/// <summary>
/// Registers a new user.
/// </summary>
/// <param name="displayName">The display name.</param>
/// <param name="email">The email address.</param>
/// <param name="password">The clear-text password.</param>
/// <returns>The identifier of the newly created user.</returns>
public Guid RegisterUser(string displayName, string email, string password)
{
Validate.NotNullOrWhitespace(displayName, nameof(displayName));
Validate.NotNullOrWhitespace(email, nameof(email));
Validate.NotNullOrWhitespace(password, nameof(password));
Validate.PasswordStrenth(password, 1, 1, 1, 1);
// Hash the clear text password.
string hashedPassword = _passwordHashingProvider.ComputeHash(password);
// Create the user.
User user = User.Register(displayName, email, hashedPassword);
_userRepository.Save(user);
// Create the user's default account.
_accountService.CreateAccount(user.Id, "Default Account");
// Create the user's default watchlist.
_watchlistService.CreateWatchlist(user.Id, "Default Watchlist", new[] { "BHP", "CBA", "TLS", "WOW" });
return(user.Id);
}