async Task DecryptDownloadedMessage(XMessage xMessage)
{
Message decryptedMessage = await TryDecryptMessageToFindSenderEnryptDecryptionKeyAndSaveIt(xMessage);
if (decryptedMessage == null) // TODO: we'll be here also when Ratchet mismatch error is happening. Then, the message should not be just dropped. Do we have the sender's Id so that we can notify him?
{
return; // Ignore the message - it was truely garbled or a resend request was already queued. In both cases we are done with it here.
}
if (decryptedMessage.MessageType.IsReceipt())
{
Message messageToConfirm = await this.repo.GetMessage(decryptedMessage.SenderLocalMessageId, decryptedMessage.SenderId);
if (messageToConfirm != null) // the message could have already been deleted
{
messageToConfirm.SendMessageState = decryptedMessage.MessageType == MessageType.DeliveryReceipt ? SendMessageState.Delivered : SendMessageState.Read;
await this.repo.UpdateMessage(messageToConfirm);
SendMessageStateUpdated?.Invoke(this, messageToConfirm);
}
return;
}
if (decryptedMessage.MessageType.IsContent())
{
if (this.contactListManager.CurrentContact == null || this.contactListManager.CurrentContact.Id != decryptedMessage.SenderId)
{
await SendReceipt(decryptedMessage, MessageType.DeliveryReceipt);
// This message will become an UNREAD message and not be displayed
await this.contactListManager.HandelUnreadAndChatPreviewForIncomingMessageFromChatWorker(decryptedMessage, countAsUnread : true);
}
else
{
await SendReceipt(decryptedMessage, MessageType.ReadReceipt);
// this message will become an READ message and display immediately
await this.contactListManager.HandelUnreadAndChatPreviewForIncomingMessageFromChatWorker(decryptedMessage, countAsUnread : false);
IncomingMessageDecrypted?.Invoke(this, decryptedMessage);
}
}
#region Incoming Contact Logic
// Check if the sender is in our contacts
// OLD: Identity contactInList = existingContacts.SingleOrDefault(c => c.ChatId == msg.SenderId);
/*
* Identity contactInList = existingContacts.SingleOrDefault(c => c.ChatId == msg.SenderId);
* if (contactInList != null && contactInList.ContactState == ContactState.Valid)
* continue; // Yes, proceed checking the nex message
*
* if (contactInList != null && contactInList.ContactState == ContactState.Added)
* {
* await VerifyContactInAddedState(contactInList);
*
* // Check if the contact is valid now
* existingContacts = await repo.GetAllContacts();
* contactInList = existingContacts.SingleOrDefault(c => c.ChatId == msg.SenderId);
* if (contactInList.ContactState == ContactState.Valid)
* continue; // Yes, proceed checking the nex message
*
* // If still not valid, drop the message
* msg.MessageType = MessageType.None; // MessageType.None will be ignored by the code below
* continue; // Proceed checking the nex message
* }
* var incomingContact = new Identity { Id = Guid.NewGuid().ToString(), UnverifiedId=msg.SenderId, ContactState = ContactState.Added, Name = "Incoming Contact" };
* await repo.AddContact(incomingContact);
* await VerifyContactInAddedState(incomingContact);
*
* // Check if the incoming contact is valid now
* existingContacts = await repo.GetAllContacts();
* contactInList = existingContacts.SingleOrDefault(c => c.ChatId == msg.SenderId);
* if (contactInList.ContactState == ContactState.Valid)
* continue; // Yes, proceed checking the next message
*
* // If still not valid, drop the message
* msg.MessageType = MessageType.None; // MessageType.None will be ignored by the code below
*/
#endregion
}
async Task CheckForResendRequestsAsync()
{
// 1. Get the hashes of messages where we did not get a delivery or read receipt
var contacts = await this.repo.GetAllContacts();
foreach (var c in contacts.Where(c => c.ContactState == ContactState.Valid).ToArray())
{
// First, look at the last message and try to detect cases where simply everything is ok
var lastMessage = await this.repo.GetLastMessage(c.Id);
if (lastMessage == null || // if there is no message, there is nothing to resend
lastMessage.Side == MessageSide.You || // if the last message was incoming, it means the other side has the keys, it's ok
lastMessage.SendMessageState == SendMessageState.Delivered || lastMessage.SendMessageState == SendMessageState.Read) // also nothing to repair
{
continue;
}
// Now let's look deeper. We may have sent a couple of messages, that are all still without receipts. That means our state is XDSNetwork.
// It's possible they could't be read, and the other side has already posted resend requests.
// Of course it's also possible the other side has just been offline though. Unfortunately, we don't know.
var moreLastMessages = await this.repo.GetMessageRange(0, 10, c.Id);
foreach (var message in moreLastMessages)
{
if (message.Side == MessageSide.Me && message.SendMessageState == SendMessageState.XDSNetwork && message.SendMessageState != SendMessageState.Resent &&
DateTime.UtcNow - message.GetEncrytedDateUtc() > TimeSpan.FromSeconds(60) && // old enough to check
DateTime.UtcNow - message.GetEncrytedDateUtc() < TimeSpan.FromDays(7)) // young enough not to be expired
{
var resendRequestQuery = new XResendRequest {
Id = message.NetworkPayloadHash, RecipientId = c.ChatId
};
var response = await this.chatClient.CheckForResendRequest(resendRequestQuery); // check if resend request has been posted, or if the sent message is still there and has not yet been fetched.
if (!response.IsSuccess)
{
return; // give up the whole procedure for all contacts, something else is broken
}
if (response.Result == 0)
{
// There is nothing on the server. Not the original message and no resend request. Possible causes:
// - The recipient did download it but did not send a resend request, or a receipt yet.
// - The message or receipt or resend request was lost.
// => keep checking. It's possible a resend request or receipt arrives, it drops out the top 10 we are checking
// or max ago for checking after messages arrives, so that we stop checking eventually.
// => but do not resend the message.
// => but do check the other messages of this contact.
message.SendMessageState = SendMessageState.Untracable;
await this.repo.UpdateMessage(message);
SendMessageStateUpdated?.Invoke(this, message);
continue;
}
if (response.Result == 1)
{
// The original message is still on the server.
// - The recipient hasn't downloaded his messages.
// => stop checking this contact
break;
}
if (response.Result == 2)
{
// yes, there is a resend request on the server.
// => resend the message
await this.chatEncryptionService.DecryptCipherTextInVisibleBubble(message);
await this.chatEncryptionService.EncryptMessage(message, true);
var resendResponse = await this.chatClient.UploadMessage(message);
if (resendResponse.IsSuccess)
{
message.SendMessageState = SendMessageState.Resent;
await this.repo.UpdateMessage(message);
SendMessageStateUpdated?.Invoke(this, message);
}
}
}
}
}
}
