Add helper functions for Exception

helpers/exception_helpers.py

@@ -0,0 +1,117 @@
+from typing import Dict, Optional, Union, Any
+from decimal import Decimal
+from sqlalchemy.orm import Session
+from fastapi import HTTPException
+from models.product import Product
+from schemas.product import ProductCreate
+
+def validate_product_data(product_data: ProductCreate) -> bool:
+    """
+    Validate product data before creation.
+    
+    Args:
+        product_data: Product data to validate
+        
+    Returns:
+        bool: True if data is valid, False otherwise
+    """
+    if not product_data.name or len(product_data.name.strip()) == 0:
+        return False
+    
+    if not product_data.price or product_data.price <= Decimal('0.00'):
+        return False
+        
+    if product_data.quantity and product_data.quantity < 0:
+        return False
+        
+    return True
+
+def check_duplicate_product(db: Session, name: str) -> bool:
+    """
+    Check if a product with the same name already exists.
+    
+    Args:
+        db: Database session
+        name: Product name to check
+        
+    Returns:
+        bool: True if duplicate exists, False otherwise
+    """
+    existing_product = db.query(Product).filter(Product.name == name).first()
+    return bool(existing_product)
+
+def create_product_safely(db: Session, product_data: ProductCreate) -> Union[Product, Dict[str, str]]:
+    """
+    Create a new product with validation and error handling.
+    
+    Args:
+        db: Database session
+        product_data: Product data for creation
+        
+    Returns:
+        Product object if created successfully, error dict otherwise
+    """
+    if not validate_product_data(product_data):
+        raise HTTPException(status_code=400, detail="Invalid product data")
+
+    if check_duplicate_product(db, product_data.name):
+        raise HTTPException(status_code=400, detail="Product with this name already exists")
+
+    try:
+        db_product = Product(
+            name=product_data.name,
+            description=product_data.description,
+            price=product_data.price,
+            quantity=product_data.quantity,
+            category_id=product_data.category_id
+        )
+        
+        db.add(db_product)
+        db.commit()
+        db.refresh(db_product)
+        return db_product
+        
+    except Exception as e:
+        db.rollback()
+        raise HTTPException(status_code=500, detail=f"Failed to create product: {str(e)}")
+
+def format_product_response(product: Product) -> Dict[str, Any]:
+    """
+    Format product data for API response.
+    
+    Args:
+        product: Product object to format
+        
+    Returns:
+        Dict containing formatted product data
+    """
+    return {
+        "id": product.id,
+        "name": product.name,
+        "description": product.description,
+        "price": str(product.price),
+        "quantity": product.quantity,
+        "category_id": product.category_id,
+        "created_at": product.created_at.isoformat() if product.created_at else None
+    }
+
+def validate_product_update(product_data: Dict[str, Any]) -> bool:
+    """
+    Validate product data for updates.
+    
+    Args:
+        product_data: Product update data to validate
+        
+    Returns:
+        bool: True if update data is valid, False otherwise
+    """
+    if "price" in product_data and product_data["price"] <= Decimal('0.00'):
+        return False
+        
+    if "quantity" in product_data and product_data["quantity"] < 0:
+        return False
+        
+    if "name" in product_data and len(product_data["name"].strip()) == 0:
+        return False
+        
+    return True