PIbd-23-Radaev-A.V.-GiftShop/GiftShop/GiftShopFileImplement/Implements/GiftStorage.cs

using GiftShopContracts.BindingModels;
using GiftShopContracts.SearchModels;
using GiftShopContracts.StoragesContracts;
using GiftShopContracts.ViewModels;
using GiftShopFileImplement.Models;

namespace GiftShopFileImplement.Implements
{
    public class GiftStorage : IGiftStorage
    {
        private readonly DataFileSingleton source;

        public GiftStorage()
        {
            source = DataFileSingleton.GetInstance();
        }

        public GiftViewModel? Delete(GiftBindingModel model)
        {
            var element = source.Gifts.FirstOrDefault(x => x.Id == model.Id);

            if (element != null)
            {
                source.Gifts.Remove(element);
                source.SaveGifts();

                return element.GetViewModel;
            }

            return null;
        }

        public GiftViewModel? GetElement(GiftSearchModel model)
        {
            if (string.IsNullOrEmpty(model.GiftName) && !model.Id.HasValue)
            {
                return null;
            }

            return source.Gifts.FirstOrDefault(x => (!string.IsNullOrEmpty(model.GiftName) && x.GiftName == model.GiftName) || (model.Id.HasValue && x.Id == model.Id))?.GetViewModel;
        }

        public List<GiftViewModel> GetFilteredList(GiftSearchModel model)
        {
            if (string.IsNullOrEmpty(model.GiftName))
            {
                return new();
            }

            return source.Gifts
                .Where(x => x.GiftName
                .Contains(model.GiftName))
                .Select(x => x.GetViewModel).ToList();
        }

        public List<GiftViewModel> GetFullList()
        {
            return source.Gifts.Select(x => x.GetViewModel).ToList();
        }

        public GiftViewModel? Insert(GiftBindingModel model)
        {
            model.Id = source.Gifts.Count > 0 ? source.Gifts.Max(x => x.Id) + 1 : 1;
            var newGift = Gift.Create(model);

            if (newGift == null)
            {
                return null;
            }

            source.Gifts.Add(newGift);
            source.SaveGifts();

            return newGift.GetViewModel;
        }

        public GiftViewModel? Update(GiftBindingModel model)
        {
            var gift = source.Gifts.FirstOrDefault(x => x.Id == model.Id);

            if (gift == null)
            {
                return null;
            }

            gift.Update(model);
            source.SaveGifts();

            return gift.GetViewModel;
        }
    }
}