ISEbd-21.Fedotov.I.A.Diner/Diner/DinerShopImplement/Implements/OrderStorage.cs

using DinerContracts.BindingModels;
using DinerContracts.SearchModels;
using DinerContracts.StoragesContracts;
using DinerContracts.ViewModels;
using DinerFileImplement.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Headers;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace DinerFileImplement.Implements
{
    public class OrderStorage : IOrderStorage
    {
        private readonly DataFileSingleton _source;

        public OrderStorage()
        {
            _source = DataFileSingleton.GetInstance();
        }

        public OrderViewModel? Delete(OrderBindingModel model)
        {
            var element = _source.Orders.FirstOrDefault(x => x.ID == model.ID);
            if (element != null) { 
                _source.Orders.Remove(element);
                _source.SaveOrder();
                return GetViewModel(element);
            }
            return null;
        }

        public OrderViewModel? GetElement(OrderSearchModel model)
        {
            if (!model.ID.HasValue) { return null; }
            return _source.Orders
                .FirstOrDefault(x => model.ID.HasValue && x.ID == model.ID)?.GetViewModel;
        }

        public List<OrderViewModel> GetFilteredList(OrderSearchModel model)
        {
            if (!model.ID.HasValue) { return new(); }
            return _source.Orders.Where(x => x.ID == model.ID).Select(GetViewModel).ToList();
        }

        public List<OrderViewModel> GetFullList()
        {
            return _source.Orders.Select(GetViewModel).ToList();
        }
        private OrderViewModel GetViewModel(Order order)
        {
            var viewModel = order.GetViewModel;
            var tmp = from p in _source.Snacks
                      where p.ID == order.SnackID 
                      select p.ProductName;
            viewModel.ProductName = tmp.FirstOrDefault(string.Empty);
            return viewModel;
        }
        public OrderViewModel? Insert(OrderBindingModel model)
        {
            model.ID = _source.Orders.Count > 0 ? _source.Orders.Max(x => x.ID) + 1 : 1;
            var newOrder = Order.Create(model);
            if (newOrder == null) { return null; }
            _source.Orders.Add(newOrder);
            _source.SaveOrder();
            return GetViewModel(newOrder);
        }

        public OrderViewModel? Update(OrderBindingModel model)
        {
            var order = _source.Orders.FirstOrDefault(x => x.ID == model.ID);
            if (order == null) { return null; }
            order.Update(model);
            _source.SaveOrder();
            return GetViewModel(order);
        }
    }
}