internal class Message
    {
        public MessageType Type { get; set; }

        public Alias Alias { get; set; }

        public string WhoSent { get; set; }

        public string WhoReceived { get; set; }

        public DateTime TimeSend { get; set; }

        public DateTime TimeReceived { get; set; }

        public string Text { get; set; }

        public object File { get; set; }

        public bool IsInput { get; set; }
    }

    internal class History : IEnumerable<Message>

    public class Alias
    {
        private Alias()
      
        public List<string> Nicks { get; set; }

        public string ID { get; set; }
        
        internal History History { get; set; }

        public Protocol MessagerType { get; private set; }
    }

    public class Contact
    {
        public Contact()

        public string Name { get; set; }

        [XmlArray("Aliases")]
        public List<Alias> Aliases { get; set; }
    }