Samir Boulahtit
c100d839f1
Implemented a complete shopping cart system with database persistence, replacing the previous stub implementation. The cart now properly stores items across sessions and follows the project's architecture patterns. Database Changes: - Add cart_items table with vendor_id, session_id, product_id, quantity, price_at_add - Create unique constraint to prevent duplicate items per session - Add indexes for session lookups and old cart cleanup - Run migration a2064e1dfcd4 to create cart_items table New Models & Schemas: - models/database/cart.py: CartItem SQLAlchemy model with relationships - models/schema/cart.py: Pydantic schemas for requests/responses * AddToCartRequest, UpdateCartItemRequest * CartResponse, CartItemResponse, CartOperationResponse, ClearCartResponse Exception Handling: - app/exceptions/cart.py: Cart-specific exceptions following project patterns * CartItemNotFoundException - item not found in cart * InsufficientInventoryForCartException - not enough inventory for cart operation * InvalidCartQuantityException - invalid quantity validation * CartValidationException - general cart validation * EmptyCartException - operations on empty cart * ProductNotAvailableForCartException - product unavailable - Updated app/exceptions/__init__.py to export cart exceptions Service Layer: - Implement cart_service.get_cart() - fetch cart from database with totals - Implement cart_service.add_to_cart() - create or update cart items with inventory checks - Implement cart_service.update_cart_item() - update quantity with validation - Implement cart_service.remove_from_cart() - delete cart item - Implement cart_service.clear_cart() - remove all items for session - Replace generic exceptions with cart-specific ones - Fix InsufficientInventoryException usage (was using wrong parameters) API Layer: - Update app/api/v1/shop/cart.py to use Pydantic schemas - Add response_model declarations to all endpoints - Add return type hints for type safety - Convert service dict responses to Pydantic models Features: - Cart items persist in database across server restarts - Inventory validation before adding/updating items - Price captured at time of adding to cart - Duplicate items update quantity instead of creating new entries - Full CRUD operations with proper error handling - Type-safe API with auto-generated OpenAPI documentation 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
442 lines
12 KiB
Python
442 lines
12 KiB
Python
# app/services/cart_service.py
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"""
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Shopping cart service.
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This module provides:
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- Session-based cart management
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- Cart item operations (add, update, remove)
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- Cart total calculations
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"""
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import logging
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from typing import Dict, List, Optional
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from datetime import datetime, timezone
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from sqlalchemy.orm import Session
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from sqlalchemy import and_
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from models.database.product import Product
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from models.database.vendor import Vendor
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from models.database.cart import CartItem
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from app.exceptions import (
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ProductNotFoundException,
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CartItemNotFoundException,
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CartValidationException,
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InsufficientInventoryForCartException,
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InvalidCartQuantityException,
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ProductNotAvailableForCartException,
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)
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logger = logging.getLogger(__name__)
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class CartService:
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"""Service for managing shopping carts."""
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def get_cart(
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self,
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db: Session,
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vendor_id: int,
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session_id: str
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) -> Dict:
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"""
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Get cart contents for a session.
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Args:
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db: Database session
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vendor_id: Vendor ID
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session_id: Session ID
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Returns:
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Cart data with items and totals
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"""
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logger.info(
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f"[CART_SERVICE] get_cart called",
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extra={
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"vendor_id": vendor_id,
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"session_id": session_id,
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}
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)
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# Fetch cart items from database
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cart_items = db.query(CartItem).filter(
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and_(
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CartItem.vendor_id == vendor_id,
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CartItem.session_id == session_id
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)
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).all()
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logger.info(
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f"[CART_SERVICE] Found {len(cart_items)} items in database",
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extra={"item_count": len(cart_items)}
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)
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# Build response
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items = []
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subtotal = 0.0
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for cart_item in cart_items:
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product = cart_item.product
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line_total = cart_item.line_total
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items.append({
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"product_id": product.id,
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"product_name": product.name,
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"quantity": cart_item.quantity,
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"price": cart_item.price_at_add,
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"line_total": line_total,
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"image_url": product.image_link if hasattr(product, 'image_link') else None,
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})
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subtotal += line_total
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cart_data = {
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"vendor_id": vendor_id,
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"session_id": session_id,
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"items": items,
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"subtotal": subtotal,
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"total": subtotal # Could add tax/shipping later
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}
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logger.info(
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f"[CART_SERVICE] get_cart returning: {len(cart_data['items'])} items, total: {cart_data['total']}",
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extra={"cart": cart_data}
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)
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return cart_data
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def add_to_cart(
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self,
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db: Session,
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vendor_id: int,
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session_id: str,
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product_id: int,
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quantity: int = 1
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) -> Dict:
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"""
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Add product to cart.
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Args:
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db: Database session
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vendor_id: Vendor ID
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session_id: Session ID
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product_id: Product ID
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quantity: Quantity to add
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Returns:
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Updated cart
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Raises:
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ProductNotFoundException: If product not found
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InsufficientInventoryException: If not enough inventory
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"""
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logger.info(
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f"[CART_SERVICE] add_to_cart called",
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extra={
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"vendor_id": vendor_id,
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"session_id": session_id,
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"product_id": product_id,
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"quantity": quantity
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}
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)
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# Verify product exists and belongs to vendor
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product = db.query(Product).filter(
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and_(
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Product.id == product_id,
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Product.vendor_id == vendor_id,
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Product.is_active == True
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)
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).first()
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if not product:
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logger.error(
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f"[CART_SERVICE] Product not found",
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extra={"product_id": product_id, "vendor_id": vendor_id}
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)
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raise ProductNotFoundException(product_id=product_id, vendor_id=vendor_id)
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logger.info(
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f"[CART_SERVICE] Product found: {product.name}",
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extra={
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"product_id": product_id,
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"product_name": product.name,
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"available_inventory": product.available_inventory
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}
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)
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# Get current price (use sale_price if available, otherwise regular price)
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current_price = product.sale_price if product.sale_price else product.price
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# Check if item already exists in cart
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existing_item = db.query(CartItem).filter(
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and_(
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CartItem.vendor_id == vendor_id,
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CartItem.session_id == session_id,
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CartItem.product_id == product_id
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)
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).first()
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if existing_item:
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# Update quantity
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new_quantity = existing_item.quantity + quantity
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# Check inventory for new total quantity
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if product.available_inventory < new_quantity:
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logger.warning(
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f"[CART_SERVICE] Insufficient inventory for update",
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extra={
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"product_id": product_id,
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"current_in_cart": existing_item.quantity,
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"adding": quantity,
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"requested_total": new_quantity,
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"available": product.available_inventory
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}
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)
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raise InsufficientInventoryForCartException(
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product_id=product_id,
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product_name=product.name,
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requested=new_quantity,
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available=product.available_inventory
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)
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existing_item.quantity = new_quantity
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db.commit()
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db.refresh(existing_item)
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logger.info(
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f"[CART_SERVICE] Updated existing cart item",
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extra={
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"cart_item_id": existing_item.id,
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"new_quantity": new_quantity
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}
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)
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return {
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"message": "Product quantity updated in cart",
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"product_id": product_id,
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"quantity": new_quantity
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}
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else:
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# Check inventory for new item
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if product.available_inventory < quantity:
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logger.warning(
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f"[CART_SERVICE] Insufficient inventory",
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extra={
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"product_id": product_id,
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"requested": quantity,
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"available": product.available_inventory
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}
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)
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raise InsufficientInventoryForCartException(
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product_id=product_id,
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product_name=product.name,
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requested=quantity,
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available=product.available_inventory
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)
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# Create new cart item
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cart_item = CartItem(
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vendor_id=vendor_id,
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session_id=session_id,
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product_id=product_id,
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quantity=quantity,
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price_at_add=current_price
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)
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db.add(cart_item)
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db.commit()
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db.refresh(cart_item)
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logger.info(
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f"[CART_SERVICE] Created new cart item",
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extra={
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"cart_item_id": cart_item.id,
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"quantity": quantity,
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"price": current_price
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}
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)
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return {
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"message": "Product added to cart",
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"product_id": product_id,
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"quantity": quantity
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}
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def update_cart_item(
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self,
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db: Session,
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vendor_id: int,
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session_id: str,
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product_id: int,
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quantity: int
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) -> Dict:
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"""
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Update quantity of item in cart.
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Args:
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db: Database session
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vendor_id: Vendor ID
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session_id: Session ID
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product_id: Product ID
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quantity: New quantity (must be >= 1)
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Returns:
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Success message
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Raises:
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ValidationException: If quantity < 1
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ProductNotFoundException: If product not found
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InsufficientInventoryException: If not enough inventory
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"""
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if quantity < 1:
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raise InvalidCartQuantityException(quantity=quantity, min_quantity=1)
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# Find cart item
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cart_item = db.query(CartItem).filter(
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and_(
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CartItem.vendor_id == vendor_id,
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CartItem.session_id == session_id,
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CartItem.product_id == product_id
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)
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).first()
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if not cart_item:
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raise CartItemNotFoundException(product_id=product_id, session_id=session_id)
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# Verify product still exists and is active
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product = db.query(Product).filter(
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and_(
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Product.id == product_id,
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Product.vendor_id == vendor_id,
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Product.is_active == True
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)
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).first()
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if not product:
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raise ProductNotFoundException(str(product_id))
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# Check inventory
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if product.available_inventory < quantity:
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raise InsufficientInventoryForCartException(
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product_id=product_id,
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product_name=product.name,
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requested=quantity,
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available=product.available_inventory
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)
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# Update quantity
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cart_item.quantity = quantity
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db.commit()
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db.refresh(cart_item)
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logger.info(
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f"[CART_SERVICE] Updated cart item quantity",
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extra={
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"cart_item_id": cart_item.id,
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"product_id": product_id,
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"new_quantity": quantity
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}
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)
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return {
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"message": "Cart updated",
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"product_id": product_id,
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"quantity": quantity
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}
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def remove_from_cart(
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self,
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db: Session,
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vendor_id: int,
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session_id: str,
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product_id: int
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) -> Dict:
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"""
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Remove item from cart.
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Args:
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db: Database session
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vendor_id: Vendor ID
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session_id: Session ID
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product_id: Product ID
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Returns:
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Success message
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Raises:
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ProductNotFoundException: If product not in cart
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"""
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# Find and delete cart item
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cart_item = db.query(CartItem).filter(
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and_(
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CartItem.vendor_id == vendor_id,
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CartItem.session_id == session_id,
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CartItem.product_id == product_id
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)
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).first()
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if not cart_item:
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raise CartItemNotFoundException(product_id=product_id, session_id=session_id)
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db.delete(cart_item)
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db.commit()
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logger.info(
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f"[CART_SERVICE] Removed item from cart",
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extra={
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"cart_item_id": cart_item.id,
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"product_id": product_id,
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"session_id": session_id
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}
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)
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return {
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"message": "Item removed from cart",
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"product_id": product_id
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}
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def clear_cart(
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self,
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db: Session,
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vendor_id: int,
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session_id: str
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) -> Dict:
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"""
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Clear all items from cart.
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Args:
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db: Database session
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vendor_id: Vendor ID
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session_id: Session ID
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Returns:
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Success message with count of items removed
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"""
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# Delete all cart items for this session
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deleted_count = db.query(CartItem).filter(
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and_(
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CartItem.vendor_id == vendor_id,
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CartItem.session_id == session_id
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)
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).delete()
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db.commit()
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logger.info(
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f"[CART_SERVICE] Cleared cart",
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extra={
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"session_id": session_id,
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"vendor_id": vendor_id,
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"items_removed": deleted_count
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}
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)
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return {
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"message": "Cart cleared",
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"items_removed": deleted_count
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}
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# Create service instance
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cart_service = CartService()
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