diff --git a/lib/reducers/message-reducer.js b/lib/reducers/message-reducer.js
index 0d5b0e052..aa29063b2 100644
--- a/lib/reducers/message-reducer.js
+++ b/lib/reducers/message-reducer.js
@@ -1,905 +1,906 @@
 // @flow
 
 import invariant from 'invariant';
 import _difference from 'lodash/fp/difference';
 import _flow from 'lodash/fp/flow';
 import _isEqual from 'lodash/fp/isEqual';
 import _keyBy from 'lodash/fp/keyBy';
 import _map from 'lodash/fp/map';
 import _mapKeys from 'lodash/fp/mapKeys';
 import _mapValues from 'lodash/fp/mapValues';
 import _omit from 'lodash/fp/omit';
 import _omitBy from 'lodash/fp/omitBy';
 import _orderBy from 'lodash/fp/orderBy';
 import _pick from 'lodash/fp/pick';
 import _pickBy from 'lodash/fp/pickBy';
 import _uniq from 'lodash/fp/uniq';
 
 import {
   createEntryActionTypes,
   saveEntryActionTypes,
   deleteEntryActionTypes,
   restoreEntryActionTypes,
 } from '../actions/entry-actions';
 import {
   fetchMessagesBeforeCursorActionTypes,
   fetchMostRecentMessagesActionTypes,
   sendTextMessageActionTypes,
   sendMultimediaMessageActionTypes,
   saveMessagesActionType,
   processMessagesActionType,
   messageStorePruneActionType,
   createLocalMessageActionType,
 } from '../actions/message-actions';
 import {
   changeThreadSettingsActionTypes,
   deleteThreadActionTypes,
   leaveThreadActionTypes,
   newThreadActionTypes,
   removeUsersFromThreadActionTypes,
   changeThreadMemberRolesActionTypes,
   joinThreadActionTypes,
 } from '../actions/thread-actions';
 import { updateMultimediaMessageMediaActionType } from '../actions/upload-actions';
 import {
   logOutActionTypes,
   deleteAccountActionTypes,
   logInActionTypes,
   resetPasswordActionTypes,
   registerActionTypes,
 } from '../actions/user-actions';
 import { messageID, combineTruncationStatuses } from '../shared/message-utils';
 import { threadHasPermission, threadInChatList } from '../shared/thread-utils';
 import threadWatcher from '../shared/thread-watcher';
 import { unshimMessageInfos } from '../shared/unshim-utils';
 import {
   type RawMessageInfo,
   type LocalMessageInfo,
   type MessageStore,
   type MessageTruncationStatus,
   type MessagesResponse,
   messageTruncationStatus,
   messageTypes,
   defaultNumberPerThread,
 } from '../types/message-types';
 import type { RawImagesMessageInfo } from '../types/messages/images';
 import type { RawMediaMessageInfo } from '../types/messages/media';
 import { type BaseAction, rehydrateActionType } from '../types/redux-types';
 import {
   fullStateSyncActionType,
   incrementalStateSyncActionType,
 } from '../types/socket-types';
 import { type RawThreadInfo, threadPermissions } from '../types/thread-types';
 import {
   updateTypes,
   type UpdateInfo,
   processUpdatesActionType,
 } from '../types/update-types';
 import { setNewSessionActionType } from '../utils/action-utils';
 
 const _mapValuesWithKeys = _mapValues.convert({ cap: false });
 
 // Input must already be ordered!
 function threadsToMessageIDsFromMessageInfos(
   orderedMessageInfos: RawMessageInfo[],
 ): { [threadID: string]: string[] } {
   const threads: { [threadID: string]: string[] } = {};
   for (let messageInfo of orderedMessageInfos) {
     const key = messageID(messageInfo);
     if (!threads[messageInfo.threadID]) {
       threads[messageInfo.threadID] = [key];
     } else {
       threads[messageInfo.threadID].push(key);
     }
   }
   return threads;
 }
 
 function threadIsWatched(
   threadInfo: ?RawThreadInfo,
   watchedIDs: $ReadOnlyArray<string>,
 ) {
   return (
     threadInfo &&
     threadHasPermission(threadInfo, threadPermissions.VISIBLE) &&
     (threadInChatList(threadInfo) || watchedIDs.includes(threadInfo.id))
   );
 }
 
 function freshMessageStore(
   messageInfos: RawMessageInfo[],
   truncationStatus: { [threadID: string]: MessageTruncationStatus },
   currentAsOf: number,
   threadInfos: { [threadID: string]: RawThreadInfo },
 ): MessageStore {
   const unshimmed = unshimMessageInfos(messageInfos);
   const orderedMessageInfos = _orderBy('time')('desc')(unshimmed);
   const messages = _keyBy(messageID)(orderedMessageInfos);
   const threadsToMessageIDs = threadsToMessageIDsFromMessageInfos(
     orderedMessageInfos,
   );
   const lastPruned = Date.now();
   const threads = _mapValuesWithKeys(
     (messageIDs: string[], threadID: string) => ({
       messageIDs,
       startReached:
         truncationStatus[threadID] === messageTruncationStatus.EXHAUSTIVE,
       lastNavigatedTo: 0,
       lastPruned,
     }),
   )(threadsToMessageIDs);
   const watchedIDs = threadWatcher.getWatchedIDs();
   for (let threadID in threadInfos) {
     const threadInfo = threadInfos[threadID];
     if (threads[threadID] || !threadIsWatched(threadInfo, watchedIDs)) {
       continue;
     }
     threads[threadID] = {
       messageIDs: [],
       // We can conclude that startReached, since no messages were returned
       startReached: true,
       lastNavigatedTo: 0,
       lastPruned,
     };
   }
   return { messages, threads, local: {}, currentAsOf };
 }
 
 // oldMessageStore is from the old state
 // newMessageInfos, truncationStatus come from server
 function mergeNewMessages(
   oldMessageStore: MessageStore,
   newMessageInfos: $ReadOnlyArray<RawMessageInfo>,
   truncationStatus: { [threadID: string]: MessageTruncationStatus },
   threadInfos: { [threadID: string]: RawThreadInfo },
   actionType: *,
 ): MessageStore {
   const unshimmed = unshimMessageInfos(newMessageInfos);
   const localIDsToServerIDs: Map<string, string> = new Map();
   const orderedNewMessageInfos = _flow(
     _map((messageInfo: RawMessageInfo) => {
       const { id: inputID } = messageInfo;
       invariant(inputID, 'new messageInfos should have serverID');
       const currentMessageInfo = oldMessageStore.messages[inputID];
       if (
         messageInfo.type === messageTypes.TEXT ||
         messageInfo.type === messageTypes.IMAGES ||
         messageInfo.type === messageTypes.MULTIMEDIA
       ) {
         const { localID: inputLocalID } = messageInfo;
         const currentLocalMessageInfo = inputLocalID
           ? oldMessageStore.messages[inputLocalID]
           : null;
         if (currentMessageInfo && currentMessageInfo.localID) {
           // If the client already has a RawMessageInfo with this serverID, keep
           // any localID associated with the existing one. This is because we
           // use localIDs as React keys and changing React keys leads to loss of
           // component state. (The conditional below is for Flow)
           if (messageInfo.type === messageTypes.TEXT) {
             messageInfo = {
               ...messageInfo,
               localID: currentMessageInfo.localID,
             };
           } else if (messageInfo.type === messageTypes.MULTIMEDIA) {
             messageInfo = ({
               ...messageInfo,
               localID: currentMessageInfo.localID,
             }: RawMediaMessageInfo);
           } else {
             messageInfo = ({
               ...messageInfo,
               localID: currentMessageInfo.localID,
             }: RawImagesMessageInfo);
           }
         } else if (currentLocalMessageInfo && currentLocalMessageInfo.localID) {
           // If the client has a RawMessageInfo with this localID, but not with
           // the serverID, that means the message creation succeeded but the
           // success action never got processed. We set a key in
           // localIDsToServerIDs here to fix the messageIDs for the rest of the
           // MessageStore too. (The conditional below is for Flow)
           invariant(inputLocalID, 'should be set');
           localIDsToServerIDs.set(inputLocalID, inputID);
           if (messageInfo.type === messageTypes.TEXT) {
             messageInfo = {
               ...messageInfo,
               localID: currentLocalMessageInfo.localID,
             };
           } else if (messageInfo.type === messageTypes.MULTIMEDIA) {
             messageInfo = ({
               ...messageInfo,
               localID: currentLocalMessageInfo.localID,
             }: RawMediaMessageInfo);
           } else {
             messageInfo = ({
               ...messageInfo,
               localID: currentLocalMessageInfo.localID,
             }: RawImagesMessageInfo);
           }
         } else {
           // If neither the serverID nor the localID from the delivered
           // RawMessageInfo exists in the client store, then this message is
           // brand new to us. Ignore any localID provided by the server.
           // (The conditional below is for Flow)
           const { localID, ...rest } = messageInfo;
           if (rest.type === messageTypes.TEXT) {
             messageInfo = { ...rest };
           } else if (rest.type === messageTypes.MULTIMEDIA) {
             messageInfo = ({ ...rest }: RawMediaMessageInfo);
           } else {
             messageInfo = ({ ...rest }: RawImagesMessageInfo);
           }
         }
       }
       return _isEqual(messageInfo)(currentMessageInfo)
         ? currentMessageInfo
         : messageInfo;
     }),
     _orderBy('time')('desc'),
   )(unshimmed);
 
   const threadsToMessageIDs = threadsToMessageIDsFromMessageInfos(
     orderedNewMessageInfos,
   );
   const oldMessageInfosToCombine = [];
   const mustResortThreadMessageIDs = [];
   const lastPruned = Date.now();
   const watchedIDs = threadWatcher.getWatchedIDs();
   const local = {};
   const threads = _flow(
     _pickBy((messageIDs: string[], threadID: string) =>
       threadIsWatched(threadInfos[threadID], watchedIDs),
     ),
     _mapValuesWithKeys((messageIDs: string[], threadID: string) => {
       const oldThread = oldMessageStore.threads[threadID];
       const truncate = truncationStatus[threadID];
       if (!oldThread) {
         if (actionType === fetchMessagesBeforeCursorActionTypes.success) {
           // Well, this is weird. Somehow fetchMessagesBeforeCursor got called
           // for a thread that doesn't exist in the messageStore. How did this
           // happen? How do we even know what cursor to use if we didn't have
           // any messages? Anyways, the messageStore is predicated on the
           // principle that it is current. We can't create a ThreadMessageInfo
           // for a thread if we can't guarantee this, as the client has no UX
           // for endReached, only for startReached. We'll have to bail out here.
           return null;
         }
         return {
           messageIDs,
           startReached: truncate === messageTruncationStatus.EXHAUSTIVE,
           lastNavigatedTo: 0,
           lastPruned,
         };
       }
       let oldMessageIDsUnchanged = true;
       const oldMessageIDs = oldThread.messageIDs.map((oldID) => {
         const newID = localIDsToServerIDs.get(oldID);
         if (newID !== null && newID !== undefined) {
           oldMessageIDsUnchanged = false;
           return newID;
         }
         return oldID;
       });
       if (truncate === messageTruncationStatus.TRUNCATED) {
         // If the result set in the payload isn't contiguous with what we have
         // now, that means we need to dump what we have in the state and replace
         // it with the result set. We do this to achieve our two goals for the
         // messageStore: currentness and contiguousness.
         return {
           messageIDs,
           startReached: false,
           lastNavigatedTo: oldThread.lastNavigatedTo,
           lastPruned: oldThread.lastPruned,
         };
       }
       const oldNotInNew = _difference(oldMessageIDs)(messageIDs);
       for (let id of oldNotInNew) {
         const oldMessageInfo = oldMessageStore.messages[id];
         invariant(oldMessageInfo, `could not find ${id} in messageStore`);
         oldMessageInfosToCombine.push(oldMessageInfo);
         const localInfo = oldMessageStore.local[id];
         if (localInfo) {
           local[id] = localInfo;
         }
       }
       const startReached =
         oldThread.startReached ||
         truncate === messageTruncationStatus.EXHAUSTIVE;
       if (_difference(messageIDs)(oldMessageIDs).length === 0) {
         if (startReached === oldThread.startReached && oldMessageIDsUnchanged) {
           return oldThread;
         }
         return {
           messageIDs: oldMessageIDs,
           startReached,
           lastNavigatedTo: oldThread.lastNavigatedTo,
           lastPruned: oldThread.lastPruned,
         };
       }
       const mergedMessageIDs = [...messageIDs, ...oldNotInNew];
       mustResortThreadMessageIDs.push(threadID);
       return {
         messageIDs: mergedMessageIDs,
         startReached,
         lastNavigatedTo: oldThread.lastNavigatedTo,
         lastPruned: oldThread.lastPruned,
       };
     }),
     _pickBy((thread) => !!thread),
   )(threadsToMessageIDs);
 
   for (let threadID in oldMessageStore.threads) {
     if (
       threads[threadID] ||
       !threadIsWatched(threadInfos[threadID], watchedIDs)
     ) {
       continue;
     }
     let thread = oldMessageStore.threads[threadID];
     const truncate = truncationStatus[threadID];
     if (truncate === messageTruncationStatus.EXHAUSTIVE) {
       thread = {
         ...thread,
         startReached: true,
       };
     }
     threads[threadID] = thread;
     for (let id of thread.messageIDs) {
       const messageInfo = oldMessageStore.messages[id];
       if (messageInfo) {
         oldMessageInfosToCombine.push(messageInfo);
       }
       const localInfo = oldMessageStore.local[id];
       if (localInfo) {
         local[id] = localInfo;
       }
     }
   }
 
   for (let threadID in threadInfos) {
     const threadInfo = threadInfos[threadID];
     if (threads[threadID] || !threadIsWatched(threadInfo, watchedIDs)) {
       continue;
     }
     threads[threadID] = {
       messageIDs: [],
       // We can conclude that startReached, since no messages were returned
       startReached: true,
       lastNavigatedTo: 0,
       lastPruned,
     };
   }
 
   const messages = _flow(
-    _orderBy('time')('desc'),
+    _orderBy(['time', 'id'])(['desc', 'desc']),
     _keyBy(messageID),
   )([...orderedNewMessageInfos, ...oldMessageInfosToCombine]);
 
   for (let threadID of mustResortThreadMessageIDs) {
     threads[threadID].messageIDs = _orderBy([
       (id: string) => messages[id].time,
-    ])('desc')(threads[threadID].messageIDs);
+      (id: string) => id,
+    ])(['desc', 'desc'])(threads[threadID].messageIDs);
   }
 
   const currentAsOf = Math.max(
     orderedNewMessageInfos.length > 0 ? orderedNewMessageInfos[0].time : 0,
     oldMessageStore.currentAsOf,
   );
 
   return { messages, threads, local, currentAsOf };
 }
 
 function filterByNewThreadInfos(
   messageStore: MessageStore,
   threadInfos: { [id: string]: RawThreadInfo },
 ): MessageStore {
   const watchedIDs = threadWatcher.getWatchedIDs();
   const watchedThreadInfos = _pickBy((threadInfo: RawThreadInfo) =>
     threadIsWatched(threadInfo, watchedIDs),
   )(threadInfos);
   const messageIDsToRemove = [];
   for (let threadID in messageStore.threads) {
     if (watchedThreadInfos[threadID]) {
       continue;
     }
     for (let id of messageStore.threads[threadID].messageIDs) {
       messageIDsToRemove.push(id);
     }
   }
   return {
     messages: _omit(messageIDsToRemove)(messageStore.messages),
     threads: _pick(Object.keys(watchedThreadInfos))(messageStore.threads),
     local: _omit(messageIDsToRemove)(messageStore.local),
     currentAsOf: messageStore.currentAsOf,
   };
 }
 
 function reduceMessageStore(
   messageStore: MessageStore,
   action: BaseAction,
   newThreadInfos: { [id: string]: RawThreadInfo },
 ): MessageStore {
   if (
     action.type === logInActionTypes.success ||
     action.type === resetPasswordActionTypes.success
   ) {
     const messagesResult = action.payload.messagesResult;
     return freshMessageStore(
       messagesResult.messageInfos,
       messagesResult.truncationStatus,
       messagesResult.currentAsOf,
       newThreadInfos,
     );
   } else if (action.type === incrementalStateSyncActionType) {
     if (
       action.payload.messagesResult.rawMessageInfos.length === 0 &&
       action.payload.updatesResult.newUpdates.length === 0
     ) {
       return messageStore;
     }
     const messagesResult = mergeUpdatesIntoMessagesResult(
       action.payload.messagesResult,
       action.payload.updatesResult.newUpdates,
     );
     return mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
       action.type,
     );
   } else if (action.type === processUpdatesActionType) {
     if (action.payload.updatesResult.newUpdates.length === 0) {
       return messageStore;
     }
 
     const mergedMessageInfos = [];
     const mergedTruncationStatuses = {};
     const { newUpdates } = action.payload.updatesResult;
     for (let updateInfo of newUpdates) {
       if (updateInfo.type !== updateTypes.JOIN_THREAD) {
         continue;
       }
       for (let messageInfo of updateInfo.rawMessageInfos) {
         mergedMessageInfos.push(messageInfo);
       }
       mergedTruncationStatuses[
         updateInfo.threadInfo.id
       ] = combineTruncationStatuses(
         updateInfo.truncationStatus,
         mergedTruncationStatuses[updateInfo.threadInfo.id],
       );
     }
     if (Object.keys(mergedTruncationStatuses).length === 0) {
       return messageStore;
     }
 
     const newMessageStore = mergeNewMessages(
       messageStore,
       mergedMessageInfos,
       mergedTruncationStatuses,
       newThreadInfos,
       action.type,
     );
     return {
       messages: newMessageStore.messages,
       threads: newMessageStore.threads,
       local: newMessageStore.local,
       currentAsOf: messageStore.currentAsOf,
     };
   } else if (
     action.type === fullStateSyncActionType ||
     action.type === processMessagesActionType
   ) {
     const { messagesResult } = action.payload;
     return mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
       action.type,
     );
   } else if (
     action.type === fetchMessagesBeforeCursorActionTypes.success ||
     action.type === fetchMostRecentMessagesActionTypes.success
   ) {
     return mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       { [action.payload.threadID]: action.payload.truncationStatus },
       newThreadInfos,
       action.type,
     );
   } else if (
     action.type === logOutActionTypes.success ||
     action.type === deleteAccountActionTypes.success ||
     action.type === deleteThreadActionTypes.success ||
     action.type === leaveThreadActionTypes.success ||
     action.type === setNewSessionActionType
   ) {
     return filterByNewThreadInfos(messageStore, newThreadInfos);
   } else if (action.type === newThreadActionTypes.success) {
     const { newThreadID } = action.payload;
     const truncationStatuses = {};
     for (let messageInfo of action.payload.newMessageInfos) {
       truncationStatuses[messageInfo.threadID] =
         messageInfo.threadID === newThreadID
           ? messageTruncationStatus.EXHAUSTIVE
           : messageTruncationStatus.UNCHANGED;
     }
     return mergeNewMessages(
       messageStore,
       action.payload.newMessageInfos,
       truncationStatuses,
       newThreadInfos,
       action.type,
     );
   } else if (action.type === registerActionTypes.success) {
     const truncationStatuses = {};
     for (let messageInfo of action.payload.rawMessageInfos) {
       truncationStatuses[messageInfo.threadID] =
         messageTruncationStatus.EXHAUSTIVE;
     }
     return mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       truncationStatuses,
       newThreadInfos,
       action.type,
     );
   } else if (
     action.type === changeThreadSettingsActionTypes.success ||
     action.type === removeUsersFromThreadActionTypes.success ||
     action.type === changeThreadMemberRolesActionTypes.success
   ) {
     return mergeNewMessages(
       messageStore,
       action.payload.newMessageInfos,
       { [action.payload.threadID]: messageTruncationStatus.UNCHANGED },
       newThreadInfos,
       action.type,
     );
   } else if (
     action.type === createEntryActionTypes.success ||
     action.type === saveEntryActionTypes.success
   ) {
     return mergeNewMessages(
       messageStore,
       action.payload.newMessageInfos,
       { [action.payload.threadID]: messageTruncationStatus.UNCHANGED },
       newThreadInfos,
       action.type,
     );
   } else if (action.type === deleteEntryActionTypes.success) {
     const payload = action.payload;
     if (payload) {
       return mergeNewMessages(
         messageStore,
         payload.newMessageInfos,
         { [payload.threadID]: messageTruncationStatus.UNCHANGED },
         newThreadInfos,
         action.type,
       );
     }
   } else if (action.type === restoreEntryActionTypes.success) {
     const { threadID } = action.payload;
     return mergeNewMessages(
       messageStore,
       action.payload.newMessageInfos,
       { [threadID]: messageTruncationStatus.UNCHANGED },
       newThreadInfos,
       action.type,
     );
   } else if (action.type === joinThreadActionTypes.success) {
     return mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       action.payload.truncationStatuses,
       newThreadInfos,
       action.type,
     );
   } else if (
     action.type === sendTextMessageActionTypes.started ||
     action.type === sendMultimediaMessageActionTypes.started
   ) {
     const { payload } = action;
     const { localID, threadID } = payload;
     invariant(localID, `localID should be set on ${action.type}`);
 
     if (messageStore.messages[localID]) {
       const messages = { ...messageStore.messages, [localID]: payload };
       const local = _pickBy(
         (localInfo: LocalMessageInfo, key: string) => key !== localID,
       )(messageStore.local);
       const threads = {
         ...messageStore.threads,
         [threadID]: {
           ...messageStore.threads[threadID],
           messageIDs: _orderBy([(id: string) => messages[id].time])('desc')(
             messageStore.threads[threadID].messageIDs,
           ),
         },
       };
       return { ...messageStore, messages, threads, local };
     }
 
     const { messageIDs } = messageStore.threads[threadID];
     for (let existingMessageID of messageIDs) {
       const existingMessageInfo = messageStore.messages[existingMessageID];
       if (existingMessageInfo && existingMessageInfo.localID === localID) {
         return messageStore;
       }
     }
 
     return {
       messages: {
         ...messageStore.messages,
         [localID]: payload,
       },
       threads: {
         ...messageStore.threads,
         [threadID]: {
           ...messageStore.threads[threadID],
           messageIDs: [localID, ...messageStore.threads[threadID].messageIDs],
         },
       },
       local: messageStore.local,
       currentAsOf: messageStore.currentAsOf,
     };
   } else if (
     action.type === sendTextMessageActionTypes.failed ||
     action.type === sendMultimediaMessageActionTypes.failed
   ) {
     const { localID } = action.payload;
     return {
       messages: messageStore.messages,
       threads: messageStore.threads,
       local: {
         ...messageStore.local,
         [localID]: { sendFailed: true },
       },
       currentAsOf: messageStore.currentAsOf,
     };
   } else if (
     action.type === sendTextMessageActionTypes.success ||
     action.type === sendMultimediaMessageActionTypes.success
   ) {
     const { payload } = action;
     const replaceMessageKey = (messageKey: string) =>
       messageKey === payload.localID ? payload.serverID : messageKey;
     let newMessages;
     if (messageStore.messages[payload.serverID]) {
       // If somehow the serverID got in there already, we'll just update the
       // serverID message and scrub the localID one
       newMessages = _omitBy(
         (messageInfo: RawMessageInfo) =>
           messageInfo.type === messageTypes.TEXT &&
           !messageInfo.id &&
           messageInfo.localID === payload.localID,
       )(messageStore.messages);
     } else if (messageStore.messages[payload.localID]) {
       // The normal case, the localID message gets replaced by the serverID one
       newMessages = _mapKeys(replaceMessageKey)(messageStore.messages);
     } else {
       // Well this is weird, we probably got deauthorized between when the
       // action was dispatched and when we ran this reducer...
       return messageStore;
     }
     newMessages[payload.serverID] = {
       ...newMessages[payload.serverID],
       id: payload.serverID,
       localID: payload.localID,
       time: payload.time,
     };
     const threadID = payload.threadID;
     const newMessageIDs = _flow(
       _uniq,
       _orderBy([(id: string) => newMessages[id].time])('desc'),
     )(messageStore.threads[threadID].messageIDs.map(replaceMessageKey));
     const currentAsOf =
       payload.interface === 'socket'
         ? Math.max(payload.time, messageStore.currentAsOf)
         : messageStore.currentAsOf;
     const local = _pickBy(
       (localInfo: LocalMessageInfo, key: string) => key !== payload.localID,
     )(messageStore.local);
     return {
       messages: newMessages,
       threads: {
         ...messageStore.threads,
         [threadID]: {
           ...messageStore.threads[threadID],
           messageIDs: newMessageIDs,
         },
       },
       local,
       currentAsOf,
     };
   } else if (action.type === saveMessagesActionType) {
     const truncationStatuses = {};
     for (let messageInfo of action.payload.rawMessageInfos) {
       truncationStatuses[messageInfo.threadID] =
         messageTruncationStatus.UNCHANGED;
     }
     const newMessageStore = mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       truncationStatuses,
       newThreadInfos,
       action.type,
     );
     return {
       messages: newMessageStore.messages,
       threads: newMessageStore.threads,
       local: newMessageStore.local,
       // We avoid bumping currentAsOf because notifs may include a contracted
       // RawMessageInfo, so we want to make sure we still fetch it
       currentAsOf: messageStore.currentAsOf,
     };
   } else if (action.type === messageStorePruneActionType) {
     const now = Date.now();
     const messageIDsToPrune = [];
     let newThreads = { ...messageStore.threads };
     for (let threadID of action.payload.threadIDs) {
       const thread = newThreads[threadID];
       if (!thread) {
         continue;
       }
       const removed = thread.messageIDs.splice(defaultNumberPerThread);
       for (let id of removed) {
         messageIDsToPrune.push(id);
       }
       thread.lastPruned = now;
       if (removed.length > 0) {
         thread.startReached = false;
       }
     }
     return {
       messages: _omit(messageIDsToPrune)(messageStore.messages),
       threads: newThreads,
       local: _omit(messageIDsToPrune)(messageStore.local),
       currentAsOf: messageStore.currentAsOf,
     };
   } else if (action.type === updateMultimediaMessageMediaActionType) {
     const { messageID: id, currentMediaID, mediaUpdate } = action.payload;
     const message = messageStore.messages[id];
     invariant(message, `message with ID ${id} could not be found`);
     invariant(
       message.type === messageTypes.IMAGES ||
         message.type === messageTypes.MULTIMEDIA,
       `message with ID ${id} is not multimedia`,
     );
 
     let replaced = false;
     const media = [];
     for (let singleMedia of message.media) {
       if (singleMedia.id !== currentMediaID) {
         media.push(singleMedia);
       } else if (singleMedia.type === 'photo') {
         replaced = true;
         media.push({
           ...singleMedia,
           ...mediaUpdate,
         });
       } else if (singleMedia.type === 'video') {
         replaced = true;
         media.push({
           ...singleMedia,
           ...mediaUpdate,
         });
       }
     }
     invariant(
       replaced,
       `message ${id} did not contain media with ID ${currentMediaID}`,
     );
 
     return {
       ...messageStore,
       messages: {
         ...messageStore.messages,
         [id]: {
           ...message,
           media,
         },
       },
     };
   } else if (action.type === createLocalMessageActionType) {
     const messageInfo = action.payload;
     return {
       ...messageStore,
       messages: {
         ...messageStore.messages,
         [messageInfo.localID]: messageInfo,
       },
       threads: {
         ...messageStore.threads,
         [messageInfo.threadID]: {
           ...messageStore.threads[messageInfo.threadID],
           messageIDs: [
             messageInfo.localID,
             ...messageStore.threads[messageInfo.threadID].messageIDs,
           ],
         },
       },
     };
   } else if (action.type === rehydrateActionType) {
     // When starting the app on native, we filter out any local-only multimedia
     // messages because the relevant context is no longer available
     const { messages, threads, local } = messageStore;
 
     const newMessages = {};
     let newThreads = threads,
       newLocal = local;
     for (let id in messages) {
       const message = messages[id];
       if (
         (message.type !== messageTypes.IMAGES &&
           message.type !== messageTypes.MULTIMEDIA) ||
         message.id
       ) {
         newMessages[id] = message;
         continue;
       }
       const { threadID } = message;
       newThreads = {
         ...newThreads,
         [threadID]: {
           ...newThreads[threadID],
           messageIDs: newThreads[threadID].messageIDs.filter(
             (curMessageID) => curMessageID !== id,
           ),
         },
       };
       newLocal = _pickBy(
         (localInfo: LocalMessageInfo, key: string) => key !== id,
       )(newLocal);
     }
 
     if (newThreads === threads) {
       return messageStore;
     }
     return {
       ...messageStore,
       messages: newMessages,
       threads: newThreads,
       local: newLocal,
     };
   }
   return messageStore;
 }
 
 function mergeUpdatesIntoMessagesResult(
   messagesResult: MessagesResponse,
   newUpdates: $ReadOnlyArray<UpdateInfo>,
 ): MessagesResponse {
   const messageIDs = new Set(
     messagesResult.rawMessageInfos.map((messageInfo) => messageInfo.id),
   );
   const mergedMessageInfos = [...messagesResult.rawMessageInfos];
   const mergedTruncationStatuses = { ...messagesResult.truncationStatuses };
   for (let updateInfo of newUpdates) {
     if (updateInfo.type !== updateTypes.JOIN_THREAD) {
       continue;
     }
     for (let messageInfo of updateInfo.rawMessageInfos) {
       if (messageIDs.has(messageInfo.id)) {
         continue;
       }
       mergedMessageInfos.push(messageInfo);
       messageIDs.add(messageInfo.id);
     }
     mergedTruncationStatuses[
       updateInfo.threadInfo.id
     ] = combineTruncationStatuses(
       updateInfo.truncationStatus,
       mergedTruncationStatuses[updateInfo.threadInfo.id],
     );
   }
   return {
     rawMessageInfos: mergedMessageInfos,
     truncationStatuses: mergedTruncationStatuses,
     currentAsOf: messagesResult.currentAsOf,
   };
 }
 
 export { freshMessageStore, reduceMessageStore };