storage.py

import pandas as pd
import os

DATA_DIR = "data"
PRODUCTS_FILE = f"{DATA_DIR}/products.xlsx"
SALES_FILE = f"{DATA_DIR}/sales.xlsx"

def initialize_files():
    os.makedirs(DATA_DIR, exist_ok=True)

    if not os.path.exists(PRODUCTS_FILE):
        df = pd.DataFrame(columns=["ID", "Name", "Category", "Price", "Quantity"])
        df.to_excel(PRODUCTS_FILE, index=False)

    if not os.path.exists(SALES_FILE):
        df = pd.DataFrame(columns=["SaleID", "ProductID", "Quantity", "TotalPrice", "Date"])
        df.to_excel(SALES_FILE, index=False)

def load_products():
    return pd.read_excel(PRODUCTS_FILE)

def save_products(df):
    df.to_excel(PRODUCTS_FILE, index=False)

def load_sales():
    return pd.read_excel(SALES_FILE)

def save_sales(df):
    df.to_excel(SALES_FILE, index=False)