Shop

using System;
using System.Data.SqlTypes;
using System.Runtime.InteropServices;

namespace Shop
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Shop shop = new Shop();
            Seller seller = new Seller();
            Buyer buyer = new Buyer();

            shop.Work(seller, buyer);
        }
    }

    class Shop
    {
        public void Work(Seller seller, Buyer buyer)
        {
            const int CommandBuyProduct = 1;
            const int CommandShowBag = 2;
            const int CommandExit = 3;

            bool isWorking = true;

            while (isWorking)
            {
                Console.WriteLine("Список товаров в магазине:\n");

                seller.ShowWarehouse();
                Console.WriteLine();
                seller.ShowMoney(buyer, seller);

                Console.WriteLine($"\nЕсли хотите купить товар введите - {CommandBuyProduct}\n" +
                    $"Если хотите посмотреть, что в сумке у покупателя введите - {CommandShowBag}\n" +
                    $"Если хотите выйти из магазина введите - {CommandExit}\n\n");

                int userInput = ReadInt();

                if (userInput == CommandBuyProduct)
                {
                    SelectionOfProducts(seller, buyer);
                }
                else if (userInput == CommandExit)
                {
                    isWorking = false;
                }
                else if (userInput == CommandShowBag)
                {
                    buyer.ShowBag();
                }
                else
                {
                    Console.WriteLine("Вы ввели не верную команду.");
                }

                Console.ReadKey();
                Console.Clear();
            }
        }

        private void SelectionOfProducts(Seller seller, Buyer buyer)
        {
            Console.WriteLine("Введите название товара:");
            string productName = Console.ReadLine();

            Console.WriteLine("Введите количество товара:");
            int value = ReadInt();

            seller.Sell(buyer, productName, value);
        }

        private int ReadInt()
        {
            int number;

            while (int.TryParse(Console.ReadLine(), out number) != true)
            {
                Console.WriteLine("Вы ввели не корректные данные");
                Console.ReadKey();
            }

            return number;
        }
    }

    class Owner
    {
        protected List<Cell> Warehouse = new List<Cell>();
        protected List<Cell> Bag = new List<Cell>();

        protected bool IsContains(List<Cell> content, string product, out int index)
        {
            for (int i = 0; i < content.Count; i++)
            {
                if (content[i].Product.Name.Contains(product))
                {
                    index = i;
                    return true;
                }
            }

            index = 0;
            return false;
        }

        public void ShowMoney(Buyer buyer, Seller seller)
        {
            Console.WriteLine($"{seller.SellerMoney} - денег у продавца.\n{buyer.BuyerMoney} - денег у покупателя.");
        }
    }

    class Buyer : Owner
    {
        public Buyer(int money = 1000)
        {
            BuyerMoney = money;
        }

        public int BuyerMoney { get; private set; }

        public void WithdrawMoney(int productPrice, int value)
        {
            BuyerMoney -= productPrice * value;
        }
        public void AddQuantity(int quantityReduseProducts, int index)
        {
            Bag[index].AddQuantity(quantityReduseProducts);
        }

        public void AddNewProductInBag(int value, int price, string productName)
        {
            Bag.Add(new Cell(value, new Product(productName, price)));
        }

        public void ShowBag()
        {
            foreach (var item in Bag)
            {
                Console.WriteLine($"{item.Product.Name}     {item.Quantity} - шт. Цена - {item.Product.Price}");
            }
        }
    }

    class Seller : Owner
    {

        public Seller(int money = 100000)
        {
            SellerMoney = money;

            Warehouse.Add(new Cell(10, new Product("Колбаса", 182)));
            Warehouse.Add(new Cell(20, new Product("Хлеб", 54)));
            Warehouse.Add(new Cell(15, new Product("Сыр", 287)));
            Warehouse.Add(new Cell(5, new Product("Масло", 216)));
            Warehouse.Add(new Cell(11, new Product("Молоко", 93)));
        }

        public int SellerMoney { get; private set; }

        public void Sell(Buyer buyer, string productName, int value)
        {
            int productPrice;

            if (buyer.BuyerMoney < 0)
            {
                Console.WriteLine("У покупателя недостаточно денег.");
                Console.ReadKey();
                return;
            }

            if (IsContains(Warehouse, productName, out int index))
            {
                productPrice = Warehouse[index].Product.Price;

                if (buyer.BuyerMoney < productPrice * value)
                {
                    Console.WriteLine("У покупателя не достаточно денег.");
                    Console.ReadKey();
                    return;
                }

                ReduseQuantity(value, index);
                TopUpMoney(productPrice, value);
                buyer.WithdrawMoney(productPrice, value);
            }
            else
            {
                return;
            }

            if (IsContains(Bag, productName, out index))
            {
                buyer.AddQuantity(value, index);
            }
            else
            {
                buyer.AddNewProductInBag(value, productPrice, productName);
            }
        }

        public void TopUpMoney(int productPrice, int value)
        {
            SellerMoney += productPrice * value;
        }

        public void ReduseQuantity(int quantityReduseProduct, int index)
        {
            Warehouse[index].ReduseQuantity(quantityReduseProduct);
        }

        public void ShowWarehouse()
        {
            foreach (var item in Warehouse)
            {
                Console.WriteLine($"{item.Product.Name}     {item.Quantity} - шт. Цена - {item.Product.Price}");
            }
        }
    }

    class Product
    {
        public Product(string name, int price)
        {
            Name = name;
            Price = price;
        }

        public string Name { get; private set; }
        public int Price { get; private set; }
    }

    class Cell
    {
        public Cell(int quantity, Product product)
        {
            Quantity = quantity;
            Product = product;
        }

        public int Quantity { get; private set; }
        public Product Product { get; private set; }

        public void ReduseQuantity(int quantityReduseProducts)
        {
            if (Quantity >= quantityReduseProducts)
            {
                for (int i = quantityReduseProducts; i > 0; i--)
                {
                    Quantity--;
                }
            }
            else
            {
                Quantity = 0;
            }
        }

        public void AddQuantity(int quantityReduseProducts)
        {
            for (int i = 1; i == quantityReduseProducts; i++)
            {
                Quantity++;
            }
        }
    }
}