From 4960e08a24a992b1fab7be27c1026a612dc4cd02 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 15 Nov 2018 19:36:04 +0400
Subject: [PATCH] Display occupied chats using drafts for support.

---
 Telegram/SourceFiles/apiwrap.cpp              |   6 +-
 Telegram/SourceFiles/auth_session.cpp         |  16 +-
 Telegram/SourceFiles/auth_session.h           |   6 +-
 Telegram/SourceFiles/data/data_drafts.cpp     |  27 ++-
 Telegram/SourceFiles/data/data_drafts.h       |  11 +-
 .../dialogs/dialogs_indexed_list.cpp          |   2 +-
 .../dialogs/dialogs_inner_widget.cpp          |   5 +-
 .../SourceFiles/dialogs/dialogs_layout.cpp    |  12 +-
 Telegram/SourceFiles/history/history.cpp      |  10 +-
 Telegram/SourceFiles/history/history.h        |   2 +-
 .../view/history_view_top_bar_widget.cpp      |  53 ++---
 .../view/history_view_top_bar_widget.h        |   3 +-
 Telegram/SourceFiles/mainwidget.cpp           |  33 ++-
 Telegram/SourceFiles/observer_peer.h          |  39 ++--
 .../support/support_autocomplete.cpp          |  12 +-
 .../SourceFiles/support/support_helper.cpp    | 220 ++++++++++++++++++
 Telegram/SourceFiles/support/support_helper.h |  56 +++++
 .../SourceFiles/window/window_controller.cpp  |   5 +
 .../SourceFiles/window/window_main_menu.cpp   |   4 +-
 Telegram/gyp/telegram_sources.txt             |   2 +
 20 files changed, 429 insertions(+), 95 deletions(-)
 create mode 100644 Telegram/SourceFiles/support/support_helper.cpp
 create mode 100644 Telegram/SourceFiles/support/support_helper.h

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index 50dbf919e..9a095ea92 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -2193,7 +2193,11 @@ void ApiWrap::saveDraftsToCloud() {
 		if (cloudDraft && cloudDraft->saveRequestId) {
 			request(base::take(cloudDraft->saveRequestId)).cancel();
 		}
-		cloudDraft = history->createCloudDraft(localDraft);
+		if (!Auth().supportMode()) {
+			cloudDraft = history->createCloudDraft(localDraft);
+		} else if (!cloudDraft) {
+			cloudDraft = history->createCloudDraft(nullptr);
+		}
 
 		auto flags = MTPmessages_SaveDraft::Flags(0);
 		auto &textWithTags = cloudDraft->textWithTags;
diff --git a/Telegram/SourceFiles/auth_session.cpp b/Telegram/SourceFiles/auth_session.cpp
index a78833585..afd4aaea8 100644
--- a/Telegram/SourceFiles/auth_session.cpp
+++ b/Telegram/SourceFiles/auth_session.cpp
@@ -25,7 +25,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/send_files_box.h"
 #include "ui/widgets/input_fields.h"
 #include "support/support_common.h"
-#include "support/support_templates.h"
+#include "support/support_helper.h"
 #include "observer_peer.h"
 
 namespace {
@@ -342,9 +342,9 @@ AuthSession::AuthSession(const MTPUser &user)
 , _notifications(std::make_unique<Window::Notifications::System>(this))
 , _data(std::make_unique<Data::Session>(this))
 , _changelogs(Core::Changelogs::Create(this))
-, _supportTemplates(
+, _supportHelper(
 	(Support::ValidateAccount(user)
-		? std::make_unique<Support::Templates>(this)
+		? std::make_unique<Support::Helper>(this)
 		: nullptr)) {
 	App::feedUser(user);
 
@@ -457,13 +457,17 @@ void AuthSession::checkAutoLockIn(TimeMs time) {
 }
 
 bool AuthSession::supportMode() const {
-	return (_supportTemplates != nullptr);
+	return (_supportHelper != nullptr);
 }
 
-not_null<Support::Templates*> AuthSession::supportTemplates() const {
+Support::Helper &AuthSession::supportHelper() const {
 	Expects(supportMode());
 
-	return _supportTemplates.get();
+	return *_supportHelper;
+}
+
+Support::Templates& AuthSession::supportTemplates() const {
+	return supportHelper().templates();
 }
 
 AuthSession::~AuthSession() = default;
diff --git a/Telegram/SourceFiles/auth_session.h b/Telegram/SourceFiles/auth_session.h
index 1c72c376f..16ab3bd61 100644
--- a/Telegram/SourceFiles/auth_session.h
+++ b/Telegram/SourceFiles/auth_session.h
@@ -21,6 +21,7 @@ enum class InputSubmitSettings;
 
 namespace Support {
 enum class SwitchSettings;
+class Helper;
 class Templates;
 } // namespace Support
 
@@ -301,7 +302,8 @@ public:
 	base::Observable<std::pair<not_null<HistoryItem*>, MsgId>> messageIdChanging;
 
 	bool supportMode() const;
-	not_null<Support::Templates*> supportTemplates() const;
+	Support::Helper &supportHelper() const;
+	Support::Templates &supportTemplates() const;
 
 	~AuthSession();
 
@@ -328,7 +330,7 @@ private:
 	// _changelogs depends on _data, subscribes on chats loading event.
 	const std::unique_ptr<Core::Changelogs> _changelogs;
 
-	const std::unique_ptr<Support::Templates> _supportTemplates;
+	const std::unique_ptr<Support::Helper> _supportHelper;
 
 	rpl::lifetime _lifetime;
 
diff --git a/Telegram/SourceFiles/data/data_drafts.cpp b/Telegram/SourceFiles/data/data_drafts.cpp
index 37e4e6296..2e29b86ed 100644
--- a/Telegram/SourceFiles/data/data_drafts.cpp
+++ b/Telegram/SourceFiles/data/data_drafts.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/history_widget.h"
 #include "mainwidget.h"
 #include "storage/localstorage.h"
+#include "support/support_helper.h"
 
 namespace Data {
 namespace {
@@ -44,8 +45,8 @@ Draft::Draft(
 }
 
 void applyPeerCloudDraft(PeerId peerId, const MTPDdraftMessage &draft) {
-	auto history = App::history(peerId);
-	auto textWithTags = TextWithTags {
+	const auto history = App::history(peerId);
+	const auto textWithTags = TextWithTags {
 		qs(draft.vmessage),
 		ConvertEntitiesToTextTags(
 			draft.has_entities()
@@ -56,14 +57,23 @@ void applyPeerCloudDraft(PeerId peerId, const MTPDdraftMessage &draft) {
 		return;
 	}
 	auto replyTo = draft.has_reply_to_msg_id() ? draft.vreply_to_msg_id.v : MsgId(0);
-	auto cloudDraft = std::make_unique<Draft>(textWithTags, replyTo, MessageCursor(QFIXED_MAX, QFIXED_MAX, QFIXED_MAX), draft.is_no_webpage());
+	auto cloudDraft = std::make_unique<Draft>(
+		textWithTags,
+		replyTo,
+		MessageCursor(QFIXED_MAX, QFIXED_MAX, QFIXED_MAX),
+		draft.is_no_webpage());
 	cloudDraft->date = draft.vdate.v;
 
 	history->setCloudDraft(std::move(cloudDraft));
 	history->createLocalDraftFromCloud();
-	history->updateChatListSortPosition();
+	if (Auth().supportMode()) {
+		history->updateChatListEntry();
+		Auth().supportHelper().cloudDraftChanged(history);
+	} else {
+		history->updateChatListSortPosition();
+	}
 
-	if (auto main = App::main()) {
+	if (const auto main = App::main()) {
 		main->applyCloudDraft(history);
 	}
 }
@@ -77,7 +87,12 @@ void clearPeerCloudDraft(PeerId peerId, TimeId date) {
 	history->clearCloudDraft();
 	history->clearLocalDraft();
 
-	history->updateChatListSortPosition();
+	if (Auth().supportMode()) {
+		history->updateChatListEntry();
+		Auth().supportHelper().cloudDraftChanged(history);
+	} else {
+		history->updateChatListSortPosition();
+	}
 
 	if (auto main = App::main()) {
 		main->applyCloudDraft(history);
diff --git a/Telegram/SourceFiles/data/data_drafts.h b/Telegram/SourceFiles/data/data_drafts.h
index 865e81506..c3ccdc3f8 100644
--- a/Telegram/SourceFiles/data/data_drafts.h
+++ b/Telegram/SourceFiles/data/data_drafts.h
@@ -47,11 +47,12 @@ inline bool draftStringIsEmpty(const QString &text) {
 	return true;
 }
 
-inline bool draftIsNull(Draft *draft) {
-	return !draft || (draftStringIsEmpty(draft->textWithTags.text) && !draft->msgId);
+inline bool draftIsNull(const Draft *draft) {
+	return !draft
+		|| (draftStringIsEmpty(draft->textWithTags.text) && !draft->msgId);
 }
 
-inline bool draftsAreEqual(Draft *a, Draft *b) {
+inline bool draftsAreEqual(const Draft *a, const Draft *b) {
 	bool aIsNull = draftIsNull(a);
 	bool bIsNull = draftIsNull(b);
 	if (aIsNull) {
@@ -60,7 +61,9 @@ inline bool draftsAreEqual(Draft *a, Draft *b) {
 		return false;
 	}
 
-	return (a->textWithTags == b->textWithTags) && (a->msgId == b->msgId) && (a->previewCancelled == b->previewCancelled);
+	return (a->textWithTags == b->textWithTags)
+		&& (a->msgId == b->msgId)
+		&& (a->previewCancelled == b->previewCancelled);
 }
 
 } // namespace Data
diff --git a/Telegram/SourceFiles/dialogs/dialogs_indexed_list.cpp b/Telegram/SourceFiles/dialogs/dialogs_indexed_list.cpp
index 784b80e49..b6a85cb8a 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_indexed_list.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_indexed_list.cpp
@@ -55,7 +55,7 @@ Row *IndexedList::addByName(Key key) {
 }
 
 void IndexedList::adjustByPos(const RowsByLetter &links) {
-	for (auto [ch, row] : links) {
+	for (const auto [ch, row] : links) {
 		if (ch == QChar(0)) {
 			_list.adjustByPos(row);
 		} else {
diff --git a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
index ce0f705cd..9fa1ae662 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
@@ -124,7 +124,8 @@ DialogsInner::DialogsInner(QWidget *parent, not_null<Window::Controller*> contro
 	auto changes = UpdateFlag::ChatPinnedChanged
 		| UpdateFlag::NameChanged
 		| UpdateFlag::PhotoChanged
-		| UpdateFlag::UserIsContact;
+		| UpdateFlag::UserIsContact
+		| UpdateFlag::OccupiedChanged;
 	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(changes, [this](const Notify::PeerUpdate &update) {
 		if (update.flags & UpdateFlag::ChatPinnedChanged) {
 			stopReorderPinned();
@@ -132,7 +133,7 @@ DialogsInner::DialogsInner(QWidget *parent, not_null<Window::Controller*> contro
 		if (update.flags & UpdateFlag::NameChanged) {
 			handlePeerNameChange(update.peer, update.oldNameFirstLetters);
 		}
-		if (update.flags & UpdateFlag::PhotoChanged) {
+		if (update.flags & (UpdateFlag::PhotoChanged | UpdateFlag::OccupiedChanged)) {
 			this->update();
 			emit App::main()->dialogsUpdated();
 		}
diff --git a/Telegram/SourceFiles/dialogs/dialogs_layout.cpp b/Telegram/SourceFiles/dialogs/dialogs_layout.cpp
index e89768168..0d9a07fd0 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_layout.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_layout.cpp
@@ -15,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/empty_userpic.h"
 #include "ui/text_options.h"
 #include "lang/lang_keys.h"
+#include "support/support_helper.h"
 #include "history/history_item.h"
 #include "history/history.h"
 
@@ -173,6 +174,11 @@ void paintRow(
 		TimeMs ms,
 		PaintItemCallback &&paintItemCallback,
 		PaintCounterCallback &&paintCounterCallback) {
+	const auto supportMode = Auth().supportMode();
+	if (supportMode) {
+		draft = nullptr;
+	}
+
 	auto active = (flags & Flag::Active);
 	auto selected = (flags & Flag::Selected);
 	auto fullRect = QRect(0, 0, fullWidth, st::dialogsRowHeight);
@@ -250,7 +256,7 @@ void paintRow(
 	auto texttop = st::dialogsPadding.y()
 		+ st::msgNameFont->height
 		+ st::dialogsSkip;
-	if (draft) {
+	if (draft || (supportMode && Support::IsOccupiedBySomeone(history))) {
 		if (!promoted) {
 			paintRowDate(p, date, rectForName, active, selected);
 		}
@@ -267,7 +273,9 @@ void paintRow(
 		if (history && !history->paintSendAction(p, nameleft, texttop, availableWidth, fullWidth, color, ms)) {
 			if (history->cloudDraftTextCache.isEmpty()) {
 				auto draftWrapped = textcmdLink(1, lng_dialogs_text_from_wrapped(lt_from, lang(lng_from_draft)));
-				auto draftText = lng_dialogs_text_with_from(lt_from_part, draftWrapped, lt_message, TextUtilities::Clean(draft->textWithTags.text));
+				auto draftText = supportMode
+					? textcmdLink(1, Support::ChatOccupiedString())
+					: lng_dialogs_text_with_from(lt_from_part, draftWrapped, lt_message, TextUtilities::Clean(draft->textWithTags.text));
 				history->cloudDraftTextCache.setText(st::dialogsTextStyle, draftText, Ui::DialogTextOptions());
 			}
 			p.setPen(active ? st::dialogsTextFgActive : (selected ? st::dialogsTextFgOver : st::dialogsTextFg));
diff --git a/Telegram/SourceFiles/history/history.cpp b/Telegram/SourceFiles/history/history.cpp
index ce64c3e94..f7f113819 100644
--- a/Telegram/SourceFiles/history/history.cpp
+++ b/Telegram/SourceFiles/history/history.cpp
@@ -348,12 +348,14 @@ void History::takeLocalDraft(History *from) {
 
 void History::createLocalDraftFromCloud() {
 	auto draft = cloudDraft();
-	if (Data::draftIsNull(draft) || !draft->date) {
+	if (Data::draftIsNull(draft) || !draft->date || Auth().supportMode()) {
 		return;
 	}
 
 	auto existing = localDraft();
-	if (Data::draftIsNull(existing) || !existing->date || draft->date >= existing->date) {
+	if (Data::draftIsNull(existing)
+		|| !existing->date
+		|| draft->date >= existing->date) {
 		if (!existing) {
 			setLocalDraft(std::make_unique<Data::Draft>(
 				draft->textWithTags,
@@ -376,7 +378,7 @@ void History::setCloudDraft(std::unique_ptr<Data::Draft> &&draft) {
 	cloudDraftTextCache.clear();
 }
 
-Data::Draft *History::createCloudDraft(Data::Draft *fromDraft) {
+Data::Draft *History::createCloudDraft(const Data::Draft *fromDraft) {
 	if (Data::draftIsNull(fromDraft)) {
 		setCloudDraft(std::make_unique<Data::Draft>(
 			TextWithTags(),
@@ -1830,7 +1832,7 @@ std::shared_ptr<AdminLog::LocalIdManager> History::adminLogIdManager() {
 TimeId History::adjustChatListTimeId() const {
 	const auto result = chatsListTimeId();
 	if (const auto draft = cloudDraft()) {
-		if (!Data::draftIsNull(draft)) {
+		if (!Data::draftIsNull(draft) && !Auth().supportMode()) {
 			return std::max(result, draft->date);
 		}
 	}
diff --git a/Telegram/SourceFiles/history/history.h b/Telegram/SourceFiles/history/history.h
index e80255eb8..44de34fbc 100644
--- a/Telegram/SourceFiles/history/history.h
+++ b/Telegram/SourceFiles/history/history.h
@@ -306,7 +306,7 @@ public:
 	void takeLocalDraft(History *from);
 	void createLocalDraftFromCloud();
 	void setCloudDraft(std::unique_ptr<Data::Draft> &&draft);
-	Data::Draft *createCloudDraft(Data::Draft *fromDraft);
+	Data::Draft *createCloudDraft(const Data::Draft *fromDraft);
 	bool skipCloudDraft(const QString &text, TimeId date) const;
 	void setSentDraftText(const QString &text);
 	void clearSentDraftText(const QString &text);
diff --git a/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp b/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp
index 2f922edc7..5fc06ced0 100644
--- a/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp
+++ b/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "calls/calls_instance.h"
 #include "data/data_peer_values.h"
 #include "data/data_feed.h"
+#include "support/support_helper.h"
 #include "observer_peer.h"
 #include "apiwrap.h"
 #include "styles/style_window.h"
@@ -52,6 +53,7 @@ TopBarWidget::TopBarWidget(
 , _search(this, st::topBarSearch)
 , _infoToggle(this, st::topBarInfo)
 , _menuToggle(this, st::topBarMenuToggle)
+, _titlePeerText(st::windowMinWidth / 3)
 , _onlineUpdater([this] { updateOnlineDisplay(); }) {
 	subscribe(Lang::Current().updated(), [this] { refreshLang(); });
 	setAttribute(Qt::WA_OpaquePaintEvent);
@@ -104,7 +106,8 @@ TopBarWidget::TopBarWidget(
 	using UpdateFlag = Notify::PeerUpdate::Flag;
 	auto flags = UpdateFlag::UserHasCalls
 		| UpdateFlag::UserOnlineChanged
-		| UpdateFlag::MembersChanged;
+		| UpdateFlag::MembersChanged
+		| UpdateFlag::OccupiedChanged;
 	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(flags, [this](const Notify::PeerUpdate &update) {
 		if (update.flags & UpdateFlag::UserHasCalls) {
 			if (update.peer->isUser()) {
@@ -331,14 +334,15 @@ void TopBarWidget::paintTopBar(Painter &p, TimeMs ms) {
 		p.setFont(st::dialogsTextFont);
 		if (paintConnectingState(p, nameleft, statustop, width(), ms)) {
 			return;
-		} else if (history->paintSendAction(
-			p,
-			nameleft,
-			statustop,
-			namewidth,
-			width(),
-			st::historyStatusFgTyping,
-			ms)) {
+		} else if (!Support::IsOccupiedBySomeone(history)
+			&& history->paintSendAction(
+				p,
+				nameleft,
+				statustop,
+				namewidth,
+				width(),
+				st::historyStatusFgTyping,
+				ms)) {
 			return;
 		} else {
 			paintStatus(p, nameleft, statustop, namewidth, width());
@@ -379,25 +383,20 @@ void TopBarWidget::paintStatus(
 		int top,
 		int availableWidth,
 		int outerWidth) {
-	auto statustext = _titlePeerText;
-	auto statuswidth = _titlePeerTextWidth;
-	if (statuswidth > availableWidth) {
-		statustext = st::dialogsTextFont->elided(
-			statustext,
-			availableWidth,
-			Qt::ElideLeft);
-		statuswidth = st::dialogsTextFont->width(statustext);
-	}
-	p.setPen(_titlePeerTextOnline
+	const auto occupied = Auth().supportMode()
+		&& Support::IsOccupiedBySomeone(_activeChat.history());
+	p.setPen(occupied
+		? st::dialogsTextPaletteDraft.linkFg
+		: _titlePeerTextOnline
 		? st::historyStatusFgActive
 		: st::historyStatusFg);
-	p.drawTextLeft(left, top, outerWidth, statustext, statuswidth);
+	_titlePeerText.drawLeftElided(p, left, top, availableWidth, outerWidth);
 }
 
 QRect TopBarWidget::getMembersShowAreaGeometry() const {
 	int membersTextLeft = _leftTaken;
 	int membersTextTop = st::topBarHeight - st::topBarArrowPadding.bottom() - st::dialogsTextFont->height;
-	int membersTextWidth = _titlePeerTextWidth;
+	int membersTextWidth = _titlePeerText.maxWidth();
 	int membersTextHeight = st::topBarHeight - membersTextTop;
 
 	return myrtlrect(membersTextLeft, membersTextTop, membersTextWidth, membersTextHeight);
@@ -745,7 +744,10 @@ void TopBarWidget::updateOnlineDisplay() {
 	QString text;
 	const auto now = unixtime();
 	bool titlePeerTextOnline = false;
-	if (const auto user = _activeChat.peer()->asUser()) {
+	if (Auth().supportMode()
+		&& Support::IsOccupiedBySomeone(_activeChat.history())) {
+		text = Support::ChatOccupiedString();
+	} else if (const auto user = _activeChat.peer()->asUser()) {
 		text = Data::OnlineText(user, now);
 		titlePeerTextOnline = Data::OnlineTextActive(user, now);
 	} else if (const auto chat = _activeChat.peer()->asChat()) {
@@ -753,7 +755,7 @@ void TopBarWidget::updateOnlineDisplay() {
 			text = lang(lng_chat_status_unaccessible);
 		} else if (chat->participants.empty()) {
 			if (!_titlePeerText.isEmpty()) {
-				text = _titlePeerText;
+				text = _titlePeerText.originalText();
 			} else if (chat->count <= 0) {
 				text = lang(lng_group_status);
 			} else {
@@ -810,10 +812,9 @@ void TopBarWidget::updateOnlineDisplay() {
 			text = lang(channel->isMegagroup() ? lng_group_status : lng_channel_status);
 		}
 	}
-	if (_titlePeerText != text) {
-		_titlePeerText = text;
+	if (_titlePeerText.originalText() != text) {
+		_titlePeerText.setText(st::dialogsTextStyle, text);
 		_titlePeerTextOnline = titlePeerTextOnline;
-		_titlePeerTextWidth = st::dialogsTextFont->width(_titlePeerText);
 		updateMembersShowArea();
 		update();
 	}
diff --git a/Telegram/SourceFiles/history/view/history_view_top_bar_widget.h b/Telegram/SourceFiles/history/view/history_view_top_bar_widget.h
index 8ee034726..25eb17128 100644
--- a/Telegram/SourceFiles/history/view/history_view_top_bar_widget.h
+++ b/Telegram/SourceFiles/history/view/history_view_top_bar_widget.h
@@ -136,9 +136,8 @@ private:
 	object_ptr<TWidget> _membersShowArea = { nullptr };
 	rpl::event_stream<bool> _membersShowAreaActive;
 
-	QString _titlePeerText;
+	Text _titlePeerText;
 	bool _titlePeerTextOnline = false;
-	int _titlePeerTextWidth = 0;
 	int _leftTaken = 0;
 	int _rightTaken = 0;
 	bool _animatingMode = false;
diff --git a/Telegram/SourceFiles/mainwidget.cpp b/Telegram/SourceFiles/mainwidget.cpp
index af393c782..ee9b36b6e 100644
--- a/Telegram/SourceFiles/mainwidget.cpp
+++ b/Telegram/SourceFiles/mainwidget.cpp
@@ -3840,13 +3840,14 @@ void MainWidget::updateOnline(bool gotOtherOffline) {
 void MainWidget::saveDraftToCloud() {
 	_history->saveFieldToHistoryLocalDraft();
 
-	auto peer = _history->peer();
-	if (auto history = App::historyLoaded(peer)) {
+	const auto peer = _history->peer();
+	if (const auto history = App::historyLoaded(peer)) {
 		writeDrafts(history);
 
-		auto localDraft = history->localDraft();
-		auto cloudDraft = history->cloudDraft();
-		if (!Data::draftsAreEqual(localDraft, cloudDraft)) {
+		const auto localDraft = history->localDraft();
+		const auto cloudDraft = history->cloudDraft();
+		if (!Data::draftsAreEqual(localDraft, cloudDraft)
+			&& !Auth().supportMode()) {
 			Auth().api().saveDraftToCloudDelayed(history);
 		}
 	}
@@ -3859,17 +3860,27 @@ void MainWidget::applyCloudDraft(History *history) {
 void MainWidget::writeDrafts(History *history) {
 	Local::MessageDraft storedLocalDraft, storedEditDraft;
 	MessageCursor localCursor, editCursor;
-	if (auto localDraft = history->localDraft()) {
-		if (!Data::draftsAreEqual(localDraft, history->cloudDraft())) {
-			storedLocalDraft = Local::MessageDraft(localDraft->msgId, localDraft->textWithTags, localDraft->previewCancelled);
+	if (const auto localDraft = history->localDraft()) {
+		if (Auth().supportMode()
+			|| !Data::draftsAreEqual(localDraft, history->cloudDraft())) {
+			storedLocalDraft = Local::MessageDraft(
+				localDraft->msgId,
+				localDraft->textWithTags,
+				localDraft->previewCancelled);
 			localCursor = localDraft->cursor;
 		}
 	}
-	if (auto editDraft = history->editDraft()) {
-		storedEditDraft = Local::MessageDraft(editDraft->msgId, editDraft->textWithTags, editDraft->previewCancelled);
+	if (const auto editDraft = history->editDraft()) {
+		storedEditDraft = Local::MessageDraft(
+			editDraft->msgId,
+			editDraft->textWithTags,
+			editDraft->previewCancelled);
 		editCursor = editDraft->cursor;
 	}
-	Local::writeDrafts(history->peer->id, storedLocalDraft, storedEditDraft);
+	Local::writeDrafts(
+		history->peer->id,
+		storedLocalDraft,
+		storedEditDraft);
 	Local::writeDraftCursors(history->peer->id, localCursor, editCursor);
 }
 
diff --git a/Telegram/SourceFiles/observer_peer.h b/Telegram/SourceFiles/observer_peer.h
index bff96e7e9..f416c2c39 100644
--- a/Telegram/SourceFiles/observer_peer.h
+++ b/Telegram/SourceFiles/observer_peer.h
@@ -39,33 +39,34 @@ struct PeerUpdate {
 		RestrictionReasonChanged  = (1 << 8),
 		UnreadViewChanged         = (1 << 9),
 		PinnedMessageChanged      = (1 << 10),
+		OccupiedChanged           = (1 << 11),
 
 		// For chats and channels
-		InviteLinkChanged         = (1 << 11),
-		MembersChanged            = (1 << 12),
-		AdminsChanged             = (1 << 13),
-		BannedUsersChanged        = (1 << 14),
-		UnreadMentionsChanged     = (1 << 15),
+		InviteLinkChanged         = (1 << 12),
+		MembersChanged            = (1 << 13),
+		AdminsChanged             = (1 << 14),
+		BannedUsersChanged        = (1 << 15),
+		UnreadMentionsChanged     = (1 << 16),
 
 		// For users
-		UserCanShareContact       = (1 << 16),
-		UserIsContact             = (1 << 17),
-		UserPhoneChanged          = (1 << 18),
-		UserIsBlocked             = (1 << 19),
-		BotCommandsChanged        = (1 << 20),
-		UserOnlineChanged         = (1 << 21),
-		BotCanAddToGroups         = (1 << 22),
-		UserCommonChatsChanged    = (1 << 23),
-		UserHasCalls              = (1 << 24),
+		UserCanShareContact       = (1 << 17),
+		UserIsContact             = (1 << 18),
+		UserPhoneChanged          = (1 << 19),
+		UserIsBlocked             = (1 << 20),
+		BotCommandsChanged        = (1 << 21),
+		UserOnlineChanged         = (1 << 22),
+		BotCanAddToGroups         = (1 << 23),
+		UserCommonChatsChanged    = (1 << 24),
+		UserHasCalls              = (1 << 25),
 
 		// For chats
-		ChatCanEdit               = (1 << 16),
+		ChatCanEdit               = (1 << 17),
 
 		// For channels
-		ChannelAmIn               = (1 << 16),
-		ChannelRightsChanged      = (1 << 17),
-		ChannelStickersChanged    = (1 << 18),
-		ChannelPromotedChanged    = (1 << 19),
+		ChannelAmIn               = (1 << 17),
+		ChannelRightsChanged      = (1 << 18),
+		ChannelStickersChanged    = (1 << 19),
+		ChannelPromotedChanged    = (1 << 20),
 	};
 	using Flags = base::flags<Flag>;
 	friend inline constexpr auto is_flag_type(Flag) { return true; }
diff --git a/Telegram/SourceFiles/support/support_autocomplete.cpp b/Telegram/SourceFiles/support/support_autocomplete.cpp
index fcf7c66d6..7b5d2e591 100644
--- a/Telegram/SourceFiles/support/support_autocomplete.cpp
+++ b/Telegram/SourceFiles/support/support_autocomplete.cpp
@@ -328,11 +328,11 @@ Autocomplete::Autocomplete(QWidget *parent, not_null<AuthSession*> session)
 }
 
 void Autocomplete::activate(not_null<Ui::InputField*> field) {
-	if (Auth().settings().supportTemplatesAutocomplete()) {
+	if (_session->settings().supportTemplatesAutocomplete()) {
 		_activate();
 	} else {
-		const auto templates = Auth().supportTemplates();
-		const auto max = templates->maxKeyLength();
+		const auto &templates = _session->supportTemplates();
+		const auto max = templates.maxKeyLength();
 		auto cursor = field->textCursor();
 		const auto position = cursor.position();
 		const auto anchor = cursor.anchor();
@@ -344,8 +344,8 @@ void Autocomplete::activate(not_null<Ui::InputField*> field) {
 				std::max(position - max, 0),
 				position);
 		const auto result = (position != anchor)
-			? templates->matchExact(text.text)
-			: templates->matchFromEnd(text.text);
+			? templates.matchExact(text.text)
+			: templates.matchFromEnd(text.text);
 		if (result) {
 			const auto till = std::max(position, anchor);
 			const auto from = till - result->key.size();
@@ -410,7 +410,7 @@ void Autocomplete::setupContent() {
 
 	const auto refresh = [=] {
 		inner->showRows(
-			_session->supportTemplates()->query(input->getLastText()));
+			_session->supportTemplates().query(input->getLastText()));
 		scroll->scrollToY(0);
 	};
 
diff --git a/Telegram/SourceFiles/support/support_helper.cpp b/Telegram/SourceFiles/support/support_helper.cpp
new file mode 100644
index 000000000..bca761df4
--- /dev/null
+++ b/Telegram/SourceFiles/support/support_helper.cpp
@@ -0,0 +1,220 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "support/support_helper.h"
+
+#include "dialogs/dialogs_key.h"
+#include "data/data_drafts.h"
+#include "history/history.h"
+#include "window/window_controller.h"
+#include "auth_session.h"
+#include "observer_peer.h"
+#include "apiwrap.h"
+
+namespace Support {
+namespace {
+
+constexpr auto kOccupyFor = TimeId(60);
+constexpr auto kReoccupyEach = 30 * TimeMs(1000);
+
+uint32 OccupationTag() {
+	return uint32(Sandbox::UserTag() & 0xFFFFFFFFU);
+}
+
+Data::Draft OccupiedDraft() {
+	const auto now = unixtime(), till = now + kOccupyFor;
+	return {
+		TextWithTags{ "t:"
+			+ QString::number(till)
+			+ ";u:"
+			+ QString::number(OccupationTag()) },
+		MsgId(0),
+		MessageCursor(),
+		false
+	};
+}
+
+uint32 ParseOccupationTag(History *history) {
+	if (!history) {
+		return 0;
+	}
+	const auto draft = history->cloudDraft();
+	if (!draft) {
+		return 0;
+	}
+	const auto &text = draft->textWithTags.text;
+#ifndef OS_MAC_OLD
+	const auto parts = text.splitRef(';');
+#else // OS_MAC_OLD
+	const auto parts = text.split(';');
+#endif // OS_MAC_OLD
+	auto valid = false;
+	auto result = uint32();
+	for (const auto &part : parts) {
+		if (part.startsWith(qstr("t:"))) {
+			if (part.mid(2).toInt() >= unixtime()) {
+				valid = true;
+			} else {
+				return 0;
+			}
+		} else if (part.startsWith(qstr("u:"))) {
+			result = part.mid(2).toUInt();
+		}
+	}
+	return valid ? result : 0;
+}
+
+TimeId OccupiedBySomeoneTill(History *history) {
+	if (!history) {
+		return 0;
+	}
+	const auto draft = history->cloudDraft();
+	if (!draft) {
+		return 0;
+	}
+	const auto &text = draft->textWithTags.text;
+#ifndef OS_MAC_OLD
+	const auto parts = text.splitRef(';');
+#else // OS_MAC_OLD
+	const auto parts = text.split(';');
+#endif // OS_MAC_OLD
+	auto valid = false;
+	auto result = TimeId();
+	for (const auto &part : parts) {
+		if (part.startsWith(qstr("t:"))) {
+			if (part.mid(2).toInt() >= unixtime()) {
+				result = part.mid(2).toInt();
+			} else {
+				return 0;
+			}
+		} else if (part.startsWith(qstr("u:"))) {
+			if (part.mid(2).toUInt() != OccupationTag()) {
+				valid = true;
+			} else {
+				return 0;
+			}
+		}
+	}
+	return valid ? result : 0;
+}
+
+} // namespace
+
+Helper::Helper(not_null<AuthSession*> session)
+: _session(session)
+, _templates(_session)
+, _reoccupyTimer([=] { reoccupy(); })
+, _checkOccupiedTimer([=] { checkOccupiedChats(); }) {
+}
+
+void Helper::registerWindow(not_null<Window::Controller*> controller) {
+	controller->activeChatValue(
+	) | rpl::map([](Dialogs::Key key) {
+		return key.history();
+	}) | rpl::distinct_until_changed(
+	) | rpl::start_with_next([=](History *history) {
+		updateOccupiedHistory(controller, history);
+	}, controller->lifetime());
+}
+
+void Helper::cloudDraftChanged(not_null<History*> history) {
+	chatOccupiedUpdated(history);
+	if (history != _occupiedHistory) {
+		return;
+	}
+	if (!IsOccupiedByMe(_occupiedHistory)) {
+		occupyInDraft();
+	}
+}
+
+void Helper::chatOccupiedUpdated(not_null<History*> history) {
+	if (const auto till = OccupiedBySomeoneTill(history)) {
+		_occupiedChats[history] = till + 2;
+		Notify::peerUpdatedDelayed(
+			history->peer,
+			Notify::PeerUpdate::Flag::OccupiedChanged);
+		checkOccupiedChats();
+	} else if (_occupiedChats.take(history)) {
+		Notify::peerUpdatedDelayed(
+			history->peer,
+			Notify::PeerUpdate::Flag::OccupiedChanged);
+	}
+}
+
+void Helper::checkOccupiedChats() {
+	const auto now = unixtime();
+	while (!_occupiedChats.empty()) {
+		const auto nearest = ranges::min_element(
+			_occupiedChats,
+			std::less<>(),
+			[](const auto &pair) { return pair.second; });
+		if (nearest->second <= now) {
+			const auto history = nearest->first;
+			_occupiedChats.erase(nearest);
+			Notify::peerUpdatedDelayed(
+				history->peer,
+				Notify::PeerUpdate::Flag::OccupiedChanged);
+		} else {
+			_checkOccupiedTimer.callOnce(
+				(nearest->second - now) * TimeMs(1000));
+			return;
+		}
+	}
+	_checkOccupiedTimer.cancel();
+}
+
+void Helper::updateOccupiedHistory(
+		not_null<Window::Controller*> controller,
+		History *history) {
+	if (IsOccupiedByMe(_occupiedHistory)) {
+		_occupiedHistory->clearCloudDraft();
+		_session->api().saveDraftToCloudDelayed(_occupiedHistory);
+	}
+	_occupiedHistory = history;
+	occupyInDraft();
+}
+
+void Helper::occupyInDraft() {
+	if (_occupiedHistory && !IsOccupiedBySomeone(_occupiedHistory)) {
+		const auto draft = OccupiedDraft();
+		_occupiedHistory->createCloudDraft(&draft);
+		_session->api().saveDraftToCloudDelayed(_occupiedHistory);
+		_reoccupyTimer.callEach(kReoccupyEach);
+	}
+}
+
+void Helper::reoccupy() {
+	if (IsOccupiedByMe(_occupiedHistory)) {
+		const auto draft = OccupiedDraft();
+		_occupiedHistory->createCloudDraft(&draft);
+		_session->api().saveDraftToCloudDelayed(_occupiedHistory);
+	}
+}
+
+Templates &Helper::templates() {
+	return _templates;
+}
+
+bool IsOccupiedByMe(History *history) {
+	if (const auto tag = ParseOccupationTag(history)) {
+		return (tag == OccupationTag());
+	}
+	return false;
+}
+
+bool IsOccupiedBySomeone(History *history) {
+	if (const auto tag = ParseOccupationTag(history)) {
+		return (tag != OccupationTag());
+	}
+	return false;
+}
+
+QString ChatOccupiedString() {
+	return QString::fromUtf8("\xe2\x9c\x8b\xef\xb8\x8f chat taken");
+}
+
+} // namespace Support
diff --git a/Telegram/SourceFiles/support/support_helper.h b/Telegram/SourceFiles/support/support_helper.h
new file mode 100644
index 000000000..89f29b4db
--- /dev/null
+++ b/Telegram/SourceFiles/support/support_helper.h
@@ -0,0 +1,56 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/timer.h"
+#include "support/support_templates.h"
+
+class AuthSession;
+
+namespace Window {
+class Controller;
+} // namespace Window
+
+namespace Support {
+
+class Helper {
+public:
+	explicit Helper(not_null<AuthSession*> session);
+
+	void registerWindow(not_null<Window::Controller*> controller);
+	void cloudDraftChanged(not_null<History*> history);
+
+	void chatOccupiedUpdated(not_null<History*> history);
+
+	Templates &templates();
+
+private:
+	void checkOccupiedChats();
+	void updateOccupiedHistory(
+		not_null<Window::Controller*> controller,
+		History *history);
+	void occupyInDraft();
+	void reoccupy();
+
+	not_null<AuthSession*> _session;
+	Templates _templates;
+
+	History *_occupiedHistory = nullptr;
+	base::Timer _reoccupyTimer;
+	base::Timer _checkOccupiedTimer;
+	base::flat_map<not_null<History*>, TimeId> _occupiedChats;
+
+	rpl::lifetime _lifetime;
+
+};
+
+bool IsOccupiedByMe(History *history);
+bool IsOccupiedBySomeone(History *history);
+QString ChatOccupiedString();
+
+} // namespace Support
diff --git a/Telegram/SourceFiles/window/window_controller.cpp b/Telegram/SourceFiles/window/window_controller.cpp
index f142e7ce1..42f5cfdcf 100644
--- a/Telegram/SourceFiles/window/window_controller.cpp
+++ b/Telegram/SourceFiles/window/window_controller.cpp
@@ -22,6 +22,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mainwindow.h"
 #include "auth_session.h"
 #include "apiwrap.h"
+#include "support/support_helper.h"
 #include "styles/style_window.h"
 #include "styles/style_dialogs.h"
 
@@ -50,6 +51,10 @@ Controller::Controller(not_null<MainWindow*> window)
 			startRoundVideo(item);
 		}
 	}, lifetime());
+
+	if (Auth().supportMode()) {
+		Auth().supportHelper().registerWindow(this);
+	}
 }
 
 void Controller::setActiveChatEntry(Dialogs::RowDescriptor row) {
diff --git a/Telegram/SourceFiles/window/window_main_menu.cpp b/Telegram/SourceFiles/window/window_main_menu.cpp
index 43d350411..415a0d987 100644
--- a/Telegram/SourceFiles/window/window_main_menu.cpp
+++ b/Telegram/SourceFiles/window/window_main_menu.cpp
@@ -214,13 +214,13 @@ void MainMenu::refreshMenu() {
 
 		const auto subscription = Ui::AttachAsChild(_menu, rpl::lifetime());
 		_menu->addAction(qsl("Reload templates"), [=] {
-			*subscription = Auth().supportTemplates()->errors(
+			*subscription = Auth().supportTemplates().errors(
 			) | rpl::start_with_next([=](QStringList errors) {
 				Ui::Toast::Show(errors.isEmpty()
 					? "Templates reloaded!"
 					: ("Errors:\n\n" + errors.join("\n\n")));
 			});
-			Auth().supportTemplates()->reload();
+			Auth().supportTemplates().reload();
 		}, &st::mainMenuReload, &st::mainMenuReloadOver);
 	}
 	_menu->addAction(lang(lng_menu_settings), [] {
diff --git a/Telegram/gyp/telegram_sources.txt b/Telegram/gyp/telegram_sources.txt
index 096b1f14c..253c827af 100644
--- a/Telegram/gyp/telegram_sources.txt
+++ b/Telegram/gyp/telegram_sources.txt
@@ -582,6 +582,8 @@
 <(src_loc)/support/support_autocomplete.h
 <(src_loc)/support/support_common.cpp
 <(src_loc)/support/support_common.h
+<(src_loc)/support/support_helper.cpp
+<(src_loc)/support/support_helper.h
 <(src_loc)/support/support_templates.cpp
 <(src_loc)/support/support_templates.h
 <(src_loc)/ui/effects/cross_animation.cpp