using System;
using System.Collections.Generic;

// Product class represents a product in the store
class Product
{
    public int ProductID { get; }
    public string Name { get; set; }
    public decimal Price { get; set; }
    public int StockQuantity { get; set; }

    public Product(int productId, string name, decimal price, int stockQuantity)
    {
        ProductID = productId;
        Name = name;
        Price = price;
        StockQuantity = stockQuantity;
    }

    public void DisplayProductInfo()
    {
        Console.WriteLine($"Product ID: {ProductID}");
        Console.WriteLine($"Name: {Name}");
        Console.WriteLine($"Price: ${Price}");
        Console.WriteLine($"Stock Quantity: {StockQuantity}");
    }
}

// ShoppingCart class represents the user's shopping cart
class ShoppingCart
{
    public List<Product> CartItems { get; } = new List<Product>();
    public decimal TotalPrice
    {
        get
        {
            decimal totalPrice = 0;
            foreach (var item in CartItems)
            {
                totalPrice += item.Price;
            }
            return totalPrice;
        }
    }

    public void AddToCart(Product product)
    {
        CartItems.Add(product);
    }

    public void RemoveFromCart(Product product)
    {
        CartItems.Remove(product);
    }

    public void DisplayCartContents()
    {
        Console.WriteLine("Shopping Cart Contents:");
        foreach (var item in CartItems)
        {
            Console.WriteLine($"{item.Name} - ${item.Price}");
        }
        Console.WriteLine($"Total Price: ${TotalPrice}");
    }
}

// User class represents a user of the online store
class User
{
    public int UserID { get; }
    public string Name { get; set; }
    public string Email { get; set; }

    public User(int userId, string name, string email)
    {
        UserID = userId;
        Name = name;
        Email = email;
    }
}

// OnlineStore class represents the online store itself
class OnlineStore
{
    public List<Product> AvailableProducts { get; } = new List<Product>();
    public List<User> RegisteredUsers { get; } = new List<User>();

    public void AddProductToStore(Product product)
    {
        AvailableProducts.Add(product);
    }

    public void RegisterUser(User user)
    {
        RegisteredUsers.Add(user);
    }

    public void DisplayAvailableProducts()
    {
        Console.WriteLine("Available Products:");
        foreach (var product in AvailableProducts)
        {
            product.DisplayProductInfo();
            Console.WriteLine();
        }
    }

    public void DisplayUserDetails(User user)
    {
        Console.WriteLine($"User ID: {user.UserID}");
        Console.WriteLine($"Name: {user.Name}");
        Console.WriteLine($"Email: {user.Email}");
    }

    public void SimulateUserActions(User user, Product product, ShoppingCart userCart)
    {
        Console.WriteLine($"{user.Name}'s Actions:");

        // Simulate user adding products to their cart
        userCart.AddToCart(product);
        Console.WriteLine($"Added {product.Name} to the cart.");
        userCart.DisplayCartContents();

        // Simulate user removing products from their cart
        userCart.RemoveFromCart(product);
        Console.WriteLine($"Removed {product.Name} from the cart.");
        userCart.DisplayCartContents();
    }

    public void SimulateUserPurchase(User user, ShoppingCart userCart)
    {
        Console.WriteLine($"{user.Name}'s Purchase:");
        Console.WriteLine($"Total Price: ${userCart.TotalPrice}");

        // Simulate updating product quantities and user's cart
        foreach (var product in userCart.CartItems)
        {
            Product storeProduct = AvailableProducts.Find(p => p.ProductID == product.ProductID);
            if (storeProduct != null)
            {
                // Update stock quantity and remove from the cart
                storeProduct.StockQuantity--;
                userCart.RemoveFromCart(product);
            }
        }

        Console.WriteLine("Purchase completed. Updated product quantities.");
        DisplayAvailableProducts();
    }
}

class Program
{
    static void Main()
    {
        // Create an online store
        OnlineStore onlineStore = new OnlineStore();

        // Create and add products to the store
        Product product1 = new Product(1, "Laptop", 800, 10);
        Product product2 = new Product(2, "Smartphone", 400, 15);
        Product product3 = new Product(3, "Headphones", 50, 20);
        onlineStore.AddProductToStore(product1);
        onlineStore.AddProductToStore(product2);
        onlineStore.AddProductToStore(product3);

        // Create users and register them
        User user1 = new User(1, "Sam", "[email protected]");
        User user2 = new User(2, "Varun", "[email protected]");
        onlineStore.RegisterUser(user1);
        onlineStore.RegisterUser(user2);

        // Simulate user actions and purchases
        ShoppingCart cartUser1 = new ShoppingCart();
        onlineStore.SimulateUserActions(user1, product1, cartUser1);
        onlineStore.SimulateUserPurchase(user1, cartUser1);

        ShoppingCart cartUser2 = new ShoppingCart();
        onlineStore.SimulateUserActions(user2, product2, cartUser2);
        onlineStore.SimulateUserPurchase(user2, cartUser2);

        // Display available products and user details
        onlineStore.DisplayAvailableProducts();
        onlineStore.DisplayUserDetails(user1);
        onlineStore.DisplayUserDetails(user2);
    }
}