public class UserRepository : RepositoryBase<User>, IUserRepository
    {
        private IPasswordHasher _passwordHasher;

        public UserRepository(ApplicationDbContext dbContext, IPasswordHasher passwordHasher) : base(dbContext)
        {
            _passwordHasher = passwordHasher;
        }

        public async Task<UserAuthenticatedDto> Authenticate(string email, string password)
        {
            var user = await FindByCondition(x => x.Email == email).FirstOrDefaultAsync();

            if (user is null)
            {
                return null;
            }

            var authenticated = _passwordHasher.Check(user.Password, password, user.Salt);

            if (!authenticated)
            {
                return null;
            }

            // authentication successful so generate jwt token
            var token = GenerateToken(user);

            var authUser = new UserAuthenticatedDto
            {
                Email = user.Email,
                ProfilePicture = user.ProfilePicture,
                Username = user.Username,
                Token = token
            };

            return authUser;
        }

        public async Task<UserAuthenticatedDto> Register(UserRegisterDto dto)
        {
            var salt = _passwordHasher.CreateSalt();
            var hashedPassword = _passwordHasher.Hash(dto.Password, salt);

            var user = new User
            {
                Email = dto.Email,
                Password = hashedPassword,
                Salt = salt,
                Username = dto.Username,
                ProfilePicture = $"https://api.adorable.io/avatars/231/{dto.Email}.png"
            };

            await DbContext.Users.AddAsync(user);
            await DbContext.SaveChangesAsync();

            var token = GenerateToken(user);

            var authUser = new UserAuthenticatedDto
            {
                Email = user.Email,
                ProfilePicture = user.ProfilePicture,
                Username = user.Username,
                Token = token
            };

            return authUser;
        }

        private string GenerateToken(User user)
        {
            var tokenHandler = new JwtSecurityTokenHandler();

            var key = Encoding.ASCII.GetBytes("here is my temporary secret");
            var tokenDescriptor = new SecurityTokenDescriptor
            {
                Subject = new ClaimsIdentity(new Claim[]
                {
                    new Claim(ClaimTypes.Name, user.Id.ToString())
                }),
                Expires = DateTime.UtcNow.AddDays(7),
                SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(key), SecurityAlgorithms.HmacSha256Signature)
            };

            var token = tokenHandler.CreateToken(tokenDescriptor);

            return tokenHandler.WriteToken(token);
        }
    }