EL_Singature/FileImplements/Implements/CertStorage.cs

using Contracts.BindingModels;
using Contracts.SearchModels;
using Contracts.ViewModels;
using Contracts.StoragesContracts;
using FileImplements.Models;

namespace FileImplements.Implements
{
    public class CertStorage : ICertStorage
	{
		private readonly DataFileSingleton source;

		public CertStorage()
		{
			source = DataFileSingleton.GetInstance();
		}
		public List<CertViewModel> GetFullList()
		{
			return source.Certs.Select(x => x.GetViewModel).ToList();
		}

		public List<CertViewModel> GetFilteredList(CertSearchModel model)
		{
			if (string.IsNullOrEmpty(model.Name))
			{
				return new();
			}

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

		public CertViewModel? GetElement(CertSearchModel model)
		{
			if (string.IsNullOrEmpty(model.Name) && !model.Id.HasValue)
			{
				return null;
			}

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

		public CertViewModel? Insert(CertBindingModel model)
		{
			model.Id = source.Certs.Count > 0 ? source.Certs.Max(x => x.Id) + 1 : 1;
			var newCert = Cert.Create(model);

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

			source.Certs.Add(newCert);
			source.SaveCerts();

			return newCert.GetViewModel;
		}

		public CertViewModel? Update(CertBindingModel model)
		{
			var Cert = source.Certs.FirstOrDefault(x => x.Id == model.Id);

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

			Cert.Update(model);
			source.SaveCerts();

			return Cert.GetViewModel;
		}

		public CertViewModel? Delete(CertBindingModel model)
		{
			var element = source.Certs.FirstOrDefault(x => x.Id == model.Id);

			if (element != null)
			{
				source.Certs.Remove(element);
				source.SaveCerts();

				return element.GetViewModel;
			}

			return null;
		}
	}
}