From 5e6c81a98ea1983df35537d3ca7e92183c86b640 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 25 Mar 2025 00:11:21 +0500
Subject: [PATCH] Parse e2e participant keys.

---
 Telegram/SourceFiles/calls/calls_instance.cpp |  42 ++++++++
 Telegram/SourceFiles/calls/calls_instance.h   |  15 +++
 .../calls/group/calls_group_call.cpp          | 102 ++++++++++++++----
 .../calls/group/calls_group_call.h            |  22 ++++
 .../calls/group/calls_group_common.cpp        |   9 +-
 .../calls/group/calls_group_common.h          |   9 +-
 Telegram/SourceFiles/data/data_group_call.cpp |   7 ++
 Telegram/SourceFiles/data/data_group_call.h   |   5 +
 Telegram/SourceFiles/tde2e/tde2e_api.cpp      |  17 ++-
 Telegram/SourceFiles/tde2e/tde2e_api.h        |  28 +++++
 .../window/window_session_controller.cpp      |  13 ++-
 11 files changed, 240 insertions(+), 29 deletions(-)

diff --git a/Telegram/SourceFiles/calls/calls_instance.cpp b/Telegram/SourceFiles/calls/calls_instance.cpp
index 65dc10fb39..f9ab9ebe68 100644
--- a/Telegram/SourceFiles/calls/calls_instance.cpp
+++ b/Telegram/SourceFiles/calls/calls_instance.cpp
@@ -230,6 +230,30 @@ void Instance::startOrJoinGroupCall(
 	});
 }
 
+void Instance::startOrJoinConferenceCall(
+		std::shared_ptr<Ui::Show> show,
+		StartConferenceCallArgs args) {
+	destroyCurrentCall();
+
+	auto call = std::make_unique<GroupCall>(
+		_delegate.get(),
+		Calls::Group::ConferenceInfo{
+			.call = args.call,
+			.linkSlug = args.linkSlug,
+			.joinMessageId = args.joinMessageId,
+		});
+	const auto raw = call.get();
+
+	args.call->peer()->session().account().sessionChanges(
+	) | rpl::start_with_next([=] {
+		destroyGroupCall(raw);
+	}, raw->lifetime());
+
+	_currentGroupCallPanel = std::make_unique<Group::Panel>(raw);
+	_currentGroupCall = std::move(call);
+	_currentGroupCallChanges.fire_copy(raw);
+}
+
 void Instance::confirmLeaveCurrent(
 		std::shared_ptr<Ui::Show> show,
 		not_null<PeerData*> peer,
@@ -409,6 +433,24 @@ void Instance::createGroupCall(
 	_currentGroupCallChanges.fire_copy(raw);
 }
 
+void Instance::createConferenceCall(Group::ConferenceInfo info) {
+	destroyCurrentCall();
+
+	auto call = std::make_unique<GroupCall>(
+		_delegate.get(),
+		std::move(info));
+	const auto raw = call.get();
+
+	raw->peer()->session().account().sessionChanges(
+	) | rpl::start_with_next([=] {
+		destroyGroupCall(raw);
+	}, raw->lifetime());
+
+	_currentGroupCallPanel = std::make_unique<Group::Panel>(raw);
+	_currentGroupCall = std::move(call);
+	_currentGroupCallChanges.fire_copy(raw);
+}
+
 void Instance::refreshDhConfig() {
 	Expects(_currentCall != nullptr);
 
diff --git a/Telegram/SourceFiles/calls/calls_instance.h b/Telegram/SourceFiles/calls/calls_instance.h
index d52a0e9a23..724140b60b 100644
--- a/Telegram/SourceFiles/calls/calls_instance.h
+++ b/Telegram/SourceFiles/calls/calls_instance.h
@@ -13,6 +13,10 @@ namespace crl {
 class semaphore;
 } // namespace crl
 
+namespace Data {
+class GroupCall;
+} // namespace Data
+
 namespace Platform {
 enum class PermissionType;
 } // namespace Platform
@@ -31,6 +35,7 @@ class Show;
 
 namespace Calls::Group {
 struct JoinInfo;
+struct ConferenceInfo;
 class Panel;
 class ChooseJoinAsProcess;
 class StartRtmpProcess;
@@ -59,6 +64,12 @@ struct StartGroupCallArgs {
 	bool scheduleNeeded = false;
 };
 
+struct StartConferenceCallArgs {
+	std::shared_ptr<Data::GroupCall> call;
+	QString linkSlug;
+	MsgId joinMessageId;
+};
+
 class Instance final : public base::has_weak_ptr {
 public:
 	Instance();
@@ -69,6 +80,9 @@ public:
 		std::shared_ptr<Ui::Show> show,
 		not_null<PeerData*> peer,
 		StartGroupCallArgs args);
+	void startOrJoinConferenceCall(
+		std::shared_ptr<Ui::Show> show,
+		StartConferenceCallArgs args);
 	void showStartWithRtmp(
 		std::shared_ptr<Ui::Show> show,
 		not_null<PeerData*> peer);
@@ -121,6 +135,7 @@ private:
 	void createGroupCall(
 		Group::JoinInfo info,
 		const MTPInputGroupCall &inputCall);
+	void createConferenceCall(Group::ConferenceInfo info);
 	void destroyGroupCall(not_null<GroupCall*> call);
 	void confirmLeaveCurrent(
 		std::shared_ptr<Ui::Show> show,
diff --git a/Telegram/SourceFiles/calls/group/calls_group_call.cpp b/Telegram/SourceFiles/calls/group/calls_group_call.cpp
index ab1b80117c..268b356527 100644
--- a/Telegram/SourceFiles/calls/group/calls_group_call.cpp
+++ b/Telegram/SourceFiles/calls/group/calls_group_call.cpp
@@ -29,6 +29,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "base/global_shortcuts.h"
 #include "base/random.h"
+#include "tde2e/tde2e_api.h"
 #include "webrtc/webrtc_video_track.h"
 #include "webrtc/webrtc_create_adm.h"
 #include "webrtc/webrtc_environment.h"
@@ -418,6 +419,21 @@ std::shared_ptr<ParticipantVideoParams> ParseVideoParams(
 	return data;
 }
 
+std::shared_ptr<TdE2E::ParticipantState> ParseParticipantState(
+		const MTPDgroupCallParticipant &data) {
+	if (!data.vpublic_key() || data.vpeer().type() != mtpc_peerUser) {
+		return nullptr;
+	}
+	const auto &v = *data.vpublic_key();
+	const auto userId = data.vpeer().c_peerUser().vuser_id().v;
+	using State = TdE2E::ParticipantState;
+	return std::make_shared<State>(State{
+		.id = uint64(userId),
+		.key = { .a = v.h.h, .b = v.h.l, .c = v.l.h, .d = v.l.l },
+	});
+
+}
+
 GroupCall::LoadPartTask::LoadPartTask(
 	base::weak_ptr<GroupCall> call,
 	int64 time,
@@ -569,18 +585,38 @@ GroupCall::GroupCall(
 	not_null<Delegate*> delegate,
 	Group::JoinInfo info,
 	const MTPInputGroupCall &inputCall)
+: GroupCall(delegate, info, {}, inputCall) {
+}
+
+GroupCall::GroupCall(
+	not_null<Delegate*> delegate,
+	Group::ConferenceInfo info)
+: GroupCall(delegate, Group::JoinInfo{
+	.peer = info.call->peer(),
+	.joinAs = info.call->peer(),
+}, info, info.call->input()) {
+}
+
+GroupCall::GroupCall(
+	not_null<Delegate*> delegate,
+	Group::JoinInfo join,
+	Group::ConferenceInfo conference,
+	const MTPInputGroupCall &inputCall)
 : _delegate(delegate)
-, _peer(info.peer)
+, _conferenceCall(conference.call)
+, _peer(join.peer)
 , _history(_peer->owner().history(_peer))
 , _api(&_peer->session().mtp())
-, _joinAs(info.joinAs)
-, _possibleJoinAs(std::move(info.possibleJoinAs))
-, _joinHash(info.joinHash)
-, _rtmpUrl(info.rtmpInfo.url)
-, _rtmpKey(info.rtmpInfo.key)
+, _joinAs(join.joinAs)
+, _possibleJoinAs(std::move(join.possibleJoinAs))
+, _joinHash(join.joinHash)
+, _conferenceLinkSlug(conference.linkSlug)
+, _conferenceJoinMessageId(conference.joinMessageId)
+, _rtmpUrl(join.rtmpInfo.url)
+, _rtmpKey(join.rtmpInfo.key)
 , _canManage(Data::CanManageGroupCallValue(_peer))
 , _id(inputCall.c_inputGroupCall().vid().v)
-, _scheduleDate(info.scheduleDate)
+, _scheduleDate(join.scheduleDate)
 , _lastSpokeCheckTimer([=] { checkLastSpoke(); })
 , _checkJoinedTimer([=] { checkJoined(); })
 , _playbackDeviceId(
@@ -601,9 +637,14 @@ GroupCall::GroupCall(
 	Webrtc::DeviceIdOrDefault(Core::App().settings().cameraDeviceIdValue()))
 , _pushToTalkCancelTimer([=] { pushToTalkCancel(); })
 , _connectingSoundTimer([=] { playConnectingSoundOnce(); })
-, _listenersHidden(info.rtmp)
-, _rtmp(info.rtmp)
+, _listenersHidden(join.rtmp)
+, _rtmp(join.rtmp)
 , _rtmpVolume(Group::kDefaultVolume) {
+	if (_conferenceCall) {
+		_e2eState = std::make_unique<TdE2E::CallState>(
+			TdE2E::CreateCallState());
+	}
+
 	_muted.value(
 	) | rpl::combine_previous(
 	) | rpl::start_with_next([=](MuteState previous, MuteState state) {
@@ -657,9 +698,9 @@ GroupCall::GroupCall(
 	setupOutgoingVideo();
 
 	if (_id) {
-		join(inputCall);
+		this->join(inputCall);
 	} else {
-		start(info.scheduleDate, info.rtmp);
+		start(join.scheduleDate, join.rtmp);
 	}
 	if (_scheduleDate) {
 		saveDefaultJoinAs(joinAs());
@@ -1055,6 +1096,9 @@ void GroupCall::setRtmpInfo(const Calls::Group::RtmpInfo &value) {
 }
 
 Data::GroupCall *GroupCall::lookupReal() const {
+	if (_conferenceCall) {
+		return _conferenceCall.get();
+	}
 	const auto real = _peer->groupCall();
 	return (real && real->id() == _id) ? real : nullptr;
 }
@@ -1373,14 +1417,24 @@ void GroupCall::rejoin(not_null<PeerData*> as) {
 					: Flag::f_invite_hash)
 				| (wasVideoStopped
 					? Flag::f_video_stopped
-					: Flag(0));
+					: Flag(0))
+				| (_conferenceJoinMessageId ? Flag::f_invite_msg_id : Flag())
+				| (_e2eState ? Flag::f_public_key : Flag());
+			const auto publicKey = _e2eState
+				? _e2eState->myKey
+				: TdE2E::PublicKey();
 			_api.request(MTPphone_JoinGroupCall(
 				MTP_flags(flags),
-				inputCall(),
+				(_conferenceLinkSlug.isEmpty()
+					? inputCall()
+					: MTP_inputGroupCallSlug(
+						MTP_string(_conferenceLinkSlug))),
 				joinAs()->input,
 				MTP_string(_joinHash),
-				MTPint256(), // public_key
-				MTPint(), // invite_msg_id
+				MTP_int256(
+					MTP_int128(publicKey.a, publicKey.b),
+					MTP_int128(publicKey.c, publicKey.d)),
+				MTP_int(_conferenceJoinMessageId.bare),
 				MTP_dataJSON(MTP_bytes(json))
 			)).done([=](
 					const MTPUpdates &updates,
@@ -1586,6 +1640,7 @@ void GroupCall::applyMeInCallLocally() {
 		: participant
 		? participant->raisedHandRating
 		: FindLocalRaisedHandRating(real->participants());
+	const auto publicKey = _e2eState ? _e2eState->myKey : TdE2E::PublicKey();
 	const auto flags = (canSelfUnmute ? Flag::f_can_self_unmute : Flag(0))
 		| (lastActive ? Flag::f_active_date : Flag(0))
 		| (_joinState.ssrc ? Flag(0) : Flag::f_left)
@@ -1594,7 +1649,8 @@ void GroupCall::applyMeInCallLocally() {
 		| Flag::f_volume // Without flag the volume is reset to 100%.
 		| Flag::f_volume_by_admin // Self volume can only be set by admin.
 		| ((muted() != MuteState::Active) ? Flag::f_muted : Flag(0))
-		| (raisedHandRating > 0 ? Flag::f_raise_hand_rating : Flag(0));
+		| (raisedHandRating > 0 ? Flag::f_raise_hand_rating : Flag(0))
+		| (_e2eState ? Flag::f_public_key : Flag(0));
 	real->applyLocalUpdate(
 		MTP_updateGroupCallParticipants(
 			inputCall(),
@@ -1611,7 +1667,9 @@ void GroupCall::applyMeInCallLocally() {
 					MTP_long(raisedHandRating),
 					MTPGroupCallParticipantVideo(),
 					MTPGroupCallParticipantVideo(),
-					AssertIsDebug() MTPint256())), // public_key
+					MTP_int256(
+						MTP_int128(publicKey.a, publicKey.b),
+						MTP_int128(publicKey.c, publicKey.d)))),
 			MTP_int(0)).c_updateGroupCallParticipants());
 }
 
@@ -1642,7 +1700,11 @@ void GroupCall::applyParticipantLocally(
 		| (participantPeer == joinAs() ? Flag::f_self : Flag(0))
 		| (participant->raisedHandRating
 			? Flag::f_raise_hand_rating
-			: Flag(0));
+			: Flag(0))
+		| (participant->e2eState ? Flag::f_public_key : Flag(0));
+	const auto publicKey = participant->e2eState
+		? participant->e2eState->key
+		: TdE2E::PublicKey();
 	_peer->groupCall()->applyLocalUpdate(
 		MTP_updateGroupCallParticipants(
 			inputCall(),
@@ -1659,7 +1721,9 @@ void GroupCall::applyParticipantLocally(
 					MTP_long(participant->raisedHandRating),
 					MTPGroupCallParticipantVideo(),
 					MTPGroupCallParticipantVideo(),
-					AssertIsDebug() MTPint256())), // public_key
+					MTP_int256(
+						MTP_int128(publicKey.a, publicKey.b),
+						MTP_int128(publicKey.c, publicKey.d)))),
 			MTP_int(0)).c_updateGroupCallParticipants());
 }
 
diff --git a/Telegram/SourceFiles/calls/group/calls_group_call.h b/Telegram/SourceFiles/calls/group/calls_group_call.h
index 8f93793bd9..a3c8d07c12 100644
--- a/Telegram/SourceFiles/calls/group/calls_group_call.h
+++ b/Telegram/SourceFiles/calls/group/calls_group_call.h
@@ -42,6 +42,11 @@ struct GroupCallParticipant;
 class GroupCall;
 } // namespace Data
 
+namespace TdE2E {
+struct ParticipantState;
+struct CallState;
+} // namespace TdE2E
+
 namespace Calls {
 
 namespace Group {
@@ -49,6 +54,7 @@ struct MuteRequest;
 struct VolumeRequest;
 struct ParticipantState;
 struct JoinInfo;
+struct ConferenceInfo;
 struct RejoinEvent;
 struct RtmpInfo;
 enum class VideoQuality;
@@ -164,6 +170,8 @@ struct ParticipantVideoParams;
 	const tl::conditional<MTPGroupCallParticipantVideo> &camera,
 	const tl::conditional<MTPGroupCallParticipantVideo> &screen,
 	const std::shared_ptr<ParticipantVideoParams> &existing);
+[[nodiscard]] std::shared_ptr<TdE2E::ParticipantState> ParseParticipantState(
+	const MTPDgroupCallParticipant &data);
 
 [[nodiscard]] const std::string &GetCameraEndpoint(
 	const std::shared_ptr<ParticipantVideoParams> &params);
@@ -217,6 +225,9 @@ public:
 		not_null<Delegate*> delegate,
 		Group::JoinInfo info,
 		const MTPInputGroupCall &inputCall);
+	GroupCall(
+		not_null<Delegate*> delegate,
+		Group::ConferenceInfo info);
 	~GroupCall();
 
 	[[nodiscard]] CallId id() const {
@@ -469,6 +480,12 @@ private:
 		return true;
 	}
 
+	GroupCall(
+		not_null<Delegate*> delegate,
+		Group::JoinInfo join,
+		Group::ConferenceInfo conference,
+		const MTPInputGroupCall &inputCall);
+
 	void broadcastPartStart(std::shared_ptr<LoadPartTask> task);
 	void broadcastPartCancel(not_null<LoadPartTask*> task);
 	void mediaChannelDescriptionsStart(
@@ -575,6 +592,7 @@ private:
 	[[nodiscard]] MTPInputGroupCall inputCall() const;
 
 	const not_null<Delegate*> _delegate;
+	const std::shared_ptr<Data::GroupCall> _conferenceCall;
 	not_null<PeerData*> _peer; // Can change in legacy group migration.
 	rpl::event_stream<PeerData*> _peerStream;
 	not_null<History*> _history; // Can change in legacy group migration.
@@ -601,9 +619,13 @@ private:
 	rpl::variable<not_null<PeerData*>> _joinAs;
 	std::vector<not_null<PeerData*>> _possibleJoinAs;
 	QString _joinHash;
+	QString _conferenceLinkSlug;
+	MsgId _conferenceJoinMessageId;
 	int64 _serverTimeMs = 0;
 	crl::time _serverTimeMsGotAt = 0;
 
+	std::unique_ptr<TdE2E::CallState> _e2eState;
+
 	QString _rtmpUrl;
 	QString _rtmpKey;
 
diff --git a/Telegram/SourceFiles/calls/group/calls_group_common.cpp b/Telegram/SourceFiles/calls/group/calls_group_common.cpp
index 75e6de992f..20223c9ebf 100644
--- a/Telegram/SourceFiles/calls/group/calls_group_common.cpp
+++ b/Telegram/SourceFiles/calls/group/calls_group_common.cpp
@@ -52,7 +52,8 @@ object_ptr<Ui::GenericBox> ScreenSharingPrivacyRequestBox() {
 
 void ConferenceCallJoinConfirm(
 		not_null<Ui::GenericBox*> box,
-		std::shared_ptr<Data::GroupCall> call) {
+		std::shared_ptr<Data::GroupCall> call,
+		Fn<void()> join) {
 	box->setTitle(tr::lng_confcall_join_title());
 
 	box->addRow(
@@ -62,7 +63,11 @@ void ConferenceCallJoinConfirm(
 			st::boxLabel));
 
 	box->addButton(tr::lng_confcall_join_button(), [=] {
-
+		const auto weak = Ui::MakeWeak(box);
+		join();
+		if (const auto strong = weak.data()) {
+			strong->closeBox();
+		}
 	});
 	box->addButton(tr::lng_cancel(), [=] {
 		box->closeBox();
diff --git a/Telegram/SourceFiles/calls/group/calls_group_common.h b/Telegram/SourceFiles/calls/group/calls_group_common.h
index 114c43e6d5..32d403ed6f 100644
--- a/Telegram/SourceFiles/calls/group/calls_group_common.h
+++ b/Telegram/SourceFiles/calls/group/calls_group_common.h
@@ -65,6 +65,12 @@ struct JoinInfo {
 	bool rtmp = false;
 };
 
+struct ConferenceInfo {
+	std::shared_ptr<Data::GroupCall> call;
+	QString linkSlug;
+	MsgId joinMessageId;
+};
+
 enum class PanelMode {
 	Default,
 	Wide,
@@ -99,6 +105,7 @@ using StickedTooltips = base::flags<StickedTooltip>;
 
 void ConferenceCallJoinConfirm(
 	not_null<Ui::GenericBox*> box,
-	std::shared_ptr<Data::GroupCall> call);
+	std::shared_ptr<Data::GroupCall> call,
+	Fn<void()> join);
 
 } // namespace Calls::Group
diff --git a/Telegram/SourceFiles/data/data_group_call.cpp b/Telegram/SourceFiles/data/data_group_call.cpp
index c30eaeebaa..fc8f9fc260 100644
--- a/Telegram/SourceFiles/data/data_group_call.cpp
+++ b/Telegram/SourceFiles/data/data_group_call.cpp
@@ -622,15 +622,22 @@ void GroupCall::applyParticipantsSlice(
 			const auto existingVideoParams = (i != end(_participants))
 				? i->videoParams
 				: nullptr;
+			const auto existingState = (i != end(_participants))
+				? i->e2eState
+				: nullptr;
 			auto videoParams = localUpdate
 				? existingVideoParams
 				: Calls::ParseVideoParams(
 					data.vvideo(),
 					data.vpresentation(),
 					existingVideoParams);
+			auto e2eState = localUpdate
+				? existingState
+				: Calls::ParseParticipantState(data);
 			const auto value = Participant{
 				.peer = participantPeer,
 				.videoParams = std::move(videoParams),
+				.e2eState = std::move(e2eState),
 				.date = data.vdate().v,
 				.lastActive = lastActive,
 				.raisedHandRating = raisedHandRating,
diff --git a/Telegram/SourceFiles/data/data_group_call.h b/Telegram/SourceFiles/data/data_group_call.h
index 8b7d16158d..d283764b12 100644
--- a/Telegram/SourceFiles/data/data_group_call.h
+++ b/Telegram/SourceFiles/data/data_group_call.h
@@ -17,6 +17,10 @@ namespace Calls {
 struct ParticipantVideoParams;
 } // namespace Calls
 
+namespace TdE2E {
+struct ParticipantState;
+} // namespace TdE2E
+
 namespace Data {
 
 [[nodiscard]] const std::string &RtmpEndpointId();
@@ -29,6 +33,7 @@ struct LastSpokeTimes {
 struct GroupCallParticipant {
 	not_null<PeerData*> peer;
 	std::shared_ptr<Calls::ParticipantVideoParams> videoParams;
+	std::shared_ptr<TdE2E::ParticipantState> e2eState;
 	TimeId date = 0;
 	TimeId lastActive = 0;
 	uint64 raisedHandRating = 0;
diff --git a/Telegram/SourceFiles/tde2e/tde2e_api.cpp b/Telegram/SourceFiles/tde2e/tde2e_api.cpp
index 109536ed33..f5c8f12001 100644
--- a/Telegram/SourceFiles/tde2e/tde2e_api.cpp
+++ b/Telegram/SourceFiles/tde2e/tde2e_api.cpp
@@ -7,16 +7,25 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "tde2e/tde2e_api.h"
 
-#include "base/algorithm.h"
+#include "base/assertion.h"
 
 #include <tde2e/td/e2e/e2e_api.h>
 
 namespace TdE2E {
 
-QByteArray GeneratePrivateKey() {
-	const auto result = tde2e_api::key_generate_temporary_private_key();
+CallState CreateCallState() {
+	const auto id = tde2e_api::key_generate_temporary_private_key();
+	Assert(id.is_ok());
+	const auto key = tde2e_api::key_to_public_key(id.value());
+	Assert(key.is_ok());
 
-	return {};
+	auto result = CallState{
+		.myKeyId = PrivateKeyId{ .v = uint64(id.value()) },
+	};
+	Assert(key.value().size() == sizeof(result.myKey));
+	memcpy(&result.myKey, key.value().data(), 32);
+
+	return result;
 }
 
 } // namespace TdE2E
diff --git a/Telegram/SourceFiles/tde2e/tde2e_api.h b/Telegram/SourceFiles/tde2e/tde2e_api.h
index 73e0063250..689a5aa86c 100644
--- a/Telegram/SourceFiles/tde2e/tde2e_api.h
+++ b/Telegram/SourceFiles/tde2e/tde2e_api.h
@@ -7,3 +7,31 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "base/basic_types.h"
+
+namespace TdE2E {
+
+struct PrivateKeyId {
+	uint64 v = 0;
+};
+
+struct PublicKey {
+	uint64 a = 0;
+	uint64 b = 0;
+	uint64 c = 0;
+	uint64 d = 0;
+};
+
+struct ParticipantState {
+	uint64 id = 0;
+	PublicKey key;
+};
+
+struct CallState {
+	PrivateKeyId myKeyId;
+	PublicKey myKey;
+};
+
+[[nodiscard]] CallState CreateCallState();
+
+} // namespace TdE2E
diff --git a/Telegram/SourceFiles/window/window_session_controller.cpp b/Telegram/SourceFiles/window/window_session_controller.cpp
index c4167c2ca8..514f4dd859 100644
--- a/Telegram/SourceFiles/window/window_session_controller.cpp
+++ b/Telegram/SourceFiles/window/window_session_controller.cpp
@@ -853,7 +853,7 @@ void SessionNavigation::resolveConferenceCall(const QString &slug) {
 		MTP_int(limit)
 	)).done([=](const MTPphone_GroupCall &result) {
 		_conferenceCallRequestId = 0;
-		_conferenceCallSlug = QString();
+		const auto slug = base::take(_conferenceCallSlug);
 
 		result.data().vcall().match([&](const auto &data) {
 			const auto call = std::make_shared<Data::GroupCall>(
@@ -863,8 +863,15 @@ void SessionNavigation::resolveConferenceCall(const QString &slug) {
 				TimeId(), // scheduleDate
 				false); // rtmp
 			call->processFullCall(result);
-			uiShow()->show(
-				Box(Calls::Group::ConferenceCallJoinConfirm, call));
+			const auto join = [=] {
+				Core::App().calls().startOrJoinConferenceCall(
+					uiShow(),
+					{ .call = call, .linkSlug = slug });
+			};
+			uiShow()->show(Box(
+				Calls::Group::ConferenceCallJoinConfirm,
+				call,
+				join));
 		});
 	}).fail([=] {
 		_conferenceCallRequestId = 0;