trigger new ratchet send on message sent success

send our new ratchet to all new members when we just sent a message
containing no senderKey in it.

an set but empty senderKey array should only be sent when a user left or
was removed.

js/models/messages.js

@@ -1238,7 +1238,7 @@
       const isOurDevice = await window.libsession.Protocols.MultiDeviceProtocol.isOurDevice(
         sentMessage.device
       );
-
+      // FIXME this is not correct and will cause issues with syncing
       // At this point the only way to check for medium
       // group is by comparing the encryption type
       const isMediumGroupMessage =
@@ -1272,6 +1272,46 @@
           sentMessage.device
         );
 
+        if (isMediumGroupMessage) {
+          // Delete all ratchets (it's important that this happens * after * sending out the update)
+          const shouldTriggerRatchetReset =
+            dataMessage &&
+            dataMessage.mediumGroupUpdate &&
+            dataMessage.mediumGroupUpdate.senderKeys &&
+            dataMessage.mediumGroupUpdate.senderKeys.length === 0;
+          if (shouldTriggerRatchetReset) {
+            const { groupPublicKey } = dataMessage.mediumGroupUpdate;
+            const groupPubKeyUint = new Uint8Array(
+              groupPublicKey.toArrayBuffer()
+            );
+            const groupId = libsession.Utils.StringUtils.decode(
+              groupPubKeyUint,
+              'hex'
+            );
+            await window.Signal.Data.removeAllClosedGroupRatchets(groupId);
+            // Send out the user's new ratchet to all members (minus the removed ones) using established channels
+            const ourPrimary = await window.Signal.Util.UserUtil.getPrimary();
+
+            const userSenderKey = await window.libsession.MediumGroup.createSenderKeyForGroup(
+              groupId,
+              ourPrimary
+            );
+
+            const currentMembers = this.getConversation().get('members');
+
+            window.log.warn(
+              'Sharing our new senderKey with remainingMembers via established channels with',
+              currentMembers
+            );
+
+            await window.libsession.MediumGroup.shareSenderKeys(
+              groupId,
+              currentMembers,
+              userSenderKey
+            );
+          }
+        }
+
         /**
          * We should hit the notify endpoint for push notification only if:
          *  • It's a one-to-one chat or a closed group

ts/receiver/mediumGroups.ts

@@ -10,12 +10,12 @@ import * as SenderKeyAPI from '../session/medium_group';
 import { getChainKey } from '../session/medium_group/ratchet';
 import { StringUtils } from '../session/utils';
 import { BufferType } from '../session/utils/String';
-import { MultiDeviceProtocol } from '../session/protocols';
 import { ConversationModel } from '../../js/models/conversations';
 import { UserUtil } from '../util';
 import {
   createSenderKeyForGroup,
   RatchetState,
+  shareSenderKeys,
 } from '../session/medium_group/senderKeys';
 
 const toHex = (d: BufferType) => StringUtils.decode(d, 'hex');
@@ -70,23 +70,6 @@ async function handleSenderKeyRequest(
   await removeFromCache(envelope);
 }
 
-export async function shareSenderKeys(
-  groupId: string,
-  recipientsPrimary: Array<string>,
-  senderKey: RatchetState
-) {
-  const message = new MediumGroupResponseKeysMessage({
-    timestamp: Date.now(),
-    groupId,
-    senderKey,
-  });
-
-  const recipients = recipientsPrimary.map(pk => PubKey.cast(pk));
-  await Promise.all(
-    recipients.map(pk => getMessageQueue().sendUsingMultiDevice(pk, message))
-  );
-}
-
 async function handleSenderKey(
   envelope: EnvelopePlus,
   groupUpdate: SignalService.MediumGroupUpdate

ts/session/index.ts

@@ -4,7 +4,8 @@ import * as Types from './types';
 import * as Utils from './utils';
 import * as Sending from './sending';
 import * as Constants from './constants';
+import * as MediumGroup from './medium_group';
 
 export * from './instance';
 
-export { Messages, Utils, Protocols, Types, Sending, Constants };
+export { Messages, Utils, Protocols, Types, Sending, Constants, MediumGroup };

ts/session/medium_group/index.ts

@@ -8,6 +8,7 @@ import {
   RatchetState,
   saveSenderKeys,
   saveSenderKeysInner,
+  shareSenderKeys,
 } from './senderKeys';
 import { getChainKey } from './ratchet';
 import { MultiDeviceProtocol } from '../protocols';
@@ -20,7 +21,6 @@ import {
   ExpirationTimerUpdateMessage,
   MediumGroupCreateMessage,
   MediumGroupMessage,
-  Message,
 } from '../messages/outgoing';
 import { MessageModel, MessageModelType } from '../../../js/models/messages';
 import { getMessageQueue } from '../../session';
@@ -28,13 +28,13 @@ import { ConversationModel } from '../../../js/models/conversations';
 import { MediumGroupUpdateMessage } from '../messages/outgoing/content/data/mediumgroup/MediumGroupUpdateMessage';
 import uuid from 'uuid';
 import { BlockedNumberController } from '../../util/blockedNumberController';
-import { shareSenderKeys } from '../../receiver/mediumGroups';
 
 export {
   createSenderKeyForGroup,
   saveSenderKeys,
   saveSenderKeysInner,
   getChainKey,
+  shareSenderKeys,
 };
 
 const toHex = (d: BufferType) => StringUtils.decode(d, 'hex');
@@ -610,8 +610,6 @@ async function sendGroupUpdateForMedium(
     (pkHex: string) => new Uint8Array(fromHex(pkHex))
   );
 
-  const remainingMembers = _.difference(groupUpdate.members, joiningMembers);
-
   const params = {
     timestamp: Date.now(),
     identifier: messageId || uuid(),
@@ -637,30 +635,6 @@ async function sendGroupUpdateForMedium(
     );
     window.log.warn('Sending to groupUpdateMessage without senderKeys');
     await getMessageQueue().sendToGroup(messageStripped);
-
-    getMessageQueue().events.addListener('success', async message => {
-      if (message.identifier === params.identifier) {
-        // console.log('Our first message encrypted with old sk is sent.');
-        // Delete all ratchets (it's important that this happens * after * sending out the update)
-        await Data.removeAllClosedGroupRatchets(groupId);
-        if (isUserLeaving) {
-          // nothing to do on desktop
-        } else {
-          // Send out the user's new ratchet to all members (minus the removed ones) using established channels
-          const userSenderKey = await createSenderKeyForGroup(
-            groupId,
-            ourPrimary
-          );
-          window.log.warn(
-            'Sharing our new senderKey with remainingMembers via message',
-            remainingMembers,
-            userSenderKey
-          );
-
-          await shareSenderKeys(groupId, remainingMembers, userSenderKey);
-        }
-      }
-    });
   } else {
     let senderKeys: Array<RatchetState>;
     if (joiningMembers.length > 0) {

ts/session/medium_group/senderKeys.ts

@@ -1,6 +1,8 @@
 import { PubKey } from '../types';
 import { StringUtils } from '../utils';
 import * as Data from '../../../js/modules/data';
+import { MediumGroupResponseKeysMessage } from '../messages/outgoing';
+import { getMessageQueue } from '..';
 
 const toHex = (buffer: ArrayBuffer) => StringUtils.decode(buffer, 'hex');
 const fromHex = (hex: string) => StringUtils.encode(hex, 'hex');
@@ -86,3 +88,20 @@ export async function saveSenderKeys(
     messageKeys
   );
 }
+
+export async function shareSenderKeys(
+  groupId: string,
+  recipientsPrimary: Array<string>,
+  senderKey: RatchetState
+) {
+  const message = new MediumGroupResponseKeysMessage({
+    timestamp: Date.now(),
+    groupId,
+    senderKey,
+  });
+
+  const recipients = recipientsPrimary.map(pk => PubKey.cast(pk));
+  await Promise.all(
+    recipients.map(pk => getMessageQueue().sendUsingMultiDevice(pk, message))
+  );
+}