoiceNotFoundException(Exception):
-    """Raised when invoice not found."""
-
-    pass
-
-
-class InvoiceSettingsNotFoundException(Exception):
-    """Raised when vendor invoice settings not found."""
-
-    pass
-
-
 class InvoiceService:
     """Service for invoice operations."""
 
@@ -205,9 +201,7 @@ class InvoiceService:
         """Get vendor invoice settings or raise exception."""
         settings = self.get_settings(db, vendor_id)
         if not settings:
-            raise InvoiceSettingsNotFoundException(
-                f"Invoice settings not configured for vendor {vendor_id}"
-            )
+            raise InvoiceSettingsNotFoundException(vendor_id)
         return settings
 
     def create_settings(
@@ -229,7 +223,7 @@ class InvoiceService:
             **data.model_dump(),
         )
         db.add(settings)
-        db.commit()
+        db.flush()
         db.refresh(settings)
 
         logger.info(f"Created invoice settings for vendor {vendor_id}")
@@ -249,7 +243,7 @@ class InvoiceService:
             setattr(settings, key, value)
 
         settings.updated_at = datetime.now(UTC)
-        db.commit()
+        db.flush()
         db.refresh(settings)
 
         logger.info(f"Updated invoice settings for vendor {vendor_id}")
@@ -278,7 +272,7 @@ class InvoiceService:
             is_vat_registered=bool(vendor.effective_tax_number),
         )
         db.add(settings)
-        db.commit()
+        db.flush()
         db.refresh(settings)
 
         logger.info(f"Created invoice settings from vendor data for vendor {vendor.id}")
@@ -435,7 +429,7 @@ class InvoiceService:
         )
 
         db.add(invoice)
-        db.commit()
+        db.flush()
         db.refresh(invoice)
 
         logger.info(
@@ -465,7 +459,7 @@ class InvoiceService:
         """Get invoice by ID or raise exception."""
         invoice = self.get_invoice(db, vendor_id, invoice_id)
         if not invoice:
-            raise InvoiceNotFoundException(f"Invoice {invoice_id} not found")
+            raise InvoiceNotFoundException(invoice_id)
         return invoice
 
     def get_invoice_by_number(
@@ -539,7 +533,7 @@ class InvoiceService:
 
         invoice.status = new_status
         invoice.updated_at = datetime.now(UTC)
-        db.commit()
+        db.flush()
         db.refresh(invoice)
 
         logger.info(f"Updated invoice {invoice.invoice_number} status to {new_status}")

app/services/subscription_service.py

@@ -163,7 +163,7 @@ class SubscriptionService:
         )
 
         db.add(subscription)
-        db.commit()
+        db.flush()
         db.refresh(subscription)
 
         logger.info(
@@ -212,7 +212,7 @@ class SubscriptionService:
         )
 
         db.add(subscription)
-        db.commit()
+        db.flush()
         db.refresh(subscription)
 
         logger.info(f"Created subscription for vendor {vendor_id}: {data.tier}")
@@ -232,7 +232,7 @@ class SubscriptionService:
             setattr(subscription, key, value)
 
         subscription.updated_at = datetime.now(UTC)
-        db.commit()
+        db.flush()
         db.refresh(subscription)
 
         logger.info(f"Updated subscription for vendor {vendor_id}")
@@ -255,7 +255,7 @@ class SubscriptionService:
         if subscription.status == SubscriptionStatus.TRIAL.value:
             subscription.status = SubscriptionStatus.ACTIVE.value
 
-        db.commit()
+        db.flush()
         db.refresh(subscription)
 
         logger.info(f"Upgraded vendor {vendor_id} from {old_tier} to {new_tier}")
@@ -275,7 +275,7 @@ class SubscriptionService:
         subscription.cancellation_reason = reason
         subscription.updated_at = datetime.now(UTC)
 
-        db.commit()
+        db.flush()
         db.refresh(subscription)
 
         logger.info(f"Cancelled subscription for vendor {vendor_id}")
@@ -342,13 +342,13 @@ class SubscriptionService:
         """
         subscription = self.get_or_create_subscription(db, vendor_id)
         subscription.increment_order_count()
-        db.commit()
+        db.flush()
 
     def reset_period_counters(self, db: Session, vendor_id: int) -> None:
         """Reset counters for a new billing period."""
         subscription = self.get_subscription_or_raise(db, vendor_id)
         subscription.reset_period_counters()
-        db.commit()
+        db.flush()
         logger.info(f"Reset period counters for vendor {vendor_id}")
 
     # =========================================================================