I want to create a simple inventory management system using classes and data structures. I am new to OOP in python

Question

The code should Capture products in stock (i.e. name, price, date supplied, supplier name, quantity), Retrieve the price when name is given upon each purchase and deducts the quantity in stock, Calculate the total price for each purchase and prints value indicating date and time of purchase, Sends an alert when quantity reaches 5 to shopkeeper and places order to supplier.

My code right now is not looping so that I can add a number of products then be able to access them, I tried using a while loop but it is running forever. Kindly help

import datetime
class Stock:
    def __init__(self, name, price, supplier, quantity,date):
        self.name = name
        self.price = price
        self.date = date
        self.supplier = supplier
        self. quantity = quantity

    def check_item(self, name):
        for i in range(len(ls)):
            if (ls[i].name == name):
                return i

    def sale(self):
        n = int(input("How many products to sale: "))
        total = 0
        for j in range(n):
            name = input("Enter Product name : ")
            quantity = int(input("Enter quantity: "))
            i = obj.check_item(name)
            if i and ls[i].quantity >= quantity:
                ls[i].quantity -= quantity
                if ls[i].quantity < 5:
                    print("Low Stock! Low Stock! Order Placed")
                    obj.place_order(name, ls[i].supplier, quantity+10)
                print("....Uncle G Shop....")
                print(datetime.date.today())
                print("Product Name  | Quantity  | Cost $")
                print(ls[i].name, end=" ")
                print(quantity, end=" ")
                print(ls[i].price * quantity)
                total += ls[i].price * quantity
                print("\n")
                print("Total Cost----->", "$" + total)
            else:
                print("Product out of stock or not enough quantity")


    def purchase(self):
        name = input("Enter Product name: ")
        date = datetime.date.today()
        i = obj.check_item(name)
        if i:
            ls[i].quantity += int(input("Enter quantity: "))
            ls[i].price = int(input("Enter product price: "))
            ls[i].date = date
        else:
            quantity = int(input("Enter quantity: "))
            price = int(input("Enter product price: "))
            supplier = input("Enter Supplier: ")
            ob = Stock(name, price, supplier, quantity, date)
            ls.append(ob)


    def place_order(self,name, supplier, quantity):
        return name, supplier, quantity

    def print_products(self):
        def __repr__(self):
            return str(self.name) + str(self.price) + str(supplier) + str(self.quantity) + str(self.date)
        return __repr__

    def main(self):
        print("Welcome To Uncle G Shop")
        print("choose an option below")
        print("\n1.Enter a Product\n2.Make a sale \n3.See all Products\n4.Exit")
        option = int(input("Enter option here: "))
        while True:
                

            if option == 1:
                obj.purchase()
            elif option == 2:
                obj.sale()
            elif option == 3:
                obj.print_products()
            elif option == 4:
                print("Have a good day")
                break
            else:
                print("Enter a valid input!")
# A list to add Products
ls = []

# an object of Stock class
obj = Stock('', 0, 0, 0, '')
obj.main()

Answer 1

Your main menu doesn't have a break from the while loop for option 4.

You also need to think again about how to use your class. At present, you have multiple methods referring to a variable, ls, created outside of the class. Either treat Stock as a class to deal with individual purchase records, or to deal with stock overall. You could maintain in the class itself a list of instances of the class and offer class methods, as well as instance methods, to manage that overall stock.

Answer 2

Regarding the looping issue, you just need to move your option = int(input("Enter option here: ")) line down inside your while loop.

Beyond that you have a lot of other issues that you may have already resolved or completely forgot about since this is a year+ old... Lol