PIbd-21_Pyatakov_KM_Markov_DP_University/UniversityDataBaseImplemet/Implements/UserStorage.cs

using Microsoft.EntityFrameworkCore;
using UniversityContracts.BindingModels;
using UniversityContracts.SearchModels;
using UniversityContracts.StoragesContracts;
using UniversityContracts.ViewModels;
using UniversityDataBaseImplemet.Models;

namespace UniversityDataBaseImplemet.Implements
{
    public class UserStorage : IUserStorage
    {
        public UserViewModel? Delete(UserBindingModel model)
        {
            using var context = new Database();
            var user = context.User
                .FirstOrDefault(record => record.Id.Equals(model.Id));
            if (user == null)
            {
                return null;
            }
            context.User.Remove(user);
            context.SaveChanges();
            return user.GetViewModel;
        }

        public UserViewModel? GetElement(UserSearchModel model)
        {
			using var context = new Database();
			if (model.Id.HasValue)
			{
				return context.User
					.FirstOrDefault(x => (x.Id == model.Id))
					?.GetViewModel;
			}
			else if (!string.IsNullOrEmpty(model.Login) && !string.IsNullOrEmpty(model.Password) && model.Role.HasValue)
			{
				return context.User
					.FirstOrDefault(x => (x.Login == model.Login && x.Password == model.Password && x.Role == model.Role))
					?.GetViewModel;
			}
			return null;
		}

        public List<UserViewModel> GetFilteredList(UserSearchModel model)
        {
            using var context = new Database();
            if (model.Id.HasValue)
            {
                return context.User
                .Where(record => record.Id.Equals(model.Id))
                .Select(record => record.GetViewModel)
                .ToList();
            }
            else return new();
        }

        public List<UserViewModel> GetFullList()
        {
            using var context = new Database();
            return context.User
                .Select(record => record.GetViewModel)
                .ToList();
        }

        public UserViewModel? Insert(UserBindingModel model)
        {
            var newUser = User.Create(model);
            if (newUser == null)
            {
                return null;
            }
            using var context = new Database();
            context.User.Add(newUser);
            context.SaveChanges();
            return newUser.GetViewModel;
        }

        public UserViewModel? Update(UserBindingModel model)
        {
            using var context = new Database();
            using var transaction = context.Database.BeginTransaction();
            try
            {
                var user = context.User
                    .FirstOrDefault(record => record.Id.Equals(model.Id));
                if (user == null)
                {
                    return null;
                }
                user.Update(model);
                context.SaveChanges();
                transaction.Commit();
                return user.GetViewModel;
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }
    }
}