Channel Admin: Add leave channel modal (#6656)

Co-authored-by: Alexander Zinchuk <alx.zinchuk@gmail.com>

CLAUDE.md

@@ -116,6 +116,7 @@ Convesion from and to Api* objects is done by `apiBuilders` (function name start
   const result = await callApi('methodName', { /* params */ });
   ```
 * Always check for `undefined` before proceeding.
+* **IMPORTANT: Do not pass `accessHash` directly to API methods.** Methods that accept separate `id` and `accessHash` parameters are outdated. Instead, pass the full `ApiPeer`, `ApiChat`, or `ApiUser` object. The `buildInput*` functions in `gramjsBuilders` will extract the necessary fields.
 
 ## 4. Example
 

src/api/gramjs/apiBuilders/messageActions.ts

@@ -556,6 +556,22 @@ export function buildApiMessageAction(action: GramJs.TypeMessageAction): ApiMess
       price: buildApiCurrencyAmount(price),
     };
   }
+  if (action instanceof GramJs.MessageActionNewCreatorPending) {
+    const { newCreatorId } = action;
+    return {
+      mediaType: 'action',
+      type: 'newCreatorPending',
+      newCreatorId: buildApiPeerId(newCreatorId, 'user'),
+    };
+  }
+  if (action instanceof GramJs.MessageActionChangeCreator) {
+    const { newCreatorId } = action;
+    return {
+      mediaType: 'action',
+      type: 'changeCreator',
+      newCreatorId: buildApiPeerId(newCreatorId, 'user'),
+    };
+  }
 
   return UNSUPPORTED_ACTION;
 }

src/api/gramjs/helpers/misc.ts

@@ -117,6 +117,11 @@ export function wrapError<T extends Error>(error: T): WrappedError<T> {
       key: 'ErrorPasswordFresh',
       variables: { time: formatWait(error.seconds) },
     };
+  } else if (error instanceof errors.SessionFreshError) {
+    messageKey = {
+      key: 'ErrorSessionFresh',
+      variables: { time: formatWait(error.seconds) },
+    };
   } else if (error instanceof errors.RPCError) {
     messageKey = {
       key: ERROR_KEYS[error.errorMessage],

src/api/gramjs/methods/chats.ts

@@ -1,5 +1,5 @@
 import { Api as GramJs } from '../../../lib/gramjs';
-import { RPCError } from '../../../lib/gramjs/errors';
+import { PasswordFreshError, RPCError, SessionFreshError } from '../../../lib/gramjs/errors';
 
 import type { ChatListType, ThreadReadState } from '../../../types';
 import {
@@ -82,13 +82,14 @@ import {
 import {
   addPhotoToLocalDb,
 } from '../helpers/localDb';
-import { isChatFolder } from '../helpers/misc';
+import { checkErrorType, isChatFolder, wrapError } from '../helpers/misc';
 import { scheduleMutedChatUpdate } from '../scheduleUnmute';
 import { sendApiUpdate } from '../updates/apiUpdateEmitter';
 import {
   applyState, updateChannelState,
 } from '../updates/updateManager';
 import { handleGramJsUpdate, invokeRequest, uploadFile } from './client';
+import { getPassword } from './twoFaSettings';
 
 type FullChatData = {
   fullInfo: ApiChatFullInfo;
@@ -960,18 +961,88 @@ export function deleteChat({
   });
 }
 
-export function leaveChannel({
-  channelId, accessHash,
-}: {
-  channelId: string; accessHash: string;
-}) {
+export function leaveChannel({ chat }: { chat: ApiChat }) {
   return invokeRequest(new GramJs.channels.LeaveChannel({
-    channel: buildInputChannel(channelId, accessHash),
+    channel: buildInputChannel(chat.id, chat.accessHash),
   }), {
     shouldReturnTrue: true,
   });
 }
 
+export async function fetchFutureCreatorAfterLeave({ chat }: { chat: ApiChat }) {
+  const result = await invokeRequest(new GramJs.channels.GetFutureCreatorAfterLeave({
+    channel: buildInputChannel(chat.id, chat.accessHash),
+  }));
+
+  if (!result) {
+    return undefined;
+  }
+
+  return buildApiUser(result);
+}
+
+export async function verifyTransferOwnership({
+  chat, user,
+}: {
+  chat: ApiChat;
+  user: ApiUser;
+}) {
+  try {
+    await invokeRequest(new GramJs.channels.EditCreator({
+      channel: buildInputChannel(chat.id, chat.accessHash),
+      userId: buildInputUser(user.id, user.accessHash),
+      password: new GramJs.InputCheckPasswordEmpty(),
+    }), {
+      shouldReturnTrue: true,
+      shouldThrow: true,
+    });
+
+    return { canTransfer: true };
+  } catch (err: any) {
+    if (!checkErrorType(err)) return undefined;
+
+    if (err instanceof RPCError && err.errorMessage === 'PASSWORD_HASH_INVALID') return { canTransfer: true };
+
+    if (err instanceof PasswordFreshError) return { errorMessage: 'PASSWORD_TOO_FRESH' };
+    if (err instanceof SessionFreshError) return { errorMessage: 'SESSION_TOO_FRESH' };
+    if (err instanceof RPCError && err.errorMessage === 'PASSWORD_MISSING') return { errorMessage: 'PASSWORD_MISSING' };
+
+    return wrapError(err);
+  }
+}
+
+export async function editChannelCreator({
+  chat, user, password,
+}: {
+  chat: ApiChat;
+  user: ApiUser;
+  password: string;
+}) {
+  try {
+    const passwordCheck = await getPassword(password);
+
+    if (!passwordCheck) {
+      return undefined;
+    }
+
+    if ('error' in passwordCheck) {
+      return passwordCheck;
+    }
+
+    return invokeRequest(new GramJs.channels.EditCreator({
+      channel: buildInputChannel(chat.id, chat.accessHash),
+      userId: buildInputUser(user.id, user.accessHash),
+      password: passwordCheck,
+    }), {
+      shouldReturnTrue: true,
+      shouldThrow: true,
+    });
+  } catch (err) {
+    if (!checkErrorType(err)) return undefined;
+    return wrapError(err);
+  }
+}
+
 export function deleteChannel({
   channelId, accessHash,
 }: {

src/api/types/messageActions.ts

@@ -346,6 +346,16 @@ export interface ApiMessageActionStarGiftPurchaseOfferDeclined extends ActionMed
   price: ApiTypeCurrencyAmount;
 }
 
+export interface ApiMessageActionNewCreatorPending extends ActionMediaType {
+  type: 'newCreatorPending';
+  newCreatorId: string;
+}
+
+export interface ApiMessageActionChangeCreator extends ActionMediaType {
+  type: 'changeCreator';
+  newCreatorId: string;
+}
+
 export interface ApiMessageActionUnsupported extends ActionMediaType {
   type: 'unsupported';
 }
@@ -366,4 +376,5 @@ export type ApiMessageAction = ApiMessageActionUnsupported | ApiMessageActionCha
   | ApiMessageActionPaidMessagesRefunded | ApiMessageActionPaidMessagesPrice | ApiMessageActionSuggestedPostApproval
   | ApiMessageActionSuggestedPostSuccess | ApiMessageActionSuggestedPostRefund | ApiMessageActionTodoCompletions
   | ApiMessageActionTodoAppendTasks | ApiMessageActionStarGiftPurchaseOffer
-  | ApiMessageActionStarGiftPurchaseOfferDeclined;
+  | ApiMessageActionStarGiftPurchaseOfferDeclined | ApiMessageActionNewCreatorPending
+  | ApiMessageActionChangeCreator;

src/assets/localization/fallback.strings

@@ -707,6 +707,7 @@
 "ErrorPhoneBanned" = "This phone number is banned";
 "ErrorFloodTime" = "Too many attempts, please try again in {time}";
 "ErrorPasswordFresh" = "The password was modified recently, try again in {time}";
+"ErrorSessionFresh" = "For security reasons, please wait {time} or use an older session";
 "ErrorUnexpected" = "Unexpected error";
 "ErrorUnexpectedMessage" = "Unexpected error: {error}";
 "ErrorEmailUnconfirmed" = "Email not confirmed";
@@ -966,6 +967,12 @@
 "ChannelEditAdminCannotEdit" = "You can't edit the rights of this admin.";
 "EditAdminRank" = "Custom title";
 "EditAdminRemoveAdmin" = "Dismiss Admin";
+"EditAdminTransferChannelOwnership" = "Transfer Channel Ownership";
+"EditAdminTransferGroupOwnership" = "Transfer Group Ownership";
+"EditAdminTransferOwnershipText" = "This will transfer **full owner rights** for **{chat}** to **{user}**. The new owner will be free to remove any of your admin privileges or even ban you.";
+"EditAdminTransferChangeOwner" = "Change Owner";
+"EditAdminTransferChannelOwnershipSuccess" = "{user} is now the owner of the channel.";
+"EditAdminTransferGroupOwnershipSuccess" = "{user} is now the owner of the group.";
 "ChannelAdminDismiss" = "Dismiss Admin";
 "ChannelPermissionsHeader" = "What can members of this group do?";
 "UserRestrictionsSend" = "Send Messages";
@@ -2388,6 +2395,8 @@
 "StarGiftAuctionBidRefundedTransaction" = "Refunded Auction Bid";
 "ActionStarGiftPrepaidUpgraded" = "{user} turned the gift into a unique collectible";
 "ActionStarGiftPrepaidUpgradedYou" = "You turned the gift into a unique collectible";
+"ActionNewCreatorPending" = "{user} will become the new owner in 7 days if {from} does not return.";
+"ActionChangeCreator" = "{from} has transferred ownership of the group to {user}.";
 "UserNoteTitle" = "Notes";
 "UserNoteHint" = "only visible to you";
 "EditUserNoteHint" = "Notes are only visible to you.";
@@ -2609,6 +2618,21 @@
 "SettingsDataClearMediaCache" = "Clear Media Cache";
 "SettingsDataClearMediaCacheDescription" = "Deletes locally cached media for this account";
 "SettingsDataClearMediaDone" = "Media cache cleared";
+"LeaveGroupTitle" = "Leave {group}?";
+"LeaveGroupDescription" = "If you leave, **{nextOwner}** will become the new owner of **{group}** in 1 week.";
+"LeaveGroupAppointOwner" = "Appoint Another Owner";
+"LeaveGroupAdmins" = "GROUP ADMINS";
+"LeaveGroupMembers" = "GROUP MEMBERS";
+"LeaveGroupJoinedDate" = "joined {date}";
+"SecurityCheck" = "Security Check";
+"SecurityCheckInfo" = "You can only confirm this action if:";
+"SecurityCheckTwoStepEnabled" = "2-Step verification is active and has been enabled for your account for more than **7 days**.";
+"SecurityCheckTwoStepNotChanged" = "Your 2-Step Verification password has not been changed the last **7 days**.";
+"SecurityCheckLoggedIn" = "You have been logged in on this device for more than **24 hours**.";
+"SecurityCheckEnableTwoStep" = "Enable 2-Step Verification";
+"EnterPassword" = "Enter Password";
+"EnterPasswordDescription" = "Please enter your Two-Step Verification password to complete this action.";
+"Transfer" = "Transfer";
 "TranslateMenuCocoon" = "Translations are powered by 🥚 **Cocoon**. {link}";
 "TranslateMenuCocoonLinkText" = "How does it work?";
 "CocoonTitle" = "Cocoon";

src/bundles/extra.ts

@@ -107,5 +107,7 @@ export { default as FrozenAccountModal } from '../components/modals/frozenAccoun
 export { default as ProfileRatingModal } from '../components/modals/profileRating/ProfileRatingModal';
 export { default as QuickPreviewModal } from '../components/modals/quickPreview/QuickPreviewModal';
 export { default as StealthModeModal } from '../components/modals/storyStealthMode/StealthModeModal';
+export { default as LeaveGroupModal } from '../components/modals/leaveGroup/LeaveGroupModal';
+export { default as TwoFaCheckModal } from '../components/modals/twoFaCheck/TwoFaCheckModal';
 export { default as QuickChatPickerModal } from '../components/modals/quickChatPicker/QuickChatPickerModal';
 export { default as CocoonModal } from '../components/modals/cocoon/CocoonModal';

src/components/common/DeleteChatModal.tsx

@@ -1,4 +1,3 @@
-import type { FC } from '../../lib/teact/teact';
 import { memo } from '../../lib/teact/teact';
 import { getActions, withGlobal } from '../../global';
 
@@ -46,7 +45,7 @@ type StateProps = {
   contactName?: string;
 };
 
-const DeleteChatModal: FC<OwnProps & StateProps> = ({
+const DeleteChatModal = ({
   isOpen,
   chat,
   isSavedDialog,
@@ -61,7 +60,7 @@ const DeleteChatModal: FC<OwnProps & StateProps> = ({
   contactName,
   onClose,
   onCloseAnimationEnd,
-}) => {
+}: OwnProps & StateProps) => {
   const {
     leaveChannel,
     deleteHistory,

src/components/common/PasswordConfirmModal.module.scss

@@ -0,0 +1,4 @@
+.description {
+  margin-bottom: 1rem;
+  color: var(--color-text-secondary);
+}

src/components/common/PasswordConfirmModal.tsx

@@ -0,0 +1,102 @@
+import { memo, useState } from '../../lib/teact/teact';
+import { getActions, withGlobal } from '../../global';
+
+import type { GlobalState } from '../../global/types';
+
+import useLang from '../../hooks/useLang';
+import useLastCallback from '../../hooks/useLastCallback';
+
+import ConfirmDialog from '../ui/ConfirmDialog';
+import PasswordForm from './PasswordForm';
+import PasswordMonkey from './PasswordMonkey';
+
+import styles from './PasswordConfirmModal.module.scss';
+
+type OwnProps = {
+  isOpen: boolean;
+  title?: string;
+  confirmLabel?: string;
+  description?: string;
+  onClose: NoneToVoidFunction;
+  onSubmit: (password: string) => void;
+};
+
+type StateProps = {
+  error?: GlobalState['twoFaSettings']['errorKey'];
+  hint?: string;
+  isLoading?: boolean;
+};
+
+const PasswordConfirmModal = ({
+  isOpen,
+  title,
+  confirmLabel,
+  description,
+  error,
+  hint,
+  isLoading,
+  onClose,
+  onSubmit,
+}: OwnProps & StateProps) => {
+  const { checkPassword, clearTwoFaError } = getActions();
+  const lang = useLang();
+
+  const [shouldShowPassword, setShouldShowPassword] = useState(false);
+  const [password, setPassword] = useState('');
+
+  const handlePasswordChange = useLastCallback((value: string) => {
+    setPassword(value);
+  });
+
+  const handleSubmit = useLastCallback(() => {
+    checkPassword({
+      currentPassword: password,
+      onSuccess: () => {
+        onSubmit(password);
+        setPassword('');
+        setShouldShowPassword(false);
+      },
+    });
+  });
+
+  const handleClose = useLastCallback(() => {
+    onClose();
+    clearTwoFaError();
+    setPassword('');
+    setShouldShowPassword(false);
+  });
+
+  return (
+    <ConfirmDialog
+      isOpen={isOpen}
+      title={title || lang('EnterPassword')}
+      confirmLabel={confirmLabel || lang('AutoDeleteConfirm')}
+      confirmHandler={handleSubmit}
+      confirmIsDestructive
+      onClose={handleClose}
+    >
+      <PasswordMonkey isBig isPasswordVisible={shouldShowPassword} />
+      {description && <p className={styles.description}>{description}</p>}
+      <PasswordForm
+        error={error && lang.withRegular(error)}
+        hint={hint}
+        isLoading={isLoading}
+        isPasswordVisible={shouldShowPassword}
+        onChangePasswordVisibility={setShouldShowPassword}
+        onClearError={clearTwoFaError}
+        onInputChange={handlePasswordChange}
+      />
+    </ConfirmDialog>
+  );
+};
+
+export default memo(withGlobal<OwnProps>(
+  (global): Complete<StateProps> => {
+    const { errorKey, hint, isLoading } = global.twoFaSettings;
+    return {
+      error: errorKey,
+      hint,
+      isLoading,
+    };
+  },
+)(PasswordConfirmModal));

src/components/common/TransferBetweenPeers.module.scss

@@ -0,0 +1,14 @@
+.root {
+  display: flex;
+  gap: 0.5rem;
+  align-items: center;
+  justify-content: center;
+
+  margin-top: 0.5rem;
+  margin-bottom: 1rem;
+}
+
+.arrow {
+  font-size: 2rem;
+  color: var(--color-text-secondary);
+}

src/components/common/TransferBetweenPeers.tsx

@@ -0,0 +1,30 @@
+import { memo } from '../../lib/teact/teact';
+
+import type { ApiPeer } from '../../api/types';
+
+import { REM } from './helpers/mediaDimensions';
+
+import Avatar from './Avatar';
+import Icon from './icons/Icon';
+
+import styles from './TransferBetweenPeers.module.scss';
+
+type OwnProps = {
+  fromPeer?: ApiPeer;
+  toPeer?: ApiPeer;
+  avatarSize?: number;
+};
+
+const DEFAULT_AVATAR_SIZE = 4 * REM;
+
+const TransferBetweenPeers = ({ fromPeer, toPeer, avatarSize = DEFAULT_AVATAR_SIZE }: OwnProps) => {
+  return (
+    <div className={styles.root}>
+      <Avatar peer={fromPeer} size={avatarSize} />
+      <Icon name="next" className={styles.arrow} />
+      <Avatar peer={toPeer} size={avatarSize} />
+    </div>
+  );
+};
+
+export default memo(TransferBetweenPeers);

src/components/common/pickers/PeerPicker.tsx

@@ -1,4 +1,4 @@
-import type React from '../../../lib/teact/teact';
+import type { TeactNode } from '../../../lib/teact/teact';
 import {
   memo, useCallback, useEffect, useMemo, useRef,
 } from '../../../lib/teact/teact';
@@ -58,10 +58,25 @@ type MultipleModeProps<CategoryType extends string> = {
   onSelectedIdsChange?: (Ids: string[]) => void;
 };
 
+export type PeerPickerSection = {
+  key: string;
+  title: string;
+  ids: string[];
+};
+
+type ItemIdsProps = {
+  itemIds: string[];
+  sections?: undefined;
+};
+
+type SectionsProps = {
+  sections: PeerPickerSection[];
+  itemIds?: undefined;
+};
+
 type OwnProps<CategoryType extends string> = {
   className?: string;
   categories?: UniqueCustomPeer<CategoryType>[];
-  itemIds: string[];
   lockedUnselectedSubtitle?: string;
   filterValue?: string;
   filterPlaceholder?: string;
@@ -81,7 +96,7 @@ type OwnProps<CategoryType extends string> = {
   onFilterChange?: (value: string) => void;
   onDisabledClick?: (id: string, isSelected: boolean) => void;
   onLoadMore?: () => void;
-} & (SingleModeProps<CategoryType> | MultipleModeProps<CategoryType>);
+} & (ItemIdsProps | SectionsProps) & (SingleModeProps<CategoryType> | MultipleModeProps<CategoryType>);
 
 const MAX_FULL_ITEMS = 10;
 const ALWAYS_FULL_ITEMS_COUNT = 5;
@@ -91,7 +106,8 @@ const ITEM_CLASS_NAME = 'PeerPickerItem';
 const PeerPicker = <CategoryType extends string = CustomPeerType>({
   className,
   categories,
-  itemIds,
+  itemIds: itemIdsProp,
+  sections,
   categoryPlaceholderKey,
   filterValue,
   filterPlaceholder,
@@ -117,6 +133,11 @@ const PeerPicker = <CategoryType extends string = CustomPeerType>({
   const oldLang = useOldLang();
   const lang = useLang();
 
+  const itemIds = useMemo(() => {
+    if (itemIdsProp) return itemIdsProp;
+    return sections.flatMap((section) => section.ids);
+  }, [itemIdsProp, sections]);
+
   const allowMultiple = optionalProps.allowMultiple;
   const lockedSelectedIds = allowMultiple ? optionalProps.lockedSelectedIds : undefined;
   const lockedUnselectedIds = allowMultiple ? optionalProps.lockedUnselectedIds : undefined;
@@ -344,6 +365,28 @@ const PeerPicker = <CategoryType extends string = CustomPeerType>({
     );
   }, [categories, categoryPlaceholderKey, oldLang, renderItem]);
 
+  const renderItems = useCallback(() => {
+    if (!sections) {
+      return viewportIds?.map((id) => renderItem(id));
+    }
+
+    const result: TeactNode[] = [];
+    sections.forEach((section) => {
+      if (section.ids.length === 0) return;
+      result.push(
+        <div key={section.key} className={styles.sectionHeader}>{section.title}</div>,
+      );
+      section.ids.forEach((id) => {
+        result.push(renderItem(id));
+      });
+    });
+    return result;
+  }, [sections, viewportIds, renderItem]);
+
+  const hasContent = sections
+    ? sections.some((s) => s.ids.length > 0)
+    : Boolean(viewportIds?.length);
+
   return (
     <div className={buildClassName(styles.container, className)}>
       {isSearchable && (
@@ -389,7 +432,7 @@ const PeerPicker = <CategoryType extends string = CustomPeerType>({
         </div>
       )}
 
-      {viewportIds?.length ? (
+      {hasContent ? (
         <InfiniteScroll
           className={buildClassName(styles.pickerList, withDefaultPadding && styles.padded, 'custom-scroll')}
           items={viewportIds}
@@ -398,7 +441,7 @@ const PeerPicker = <CategoryType extends string = CustomPeerType>({
           onLoadMore={getMore}
           noScrollRestore={noScrollRestore}
         >
-          {viewportIds.map((id) => renderItem(id))}
+          {renderItems()}
         </InfiniteScroll>
       ) : !isLoading && viewportIds && !viewportIds.length ? (
         <p className={styles.noResults}>{notFoundText || 'Sorry, nothing found.'}</p>

src/components/common/pickers/PickerStyles.module.scss

@@ -45,6 +45,15 @@
   }
 }
 
+.sectionHeader {
+  margin: 0;
+  padding: 0.75rem 0.25rem 0.5rem;
+
+  font-size: 0.75rem;
+  font-weight: var(--font-weight-medium);
+  color: var(--color-text-secondary);
+}
+
 .peerChip {
   max-width: calc(50% - 0.5rem);
   margin-bottom: 0.5rem;

src/components/middle/message/ActionMessageText.tsx

@@ -1045,6 +1045,22 @@ const ActionMessageText = ({
       case 'phoneCall': // Rendered as a regular message, but considered an action for the summary
         return lang(getCallMessageKey(action, isOutgoing));
 
+      case 'newCreatorPending': {
+        const { newCreatorId } = action;
+        const newCreator = selectPeer(global, newCreatorId);
+        const newCreatorTitle = (newCreator && getPeerTitle(lang, newCreator)) || userFallbackText;
+        const newCreatorLink = renderPeerLink(newCreator?.id, newCreatorTitle, asPreview);
+        return lang('ActionNewCreatorPending', { user: newCreatorLink, from: senderLink }, { withNodes: true });
+      }
+
+      case 'changeCreator': {
+        const { newCreatorId } = action;
+        const newCreator = selectPeer(global, newCreatorId);
+        const newCreatorTitle = (newCreator && getPeerTitle(lang, newCreator)) || userFallbackText;
+        const newCreatorLink = renderPeerLink(newCreator?.id, newCreatorTitle, asPreview);
+        return lang('ActionChangeCreator', { user: newCreatorLink, from: senderLink }, { withNodes: true });
+      }
+
       case 'starGiftPurchaseOffer': {
         const { gift, price } = action;
 

src/components/modals/ModalContainer.tsx

@@ -43,6 +43,7 @@ import GiftInfoValueModal from './gift/value/GiftInfoValueModal.async';
 import GiftWithdrawModal from './gift/withdraw/GiftWithdrawModal.async';
 import GiftCodeModal from './giftcode/GiftCodeModal.async';
 import InviteViaLinkModal from './inviteViaLink/InviteViaLinkModal.async';
+import LeaveGroupModal from './leaveGroup/LeaveGroupModal.async';
 import LocationAccessModal from './locationAccess/LocationAccessModal.async';
 import MapModal from './map/MapModal.async';
 import OneTimeMediaModal from './oneTimeMedia/OneTimeMediaModal.async';
@@ -66,6 +67,7 @@ import StealthModeModal from './storyStealthMode/StealthModeModal.async';
 import SuggestedPostApprovalModal from './suggestedPostApproval/SuggestedPostApprovalModal.async';
 import SuggestedStatusModal from './suggestedStatus/SuggestedStatusModal.async';
 import SuggestMessageModal from './suggestMessage/SuggestMessageModal.async';
+import TwoFaCheckModal from './twoFaCheck/TwoFaCheckModal.async';
 import UrlAuthModal from './urlAuth/UrlAuthModal.async';
 import WebAppModal from './webApp/WebAppModal.async';
 
@@ -131,6 +133,8 @@ type ModalKey = keyof Pick<TabState,
   'storyStealthModal' |
   'isPasskeyModalOpen' |
   'birthdaySetupModal' |
+  'leaveGroupModal' |
+  'isTwoFaCheckModalOpen' |
   'isQuickChatPickerOpen' |
   'isCocoonModalOpen'
 >;
@@ -208,6 +212,8 @@ const MODALS: ModalRegistry = {
   storyStealthModal: StealthModeModal,
   isPasskeyModalOpen: PasskeyModal,
   birthdaySetupModal: BirthdaySetupModal,
+  leaveGroupModal: LeaveGroupModal,
+  isTwoFaCheckModalOpen: TwoFaCheckModal,
   isQuickChatPickerOpen: QuickChatPickerModal,
   isCocoonModalOpen: CocoonModal,
 };

src/components/modals/gift/auction/GiftAuctionChangeRecipientModal.tsx

@@ -6,18 +6,14 @@ import type { TabState } from '../../../../global/types';
 
 import { getPeerTitle } from '../../../../global/helpers/peers';
 import { selectPeer } from '../../../../global/selectors';
-import { REM } from '../../../common/helpers/mediaDimensions';
 
 import useCurrentOrPrev from '../../../../hooks/useCurrentOrPrev';
 import useLang from '../../../../hooks/useLang';
 import useLastCallback from '../../../../hooks/useLastCallback';
 
-import Avatar from '../../../common/Avatar';
-import Icon from '../../../common/icons/Icon';
+import TransferBetweenPeers from '../../../common/TransferBetweenPeers';
 import ConfirmDialog from '../../../ui/ConfirmDialog';
 
-import styles from './GiftAuctionChangeRecipientModal.module.scss';
-
 export type OwnProps = {
   modal: TabState['giftAuctionChangeRecipientModal'];
 };
@@ -27,8 +23,6 @@ type StateProps = {
   newPeer?: ApiPeer;
 };
 
-const AVATAR_SIZE = 4 * REM;
-
 const GiftAuctionChangeRecipientModal = ({ modal, oldPeer, newPeer }: OwnProps & StateProps) => {
   const { closeGiftAuctionChangeRecipientModal, openGiftAuctionBidModal } = getActions();
   const lang = useLang();
@@ -60,11 +54,7 @@ const GiftAuctionChangeRecipientModal = ({ modal, oldPeer, newPeer }: OwnProps &
       confirmLabel={lang('Continue')}
       confirmHandler={handleConfirm}
     >
-      <div className={styles.preview}>
-        <Avatar peer={renderingOldPeer} size={AVATAR_SIZE} />
-        <Icon name="next" className={styles.arrow} />
-        <Avatar peer={renderingNewPeer} size={AVATAR_SIZE} />
-      </div>
+      <TransferBetweenPeers fromPeer={renderingOldPeer} toPeer={renderingNewPeer} />
       <p>
         {lang('GiftAuctionChangeRecipientDescription', {
           oldPeer: getPeerTitle(lang, renderingOldPeer),

src/components/modals/leaveGroup/LeaveGroupModal.async.tsx

@@ -0,0 +1,14 @@
+import type { OwnProps } from './LeaveGroupModal';
+
+import { Bundles } from '../../../util/moduleLoader';
+
+import useModuleLoader from '../../../hooks/useModuleLoader';
+
+const LeaveGroupModalAsync = (props: OwnProps) => {
+  const { modal } = props;
+  const LeaveGroupModal = useModuleLoader(Bundles.Extra, 'LeaveGroupModal', !modal);
+
+  return LeaveGroupModal ? <LeaveGroupModal key={modal?.chatId} {...props} /> : undefined;
+};
+
+export default LeaveGroupModalAsync;

src/components/modals/leaveGroup/LeaveGroupModal.module.scss

@@ -0,0 +1,8 @@
+.dialog {
+  max-width: 22rem !important;
+}
+
+.passwordDescription {
+  margin-bottom: 1rem;
+  color: var(--color-text-secondary);
+}

src/components/modals/leaveGroup/LeaveGroupModal.tsx

@@ -0,0 +1,317 @@
+import {
+  memo, useCallback, useEffect, useMemo, useState,
+} from '../../../lib/teact/teact';
+import { getActions, withGlobal } from '../../../global';
+
+import type { ApiChat, ApiChatFullInfo, ApiPeer } from '../../../api/types';
+import type { GlobalState, TabState } from '../../../global/types';
+
+import { getPeerTitle } from '../../../global/helpers/peers';
+import { selectChat, selectChatFullInfo, selectPeer } from '../../../global/selectors';
+
+import useSelector from '../../../hooks/data/useSelector';
+import useCurrentOrPrev from '../../../hooks/useCurrentOrPrev';
+import useFlag from '../../../hooks/useFlag';
+import useLang from '../../../hooks/useLang';
+import useLastCallback from '../../../hooks/useLastCallback';
+import usePeerSearch, { prepareChatMemberSearch } from '../../../hooks/usePeerSearch';
+
+import PasswordConfirmModal from '../../common/PasswordConfirmModal';
+import PeerPicker, { type PeerPickerSection } from '../../common/pickers/PeerPicker';
+import PickerModal from '../../common/pickers/PickerModal';
+import TransferBetweenPeers from '../../common/TransferBetweenPeers';
+import Button from '../../ui/Button';
+import Modal from '../../ui/Modal';
+
+import styles from './LeaveGroupModal.module.scss';
+
+export type OwnProps = {
+  modal: TabState['leaveGroupModal'];
+};
+
+type StateProps = {
+  chat?: ApiChat;
+  currentUser?: ApiPeer;
+  currentUserId?: string;
+  nextOwner?: ApiPeer;
+  chatFullInfo?: ApiChatFullInfo;
+};
+
+const LeaveGroupModal = ({
+  modal,
+  chat,
+  currentUser,
+  currentUserId,
+  nextOwner,
+  chatFullInfo,
+}: OwnProps & StateProps) => {
+  const {
+    closeLeaveGroupModal, leaveChannel, loadMoreMembers, loadFullChat,
+    transferChannelOwnership, verifyTransferOwnership, openTwoFaCheckModal,
+  } = getActions();
+  const lang = useLang();
+
+  const [isPickerOpen, openPicker, closePicker] = useFlag();
+  const [isPasswordModalOpen, openPasswordModal, closePasswordModal] = useFlag();
+  const [newOwnerId, setNewOwnerId] = useState<string | undefined>(modal?.nextOwnerId);
+  const [search, setSearch] = useState('');
+
+  const isOpen = Boolean(modal);
+  const renderingChat = useCurrentOrPrev(chat);
+  const renderingCurrentUser = useCurrentOrPrev(currentUser);
+
+  useEffect(() => {
+    if (chat && !chatFullInfo) {
+      loadFullChat({ chatId: chat.id });
+    }
+  }, [chat, chatFullInfo]);
+
+  const newOwner = (!newOwnerId || newOwnerId === modal?.nextOwnerId) ? nextOwner : undefined;
+
+  const renderingNewOwner = useCurrentOrPrev(newOwner);
+
+  const selectNewOwnerPeer = useCallback((global: GlobalState) => {
+    return newOwnerId ? selectPeer(global, newOwnerId) : undefined;
+  }, [newOwnerId]);
+  const selectedNewOwnerPeer = useSelector(selectNewOwnerPeer);
+  const newOwnerPeer = selectedNewOwnerPeer || renderingNewOwner;
+
+  const { adminIds, memberIds, allIds } = useMemo(() => {
+    if (!currentUserId) {
+      return { adminIds: [], memberIds: [], allIds: [] };
+    }
+
+    const adminMembersById = chatFullInfo?.adminMembersById;
+    const allMembers = chatFullInfo?.members;
+
+    const adminUserIds = adminMembersById
+      ? Object.values(adminMembersById)
+        .filter((member) => member.userId !== currentUserId && !member.isOwner)
+        .map((member) => member.userId)
+      : [];
+
+    const memberUserIds = (allMembers || [])
+      .filter((member) => {
+        return member.userId !== currentUserId
+          && !member.isOwner
+          && !member.isAdmin;
+      })
+      .map((member) => member.userId);
+
+    return {
+      adminIds: adminUserIds,
+      memberIds: memberUserIds,
+      allIds: [...adminUserIds, ...memberUserIds],
+    };
+  }, [currentUserId, chatFullInfo]);
+
+  const hasAdmins = adminIds.length > 0;
+
+  const isOwnerChanged = Boolean(newOwnerId && newOwnerId !== modal?.nextOwnerId);
+
+  const memberSearchFn = useMemo(() => {
+    return chat ? prepareChatMemberSearch(chat) : undefined;
+  }, [chat]);
+
+  const { result: searchResults, isLoading: isSearchLoading } = usePeerSearch({
+    query: search,
+    queryFn: memberSearchFn,
+    defaultValue: allIds,
+    isDisabled: !chat,
+  });
+
+  const { sections, filteredIds } = useMemo(() => {
+    if (search) {
+      const filtered = (searchResults || []).filter((id) => id !== currentUserId && allIds.includes(id));
+      return { sections: undefined, filteredIds: filtered };
+    }
+
+    if (!hasAdmins) {
+      return { sections: undefined, filteredIds: allIds };
+    }
+
+    const hasMembers = memberIds.length > 0;
+    if (!hasMembers) {
+      return {
+        sections: undefined,
+        filteredIds: adminIds,
+      };
+    }
+
+    return {
+      sections: [
+        { key: 'admins', title: lang('LeaveGroupAdmins'), ids: adminIds },
+        { key: 'members', title: lang('LeaveGroupMembers'), ids: memberIds },
+      ] as PeerPickerSection[],
+      filteredIds: allIds,
+    };
+  }, [search, searchResults, currentUserId, allIds, hasAdmins, adminIds, memberIds, lang]);
+
+  const pickerTitle = lang('LeaveGroupAppointOwner');
+
+  const handleLeave = useLastCallback(() => {
+    const chatId = modal?.chatId;
+    if (!chatId) return;
+
+    if (isOwnerChanged && newOwnerId) {
+      verifyTransferOwnership({
+        chatId,
+        userId: newOwnerId,
+        onSuccess: openPasswordModal,
+        onPasswordMissing: openTwoFaCheckModal,
+        onPasswordTooFresh: openTwoFaCheckModal,
+        onSessionTooFresh: openTwoFaCheckModal,
+      });
+    } else {
+      openPasswordModal();
+    }
+  });
+
+  const handleLeaveAndTransfer = useLastCallback((password: string) => {
+    const chatId = modal?.chatId;
+    if (!chatId) return;
+
+    if (isOwnerChanged && newOwnerId) {
+      transferChannelOwnership({
+        chatId,
+        userId: newOwnerId,
+        password,
+        onSuccess: () => leaveChannel({ chatId, shouldSkipOwnershipCheck: true }),
+      });
+    } else {
+      leaveChannel({ chatId, shouldSkipOwnershipCheck: true });
+    }
+    closeLeaveGroupModal();
+  });
+
+  const handleAppointOwner = useLastCallback(() => {
+    openPicker();
+  });
+
+  const handleSelectNewOwner = useLastCallback((userId: string) => {
+    setNewOwnerId(userId);
+    closePicker();
+  });
+
+  const handleClosePicker = useLastCallback(() => {
+    closePicker();
+  });
+
+  const handleLoadMore = useLastCallback(() => {
+    if (modal?.chatId) {
+      loadMoreMembers({ chatId: modal.chatId });
+    }
+  });
+
+  if (!renderingChat || !renderingCurrentUser) return undefined;
+
+  const chatTitle = getPeerTitle(lang, renderingChat);
+  const newOwnerName = newOwnerPeer ? getPeerTitle(lang, newOwnerPeer) : undefined;
+
+  return (
+    <>
+      <Modal
+        isOpen={isOpen && !isPickerOpen && !isPasswordModalOpen}
+        dialogClassName={styles.dialog}
+        onClose={closeLeaveGroupModal}
+      >
+        {newOwnerPeer && (
+          <TransferBetweenPeers fromPeer={renderingCurrentUser} toPeer={newOwnerPeer} />
+        )}
+        <h3>{lang('LeaveGroupTitle', { group: chatTitle })}</h3>
+        <p>
+          {lang('LeaveGroupDescription', {
+            nextOwner: newOwnerName,
+            group: chatTitle,
+          }, {
+            withNodes: true,
+            withMarkdown: true,
+          })}
+        </p>
+        <div className="dialog-buttons-column">
+          <Button
+            color="danger"
+            className="confirm-dialog-button"
+            isText
+            onClick={handleLeave}
+          >
+            {lang('GroupLeaveGroup')}
+          </Button>
+          {allIds.length > 0 && (
+            <Button
+              className="confirm-dialog-button"
+              isText
+              onClick={handleAppointOwner}
+            >
+              {lang('LeaveGroupAppointOwner')}
+            </Button>
+          )}
+          <Button className="confirm-dialog-button" isText onClick={() => closeLeaveGroupModal()}>
+            {lang('Cancel')}
+          </Button>
+        </div>
+      </Modal>
+      <PickerModal
+        isOpen={isPickerOpen}
+        title={pickerTitle}
+        hasCloseButton
+        shouldAdaptToSearch
+        withFixedHeight
+        onClose={handleClosePicker}
+      >
+        {sections ? (
+          <PeerPicker
+            sections={sections}
+            filterValue={search}
+            filterPlaceholder={lang('Search')}
+            isSearchable
+            isLoading={isSearchLoading}
+            withStatus
+            withDefaultPadding
+            onFilterChange={setSearch}
+            onSelectedIdChange={handleSelectNewOwner}
+            onLoadMore={handleLoadMore}
+          />
+        ) : (
+          <PeerPicker
+            itemIds={filteredIds}
+            filterValue={search}
+            filterPlaceholder={lang('Search')}
+            isSearchable
+            isLoading={isSearchLoading}
+            withStatus
+            withDefaultPadding
+            onFilterChange={setSearch}
+            onSelectedIdChange={handleSelectNewOwner}
+            onLoadMore={handleLoadMore}
+          />
+        )}
+      </PickerModal>
+      <PasswordConfirmModal
+        isOpen={isPasswordModalOpen}
+        title={lang('EnterPassword')}
+        confirmLabel={lang('Transfer')}
+        description={lang('EnterPasswordDescription')}
+        onClose={closePasswordModal}
+        onSubmit={handleLeaveAndTransfer}
+      />
+    </>
+  );
+};
+
+export default memo(withGlobal<OwnProps>(
+  (global, { modal }): Complete<StateProps> => {
+    const chat = modal?.chatId ? selectChat(global, modal.chatId) : undefined;
+    const currentUser = global.currentUserId ? selectPeer(global, global.currentUserId) : undefined;
+    const nextOwner = modal?.nextOwnerId ? selectPeer(global, modal.nextOwnerId) : undefined;
+    const fullInfo = modal?.chatId ? selectChatFullInfo(global, modal.chatId) : undefined;
+
+    return {
+      chat,
+      currentUser,
+      currentUserId: global.currentUserId,
+      nextOwner,
+      chatFullInfo: fullInfo,
+    };
+  },
+)(LeaveGroupModal));

src/components/modals/twoFaCheck/TwoFaCheckModal.async.tsx

@@ -0,0 +1,14 @@
+import type { OwnProps } from './TwoFaCheckModal';
+
+import { Bundles } from '../../../util/moduleLoader';
+
+import useModuleLoader from '../../../hooks/useModuleLoader';
+
+const TwoFaCheckModalAsync = (props: OwnProps) => {
+  const { modal } = props;
+  const TwoFaCheckModal = useModuleLoader(Bundles.Extra, 'TwoFaCheckModal', !modal);
+
+  return TwoFaCheckModal ? <TwoFaCheckModal {...props} /> : undefined;
+};
+
+export default TwoFaCheckModalAsync;

src/components/modals/twoFaCheck/TwoFaCheckModal.module.scss

@@ -0,0 +1,18 @@
+.dialog :global(.modal-dialog) {
+  max-width: 22rem !important;
+}
+
+.list {
+  margin-block: 1.5rem;
+  padding-left: 1rem;
+  text-align: left;
+
+  li {
+    margin-bottom: 1rem;
+    color: var(--color-text-secondary);
+
+    &:last-child {
+      margin-bottom: 0;
+    }
+  }
+}

src/components/modals/twoFaCheck/TwoFaCheckModal.tsx

@@ -0,0 +1,62 @@
+import { memo } from '../../../lib/teact/teact';
+import { getActions, withGlobal } from '../../../global';
+
+import type { TabState } from '../../../global/types';
+import { SettingsScreens } from '../../../types';
+
+import useLang from '../../../hooks/useLang';
+import useLastCallback from '../../../hooks/useLastCallback';
+
+import ConfirmDialog from '../../ui/ConfirmDialog';
+
+import styles from './TwoFaCheckModal.module.scss';
+
+export type OwnProps = {
+  modal: TabState['isTwoFaCheckModalOpen'];
+};
+
+type StateProps = {
+  hasPassword?: boolean;
+};
+
+const TwoFaCheckModal = ({ modal, hasPassword }: OwnProps & StateProps) => {
+  const {
+    closeTwoFaCheckModal, openSettingsScreen,
+  } = getActions();
+  const lang = useLang();
+
+  const isOpen = Boolean(modal);
+
+  const handleEnableTwoFa = useLastCallback(() => {
+    openSettingsScreen({ screen: SettingsScreens.TwoFaDisabled });
+    closeTwoFaCheckModal();
+  });
+
+  return (
+    <ConfirmDialog
+      isOpen={isOpen}
+      title={lang('SecurityCheck')}
+      className={styles.dialog}
+      confirmLabel={hasPassword ? lang('OK') : lang('SecurityCheckEnableTwoStep')}
+      confirmHandler={hasPassword ? closeTwoFaCheckModal : handleEnableTwoFa}
+      isOnlyConfirm={hasPassword}
+      areButtonsInColumn={!hasPassword}
+      onClose={closeTwoFaCheckModal}
+    >
+      <p>{lang('SecurityCheckInfo')}</p>
+      <ul className={styles.list}>
+        <li>{lang('SecurityCheckTwoStepEnabled', undefined, { withNodes: true, withMarkdown: true })}</li>
+        <li>{lang('SecurityCheckTwoStepNotChanged', undefined, { withNodes: true, withMarkdown: true })}</li>
+        <li>{lang('SecurityCheckLoggedIn', undefined, { withNodes: true, withMarkdown: true })}</li>
+      </ul>
+    </ConfirmDialog>
+  );
+};
+
+export default memo(withGlobal<OwnProps>(
+  (global): Complete<StateProps> => {
+    return {
+      hasPassword: global.settings.byKey.hasPassword,
+    };
+  },
+)(TwoFaCheckModal));

src/components/right/management/ManageGroupAdminRights.tsx

@@ -8,13 +8,15 @@ import type {
 } from '../../../api/types';
 import { ManagementScreens } from '../../../types';
 
-import { getUserFullName, isChatBasicGroup, isChatChannel } from '../../../global/helpers';
+import { getUserFullName, isChatBasicGroup, isChatChannel, isUserBot } from '../../../global/helpers';
 import { selectChat, selectChatFullInfo } from '../../../global/selectors';
 
 import useFlag from '../../../hooks/useFlag';
 import useHistoryBack from '../../../hooks/useHistoryBack';
 import useLang from '../../../hooks/useLang';
+import useLastCallback from '../../../hooks/useLastCallback';
 
+import PasswordConfirmModal from '../../common/PasswordConfirmModal';
 import PrivateChatInfo from '../../common/PrivateChatInfo';
 import Checkbox from '../../ui/Checkbox';
 import ConfirmDialog from '../../ui/ConfirmDialog';
@@ -58,12 +60,17 @@ const ManageGroupAdminRights = ({
   onClose,
   onScreenSelect,
 }: OwnProps & StateProps) => {
-  const { updateChatAdmin } = getActions();
+  const {
+    updateChatAdmin, transferChannelOwnership, showNotification,
+    openTwoFaCheckModal, verifyTransferOwnership,
+  } = getActions();
 
   const [permissions, setPermissions] = useState<ApiChatAdminRights>({});
   const [isTouched, setIsTouched] = useState(Boolean(isNewAdmin));
   const [isLoading, setIsLoading] = useState(false);
   const [isDismissConfirmationDialogOpen, openDismissConfirmationDialog, closeDismissConfirmationDialog] = useFlag();
+  const [isTransferDialogOpen, openTransferDialog, closeTransferDialog] = useFlag();
+  const [isPasswordModalOpen, openPasswordModal, closePasswordModal] = useFlag();
   const [customTitle, setCustomTitle] = useState('');
   const lang = useLang();
 
@@ -196,6 +203,52 @@ const ManageGroupAdminRights = ({
     setIsTouched(true);
   }, []);
 
+  const handleStartTransfer = useLastCallback(() => {
+    if (!selectedUserId) return;
+
+    verifyTransferOwnership({
+      chatId: chat.id,
+      userId: selectedUserId,
+      onSuccess: openTransferDialog,
+      onPasswordMissing: openTwoFaCheckModal,
+      onPasswordTooFresh: openTwoFaCheckModal,
+      onSessionTooFresh: openTwoFaCheckModal,
+    });
+  });
+
+  const handleConfirmTransfer = useLastCallback(() => {
+    closeTransferDialog();
+    openPasswordModal();
+  });
+
+  const handleTransferOwnership = useLastCallback((password: string) => {
+    if (!selectedUserId) return;
+
+    const user = usersById[selectedUserId];
+    const userName = user ? getUserFullName(user) : '';
+
+    transferChannelOwnership({
+      chatId: chat.id,
+      userId: selectedUserId,
+      password,
+      onSuccess: () => {
+        showNotification({
+          message: lang(
+            isChannel ? 'EditAdminTransferChannelOwnershipSuccess' : 'EditAdminTransferGroupOwnershipSuccess',
+            { user: userName },
+          ),
+        });
+      },
+    });
+
+    closePasswordModal();
+  });
+
+  const selectedUser = selectedUserId ? usersById[selectedUserId] : undefined;
+  const canTransferOwnership = Boolean(
+    chat.isCreator && selectedUser && !isUserBot(selectedUser) && selectedUserId !== currentUserId,
+  );
+
   if (!selectedChatMember) {
     return undefined;
   }
@@ -395,6 +448,11 @@ const ManageGroupAdminRights = ({
             />
           )}
 
+          {canTransferOwnership && currentUserId !== selectedUserId && !isFormFullyDisabled && !isNewAdmin && (
+            <ListItem icon="key" ripple onClick={handleStartTransfer}>
+              {lang(isChannel ? 'EditAdminTransferChannelOwnership' : 'EditAdminTransferGroupOwnership')}
+            </ListItem>
+          )}
           {currentUserId !== selectedUserId && !isFormFullyDisabled && !isNewAdmin && (
             <ListItem icon="delete" ripple destructive onClick={openDismissConfirmationDialog}>
               {lang('EditAdminRemoveAdmin')}
@@ -422,6 +480,24 @@ const ManageGroupAdminRights = ({
           confirmIsDestructive
         />
       )}
+      <ConfirmDialog
+        isOpen={isTransferDialogOpen}
+        onClose={closeTransferDialog}
+        title={lang(isChannel ? 'EditAdminTransferChannelOwnership' : 'EditAdminTransferGroupOwnership')}
+        textParts={lang('EditAdminTransferOwnershipText', {
+          chat: chat.title,
+          user: selectedUserId ? getUserFullName(usersById[selectedUserId]) : '',
+        }, { withNodes: true, withMarkdown: true })}
+        confirmLabel={lang('EditAdminTransferChangeOwner')}
+        confirmHandler={handleConfirmTransfer}
+      />
+      <PasswordConfirmModal
+        isOpen={isPasswordModalOpen}
+        title={lang(isChannel ? 'EditAdminTransferChannelOwnership' : 'EditAdminTransferGroupOwnership')}
+        confirmLabel={lang('EditAdminTransferChangeOwner')}
+        onClose={closePasswordModal}
+        onSubmit={handleTransferOwnership}
+      />
     </div>
   );
 };

src/global/actions/api/chats.ts

@@ -889,12 +889,28 @@ addActionHandler('deleteChat', (global, actions, payload): ActionReturnType => {
 });
 
 addActionHandler('leaveChannel', async (global, actions, payload): Promise<void> => {
-  const { chatId, tabId = getCurrentTabId() } = payload;
+  const { chatId, shouldSkipOwnershipCheck, tabId = getCurrentTabId() } = payload;
   const chat = selectChat(global, chatId);
   if (!chat) {
     return;
   }
 
+  if (!shouldSkipOwnershipCheck && chat.isCreator && chat.accessHash) {
+    const futureCreator = await callApi('fetchFutureCreatorAfterLeave', { chat });
+    if (futureCreator) {
+      global = getGlobal();
+      const hasPassword = global.settings.byKey.hasPassword;
+      if (!hasPassword) {
+        actions.openTwoFaCheckModal({ tabId });
+        return;
+      }
+
+      actions.openLeaveGroupModal({ chatId, nextOwnerId: futureCreator.id, tabId });
+      return;
+    }
+  }
+
+  global = getGlobal();
   global = leaveChat(global, chatId);
   setGlobal(global);
 
@@ -902,15 +918,76 @@ addActionHandler('leaveChannel', async (global, actions, payload): Promise<void>
     actions.openChat({ id: undefined, tabId });
   }
 
-  const { id: channelId, accessHash } = chat;
-  if (channelId && accessHash) {
-    await callApi('leaveChannel', { channelId, accessHash });
-    global = getGlobal();
-    const chatMessages = selectChatMessages(global, chatId);
-    const localMessageIds = Object.keys(chatMessages).map(Number).filter(isLocalMessageId);
-    global = deleteChatMessages(global, chatId, localMessageIds);
-    setGlobal(global);
+  await callApi('leaveChannel', { chat });
+  global = getGlobal();
+  const chatMessages = selectChatMessages(global, chatId);
+  const localMessageIds = Object.keys(chatMessages).map(Number).filter(isLocalMessageId);
+  global = deleteChatMessages(global, chatId, localMessageIds);
+  setGlobal(global);
+});
+
+addActionHandler('verifyTransferOwnership', async (global, actions, payload): Promise<void> => {
+  const {
+    chatId, userId, onSuccess, onPasswordMissing, onPasswordTooFresh, onSessionTooFresh,
+  } = payload;
+
+  const chat = selectChat(global, chatId);
+  const user = selectUser(global, userId);
+  if (!chat || !user) {
+    return;
   }
+
+  const result = await callApi('verifyTransferOwnership', {
+    chat,
+    user,
+  });
+
+  if (!result) {
+    return;
+  }
+
+  if ('canTransfer' in result) {
+    onSuccess?.();
+    return;
+  }
+
+  switch (result.errorMessage) {
+    case 'PASSWORD_MISSING':
+      onPasswordMissing?.();
+      break;
+    case 'PASSWORD_TOO_FRESH':
+      onPasswordTooFresh?.();
+      break;
+    case 'SESSION_TOO_FRESH':
+      onSessionTooFresh?.();
+      break;
+    default:
+      break;
+  }
+});
+
+addActionHandler('transferChannelOwnership', async (global, actions, payload): Promise<void> => {
+  const {
+    chatId, userId, password, onSuccess,
+  } = payload;
+
+  const chat = selectChat(global, chatId);
+  const user = selectUser(global, userId);
+  if (!chat?.accessHash || !user?.accessHash) {
+    return;
+  }
+
+  const result = await callApi('editChannelCreator', {
+    chat,
+    user,
+    password,
+  });
+
+  if (result !== true) {
+    return;
+  }
+
+  onSuccess?.();
 });
 
 addActionHandler('deleteChannel', (global, actions, payload): ActionReturnType => {

src/global/actions/ui/misc.ts

@@ -952,6 +952,29 @@ addCallback((global: GlobalState) => {
   prevBlurredTabsCount = blurredTabsCount;
 });
 
+addActionHandler('openLeaveGroupModal', (global, actions, payload): ActionReturnType => {
+  const { chatId, nextOwnerId, tabId = getCurrentTabId() } = payload;
+
+  return updateTabState(global, {
+    leaveGroupModal: {
+      chatId,
+      nextOwnerId,
+    },
+  }, tabId);
+});
+
+addTabStateResetterAction('closeLeaveGroupModal', 'leaveGroupModal');
+
+addActionHandler('openTwoFaCheckModal', (global, actions, payload): ActionReturnType => {
+  const { tabId = getCurrentTabId() } = payload || {};
+
+  return updateTabState(global, {
+    isTwoFaCheckModalOpen: true,
+  }, tabId);
+});
+
+addTabStateResetterAction('closeTwoFaCheckModal', 'isTwoFaCheckModalOpen');
+
 addActionHandler('openQuickChatPicker', (global, actions, payload): ActionReturnType => {
   const { tabId = getCurrentTabId() } = payload || {};
 

src/global/types/actions.ts

@@ -401,7 +401,10 @@ export interface ActionPayloads {
   joinChannel: {
     chatId: string;
   } & WithTabId;
-  leaveChannel: { chatId: string } & WithTabId;
+  leaveChannel: {
+    chatId: string;
+    shouldSkipOwnershipCheck?: boolean;
+  } & WithTabId;
   deleteChannel: { chatId: string } & WithTabId;
   toggleChatPinned: {
     id: string;
@@ -2556,6 +2559,29 @@ export interface ActionPayloads {
   openGiftRecipientPicker: WithTabId | undefined;
   closeGiftRecipientPicker: WithTabId | undefined;
 
+  openLeaveGroupModal: {
+    chatId: string;
+    nextOwnerId?: string;
+  } & WithTabId;
+  closeLeaveGroupModal: WithTabId | undefined;
+
+  openTwoFaCheckModal: WithTabId | undefined;
+  closeTwoFaCheckModal: WithTabId | undefined;
+
+  verifyTransferOwnership: {
+    chatId: string;
+    userId: string;
+    onSuccess?: VoidFunction;
+    onPasswordMissing?: VoidFunction;
+    onPasswordTooFresh?: VoidFunction;
+    onSessionTooFresh?: VoidFunction;
+  };
+  transferChannelOwnership: {
+    chatId: string;
+    userId: string;
+    password: string;
+    onSuccess?: VoidFunction;
+  } & WithTabId;
   openQuickChatPicker: WithTabId | undefined;
   closeQuickChatPicker: WithTabId | undefined;
 

src/global/types/tabState.ts

@@ -971,6 +971,13 @@ export type TabState = {
 
   isPasskeyModalOpen?: boolean;
 
+  leaveGroupModal?: {
+    chatId: string;
+    nextOwnerId?: string;
+  };
+
+  isTwoFaCheckModalOpen?: true;
+
   isWaitingForStarGiftUpgrade?: true;
   isWaitingForStarGiftTransfer?: true;
   insertingPeerIdMention?: string;

src/lib/gramjs/errors/RPCErrorList.ts

@@ -148,6 +148,18 @@ export class PasswordFreshError extends BadRequestError {
   }
 }
 
+export class SessionFreshError extends BadRequestError {
+  public seconds: number;
+
+  constructor(args: any) {
+    const seconds = Number(args.capture || 0);
+    super(`Session is fresh, please try again in ${seconds} seconds.`, args.request);
+
+    this.message = `Session is fresh, please try again in ${seconds} seconds.`;
+    this.seconds = seconds;
+  }
+}
+
 export class PasskeyLoginRequestedError extends Error {
   public credentialJson: PublicKeyCredentialJSON;
 
@@ -185,6 +197,7 @@ export const rpcErrorRe = new Map<RegExp, any>([
   [/NETWORK_MIGRATE_(\d+)/, NetworkMigrateError],
   [/EMAIL_UNCONFIRMED_(\d+)/, EmailUnconfirmedError],
   [/PASSWORD_TOO_FRESH_(\d+)/, PasswordFreshError],
+  [/SESSION_TOO_FRESH_(\d+)/, SessionFreshError],
   [/^Timeout$/, TimedOutError],
   [/PASSKEY_CREDENTIAL_NOT_FOUND/, PasskeyCredentialNotFoundError],
 ]);

src/lib/gramjs/tl/apiTl.ts

@@ -1836,6 +1836,7 @@ channels.readMessageContents#eab5dc38 channel:InputChannel id:Vector<int> = Bool
 channels.togglePreHistoryHidden#eabbb94c channel:InputChannel enabled:Bool = Updates;
 channels.getGroupsForDiscussion#f5dad378 = messages.Chats;
 channels.setDiscussionGroup#40582bb2 broadcast:InputChannel group:InputChannel = Bool;
+channels.editCreator#8f38cd1f channel:InputChannel user_id:InputUser password:InputCheckPasswordSRP = Updates;
 channels.getSendAs#e785a43f flags:# for_paid_reactions:flags.0?true for_live_stories:flags.1?true peer:InputPeer = channels.SendAsPeers;
 channels.deleteParticipantHistory#367544db channel:InputChannel participant:InputPeer = messages.AffectedHistory;
 channels.toggleJoinToSend#e4cb9580 channel:InputChannel enabled:Bool = Updates;
@@ -1852,6 +1853,7 @@ channels.updatePaidMessagesPrice#4b12327b flags:# broadcast_messages_allowed:fla
 channels.toggleAutotranslation#167fc0a1 channel:InputChannel enabled:Bool = Updates;
 channels.checkSearchPostsFlood#22567115 flags:# query:flags.0?string = SearchPostsFlood;
 channels.setMainProfileTab#3583fcb1 channel:InputChannel tab:ProfileTab = Bool;
+channels.getFutureCreatorAfterLeave#a00918af channel:InputChannel = User;
 bots.setBotInfo#10cf3123 flags:# bot:flags.2?InputUser lang_code:string name:flags.3?string about:flags.0?string description:flags.1?string = Bool;
 bots.canSendMessage#1359f4e6 bot:InputUser = Bool;
 bots.allowSendMessage#f132e3ef bot:InputUser = Updates;

src/lib/gramjs/tl/static/api.json

@@ -295,6 +295,7 @@
     "channels.togglePreHistoryHidden",
     "channels.getGroupsForDiscussion",
     "channels.setDiscussionGroup",
+    "channels.editCreator",
     "channels.getSendAs",
     "channels.toggleJoinToSend",
     "channels.toggleJoinRequest",
@@ -396,6 +397,7 @@
     "channels.toggleForum",
     "channels.toggleParticipantsHidden",
     "channels.toggleViewForumAsMessages",
+    "channels.getFutureCreatorAfterLeave",
     "photos.uploadContactProfilePhoto",
     "messages.getMessagesViews",
     "chatlists.exportChatlistInvite",

src/types/language.d.ts

@@ -844,6 +844,9 @@ export interface LangPair {
   'ChannelEditAdminCannotEdit': undefined;
   'EditAdminRank': undefined;
   'EditAdminRemoveAdmin': undefined;
+  'EditAdminTransferChannelOwnership': undefined;
+  'EditAdminTransferGroupOwnership': undefined;
+  'EditAdminTransferChangeOwner': undefined;
   'ChannelAdminDismiss': undefined;
   'ChannelPermissionsHeader': undefined;
   'UserRestrictionsSend': undefined;
@@ -1917,6 +1920,18 @@ export interface LangPair {
   'SettingsDataClearMediaCache': undefined;
   'SettingsDataClearMediaCacheDescription': undefined;
   'SettingsDataClearMediaDone': undefined;
+  'LeaveGroupAppointOwner': undefined;
+  'LeaveGroupAdmins': undefined;
+  'LeaveGroupMembers': undefined;
+  'SecurityCheck': undefined;
+  'SecurityCheckInfo': undefined;
+  'SecurityCheckTwoStepEnabled': undefined;
+  'SecurityCheckTwoStepNotChanged': undefined;
+  'SecurityCheckLoggedIn': undefined;
+  'SecurityCheckEnableTwoStep': undefined;
+  'EnterPassword': undefined;
+  'EnterPasswordDescription': undefined;
+  'Transfer': undefined;
   'TranslateMenuCocoonLinkText': undefined;
   'CocoonTitle': undefined;
   'CocoonDescription': undefined;
@@ -2101,6 +2116,9 @@ export interface LangPairWithVariables<V = LangVariable> {
   'ErrorPasswordFresh': {
     'time': V;
   };
+  'ErrorSessionFresh': {
+    'time': V;
+  };
   'ErrorUnexpectedMessage': {
     'error': V;
   };
@@ -2150,6 +2168,16 @@ export interface LangPairWithVariables<V = LangVariable> {
   'AreYouSureDeleteThisChatWithGroup': {
     'chat': V;
   };
+  'EditAdminTransferOwnershipText': {
+    'chat': V;
+    'user': V;
+  };
+  'EditAdminTransferChannelOwnershipSuccess': {
+    'user': V;
+  };
+  'EditAdminTransferGroupOwnershipSuccess': {
+    'user': V;
+  };
   'LinkExpiresIn': {
     'time': V;
   };
@@ -3274,6 +3302,14 @@ export interface LangPairWithVariables<V = LangVariable> {
   'ActionStarGiftPrepaidUpgraded': {
     'user': V;
   };
+  'ActionNewCreatorPending': {
+    'user': V;
+    'from': V;
+  };
+  'ActionChangeCreator': {
+    'from': V;
+    'user': V;
+  };
   'FileTransferProgress': {
     'currentSize': V;
     'totalSize': V;
@@ -3375,6 +3411,16 @@ export interface LangPairWithVariables<V = LangVariable> {
     'status': V;
     'onlineCount': V;
   };
+  'LeaveGroupTitle': {
+    'group': V;
+  };
+  'LeaveGroupDescription': {
+    'nextOwner': V;
+    'group': V;
+  };
+  'LeaveGroupJoinedDate': {
+    'date': V;
+  };
   'TranslateMenuCocoon': {
     'link': V;
   };

src/util/getReadableErrorText.ts

@@ -71,6 +71,8 @@ const READABLE_ERROR_MESSAGES: Record<string, string> = {
   ADMIN_RANK_EMOJI_NOT_ALLOWED: 'An admin rank cannot contain emojis',
   ADMIN_RANK_INVALID: 'The specified admin rank is invalid',
   FRESH_CHANGE_ADMINS_FORBIDDEN: 'You were just elected admin, you can\'t add or modify other admins yet',
+  SESSION_TOO_FRESH: 'Session is fresh, please try again later',
+  SESSION_IS_FRESH: 'Session is fresh, please try again later',
   INPUT_USER_DEACTIVATED: 'Can\'t do this action to a deleted account',
   BOT_PRECHECKOUT_TIMEOUT: 'The request for payment has expired',
   PROVIDER_ACCOUNT_TIMEOUT: 'Request to the payment provider has expired',