db.py

#!/usr/bin/env python3

import json
import os
import argparse

# JSON file to store the inventory data

class InventoryManager:
    def __init__(self, file_name="inventory.json"):
        self.file_name = file_name
        self.inventory = self.load_inventory()

    def load_inventory(self):
        """Load the inventory from the JSON file, or initialize an empty dictionary if the file doesn't exist."""
        if os.path.exists(self.file_name):
            with open(self.file_name, "r") as file:
                return json.load(file)
        return {}

    def save_inventory(self):
        """Save the inventory to the JSON file."""
        with open(self.file_name, "w") as file:
            json.dump(self.inventory, file)

    def add_item(self):
        """Add or update an item in the inventory."""
        item = input("Enter the item name to add/update: ")
        quantity = input(f"Enter the quantity for '{item}': ")

        if not quantity.isdigit() or int(quantity) <= 0:
            print("Invalid quantity. Please enter a positive number.")
            return

        quantity = int(quantity)

        if item in self.inventory:
            print(f"Current price for '{item}' is {self.inventory[item]['price']:.2f}.")
            price = input(f"Enter the price for '{item}' (or press Enter to keep the current price): ")

            if price == "":
                price = self.inventory[item]['price']
            elif not price.replace('.', '', 1).isdigit() or float(price) <= 0:
                print("Invalid price. Please enter a positive number.")
                return
            else:
                price = float(price)

            self.inventory[item]["quantity"] += quantity
            self.inventory[item]["price"] = price
            print(f"Updated '{item}': quantity {self.inventory[item]['quantity']}, price {self.inventory[item]['price']:.2f}.")
        else:
            price = input(f"Enter the price for '{item}': ")
            if not price.replace('.', '', 1).isdigit() or float(price) <= 0:
                print("Invalid price. Please enter a positive number.")
                return

            price = float(price)
            self.inventory[item] = {"quantity": quantity, "price": price}
            print(f"Added '{item}' with quantity {quantity} and price {price:.2f}.")

        self.save_inventory()

    def adjust_price(self):
        """Adjust the price of an item in the inventory."""
        item = input("Enter the item name to adjust the price: ")
        if item in self.inventory:
            print(f"Current price for '{item}' is {self.inventory[item]['price']:.2f}.")
            new_price = input(f"Enter the new price for '{item}': ")

            if not new_price.replace('.', '', 1).isdigit() or float(new_price) <= 0:
                print("Invalid price. Please enter a positive number.")
                return

            new_price = float(new_price)
            self.inventory[item]["price"] = new_price
            print(f"Updated price for '{item}' is now {new_price:.2f}.")
            self.save_inventory()
        else:
            print(f"'{item}' is not in the inventory.")

    def deduct_quantity(self):
        """Deduct a specified quantity from an item in the inventory."""
        while True:
            item = input("Enter the item name to deduct from (or enter '?' to view the inventory): ")
            if item == "?":
                self.print_inventory()
            else:
                if item in self.inventory:
                    quantity = input(f"Enter the quantity to deduct from '{item}': ")

                    if not quantity.isdigit() or int(quantity) <= 0:
                        print("Invalid quantity. Please enter a positive number.")
                        return

                    quantity = int(quantity)
                    if quantity > self.inventory[item]["quantity"]:
                        print(f"Cannot deduct {quantity}. '{item}' only has {self.inventory[item]['quantity']} in stock.")
                    else:
                        self.inventory[item]["quantity"] -= quantity
                        print(f"Deducted {quantity} from '{item}'. Remaining quantity: {self.inventory[item]['quantity']}.")
                        if self.inventory[item]["quantity"] == 0:
                            print(f"'{item}' has been removed from the inventory as its quantity is now 0.")
                            del self.inventory[item]

                    self.save_inventory()
                    break
                else:
                    print(f"'{item}' is not in the inventory.")

    def remove_item(self):
        """Remove an item from the inventory, with a warning and confirmation."""
        item = input("Enter the item name to remove: ")
        if item in self.inventory:
            print(f"Warning: You are about to remove '{item}' from the inventory.")
            confirm = input("Are you sure? (yes/no): ").strip().lower()
            if confirm == "yes":
                del self.inventory[item]
                self.save_inventory()
                print(f"'{item}' has been removed from the inventory.")
            else:
                print(f"'{item}' was not removed.")
        else:
            print(f"'{item}' is not in the inventory.")

    def print_inventory(self):
        """Print the current inventory in a table format, sorted by item name."""
        if self.inventory:
            print(f"\n{'Item':<20}{'Quantity':<10}{'Price':<10}{'Total':<10}")
            print("-" * 50)
            for item, details in sorted(self.inventory.items()):
                total = details["quantity"] * details["price"]
                print(f"{item:<20}{details['quantity']:<10}{details['price']:<10.2f}{total:<10.2f}")
            print("-" * 50)
        else:
            print("The inventory is empty.")

    def find_item(self):
        """Find an item in the inventory and return its quantity, price, and total value."""
        item = input("Enter the item name to find: ")
        if item in self.inventory:
            quantity = self.inventory[item]["quantity"]
            price = self.inventory[item]["price"]
            total = quantity * price
            print(f"'{item}' has quantity {quantity}, price {price:.2f}, and total value {total:.2f}.")
        else:
            print(f"'{item}' is not in the inventory.")


def display_menu():
    """Display the menu options."""
    print("\nMenu:")
    print("1. Add an item")
    print("2. Remove an item")
    print("3. Print the inventory")
    print("4. Find an item's details")
    print("5. Deduct quantity from an item")
    print("6. Adjust the price of an item")
    print("7. Exit")


def main():
    """Main function to handle the menu and user choices."""

    parser = argparse.ArgumentParser(description="Inventory Management System")
    parser.add_argument("-f", "--file", default="inventory.json", help="Path to the JSON inventory file")
    args = parser.parse_args()

    file_name = args.file
    manager = InventoryManager(file_name)

    while True:
        display_menu()
        choice = input("Enter your choice (1-7): ")

        if choice == "1":
            manager.add_item()
        elif choice == "2":
            manager.remove_item()
        elif choice == "3":
            manager.print_inventory()
        elif choice == "4":
            manager.find_item()
        elif choice == "5":
            manager.deduct_quantity()
        elif choice == "6":
            manager.adjust_price()
        elif choice == "7":
            print("Exiting the program. Goodbye!")
            break
        else:
            print("Invalid choice. Please enter a number between 1 and 7.")


# Run the program
if __name__ == "__main__":
    main()