public MenuViewModel(User user)
{
this.user = user;
this.tangle = new TangleMessenger(this.user.Seed);
this.ntru = new NtruKex();
this.ipfsHelper = new IpfsHelper();
}
public ChatViewModel(ListView messagesListView, Contact contact)
{
this.ntruKex = new NtruKex();
this.contact = contact;
this.messagesListView = messagesListView;
this.Messages = new ObservableCollection <MessageViewModel>();
this.OutGoingText = null;
}
public ChatViewModel(Contact contact, User user)
{
this.ntruKex = new NtruKex();
this.profileImageUrl = contact.ImageUrl;
this.user = user;
this.contact = contact;
var trytes = this.user.TangleMessenger.GetMessages(this.contact.PublicKeyAdress);
var contactInfos = IotaHelper.FilterRequestInfos(trytes);
contact.PublicNtruKey = contactInfos.PublicNtruKey;
this.Messages = new ObservableCollection <MessageViewModel>();
this.GetMessagesAsync(this.Messages);
this.OutGoingText = null;
this.SendCommand = new Command(async() => { await this.SendMessage(); });
}
public static List <ChatMessage> FilterChatMessages(IEnumerable <TryteString> trytes, NtruKex ntruKex, IAsymmetricKeyPair keyPair)
{
var chatMessages = new List <ChatMessage>();
foreach (var tryte in trytes)
{
try
{
var trytesString = tryte.ToString();
var indexBreak = trytesString.IndexOf("9CHIOTAYOURIOTACHATAPP9", StringComparison.Ordinal);
var messageTrytes = new TryteString(trytesString.Substring(0, indexBreak));
var dateTrytes = new TryteString(trytesString.Substring(indexBreak + 23, trytesString.Length - indexBreak - 23));
// can only decrypt messages from other user (send with own public key)!
var decryptedMessage = ntruKex.Decrypt(keyPair, messageTrytes.ToBytes());
var date = DateTime.Parse(dateTrytes.ToUtf8String());
var chatMessage = new ChatMessage {
Message = decryptedMessage, Date = date
};
chatMessages.Add(chatMessage);
}
catch
{
continue;
}
}
return(chatMessages);
}
