WIP gettnig there

backend/app/main.py

@@ -211,6 +211,7 @@ class DrugVariantResponse(BaseModel):
     unit: str
     base_unit: str
     low_stock_threshold: float
+    has_inventory_history: bool = False
     packs: List[VariantPackResponse] = []
     batches: List[BatchResponse] = []
     
@@ -318,6 +319,19 @@ def write_audit_log(
 
 def enrich_variant_with_batches(db: Session, variant: DrugVariant) -> Dict[str, Any]:
     """Return variant data with active batch details for API responses."""
+    has_batch_history = (
+        db.query(Batch.id)
+        .filter(Batch.drug_variant_id == variant.id)
+        .first()
+        is not None
+    )
+    has_dispense_history = (
+        db.query(Dispensing.id)
+        .filter(Dispensing.drug_variant_id == variant.id)
+        .first()
+        is not None
+    )
+
     variant_dict = {
         "id": variant.id,
         "drug_id": variant.drug_id,
@@ -326,6 +340,7 @@ def enrich_variant_with_batches(db: Session, variant: DrugVariant) -> Dict[str,
         "unit": variant.unit,
         "base_unit": variant.unit,
         "low_stock_threshold": variant.low_stock_threshold,
+        "has_inventory_history": has_batch_history or has_dispense_history,
     }
     packs = (
         db.query(VariantPack)
@@ -861,6 +876,26 @@ def delete_drug(drug_id: int, db: Session = Depends(get_db), current_user: User
         raise HTTPException(status_code=404, detail="Drug not found")
     
     variant_ids = [row[0] for row in db.query(DrugVariant.id).filter(DrugVariant.drug_id == drug_id).all()]
+    
+    if variant_ids:
+        has_batch_history = (
+            db.query(Batch.id)
+            .filter(Batch.drug_variant_id.in_(variant_ids))
+            .first()
+            is not None
+        )
+        has_dispense_history = (
+            db.query(Dispensing.id)
+            .filter(Dispensing.drug_variant_id.in_(variant_ids))
+            .first()
+            is not None
+        )
+        
+        if has_batch_history or has_dispense_history:
+            raise HTTPException(
+                status_code=400,
+                detail="Cannot delete drug with variants that have batch or dispensing history. Archive or manage records first.",
+            )
     if variant_ids:
         batch_ids = [row[0] for row in db.query(Batch.id).filter(Batch.drug_variant_id.in_(variant_ids)).all()]
         if batch_ids:
@@ -972,6 +1007,39 @@ def update_drug_variant(variant_id: int, variant_update: DrugVariantUpdate, db:
         payload["unit"] = cleaned_base_unit
     payload.pop("base_unit", None)
 
+    has_batch_history = (
+        db.query(Batch.id)
+        .filter(Batch.drug_variant_id == variant_id)
+        .first()
+        is not None
+    )
+    has_dispense_history = (
+        db.query(Dispensing.id)
+        .filter(Dispensing.drug_variant_id == variant_id)
+        .first()
+        is not None
+    )
+    is_locked = has_batch_history or has_dispense_history
+
+    locked_field_changes = []
+    if is_locked:
+        if "strength" in payload and payload["strength"] != variant.strength:
+            locked_field_changes.append("strength")
+        if "unit" in payload and payload["unit"] != variant.unit:
+            locked_field_changes.append("base_unit")
+        if "quantity" in payload and payload["quantity"] != variant.quantity:
+            locked_field_changes.append("quantity")
+
+    if locked_field_changes:
+        raise HTTPException(
+            status_code=400,
+            detail=(
+                "Cannot change "
+                + ", ".join(locked_field_changes)
+                + " after batches or dispensing history exist for this variant"
+            ),
+        )
+
     for field, value in payload.items():
         setattr(variant, field, value)
 
@@ -995,6 +1063,25 @@ def delete_drug_variant(variant_id: int, db: Session = Depends(get_db), current_
     if not variant:
         raise HTTPException(status_code=404, detail="Drug variant not found")
     
+    has_batch_history = (
+        db.query(Batch.id)
+        .filter(Batch.drug_variant_id == variant_id)
+        .first()
+        is not None
+    )
+    has_dispense_history = (
+        db.query(Dispensing.id)
+        .filter(Dispensing.drug_variant_id == variant_id)
+        .first()
+        is not None
+    )
+    
+    if has_batch_history or has_dispense_history:
+        raise HTTPException(
+            status_code=400,
+            detail="Cannot delete variant with batch or dispensing history. Archive or manage records first.",
+        )
+    
     batch_ids = [row[0] for row in db.query(Batch.id).filter(Batch.drug_variant_id == variant_id).all()]
     if batch_ids:
         db.query(DispensingAllocation).filter(DispensingAllocation.batch_id.in_(batch_ids)).delete(synchronize_session=False)