using System;

using System.Collections.Generic;

using System.Data.Entity;

using Unity;

using Moq;

namespace Domain

{

public class Program

{

    public static void Main()

    {       

            Console.WriteLine("Please enter Product(s) Name like to purchase.");

​

            IProdToPurchase objProdPurchase = Factory.createProdPurchaseInstance();

            string p = Console.ReadLine();

            while (p != "")

            {

                objProdPurchase.Add(p);

                p = Console.ReadLine();

            }

            ICostCalculater objCostCalc = Factory.createCalculatorInstance();

            objCostCalc.calculateCost(objProdPurchase);

            Console.ReadLine();

    }

}

​

    //Concrete class to calculate Cost of Items purchased

    public class CostCalculator : ICostCalculater

    {

         List<Product> _listAllProducts;

        private double _totalSalesTax = 0.0;

        private double _totalCost = 0.0;

​

        public CostCalculator()

        {

            getAllProductsFromDB();

        }

​

        private void getAllProductsFromDB()

        {

            using (ProductDBContext db = new ProductDBContext())

            {

                _listAllProducts = db.Products;

            }

        }

        public void calculateCost(IProdToPurchase products)

        {

            Console.WriteLine("========= INVOICE =========");

            foreach (string prodName in products.GetProdsToPurchase())

            {

                Product prod = _listAllProducts.Find(p => p.Name == prodName);

                if (prod != null)

                {

                    int nQty = 1;

​

                    double nTaxPerct = SalesTax.GetSalexTax(prod.Category);

                    double nTaxValue = nQty * prod.Price * nTaxPerct;

                    double nCostValue = nQty * prod.Price * (1 + nTaxPerct);

                    _totalSalesTax += nTaxValue;

                    _totalCost += nCostValue;

                    Console.WriteLine(string.Format("Product {0} :  Sales Tax {1}, Cost {2}", prod.Name, nTaxValue, nCostValue));

                }

            }

​

            Console.WriteLine("========================================");

            Console.WriteLine(string.Format("Total Sales Tax {0}", _totalSalesTax));

            Console.WriteLine(string.Format("Total Cost including Sales Tax {0}", _totalCost));

            Console.WriteLine("========================================");

        }

​

        public double TotalTax

        {

            get { return _totalSalesTax; }

        }

​

        public double TotalCost

        {

            get { return _totalCost; }

        }

    }

​

    //Class to return Sales Tax as per product category

    public class SalesTax

    {

         public static double GetSalexTax(char category)

        {

            switch (category)

            {

                case 'A':

                    return 0.10;

                case 'B':

                    return 0.20;

                default:

                    return 0.0;                    

            }

        }

    }

​

​

    //Factory class to retrieve instance of CostCalculater and ProdsToPurchase concrete classes

    public class Factory

    {

        public static ICostCalculater createCalculatorInstance()

        {

            IUnityContainer _container = new UnityContainer();

            _container.RegisterType(typeof(ICostCalculater), typeof(CostCalculator));

            ICostCalculater inst = _container.Resolve<ICostCalculater>();

​

            return inst;

        }

​

        public static IProdToPurchase createProdPurchaseInstance()

        {

            IUnityContainer _container = new UnityContainer();

            _container.RegisterType(typeof(IProdToPurchase), typeof(ProdsToPurchase));

            IProdToPurchase inst = _container.Resolve<IProdToPurchase>();

​

            return inst;

        }

    }

​

    public interface ICostCalculater

    {

        void calculateCost(IProdToPurchase products);

    }

    public interface IProdToPurchase

    {

        void Add(string sProdName);

        List<string> GetProdsToPurchase();

    }

    //This class will accept all Products name selected by customer to purchase and returns final list to calculate total cost

    public class ProdsToPurchase : IProdToPurchase

    {

        List<string> _listProdsToPurchase = new List<string>();

        public void Add(string sProdName)

        {

            _listProdsToPurchase.Add(sProdName);

        }

​

        public List<string> GetProdsToPurchase()

        {

            return _listProdsToPurchase;

        }

    }

​

​

  //Model class

    public class Product

    {

        private char _category = ' ';

        private string _name = "";

        private double _price;

        public char Category

        {

            get

            {

                return _category;

            }

            set

            {

                _category = value;

            }

        }

​

        public string Name

        {

            get

            {

                return _name;

            }

            set

            {

                _name = value;

            }

        }

​

        public double Price

        {

            get { return _price; }

            set { _price = value; }

        }

    }

​

​

    //Interface between core application and Database

    public class ProductDBContext : DbContext

    {

        private List<Product> _products = new List<Product>();

        public ProductDBContext()  : base("name=SampleDB")

        {

​

        }

​

        public List<Product> Products

        {

            get

            {

                _products.Add(new Product() { Name = "Oil", Category = 'A', Price = 130 });

                _products.Add(new Product() { Name = "Paste", Category = 'B', Price = 85.50 });

                _products.Add(new Product() { Name = "Washing Powder", Category = 'A', Price = 249.90 });

                _products.Add(new Product() { Name = "Ketchup", Category = 'c', Price = 110.00 });

                _products.Add(new Product() { Name = "Horlicks", Category = 'B', Price = 520.00 });

​

                return _products;

            }

​

            set { _products = value; }

        }

    }

​

}

​

​

namespace Domain

{

    public class CostCalculatorTest

    {

        public void TestMethod1()

        {

            //Arrange

            ICostCalculater objCostC = Factory.createCalculatorInstance();

            var objMock = new Mock<IProdToPurchase>();

            objMock.Setup(p => p.GetProdsToPurchase()).Returns(() => { List<string> _lst = new List<string>(); _lst.Add("Oil"); _lst.Add("Paste"); _lst.Add("Horlicks"); return _lst; });

​

            //Act

            objCostC.calculateCost(objMock.Object);

​

            //Assert            

            //Assert.AreEqual(((CostCalculator)objCostC).TotalTax, 134.10);

            //Assert.AreEqual(((CostCalculator)objCostC).TotalCost, 869.60);

        }

    }

​

}