sharp-chat/SharpChat/Packet/AuthFailPacket.cs

using System;

namespace SharpChat.Packet {
    public class AuthFailPacket : ServerPacket {
        public enum FailReason {
            AuthInvalid,
            MaxSessions,
            Banned,
            Null,
        }

        private readonly FailReason Reason;
        private readonly long Expires;

        public AuthFailPacket(FailReason reason) {
            Reason = reason;
        }

        public AuthFailPacket(DateTimeOffset expires) {
            Reason = FailReason.Banned;
            Expires = expires.Year >= 2100 ? -1 : expires.ToUnixTimeSeconds();
        }

        public override string Pack() {
            string packet = string.Format("1\tn\t{0}fail", Reason switch {
                FailReason.AuthInvalid => "auth",
                FailReason.MaxSessions => "sock",
                FailReason.Banned => "join",
                _ => "user",
            });

            if(Reason == FailReason.Banned)
                packet += string.Format("\t{0}", Expires);

            return packet;
        }
    }
}