AspNetCoreLearnOfficial/WebAPIWithEF/Services/PizzaService.cs

using Microsoft.AspNetCore.Http.HttpResults;
using Microsoft.EntityFrameworkCore;
using WebAPIWithEF.Data;
using WebAPIWithEF.Models;

namespace WebAPIWithEF.Services
{
    public class PizzaService
    {
        private readonly PizzaContext _context;

        public PizzaService(PizzaContext context)
        {
            _context = context;
        }

        public IEnumerable<Pizza> GetAll()
        {
            return _context.Pizzas
                .AsNoTracking() // just read service (not track changes of the entity)
                .ToList();
        }

        public Pizza? GetById(int id)
        {
            return _context.Pizzas
                .Include(p => p.Toppings)
                .Include(p => p.Sauce)
                .AsNoTracking()
                .SingleOrDefault(p => p.Id == id);
        }

        public Pizza? Create(Pizza newPizza)
        {
            _context.Pizzas.Add(newPizza);
            _context.SaveChanges();

            return newPizza;
        }

        public void AddTopping(int PizzaId, int ToppingId)
        {
            var pizzaToUpdate = _context.Pizzas.Include(p => p.Toppings).SingleOrDefault(p => p.Id == PizzaId);
            var toppingToAdd = _context.Toppings.Find(ToppingId);
            if (pizzaToUpdate is null || toppingToAdd is null)
                throw new InvalidOperationException("Pizza or topping does not exist");

            if (pizzaToUpdate.Toppings is null)
                pizzaToUpdate.Toppings = new List<Topping>();

            pizzaToUpdate.Toppings.Add(toppingToAdd);

            _context.SaveChanges();
        }

        public void UpdateSauce(int PizzaId, int SauceId)
        {
            var pizzaToUpdate = _context.Pizzas.Find(PizzaId);
            var sauceToUpdate = _context.Sauces.Find(SauceId);
            if (pizzaToUpdate is null || sauceToUpdate is null)
                throw new InvalidOperationException("Pizza or sauce does not exist");

            pizzaToUpdate.Sauce = sauceToUpdate;

            _context.SaveChanges();
        }

        public void DeleteById(int id)
        {
            var pizzaToDelete = _context.Pizzas.Find(id);
            if (pizzaToDelete is null)
                return;

            _context.Pizzas.Remove(pizzaToDelete);

            _context.SaveChanges();
        }
    }
}