users/src/Nocr.Users.AppServices/Users/User.cs

namespace Nocr.Users.AppServices.Users;

public sealed class User
{
    public long Id { get; set; }

    public string Username { get; private set; }

    private List<UserIdentity> _identities = new List<UserIdentity>();

    public IReadOnlyCollection<UserIdentity> Identities => _identities;

    private User(string username, params UserIdentity[] identities)
    {
        Username = username;
        
        // TODO: Check that there is no repeating identity types
        _identities.AddRange(identities);
    }

    public static User Initialize(string username, params UserIdentity[] identities)
    {
        if (string.IsNullOrWhiteSpace(username))
        {
            throw new ArgumentNullException(nameof(username));
        }

        if (username.Length is < 5 or > 32)
        {
            throw new ArgumentException("Username length should be between 5 and 32 symbols", username);
        }

        return new User(username, identities);
    }
}