from sqlalchemy.orm import Session
from database import Product, Transaction
import uuid
from datetime import datetime

def add_product(db: Session, name: str, current_stock: float, safety_stock: float, lead_time: float, monthly_demand: float, product_class: str):
    product = Product(name=name, current_stock=current_stock, safety_stock=safety_stock, lead_time=lead_time, monthly_demand=monthly_demand, product_class=product_class)  # Create new product
    db.add(product)
    db.commit()
    db.refresh(product)
    return product

def get_all_products(db: Session):
    return db.query(Product).all()  # Fetch all products

def get_product_by_id(db: Session, product_id: int):
    product = db.query(Product).filter(Product.id == product_id).first()
    if not product:
        raise ValueError("Product not found")
    return product

# In-memory session-based functions
def add_product_memory(session_products: list, name: str, current_stock: float, safety_stock: float, lead_time: float, monthly_demand: float, product_class: str):
    if any(p["name"].lower() == name.lower() for p in session_products):
        raise ValueError("Product name already exists in your session")
    product = {"id": str(uuid.uuid4()), "name": name, "current_stock": current_stock, "safety_stock": safety_stock, "lead_time": lead_time, "monthly_demand": monthly_demand, "product_class": product_class}  # Create new in-memory product
    session_products.append(product)
    return product

def update_product_memory(session_products: list, product_id: str, name: str, current_stock: float, safety_stock: float, lead_time: float, monthly_demand: float, product_class: str):
    if any(p["name"].lower() == name.lower() and p["id"] != product_id for p in session_products):
        raise ValueError("Product name already exists in your session")
    for product in session_products:
        if product["id"] == product_id:
            product.update({"name": name, "current_stock": current_stock, "safety_stock": safety_stock, "lead_time": lead_time, "monthly_demand": monthly_demand, "product_class": product_class})
            return product
    raise ValueError("Product not found")

def delete_product_memory(session_products: list, product_id: str):
    for i, product in enumerate(session_products):
        if product["id"] == product_id:
            session_products.pop(i)
            return
    raise ValueError("Product not found")

def add_stock_memory(session_products: list, session_transactions: list, product_id: str, quantity: float):
    for product in session_products:
        if product["id"] == product_id:
            product["current_stock"] += quantity
            session_transactions.append({"id": str(uuid.uuid4()), "product_id": product_id, "quantity": quantity, "transaction_type": "ADD", "timestamp": datetime.now()})  # Record stock addition
            return
    raise ValueError("Product not found")

def remove_stock_memory(session_products: list, session_transactions: list, product_id: str, quantity: float):
    for product in session_products:
        if product["id"] == product_id:
            if product["current_stock"] < quantity:
                raise ValueError("Insufficient stock")
            product["current_stock"] -= quantity
            session_transactions.append({"id": str(uuid.uuid4()), "product_id": product_id, "quantity": quantity, "transaction_type": "REMOVE", "timestamp": datetime.now()})  # Record stock removal
            return
    raise ValueError("Product not found")

def get_transactions_memory(session_transactions: list):
    return session_transactions  # Fetch all transactions