sharp-chat/SharpChat/S2CPackets/ForceDisconnectS2CPacket.cs

using System.Text;

namespace SharpChat.S2CPackets {
    public enum ForceDisconnectReason {
        Kicked = 0,
        Banned = 1,
    }

    public class ForceDisconnectS2CPacket : S2CPacket {
        public ForceDisconnectReason Reason { get; private set; }
        public DateTimeOffset Expires { get; private set; }

        public ForceDisconnectS2CPacket(ForceDisconnectReason reason, DateTimeOffset? expires = null) {
            Reason = reason;

            if(reason == ForceDisconnectReason.Banned) {
                if(!expires.HasValue)
                    throw new ArgumentNullException(nameof(expires));
                Expires = expires.Value;
            }
        }

        public IEnumerable<string> Pack() {
            StringBuilder sb = new();

            sb.Append('9');
            sb.Append('\t');
            sb.Append((int)Reason);

            if(Reason == ForceDisconnectReason.Banned) {
                sb.Append('\t');
                if(Expires.Year >= 2100)
                    sb.Append("-1");
                else
                    sb.Append(Expires.ToUnixTimeSeconds());
            }

            yield return sb.ToString();
        }
    }
}