Auxilium_Server.Program.HandlePMPacket C# (CSharp) Method

        static void HandlePMPacket(Client c, string recipient, string message, string subject, ushort id = default(ushort))
        {
            if (!(IsValidName(recipient) && IsValidData(message) && IsValidData(subject)))
            {
                c.Disconnect();
                return;
            }

            Client u = ClientFromUsername(recipient);
            if (u == null)
                return;

            PrivateMessage pm = null;

            if (id == default(ushort) && !privateMessages.Exists(x => x.Id == id))
            {
                pm = new PrivateMessage(id = (ushort)_random.Next(ushort.MinValue, ushort.MaxValue), subject, c.Value.Username, DateTime.Now, message);
                privateMessages.Add(pm);

                byte[] confirm = Packer.Serialize((byte)ServerPacket.PMConfirm, id, u.Value.Username, message, subject, DateTime.Now);
                c.Send(confirm);
            }
            else
            {
                pm = privateMessages.Find(x => x.Id == id);
                pm.Message.Add(message);
            }

            byte[] data = Packer.Serialize((byte)ServerPacket.PM, id, c.Value.Username, u.Value.Username, message, subject, DateTime.Now);
            u.Send(data);
        }