Calls: Add peer-to-peer calls with fallback to group calls

src/api/gramjs/methods/chats.ts

@@ -495,10 +495,10 @@ export async function updateChatMutedState({
 }
 
 export async function createChannel({
-  title, about, users,
+  title, about = '', users,
 }: {
-  title: string; about?: string; users: ApiUser[];
-}): Promise<ApiChat | undefined> {
+  title: string; about?: string; users?: ApiUser[];
+}, noErrorUpdate = false): Promise<ApiChat | undefined> {
   const result = await invokeRequest(new GramJs.channels.CreateChannel({
     broadcast: true,
     title,
@@ -527,10 +527,16 @@ export async function createChannel({
 
   const channel = buildApiChatFromPreview(newChannel)!;
 
-  await invokeRequest(new GramJs.channels.InviteToChannel({
-    channel: buildInputEntity(channel.id, channel.accessHash) as GramJs.InputChannel,
-    users: users.map(({ id, accessHash }) => buildInputEntity(id, accessHash)) as GramJs.InputUser[],
-  }));
+  if (users?.length) {
+    try {
+      await invokeRequest(new GramJs.channels.InviteToChannel({
+        channel: buildInputEntity(channel.id, channel.accessHash) as GramJs.InputChannel,
+        users: users.map(({ id, accessHash }) => buildInputEntity(id, accessHash)) as GramJs.InputUser[],
+      }), true, noErrorUpdate);
+    } catch (err) {
+      // `noErrorUpdate` will cause an exception which we don't want either
+    }
+  }
 
   return channel;
 }
@@ -1027,20 +1033,25 @@ export async function openChatByInvite(hash: string) {
   return { chatId: chat.id };
 }
 
-export function addChatMembers(chat: ApiChat, users: ApiUser[]) {
-  if (chat.type === 'chatTypeChannel' || chat.type === 'chatTypeSuperGroup') {
-    return invokeRequest(new GramJs.channels.InviteToChannel({
-      channel: buildInputEntity(chat.id, chat.accessHash) as GramJs.InputChannel,
-      users: users.map((user) => buildInputEntity(user.id, user.accessHash)) as GramJs.InputUser[],
-    }), true);
-  }
+export function addChatMembers(chat: ApiChat, users: ApiUser[], noErrorUpdate = false) {
+  try {
+    if (chat.type === 'chatTypeChannel' || chat.type === 'chatTypeSuperGroup') {
+      return invokeRequest(new GramJs.channels.InviteToChannel({
+        channel: buildInputEntity(chat.id, chat.accessHash) as GramJs.InputChannel,
+        users: users.map((user) => buildInputEntity(user.id, user.accessHash)) as GramJs.InputUser[],
+      }), true, noErrorUpdate);
+    }
 
-  return Promise.all(users.map((user) => {
-    return invokeRequest(new GramJs.messages.AddChatUser({
-      chatId: buildInputEntity(chat.id) as BigInt.BigInteger,
-      userId: buildInputEntity(user.id, user.accessHash) as GramJs.InputUser,
-    }), true);
-  }));
+    return Promise.all(users.map((user) => {
+      return invokeRequest(new GramJs.messages.AddChatUser({
+        chatId: buildInputEntity(chat.id) as BigInt.BigInteger,
+        userId: buildInputEntity(user.id, user.accessHash) as GramJs.InputUser,
+      }), true, noErrorUpdate);
+    }));
+  } catch (err) {
+    // `noErrorUpdate` will cause an exception which we don't want either
+    return undefined;
+  }
 }
 
 export function deleteChatMember(chat: ApiChat, user: ApiUser) {

src/api/gramjs/methods/management.ts

@@ -42,15 +42,19 @@ export async function setChatUsername(
   }
 }
 
-export async function updatePrivateLink(
-  { chat }: { chat: ApiChat },
-) {
+export async function updatePrivateLink({
+  chat, usageLimit, expireDate,
+}: {
+  chat: ApiChat; usageLimit?: number; expireDate?: number;
+}) {
   const result = await invokeRequest(new GramJs.messages.ExportChatInvite({
     peer: buildInputPeer(chat.id, chat.accessHash),
+    usageLimit,
+    expireDate,
   }));
 
-  if (!result || !(result instanceof GramJs.ChatInviteExported)) {
-    return;
+  if (!result) {
+    return undefined;
   }
 
   onUpdate({
@@ -60,4 +64,6 @@ export async function updatePrivateLink(
       inviteLink: result.link,
     },
   });
+
+  return result.link;
 }

src/bundles/calls.ts

@@ -1,2 +1,3 @@
 export { default as GroupCall } from '../components/calls/group/GroupCall';
 export { default as ActiveCallHeader } from '../components/calls/ActiveCallHeader';
+export { default as CallFallbackConfirm } from '../components/calls/CallFallbackConfirm';

src/components/calls/CallFallbackConfirm.async.tsx

@@ -0,0 +1,15 @@
+import React, { FC, memo } from '../../lib/teact/teact';
+import useModuleLoader from '../../hooks/useModuleLoader';
+import { Bundles } from '../../util/moduleLoader';
+
+type OwnProps = {
+  isOpen: boolean;
+};
+
+const CallFallbackConfirmAsync: FC<OwnProps> = ({ isOpen }) => {
+  const CallFallbackConfirm = useModuleLoader(Bundles.Calls, 'CallFallbackConfirm', !isOpen);
+
+  return CallFallbackConfirm ? <CallFallbackConfirm isOpen={isOpen} /> : undefined;
+};
+
+export default memo(CallFallbackConfirmAsync);

src/components/calls/CallFallbackConfirm.tsx

@@ -0,0 +1,68 @@
+import React, { FC, memo, useState } from '../../lib/teact/teact';
+import { withGlobal } from '../../lib/teact/teactn';
+
+import { GlobalActions } from '../../global/types';
+
+import { pick } from '../../util/iteratees';
+
+import ConfirmDialog from '../ui/ConfirmDialog';
+import Checkbox from '../ui/Checkbox';
+import { selectCallFallbackChannelTitle } from '../../modules/selectors/calls';
+import { getUserFullName } from '../../modules/helpers';
+import { selectCurrentMessageList, selectUser } from '../../modules/selectors';
+import useCurrentOrPrev from '../../hooks/useCurrentOrPrev';
+
+export type OwnProps = {
+  isOpen: boolean;
+};
+
+interface StateProps {
+  userFullName?: string;
+  channelTitle: string;
+}
+
+type DispatchProps = Pick<GlobalActions, 'closeCallFallbackConfirm' | 'inviteToCallFallback'>;
+
+const CallFallbackConfirm: FC<OwnProps & StateProps & DispatchProps> = ({
+  isOpen,
+  channelTitle,
+  userFullName,
+  closeCallFallbackConfirm,
+  inviteToCallFallback,
+}) => {
+  const [shouldRemove, setShouldRemove] = useState(true);
+  const renderingUserFullName = useCurrentOrPrev(userFullName, true);
+
+  return (
+    <ConfirmDialog
+      title="Start Call"
+      isOpen={isOpen}
+      confirmHandler={() => {
+        inviteToCallFallback({ shouldRemove });
+      }}
+      onClose={closeCallFallbackConfirm}
+    >
+      <p>The call will be started in a private channel <b>{channelTitle}</b>.</p>
+      <Checkbox
+        label={`Remove ${renderingUserFullName} from this channel after the call`}
+        checked={shouldRemove}
+        onCheck={setShouldRemove}
+      />
+    </ConfirmDialog>
+  );
+};
+
+export default memo(withGlobal<OwnProps>(
+  (global): StateProps => {
+    const { chatId } = selectCurrentMessageList(global) || {};
+    const user = chatId ? selectUser(global, chatId) : undefined;
+
+    return {
+      userFullName: user ? getUserFullName(user) : undefined,
+      channelTitle: selectCallFallbackChannelTitle(global),
+    };
+  },
+  (setGlobal, actions): DispatchProps => pick(actions, [
+    'closeCallFallbackConfirm', 'inviteToCallFallback',
+  ]),
+)(CallFallbackConfirm));

src/components/main/Main.tsx

@@ -46,6 +46,7 @@ import HistoryCalendar from './HistoryCalendar.async';
 import StickerSetModal from '../common/StickerSetModal.async';
 import GroupCall from '../calls/group/GroupCall.async';
 import ActiveCallHeader from '../calls/ActiveCallHeader.async';
+import CallFallbackConfirm from '../calls/CallFallbackConfirm.async';
 
 import './Main.scss';
 
@@ -67,6 +68,7 @@ type StateProps = {
   animationLevel: number;
   language?: LangCode;
   wasTimeFormatSetManually?: boolean;
+  isCallFallbackConfirmOpen: boolean;
 };
 
 type DispatchProps = Pick<GlobalActions, (
@@ -100,6 +102,7 @@ const Main: FC<StateProps & DispatchProps> = ({
   animationLevel,
   language,
   wasTimeFormatSetManually,
+  isCallFallbackConfirmOpen,
   loadAnimatedEmojis,
   loadNotificationSettings,
   loadNotificationExceptions,
@@ -282,6 +285,7 @@ const Main: FC<StateProps & DispatchProps> = ({
         </>
       )}
       <DownloadManager />
+      <CallFallbackConfirm isOpen={isCallFallbackConfirmOpen} />
     </div>
   );
 };
@@ -333,6 +337,7 @@ export default memo(withGlobal(
       animationLevel,
       language,
       wasTimeFormatSetManually,
+      isCallFallbackConfirmOpen: Boolean(global.groupCalls.isFallbackConfirmOpen),
     };
   },
   (setGlobal, actions): DispatchProps => pick(actions, [

src/components/middle/HeaderActions.tsx

@@ -13,7 +13,9 @@ import { IAnchorPosition } from '../../types';
 
 import { ARE_CALLS_SUPPORTED, IS_SINGLE_COLUMN_LAYOUT } from '../../util/environment';
 import { pick } from '../../util/iteratees';
-import { isChatBasicGroup, isChatChannel, isChatSuperGroup } from '../../modules/helpers';
+import {
+  isChatBasicGroup, isChatChannel, isChatSuperGroup, isUserId,
+} from '../../modules/helpers';
 import {
   selectChat,
   selectChatBot,
@@ -43,13 +45,16 @@ interface StateProps {
   canRestartBot?: boolean;
   canSubscribe?: boolean;
   canSearch?: boolean;
+  canCall?: boolean;
   canMute?: boolean;
   canLeave?: boolean;
   canEnterVoiceChat?: boolean;
   canCreateVoiceChat?: boolean;
 }
 
-type DispatchProps = Pick<GlobalActions, 'joinChannel' | 'sendBotCommand' | 'openLocalTextSearch' | 'restartBot'>;
+type DispatchProps = Pick<GlobalActions, (
+  'joinChannel' | 'sendBotCommand' | 'openLocalTextSearch' | 'restartBot' | 'openCallFallbackConfirm'
+)>;
 
 // Chrome breaks layout when focusing input during transition
 const SEARCH_FOCUS_DELAY_MS = 400;
@@ -63,6 +68,7 @@ const HeaderActions: FC<OwnProps & StateProps & DispatchProps> = ({
   canRestartBot,
   canSubscribe,
   canSearch,
+  canCall,
   canMute,
   canLeave,
   canEnterVoiceChat,
@@ -73,6 +79,7 @@ const HeaderActions: FC<OwnProps & StateProps & DispatchProps> = ({
   sendBotCommand,
   openLocalTextSearch,
   restartBot,
+  openCallFallbackConfirm,
 }) => {
   // eslint-disable-next-line no-null/no-null
   const menuButtonRef = useRef<HTMLButtonElement>(null);
@@ -170,6 +177,17 @@ const HeaderActions: FC<OwnProps & StateProps & DispatchProps> = ({
               <i className="icon-search" />
             </Button>
           )}
+          {canCall && (
+            <Button
+              round
+              color="translucent"
+              size="smaller"
+              onClick={openCallFallbackConfirm}
+              ariaLabel="Call"
+            >
+              <i className="icon-phone" />
+            </Button>
+          )}
         </>
       )}
       <Button
@@ -197,6 +215,7 @@ const HeaderActions: FC<OwnProps & StateProps & DispatchProps> = ({
           canRestartBot={canRestartBot}
           canSubscribe={canSubscribe}
           canSearch={canSearch}
+          canCall={canCall}
           canMute={canMute}
           canLeave={canLeave}
           canEnterVoiceChat={canEnterVoiceChat}
@@ -216,7 +235,7 @@ export default memo(withGlobal<OwnProps>(
     const chat = selectChat(global, chatId);
     const isChannel = Boolean(chat && isChatChannel(chat));
 
-    if (chat?.isRestricted || selectIsInSelectMode(global)) {
+    if (!chat || chat.isRestricted || selectIsInSelectMode(global)) {
       return {
         noMenu: true,
       };
@@ -231,13 +250,14 @@ export default memo(withGlobal<OwnProps>(
     const canRestartBot = Boolean(bot && selectIsUserBlocked(global, bot.id));
     const canStartBot = !canRestartBot && Boolean(selectIsChatBotNotStarted(global, chatId));
     const canSubscribe = Boolean(
-      isMainThread && chat && (isChannel || isChatSuperGroup(chat)) && chat.isNotJoined,
+      isMainThread && (isChannel || isChatSuperGroup(chat)) && chat.isNotJoined,
     );
     const canSearch = isMainThread || isDiscussionThread;
+    const canCall = ARE_CALLS_SUPPORTED && isUserId(chat.id) && !isChatWithSelf && !bot;
     const canMute = isMainThread && !isChatWithSelf && !canSubscribe;
     const canLeave = isMainThread && !canSubscribe;
-    const canEnterVoiceChat = ARE_CALLS_SUPPORTED && chat && chat.isCallActive;
-    const canCreateVoiceChat = ARE_CALLS_SUPPORTED && chat && !chat.isCallActive
+    const canEnterVoiceChat = ARE_CALLS_SUPPORTED && chat.isCallActive;
+    const canCreateVoiceChat = ARE_CALLS_SUPPORTED && !chat.isCallActive
       && (chat.adminRights?.manageCall || (chat.isCreator && isChatBasicGroup(chat)));
 
     return {
@@ -248,6 +268,7 @@ export default memo(withGlobal<OwnProps>(
       canRestartBot,
       canSubscribe,
       canSearch,
+      canCall,
       canMute,
       canLeave,
       canEnterVoiceChat,
@@ -255,6 +276,6 @@ export default memo(withGlobal<OwnProps>(
     };
   },
   (setGlobal, actions): DispatchProps => pick(actions, [
-    'joinChannel', 'sendBotCommand', 'openLocalTextSearch', 'restartBot',
+    'joinChannel', 'sendBotCommand', 'openLocalTextSearch', 'restartBot', 'openCallFallbackConfirm',
   ]),
 )(HeaderActions));

src/components/middle/HeaderMenuContainer.tsx

@@ -28,7 +28,7 @@ import './HeaderMenuContainer.scss';
 
 type DispatchProps = Pick<GlobalActions, (
   'updateChatMutedState' | 'enterMessageSelectMode' | 'sendBotCommand' | 'restartBot' | 'openLinkedChat' |
-  'joinGroupCall' | 'createGroupCall' | 'addContact'
+  'joinGroupCall' | 'createGroupCall' | 'addContact' | 'openCallFallbackConfirm'
 )>;
 
 export type OwnProps = {
@@ -42,6 +42,7 @@ export type OwnProps = {
   canRestartBot?: boolean;
   canSubscribe?: boolean;
   canSearch?: boolean;
+  canCall?: boolean;
   canMute?: boolean;
   canLeave?: boolean;
   canEnterVoiceChat?: boolean;
@@ -71,6 +72,7 @@ const HeaderMenuContainer: FC<OwnProps & StateProps & DispatchProps> = ({
   canRestartBot,
   canSubscribe,
   canSearch,
+  canCall,
   canMute,
   canLeave,
   canEnterVoiceChat,
@@ -93,6 +95,7 @@ const HeaderMenuContainer: FC<OwnProps & StateProps & DispatchProps> = ({
   createGroupCall,
   openLinkedChat,
   addContact,
+  openCallFallbackConfirm,
 }) => {
   const [isMenuOpen, setIsMenuOpen] = useState(true);
   const [isDeleteModalOpen, setIsDeleteModalOpen] = useState(false);
@@ -157,6 +160,11 @@ const HeaderMenuContainer: FC<OwnProps & StateProps & DispatchProps> = ({
     closeMenu();
   }, [closeMenu, onSubscribeChannel]);
 
+  const handleCall = useCallback(() => {
+    openCallFallbackConfirm();
+    closeMenu();
+  }, [closeMenu, openCallFallbackConfirm]);
+
   const handleSearch = useCallback(() => {
     onSearchClick();
     closeMenu();
@@ -216,6 +224,14 @@ const HeaderMenuContainer: FC<OwnProps & StateProps & DispatchProps> = ({
               {lang('AddContact')}
             </MenuItem>
           )}
+          {IS_SINGLE_COLUMN_LAYOUT && canCall && (
+            <MenuItem
+              icon="phone"
+              onClick={handleCall}
+            >
+              {lang('Call')}
+            </MenuItem>
+          )}
           {IS_SINGLE_COLUMN_LAYOUT && canSearch && (
             <MenuItem
               icon="search"
@@ -306,5 +322,6 @@ export default memo(withGlobal<OwnProps>(
     'createGroupCall',
     'openLinkedChat',
     'addContact',
+    'openCallFallbackConfirm',
   ]),
 )(HeaderMenuContainer));

src/components/right/hooks/useProfileViewportIds.ts

@@ -49,10 +49,6 @@ export default function useProfileViewportIds(
     resultType, loadMoreMembers, lastSyncTime, memberIds,
   );
 
-  const [commonChatViewportIds, getMoreCommonChats, noProfileInfoForCommonChats] = useInfiniteScrollForLoadableItems(
-    resultType, loadCommonChats, lastSyncTime, chatIds,
-  );
-
   const [mediaViewportIds, getMoreMedia, noProfileInfoForMedia] = useInfiniteScrollForSharedMedia(
     'media', resultType, searchMessages, lastSyncTime, chatMessages, foundIds,
   );
@@ -73,6 +69,10 @@ export default function useProfileViewportIds(
     'voice', resultType, searchMessages, lastSyncTime, chatMessages, foundIds,
   );
 
+  const [commonChatViewportIds, getMoreCommonChats, noProfileInfoForCommonChats] = useInfiniteScrollForLoadableItems(
+    resultType, loadCommonChats, lastSyncTime, chatIds,
+  );
+
   let viewportIds: number[] | string[] | undefined;
   let getMore: AnyToVoidFunction | undefined;
   let noProfileInfo = false;

src/components/ui/ConfirmDialog.tsx

@@ -18,6 +18,7 @@ type OwnProps = {
   confirmHandler: () => void;
   confirmIsDestructive?: boolean;
   isButtonsInOneRow?: boolean;
+  children?: any;
 };
 
 const ConfirmDialog: FC<OwnProps> = ({
@@ -32,6 +33,7 @@ const ConfirmDialog: FC<OwnProps> = ({
   confirmHandler,
   confirmIsDestructive,
   isButtonsInOneRow,
+  children,
 }) => {
   const lang = useLang();
 
@@ -48,7 +50,7 @@ const ConfirmDialog: FC<OwnProps> = ({
       {text && text.split('\\n').map((textPart) => (
         <p>{textPart}</p>
       ))}
-      {textParts}
+      {textParts || children}
       <div className={isButtonsInOneRow ? 'dialog-buttons mt-2' : ''}>
         <Button
           className="confirm-dialog-button"

src/global/cache.ts

@@ -222,6 +222,7 @@ function updateCache() {
       'shouldShowContextMenuHint',
       'leftColumnWidth',
       'serviceNotifications',
+      // TODO Support 'groupCalls'
     ]),
     audioPlayer: {
       volume: global.audioPlayer.volume,
@@ -237,6 +238,7 @@ function updateCache() {
     },
     settings: reduceSettings(global),
     chatFolders: reduceChatFolders(global),
+    groupCalls: reduceGroupCalls(global),
   };
 
   const json = JSON.stringify(reducedGlobal);
@@ -332,6 +334,16 @@ function reduceChatFolders(global: GlobalState): GlobalState['chatFolders'] {
   };
 }
 
+function reduceGroupCalls(global: GlobalState): GlobalState['groupCalls'] {
+  return {
+    ...global.groupCalls,
+    byId: {},
+    activeGroupCallId: undefined,
+    isGroupCallPanelHidden: undefined,
+    isFallbackConfirmOpen: undefined,
+  };
+}
+
 function setupHeavyAnimationListeners() {
   document.addEventListener(ANIMATION_START_EVENT, () => {
     isHeavyAnimating = true;

src/global/types.ts

@@ -48,7 +48,10 @@ import {
   AudioOrigin,
 } from '../types';
 
-export type MessageListType = 'thread' | 'pinned' | 'scheduled';
+export type MessageListType =
+  'thread'
+  | 'pinned'
+  | 'scheduled';
 
 export interface MessageList {
   chatId: string;
@@ -168,6 +171,9 @@ export type GlobalState = {
     byId: Record<string, ApiGroupCall>;
     activeGroupCallId?: string;
     isGroupCallPanelHidden?: boolean;
+    isFallbackConfirmOpen?: boolean;
+    fallbackChatId?: string;
+    fallbackUserIdsToRemove?: string[];
   };
 
   scheduledMessages: {
@@ -551,7 +557,8 @@ export type ActionTypes = (
   'joinGroupCall' | 'toggleGroupCallMute' | 'toggleGroupCallPresentation' | 'leaveGroupCall' |
   'toggleGroupCallVideo' | 'requestToSpeak' | 'setGroupCallParticipantVolume' | 'toggleGroupCallPanel' |
   'createGroupCall' | 'joinVoiceChatByLink' | 'subscribeToGroupCallUpdates' | 'createGroupCallInviteLink' |
-  'loadMoreGroupCallParticipants' | 'connectToActiveGroupCall' | 'playGroupCallSound'
+  'loadMoreGroupCallParticipants' | 'connectToActiveGroupCall' | 'playGroupCallSound' |
+  'openCallFallbackConfirm' | 'closeCallFallbackConfirm' | 'inviteToCallFallback'
 );
 
 export type GlobalActions = Record<ActionTypes, (...args: any[]) => void>;

src/lib/teact/teact.ts

@@ -617,9 +617,9 @@ export function useMemo<T extends any>(resolver: () => T, dependencies: any[], d
   return current;
 }
 
-export function useCallback<F extends AnyFunction>(newCallback: F, dependencies: any[]): F {
+export function useCallback<F extends AnyFunction>(newCallback: F, dependencies: any[], debugKey?: string): F {
   // eslint-disable-next-line react-hooks/exhaustive-deps
-  return useMemo(() => newCallback, dependencies);
+  return useMemo(() => newCallback, dependencies, debugKey);
 }
 
 export function useRef<T>(initial: T): { current: T };

src/modules/actions/api/calls.async.ts

@@ -1,3 +1,4 @@
+import { addReducer, getGlobal, setGlobal } from '../../../lib/teact/teactn';
 import {
   joinGroupCall,
   startSharingScreen,
@@ -7,11 +8,15 @@ import {
   setVolume,
   handleUpdateGroupCallParticipants, handleUpdateGroupCallConnection,
 } from '../../../lib/secret-sauce';
-import { addReducer, getGlobal, setGlobal } from '../../../lib/teact/teactn';
+
+import { ApiUpdate } from '../../../api/types';
+
+import { GROUP_CALL_VOLUME_MULTIPLIER } from '../../../config';
 import { callApi } from '../../../api/gramjs';
-import { selectChat, selectUser } from '../../selectors';
+import { selectChat, selectCurrentMessageList, selectUser } from '../../selectors';
 import {
   selectActiveGroupCall,
+  selectCallFallbackChannelTitle,
   selectGroupCallParticipant,
 } from '../../selectors/calls';
 import {
@@ -20,12 +25,16 @@ import {
   updateGroupCall,
   updateGroupCallParticipant,
 } from '../../reducers/calls';
-import { ApiUpdate } from '../../../api/types';
-import { GROUP_CALL_VOLUME_MULTIPLIER } from '../../../config';
 import { omit } from '../../../util/iteratees';
+import { getServerTime } from '../../../util/serverTime';
+import { fetchFile } from '../../../util/files';
 import { getGroupCallAudioContext, getGroupCallAudioElement, removeGroupCallAudioElement } from '../ui/calls';
 import { loadFullChat } from './chats';
 
+import callFallbackAvatarPath from '../../../assets/call-fallback-avatar.png';
+
+const FALLBACK_INVITE_EXPIRE_SECONDS = 1800; // 30 min
+
 addReducer('apiUpdate', (global, actions, update: ApiUpdate) => {
   const { activeGroupCallId } = global.groupCalls;
 
@@ -88,16 +97,25 @@ addReducer('leaveGroupCall', (global, actions, payload) => {
     return;
   }
 
-  global = updateActiveGroupCall(global, {
-    connectionState: 'disconnected',
-  }, groupCall.participantsCount - 1);
+  setGlobal(updateActiveGroupCall(global, { connectionState: 'disconnected' }, groupCall.participantsCount - 1));
 
   (async () => {
     await callApi('leaveGroupCall', {
       call: groupCall,
     });
 
+    let shouldResetFallbackState = false;
     if (shouldDiscard) {
+      global = getGlobal();
+
+      if (global.groupCalls.fallbackChatId === groupCall.chatId) {
+        shouldResetFallbackState = true;
+
+        global.groupCalls.fallbackUserIdsToRemove?.forEach((userId) => {
+          actions.deleteChatMember({ chatId: global.groupCalls.fallbackChatId, userId });
+        });
+      }
+
       await callApi('discardGroupCall', {
         call: groupCall,
       });
@@ -116,6 +134,10 @@ addReducer('leaveGroupCall', (global, actions, payload) => {
         ...global.groupCalls,
         isGroupCallPanelHidden: true,
         activeGroupCallId: undefined,
+        ...(shouldResetFallbackState && {
+          fallbackChatId: undefined,
+          fallbackUserIdsToRemove: undefined,
+        }),
       },
     });
 
@@ -281,3 +303,81 @@ addReducer('connectToActiveGroupCall', (global, actions) => {
     }
   })();
 });
+
+addReducer('inviteToCallFallback', (global, actions, payload) => {
+  const { chatId } = selectCurrentMessageList(global) || {};
+  if (!chatId) {
+    return;
+  }
+
+  const user = selectUser(global, chatId);
+  if (!user) {
+    return;
+  }
+
+  const { shouldRemove } = payload;
+
+  (async () => {
+    const fallbackChannelTitle = selectCallFallbackChannelTitle(global);
+
+    let fallbackChannel = Object.values(global.chats.byId).find((channel) => {
+      return (
+        channel.title === fallbackChannelTitle
+        && channel.isCreator
+        && !channel.isRestricted
+      );
+    });
+    if (!fallbackChannel) {
+      fallbackChannel = await callApi('createChannel', {
+        title: fallbackChannelTitle,
+        users: [user],
+      });
+
+      if (!fallbackChannel) {
+        return;
+      }
+
+      const photo = await fetchFile(callFallbackAvatarPath, 'avatar.png');
+      void callApi('editChatPhoto', {
+        chatId: fallbackChannel.id,
+        accessHash: fallbackChannel.accessHash,
+        photo,
+      });
+    } else {
+      actions.updateChatMemberBannedRights({
+        chatId: fallbackChannel.id,
+        userId: chatId,
+        bannedRights: {},
+      });
+
+      void callApi('addChatMembers', fallbackChannel, [user], true);
+    }
+
+    const inviteLink = await callApi('updatePrivateLink', {
+      chat: fallbackChannel,
+      usageLimit: 1,
+      expireDate: getServerTime(global.serverTimeOffset) + FALLBACK_INVITE_EXPIRE_SECONDS,
+    });
+    if (!inviteLink) {
+      return;
+    }
+
+    if (shouldRemove) {
+      global = getGlobal();
+      const fallbackUserIdsToRemove = global.groupCalls.fallbackUserIdsToRemove || [];
+      setGlobal({
+        ...global,
+        groupCalls: {
+          ...global.groupCalls,
+          fallbackChatId: fallbackChannel.id,
+          fallbackUserIdsToRemove: [...fallbackUserIdsToRemove, chatId],
+        },
+      });
+    }
+
+    actions.sendMessage({ text: `Join a call: ${inviteLink}` });
+    actions.openChat({ id: fallbackChannel.id });
+    actions.createGroupCall({ chatId: fallbackChannel.id });
+    actions.closeCallFallbackConfirm();
+  })();
+});

src/modules/actions/ui/calls.ts

@@ -61,11 +61,13 @@ async function fetchGroupCall(groupCall: Partial<ApiGroupCall>) {
 
   const existingGroupCall = selectGroupCall(global, groupCall.id!);
 
-  global = updateGroupCall(global,
+  global = updateGroupCall(
+    global,
     groupCall.id!,
     omit(result.groupCall, ['connectionState']),
     undefined,
-    existingGroupCall?.isLoaded ? undefined : result.groupCall.participantsCount);
+    existingGroupCall?.isLoaded ? undefined : result.groupCall.participantsCount,
+  );
   global = addUsers(global, buildCollectionByKey(result.users, 'id'));
   global = addChats(global, buildCollectionByKey(result.chats, 'id'));
 
@@ -309,3 +311,23 @@ export function removeGroupCallAudioElement() {
   audioContext = undefined;
   audioElement = undefined;
 }
+
+addReducer('openCallFallbackConfirm', (global) => {
+  return {
+    ...global,
+    groupCalls: {
+      ...global.groupCalls,
+      isFallbackConfirmOpen: true,
+    },
+  };
+});
+
+addReducer('closeCallFallbackConfirm', (global) => {
+  return {
+    ...global,
+    groupCalls: {
+      ...global.groupCalls,
+      isFallbackConfirmOpen: false,
+    },
+  };
+});

src/modules/selectors/calls.ts

@@ -1,6 +1,7 @@
 import { GlobalState } from '../../global/types';
 import { selectChat } from './chats';
-import { isChatBasicGroup } from '../helpers';
+import { getUserFullName, isChatBasicGroup } from '../helpers';
+import { selectUser } from './users';
 
 export function selectChatGroupCall(global: GlobalState, chatId: string) {
   const chat = selectChat(global, chatId);
@@ -36,3 +37,9 @@ export function selectActiveGroupCall(global: GlobalState) {
 
   return selectGroupCall(global, activeGroupCallId);
 }
+
+export function selectCallFallbackChannelTitle(global: GlobalState) {
+  const currentUser = selectUser(global, global.currentUserId!);
+
+  return `Calls: ${getUserFullName(currentUser!)}`;
+}