Initial chat-translation feature implementation.

Telegram/CMakeLists.txt

@@ -756,6 +756,10 @@ PRIVATE
     history/view/history_view_sticker_toast.h
     history/view/history_view_transcribe_button.cpp
     history/view/history_view_transcribe_button.h
+    history/view/history_view_translate_bar.cpp
+    history/view/history_view_translate_bar.h
+    history/view/history_view_translate_tracker.cpp
+    history/view/history_view_translate_tracker.h
     history/view/history_view_top_bar_widget.cpp
     history/view/history_view_top_bar_widget.h
     history/view/history_view_view_button.cpp
@@ -782,6 +786,8 @@ PRIVATE
     history/history_inner_widget.h
     history/history_location_manager.cpp
     history/history_location_manager.h
+    history/history_translation.cpp
+    history/history_translation.h
     history/history_unread_things.cpp
     history/history_unread_things.h
     history/history_view_highlight_manager.cpp

Telegram/SourceFiles/boxes/language_box.cpp

@@ -31,6 +31,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "lang/lang_instance.h"
 #include "lang/lang_cloud_manager.h"
 #include "settings/settings_common.h"
+#include "spellcheck/spellcheck_types.h"
 #include "styles/style_layers.h"
 #include "styles/style_boxes.h"
 #include "styles/style_info.h"
@@ -43,6 +44,16 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtGui/QClipboard>
 
 namespace {
+namespace {
+
+[[nodiscard]] std::vector<QLocale> SkipLocalesFromSettings() {
+	const auto list = Core::App().settings().skipTranslationLanguages();
+	return list
+		| ranges::views::transform(&LanguageId::locale)
+		| ranges::to_vector;
+}
+
+} // namespace
 
 using Language = Lang::Language;
 using Languages = Lang::CloudManager::Languages;
@@ -1138,19 +1149,19 @@ void LanguageBox::prepare() {
 		}),
 		st::settingsButtonNoIcon);
 
-	label->fire(Ui::Translate::LocalesFromSettings());
+	label->fire(SkipLocalesFromSettings());
 	translateSkip->setClickedCallback([=] {
 		Ui::BoxShow(this).showBox(
-			Box(Ui::ChooseLanguageBox, [=](std::vector<QLocale> locales) {
+			Box(Ui::ChooseLanguageBox, [=](Locales locales) {
 				label->fire_copy(locales);
-				const auto result = ranges::views::all(
+				using namespace ranges::views;
+				Core::App().settings().setSkipTranslationLanguages(all(
 					locales
-				) | ranges::views::transform([](const QLocale &l) {
-					return int(l.language());
-				}) | ranges::to_vector;
-				Core::App().settings().setSkipTranslationForLanguages(result);
+				) | transform([](const QLocale &l) {
+					return LanguageId{ l.language() };
+				}) | ranges::to_vector);
 				Core::App().saveSettingsDelayed();
-			}, Ui::Translate::LocalesFromSettings()),
+			}, SkipLocalesFromSettings()),
 			Ui::LayerOption::KeepOther);
 	});
 	Settings::AddSkip(topContainer);

Telegram/SourceFiles/boxes/translate_box.cpp

@@ -16,9 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_session.h"
 #include "mtproto/sender.h"
 #include "settings/settings_common.h"
-#ifndef TDESKTOP_DISABLE_SPELLCHECK
 #include "spellcheck/platform/platform_language.h"
-#endif
 #include "ui/effects/loading_element.h"
 #include "ui/layers/generic_box.h"
 #include "ui/painter.h"
@@ -252,29 +250,6 @@ rpl::producer<Qt::MouseButton> ShowButton::clicks() const {
 
 } // namespace
 
-namespace Translate {
-
-std::vector<QLocale> LocalesFromSettings() {
-	const auto langs = Core::App().settings().skipTranslationForLanguages();
-	if (langs.empty()) {
-		return { QLocale(QLocale::English) };
-	}
-	return ranges::views::all(
-		langs
-	) | ranges::view::transform([](int langId) {
-		const auto lang = QLocale::Language(langId);
-		return (lang == QLocale::English)
-			? QLocale(Lang::LanguageIdOrDefault(Lang::Id()))
-			: (lang == QLocale::C)
-			? QLocale(QLocale::English)
-			: QLocale(lang);
-	}) | ranges::to_vector;
-}
-
-} // namespace Translate
-
-using namespace Translate;
-
 QString LanguageName(const QLocale &locale) {
 	if (locale.language() == QLocale::English
 			&& (locale.country() == QLocale::UnitedStates
@@ -297,7 +272,7 @@ void TranslateBox(
 	box->setWidth(st::boxWideWidth);
 	box->addButton(tr::lng_box_ok(), [=] { box->closeBox(); });
 	const auto container = box->verticalLayout();
-	const auto defaultId = LocalesFromSettings().front().name().mid(0, 2);
+	const auto translateTo = Core::App().settings().translateTo().locale();
 
 	const auto api = box->lifetime().make_state<MTP::Sender>(
 		&peer->session().mtp());
@@ -316,7 +291,7 @@ void TranslateBox(
 		msgId = 0;
 	}
 
-	using Flag = MTPmessages_translateText::Flag;
+	using Flag = MTPmessages_TranslateText::Flag;
 	const auto flags = msgId
 		? (Flag::f_peer | Flag::f_id)
 		: !text.text.isEmpty()
@@ -428,7 +403,7 @@ void TranslateBox(
 				: MTP_vector<MTPTextWithEntities>(1, MTP_textWithEntities(
 					MTP_string(text.text),
 					MTP_vector<MTPMessageEntity>()))),
-			MTP_string(toLang)
+			MTP_string(toLang.mid(0, 2))
 		)).done([=](const MTPmessages_TranslatedText &result) {
 			const auto &data = result.data();
 			const auto &list = data.vresult().v;
@@ -439,8 +414,8 @@ void TranslateBox(
 			showText(tr::lng_translate_box_error(tr::now));
 		}).send();
 	};
-	send(defaultId);
-	state->locale.fire(QLocale(defaultId));
+	send(translateTo.name());
+	state->locale.fire_copy(translateTo);
 
 	box->addLeftButton(tr::lng_settings_language(), [=] {
 		if (loading->toggled()) {
@@ -449,10 +424,10 @@ void TranslateBox(
 		Ui::BoxShow(box).showBox(Box(ChooseLanguageBox, [=](
 				std::vector<QLocale> locales) {
 			const auto &locale = locales.front();
+			send(locale.name());
 			state->locale.fire_copy(locale);
 			loading->show(anim::type::instant);
 			translated->hide(anim::type::instant);
-			send(locale.name().mid(0, 2));
 		}, std::vector<QLocale>()));
 	});
 }
@@ -574,12 +549,9 @@ bool SkipTranslate(TextWithEntities textWithEntities) {
 	}
 #ifndef TDESKTOP_DISABLE_SPELLCHECK
 	const auto result = Platform::Language::Recognize(text);
-	if (result.unknown) {
-		return false;
-	}
-	return ranges::any_of(LocalesFromSettings(), [&](const QLocale &l) {
-		return result.locale.language() == l.language();
-	});
+	const auto skip = Core::App().settings().skipTranslationLanguages();
+	const auto test = (result == result);
+	return result.known() && ranges::contains(skip, result);
 #else
     return false;
 #endif

Telegram/SourceFiles/boxes/translate_box.h

@@ -10,9 +10,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 class PeerData;
 
 namespace Ui {
-namespace Translate {
-[[nodiscard]] std::vector<QLocale> LocalesFromSettings();
-} // namespace Translate
 
 class GenericBox;
 

Telegram/SourceFiles/chat_helpers/message_field.cpp

@@ -223,13 +223,13 @@ void EditLinkBox(
 	QObject::connect(text, &Ui::InputField::tabbed, [=] { url->setFocus(); });
 }
 
-TextWithEntities StripSupportHashtag(TextWithEntities &&text) {
+TextWithEntities StripSupportHashtag(TextWithEntities text) {
 	static const auto expression = QRegularExpression(
 		u"\\n?#tsf[a-z0-9_-]*[\\s#a-z0-9_-]*$"_q,
 		QRegularExpression::CaseInsensitiveOption);
 	const auto match = expression.match(text.text);
 	if (!match.hasMatch()) {
-		return std::move(text);
+		return text;
 	}
 	text.text.chop(match.capturedLength());
 	const auto length = text.text.size();
@@ -246,7 +246,7 @@ TextWithEntities StripSupportHashtag(TextWithEntities &&text) {
 		}
 		++i;
 	}
-	return std::move(text);
+	return text;
 }
 
 } // namespace

Telegram/SourceFiles/core/core_settings.cpp

@@ -17,6 +17,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "media/player/media_player_instance.h"
 #include "ui/gl/gl_detection.h"
 #include "calls/group/calls_group_common.h"
+#include "spellcheck/spellcheck_types.h"
 
 namespace Core {
 namespace {
@@ -91,10 +92,13 @@ Settings::Settings()
 , _dialogsWidthRatio(DefaultDialogsWidthRatio()) {
 }
 
+Settings::~Settings() = default;
+
 QByteArray Settings::serialize() const {
 	const auto themesAccentColors = _themesAccentColors.serialize();
 	const auto windowPosition = Serialize(_windowPosition);
 	const auto proxy = _proxy.serialize();
+	const auto skipLanguages = _skipTranslationLanguages.current();
 
 	auto recentEmojiPreloadGenerated = std::vector<RecentEmojiPreload>();
 	if (_recentEmojiPreload.empty()) {
@@ -152,7 +156,10 @@ QByteArray Settings::serialize() const {
 		+ Serialize::stringSize(_customDeviceModel.current())
 		+ sizeof(qint32) * 4
 		+ (_accountsOrder.size() * sizeof(quint64))
-		+ sizeof(qint32) * 5;
+		+ sizeof(qint32) * 7
+		+ (skipLanguages.size() * sizeof(quint64))
+		+ sizeof(qint32)
+		+ sizeof(quint64);
 
 	auto result = QByteArray();
 	result.reserve(size);
@@ -270,13 +277,17 @@ QByteArray Settings::serialize() const {
 			<< qint32(_translateButtonEnabled ? 1 : 0);
 
 		stream
-			<< qint32(_skipTranslationForLanguages.size());
-		for (const auto &lang : _skipTranslationForLanguages) {
-			stream << quint64(lang);
+			<< qint32(skipLanguages.size());
+		for (const auto &id : skipLanguages) {
+			stream << quint64(id.value);
 		}
 
 		stream
 			<< qint32(_rememberedDeleteMessageOnlyForYou ? 1 : 0);
+
+		stream
+			<< qint32(_translateChatEnabled.current() ? 1 : 0)
+			<< quint64(QLocale::Language(_translateToRaw.current()));
 	}
 	return result;
 }
@@ -371,9 +382,11 @@ void Settings::addFromSerialized(const QByteArray &serialized) {
 	qint32 suggestAnimatedEmoji = _suggestAnimatedEmoji ? 1 : 0;
 	qint32 cornerReaction = _cornerReaction.current() ? 1 : 0;
 	qint32 legacySkipTranslationForLanguage = _translateButtonEnabled ? 1 : 0;
-	qint32 skipTranslationForLanguagesCount = 0;
-	std::vector<int> skipTranslationForLanguages;
+	qint32 skipTranslationLanguagesCount = 0;
+	std::vector<LanguageId> skipTranslationLanguages;
 	qint32 rememberedDeleteMessageOnlyForYou = _rememberedDeleteMessageOnlyForYou ? 1 : 0;
+	qint32 translateChatEnabled = _translateChatEnabled.current() ? 1 : 0;
+	quint64 translateToRaw = _translateToRaw.current();
 
 	stream >> themesAccentColors;
 	if (!stream.atEnd()) {
@@ -575,17 +588,24 @@ void Settings::addFromSerialized(const QByteArray &serialized) {
 		stream >> legacySkipTranslationForLanguage;
 	}
 	if (!stream.atEnd()) {
-		stream >> skipTranslationForLanguagesCount;
+		stream >> skipTranslationLanguagesCount;
 		if (stream.status() == QDataStream::Ok) {
-			for (auto i = 0; i != skipTranslationForLanguagesCount; ++i) {
+			for (auto i = 0; i != skipTranslationLanguagesCount; ++i) {
 				quint64 language;
 				stream >> language;
-				skipTranslationForLanguages.emplace_back(language);
+				skipTranslationLanguages.push_back({
+					QLocale::Language(language)
+				});
 			}
 		}
 
 		stream >> rememberedDeleteMessageOnlyForYou;
 	}
+	if (!stream.atEnd()) {
+		stream
+			>> translateChatEnabled
+			>> translateToRaw;
+	}
 	if (stream.status() != QDataStream::Ok) {
 		LOG(("App Error: "
 			"Bad data for Core::Settings::constructFromSerialized()"));
@@ -756,18 +776,21 @@ void Settings::addFromSerialized(const QByteArray &serialized) {
 	_suggestAnimatedEmoji = (suggestAnimatedEmoji == 1);
 	_cornerReaction = (cornerReaction == 1);
 	{ // Parse the legacy translation setting.
-		_skipTranslationForLanguages = skipTranslationForLanguages;
 		if (legacySkipTranslationForLanguage == 0) {
 			_translateButtonEnabled = false;
 		} else if (legacySkipTranslationForLanguage == 1) {
 			_translateButtonEnabled = true;
 		} else {
 			_translateButtonEnabled = (legacySkipTranslationForLanguage > 0);
-			_skipTranslationForLanguages.push_back(
-				std::abs(legacySkipTranslationForLanguage));
+			skipTranslationLanguages.push_back({
+				QLocale::Language(std::abs(legacySkipTranslationForLanguage))
+			});
 		}
+		_skipTranslationLanguages = std::move(skipTranslationLanguages);
 	}
 	_rememberedDeleteMessageOnlyForYou = (rememberedDeleteMessageOnlyForYou == 1);
+	_translateChatEnabled = (translateChatEnabled == 1);
+	_translateToRaw = int(QLocale::Language(translateToRaw));
 }
 
 QString Settings::getSoundPath(const QString &key) const {
@@ -1080,14 +1103,76 @@ float64 Settings::DefaultDialogsWidthRatio() {
 void Settings::setTranslateButtonEnabled(bool value) {
 	_translateButtonEnabled = value;
 }
+
 bool Settings::translateButtonEnabled() const {
 	return _translateButtonEnabled;
 }
-void Settings::setSkipTranslationForLanguages(std::vector<int> languages) {
-	_skipTranslationForLanguages = std::move(languages);
+
+void Settings::setTranslateChatEnabled(bool value) {
+	_translateChatEnabled = value;
 }
-std::vector<int> Settings::skipTranslationForLanguages() const {
-	return _skipTranslationForLanguages;
+
+bool Settings::translateChatEnabled() const {
+	return _translateChatEnabled.current();
+}
+
+rpl::producer<bool> Settings::translateChatEnabledValue() const {
+	return _translateChatEnabled.value();
+}
+
+[[nodiscard]] const std::vector<LanguageId> &DefaultSkipLanguages() {
+	using namespace Platform;
+
+	static auto Result = [&] {
+		auto list = std::vector<LanguageId>();
+		list.push_back({ LanguageId::FromName(Lang::Id()) });
+		const auto systemId = LanguageId::FromName(SystemLanguage());
+		if (list.back() != systemId) {
+			list.push_back(systemId);
+		}
+
+		Ensures(!list.empty());
+		return list;
+	}();
+	return Result;
+}
+
+[[nodiscard]] std::vector<LanguageId> NonEmptySkipList(
+		std::vector<LanguageId> list) {
+	return list.empty() ? DefaultSkipLanguages() : list;
+}
+
+void Settings::setTranslateTo(LanguageId id) {
+	_translateToRaw = int(id.value);
+}
+
+LanguageId Settings::translateTo() const {
+	if (const auto raw = _translateToRaw.current()) {
+		return { QLocale::Language(raw) };
+	}
+	return DefaultSkipLanguages().front();
+}
+
+rpl::producer<LanguageId> Settings::translateToValue() const {
+	return _translateToRaw.value() | rpl::map([=](int raw) {
+		return raw
+			? LanguageId{ QLocale::Language(raw) }
+			: DefaultSkipLanguages().front();
+	}) | rpl::distinct_until_changed();
+}
+
+void Settings::setSkipTranslationLanguages(
+		std::vector<LanguageId> languages) {
+	_skipTranslationLanguages = std::move(languages);
+}
+
+auto Settings::skipTranslationLanguages() const -> std::vector<LanguageId> {
+	return NonEmptySkipList(_skipTranslationLanguages.current());
+}
+
+auto Settings::skipTranslationLanguagesValue() const
+-> rpl::producer<std::vector<LanguageId>> {
+	return _skipTranslationLanguages.value() | rpl::map(NonEmptySkipList);
 }
 
 void Settings::setRememberedDeleteMessageOnlyForYou(bool value) {

Telegram/SourceFiles/core/core_settings.h

@@ -15,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "emoji.h"
 
 enum class RectPart;
+struct LanguageId;
 
 namespace Ui {
 enum class InputSubmitSettings;
@@ -99,6 +100,7 @@ public:
 	static constexpr auto kDefaultVolume = 0.9;
 
 	Settings();
+	~Settings();
 
 	[[nodiscard]] rpl::producer<> saveDelayedRequests() const {
 		return _saveDelayed.events();
@@ -724,8 +726,16 @@ public:
 
 	void setTranslateButtonEnabled(bool value);
 	[[nodiscard]] bool translateButtonEnabled() const;
-	void setSkipTranslationForLanguages(std::vector<int> languages);
-	[[nodiscard]] std::vector<int> skipTranslationForLanguages() const;
+	void setTranslateChatEnabled(bool value);
+	[[nodiscard]] bool translateChatEnabled() const;
+	[[nodiscard]] rpl::producer<bool> translateChatEnabledValue() const;
+	void setTranslateTo(LanguageId id);
+	[[nodiscard]] LanguageId translateTo() const;
+	[[nodiscard]] rpl::producer<LanguageId> translateToValue() const;
+	void setSkipTranslationLanguages(std::vector<LanguageId> languages);
+	[[nodiscard]] std::vector<LanguageId> skipTranslationLanguages() const;
+	[[nodiscard]] auto skipTranslationLanguagesValue() const
+		-> rpl::producer<std::vector<LanguageId>>;
 
 	void setRememberedDeleteMessageOnlyForYou(bool value);
 	[[nodiscard]] bool rememberedDeleteMessageOnlyForYou() const;
@@ -845,7 +855,10 @@ private:
 	HistoryView::DoubleClickQuickAction _chatQuickAction =
 		HistoryView::DoubleClickQuickAction();
 	bool _translateButtonEnabled = false;
-	std::vector<int> _skipTranslationForLanguages;
+	rpl::variable<bool> _translateChatEnabled = true;
+	rpl::variable<int> _translateToRaw = 0;
+	rpl::variable<std::vector<LanguageId>> _skipTranslationLanguages;
+	rpl::event_stream<> _skipTranslationLanguagesChanges;
 	bool _rememberedDeleteMessageOnlyForYou = false;
 
 	bool _tabbedReplacedWithInfo = false; // per-window

Telegram/SourceFiles/data/data_changes.h

@@ -56,52 +56,53 @@ struct PeerUpdate {
 		None = 0,
 
 		// Common flags
-		Name              = (1ULL << 0),
-		Username          = (1ULL << 1),
-		Photo             = (1ULL << 2),
-		About             = (1ULL << 3),
-		Notifications     = (1ULL << 4),
-		Migration         = (1ULL << 5),
-		UnavailableReason = (1ULL << 6),
-		ChatThemeEmoji    = (1ULL << 7),
-		IsBlocked         = (1ULL << 8),
-		MessagesTTL       = (1ULL << 9),
-		FullInfo          = (1ULL << 10),
-		Usernames         = (1ULL << 11),
+		Name                = (1ULL << 0),
+		Username            = (1ULL << 1),
+		Photo               = (1ULL << 2),
+		About               = (1ULL << 3),
+		Notifications       = (1ULL << 4),
+		Migration           = (1ULL << 5),
+		UnavailableReason   = (1ULL << 6),
+		ChatThemeEmoji      = (1ULL << 7),
+		IsBlocked           = (1ULL << 8),
+		MessagesTTL         = (1ULL << 9),
+		FullInfo            = (1ULL << 10),
+		Usernames           = (1ULL << 11),
+		TranslationDisabled = (1ULL << 12),
 
 		// For users
-		CanShareContact   = (1ULL << 12),
-		IsContact         = (1ULL << 13),
-		PhoneNumber       = (1ULL << 14),
-		OnlineStatus      = (1ULL << 15),
-		BotCommands       = (1ULL << 16),
-		BotCanBeInvited   = (1ULL << 17),
-		BotStartToken     = (1ULL << 18),
-		CommonChats       = (1ULL << 19),
-		HasCalls          = (1ULL << 20),
-		SupportInfo       = (1ULL << 21),
-		IsBot             = (1ULL << 22),
-		EmojiStatus       = (1ULL << 23),
+		CanShareContact     = (1ULL << 13),
+		IsContact           = (1ULL << 14),
+		PhoneNumber         = (1ULL << 15),
+		OnlineStatus        = (1ULL << 16),
+		BotCommands         = (1ULL << 17),
+		BotCanBeInvited     = (1ULL << 18),
+		BotStartToken       = (1ULL << 19),
+		CommonChats         = (1ULL << 20),
+		HasCalls            = (1ULL << 21),
+		SupportInfo         = (1ULL << 22),
+		IsBot               = (1ULL << 23),
+		EmojiStatus         = (1ULL << 24),
 
 		// For chats and channels
-		InviteLinks       = (1ULL << 24),
-		Members           = (1ULL << 25),
-		Admins            = (1ULL << 26),
-		BannedUsers       = (1ULL << 27),
-		Rights            = (1ULL << 28),
-		PendingRequests   = (1ULL << 29),
-		Reactions         = (1ULL << 30),
+		InviteLinks         = (1ULL << 25),
+		Members             = (1ULL << 26),
+		Admins              = (1ULL << 27),
+		BannedUsers         = (1ULL << 28),
+		Rights              = (1ULL << 29),
+		PendingRequests     = (1ULL << 30),
+		Reactions           = (1ULL << 31),
 
 		// For channels
-		ChannelAmIn       = (1ULL << 31),
-		StickersSet       = (1ULL << 32),
-		ChannelLinkedChat = (1ULL << 33),
-		ChannelLocation   = (1ULL << 34),
-		Slowmode          = (1ULL << 35),
-		GroupCall         = (1ULL << 36),
+		ChannelAmIn         = (1ULL << 32),
+		StickersSet         = (1ULL << 33),
+		ChannelLinkedChat   = (1ULL << 34),
+		ChannelLocation     = (1ULL << 35),
+		Slowmode            = (1ULL << 36),
+		GroupCall           = (1ULL << 37),
 
 		// For iteration
-		LastUsedBit       = (1ULL << 36),
+		LastUsedBit         = (1ULL << 37),
 	};
 	using Flags = base::flags<Flag>;
 	friend inline constexpr auto is_flag_type(Flag) { return true; }
@@ -128,8 +129,10 @@ struct HistoryUpdate {
 		OutboxRead         = (1U << 10),
 		BotKeyboard        = (1U << 11),
 		CloudDraft         = (1U << 12),
+		TranslateFrom      = (1U << 13),
+		TranslatedTo       = (1U << 14),
 
-		LastUsedBit        = (1U << 12),
+		LastUsedBit        = (1U << 14),
 	};
 	using Flags = base::flags<Flag>;
 	friend inline constexpr auto is_flag_type(Flag) { return true; }

Telegram/SourceFiles/data/data_channel.cpp

@@ -1040,6 +1040,7 @@ void ApplyChannelUpdate(
 		}
 	}
 	channel->setThemeEmoji(qs(update.vtheme_emoticon().value_or_empty()));
+	channel->setTranslationDisabled(update.is_translations_disabled());
 	if (const auto allowed = update.vavailable_reactions()) {
 		channel->setAllowedReactions(Data::Parse(*allowed));
 	} else {

Telegram/SourceFiles/data/data_chat.cpp

@@ -470,6 +470,7 @@ void ApplyChatUpdate(not_null<ChatData*> chat, const MTPDchatFull &update) {
 	}
 	chat->checkFolder(update.vfolder_id().value_or_empty());
 	chat->setThemeEmoji(qs(update.vtheme_emoticon().value_or_empty()));
+	chat->setTranslationDisabled(update.is_translations_disabled());
 	if (const auto allowed = update.vavailable_reactions()) {
 		chat->setAllowedReactions(Data::Parse(*allowed));
 	} else {

Telegram/SourceFiles/data/data_media_types.cpp

@@ -655,6 +655,8 @@ ItemPreview MediaPhoto::toPreview(ToPreviewOptions options) const {
 	const auto type = tr::lng_in_dlg_photo(tr::now);
 	const auto caption = options.hideCaption
 		? TextWithEntities()
+		: options.translated
+		? parent()->translatedText()
 		: parent()->originalText();
 	const auto hasMiniImages = !images.empty();
 	return {
@@ -899,6 +901,8 @@ ItemPreview MediaFile::toPreview(ToPreviewOptions options) const {
 	}();
 	const auto caption = options.hideCaption
 		? TextWithEntities()
+		: options.translated
+		? parent()->translatedText()
 		: parent()->originalText();
 	const auto hasMiniImages = !images.empty();
 	return {

Telegram/SourceFiles/data/data_peer.cpp

@@ -546,6 +546,32 @@ void PeerData::checkFolder(FolderId folderId) {
 	}
 }
 
+void PeerData::setTranslationDisabled(bool disabled) {
+	const auto flag = disabled
+		? TranslationFlag::Disabled
+		: TranslationFlag::Enabled;
+	if (_translationFlag != flag) {
+		_translationFlag = flag;
+		session().changes().peerUpdated(
+			this,
+			UpdateFlag::TranslationDisabled);
+	}
+}
+
+PeerData::TranslationFlag PeerData::translationFlag() const {
+	return _translationFlag;
+}
+
+void PeerData::saveTranslationDisabled(bool disabled) {
+	setTranslationDisabled(disabled);
+
+	using Flag = MTPmessages_TogglePeerTranslations::Flag;
+	session().api().request(MTPmessages_TogglePeerTranslations(
+		MTP_flags(disabled ? Flag::f_disabled : Flag()),
+		input
+	)).send();
+}
+
 void PeerData::setSettings(const MTPPeerSettings &data) {
 	data.match([&](const MTPDpeerSettings &data) {
 		_requestChatTitle = data.vrequest_chat_title().value_or_empty();

Telegram/SourceFiles/data/data_peer.h

@@ -349,6 +349,15 @@ public:
 		return _requestChatDate;
 	}
 
+	enum class TranslationFlag : uchar {
+		Unknown,
+		Disabled,
+		Enabled,
+	};
+	void setTranslationDisabled(bool disabled);
+	[[nodiscard]] TranslationFlag translationFlag() const;
+	void saveTranslationDisabled(bool disabled);
+
 	void setSettings(const MTPPeerSettings &data);
 
 	enum class BlockStatus : char {
@@ -439,6 +448,7 @@ private:
 	Settings _settings = PeerSettings(PeerSetting::Unknown);
 	BlockStatus _blockStatus = BlockStatus::Unknown;
 	LoadedStatus _loadedStatus = LoadedStatus::Not;
+	TranslationFlag _translationFlag = TranslationFlag::Unknown;
 	bool _userpicHasVideo = false;
 
 	QString _requestChatTitle;

Telegram/SourceFiles/data/data_types.h

@@ -288,6 +288,9 @@ enum class MessageFlag : uint64 {
 
 	// Profile photo suggestion, views have special media type.
 	IsUserpicSuggestion   = (1ULL << 33),
+
+	OnlyEmojiAndSpaces    = (1ULL << 34),
+	OnlyEmojiAndSpacesSet = (1ULL << 35),
 };
 inline constexpr bool is_flag_type(MessageFlag) { return true; }
 using MessageFlags = base::flags<MessageFlag>;

Telegram/SourceFiles/data/data_user.cpp

@@ -423,6 +423,7 @@ void ApplyUserUpdate(not_null<UserData*> user, const MTPDuserFull &update) {
 	user->setCommonChatsCount(update.vcommon_chats_count().v);
 	user->checkFolder(update.vfolder_id().value_or_empty());
 	user->setThemeEmoji(qs(update.vtheme_emoticon().value_or_empty()));
+	user->setTranslationDisabled(update.is_translations_disabled());
 
 	if (const auto info = user->botInfo.get()) {
 		const auto group = update.vbot_group_admin_rights()

Telegram/SourceFiles/history/history.cpp

@@ -9,12 +9,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "history/view/history_view_element.h"
 #include "history/view/history_view_item_preview.h"
+#include "dialogs/dialogs_indexed_list.h"
+#include "history/history_inner_widget.h"
 #include "history/history_item.h"
 #include "history/history_item_components.h"
 #include "history/history_item_helpers.h"
-#include "history/history_inner_widget.h"
+#include "history/history_translation.h"
 #include "history/history_unread_things.h"
-#include "dialogs/dialogs_indexed_list.h"
 #include "dialogs/ui/dialogs_layout.h"
 #include "data/notify/data_notify_settings.h"
 #include "data/stickers/data_stickers.h"
@@ -44,6 +45,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_session.h"
 #include "window/notifications_manager.h"
 #include "calls/calls_instance.h"
+#include "spellcheck/spellcheck_types.h"
 #include "storage/localstorage.h"
 #include "storage/storage_facade.h"
 #include "storage/storage_shared_media.h"
@@ -3456,6 +3458,46 @@ bool History::isTopPromoted() const {
 	return (_flags & Flag::IsTopPromoted);
 }
 
+void History::translateOfferFrom(LanguageId id) {
+	if (!id) {
+		if (translatedTo()) {
+			_translation->offerFrom(id);
+		} else if (_translation) {
+			_translation = nullptr;
+			session().changes().historyUpdated(
+				this,
+				UpdateFlag::TranslateFrom);
+		}
+	} else if (!_translation) {
+		_translation = std::make_unique<HistoryTranslation>(this, id);
+	} else {
+		_translation->offerFrom(id);
+	}
+}
+
+LanguageId History::translateOfferedFrom() const {
+	return _translation ? _translation->offeredFrom() : LanguageId();
+}
+
+void History::translateTo(LanguageId id) {
+	if (!_translation) {
+		return;
+	} else if (!id && !translateOfferedFrom()) {
+		_translation = nullptr;
+		session().changes().historyUpdated(this, UpdateFlag::TranslatedTo);
+	} else {
+		_translation->translateTo(id);
+	}
+}
+
+LanguageId History::translatedTo() const {
+	return _translation ? _translation->translatedTo() : LanguageId();
+}
+
+HistoryTranslation *History::translation() const {
+	return _translation.get();
+}
+
 HistoryBlock::HistoryBlock(not_null<History*> history)
 : _history(history) {
 }

Telegram/SourceFiles/history/history.h

@@ -18,9 +18,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 class History;
 class HistoryBlock;
+class HistoryTranslation;
 class HistoryItem;
 struct HistoryMessageMarkupData;
 class HistoryMainElementDelegateMixin;
+struct LanguageId;
 
 namespace Main {
 class Session;
@@ -425,6 +427,13 @@ public:
 
 	[[nodiscard]] bool isTopPromoted() const;
 
+	void translateOfferFrom(LanguageId id);
+	[[nodiscard]] LanguageId translateOfferedFrom() const;
+	void translateTo(LanguageId id);
+	[[nodiscard]] LanguageId translatedTo() const;
+
+	[[nodiscard]] HistoryTranslation *translation() const;
+
 	const not_null<PeerData*> peer;
 
 	// Still public data.
@@ -617,6 +626,7 @@ private:
 		HistoryBlock *block = nullptr;
 	};
 	std::unique_ptr<BuildingBlock> _buildingFrontBlock;
+	std::unique_ptr<HistoryTranslation> _translation;
 
 	Data::HistoryDrafts _drafts;
 	base::flat_map<MsgId, TimeId> _acceptCloudDraftsAfter;
@@ -628,6 +638,7 @@ private:
 
 	HistoryView::SendActionPainter _sendActionPainter;
 
+
 };
 
 class HistoryBlock {

Telegram/SourceFiles/history/history_inner_widget.cpp

@@ -57,6 +57,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "chat_helpers/message_field.h"
 #include "chat_helpers/emoji_interactions.h"
 #include "history/history_widget.h"
+#include "history/view/history_view_translate_tracker.h"
 #include "base/platform/base_platform_info.h"
 #include "base/qt/qt_common_adapters.h"
 #include "base/qt/qt_key_modifiers.h"
@@ -324,6 +325,7 @@ HistoryInner::HistoryInner(
 	&controller->session(),
 	[=](not_null<const Element*> view) { return itemTop(view); }))
 , _migrated(history->migrateFrom())
+, _translateTracker(std::make_unique<HistoryView::TranslateTracker>(history))
 , _pathGradient(
 	HistoryView::MakePathShiftGradient(
 		controller->chatStyle(),
@@ -340,6 +342,7 @@ HistoryInner::HistoryInner(
 	_history->delegateMixin()->setCurrent(this);
 	if (_migrated) {
 		_migrated->delegateMixin()->setCurrent(this);
+		_migrated->translateTo(_history->translatedTo());
 	}
 
 	Window::ChatThemeValueFromPeer(
@@ -431,7 +434,8 @@ HistoryInner::HistoryInner(
 
 	session().changes().historyUpdates(
 		_history,
-		Data::HistoryUpdate::Flag::OutboxRead
+		(Data::HistoryUpdate::Flag::OutboxRead
+			| Data::HistoryUpdate::Flag::TranslatedTo)
 	) | rpl::start_with_next([=] {
 		update();
 	}, lifetime());
@@ -910,6 +914,7 @@ void HistoryInner::paintEvent(QPaintEvent *e) {
 
 	const auto historyDisplayedEmpty = _history->isDisplayedEmpty()
 		&& (!_migrated || _migrated->isDisplayedEmpty());
+	const auto translatedTo = _history->translatedTo();
 	if (_botAbout && !_botAbout->info->text.isEmpty() && _botAbout->height > 0) {
 		const auto st = context.st;
 		const auto stm = &st->messageStyle(false, false);
@@ -958,9 +963,11 @@ void HistoryInner::paintEvent(QPaintEvent *e) {
 		return;
 	}
 
+	_translateTracker->startBunch();
 	auto readTill = (HistoryItem*)nullptr;
 	auto readContents = base::flat_set<not_null<HistoryItem*>>();
 	const auto guard = gsl::finally([&] {
+		_translateTracker->finishBunch();
 		if (readTill && _widget->markingMessagesRead()) {
 			session().data().histories().readInboxTill(readTill);
 		}
@@ -974,6 +981,7 @@ void HistoryInner::paintEvent(QPaintEvent *e) {
 			not_null<Element*> view,
 			int top,
 			int height) {
+		_translateTracker->add(view, translatedTo);
 		const auto item = view->data();
 		const auto isSponsored = item->isSponsored();
 		const auto isUnread = !item->out()
@@ -2414,7 +2422,8 @@ void HistoryInner::showContextMenu(QContextMenuEvent *e, bool showFromTouch) {
 							[=] { copyContextText(itemId); },
 							&st::menuIconCopy);
 					}
-					if (view->hasVisibleText() || mediaHasTextForCopy) {
+					if ((!item->translation() || !_history->translatedTo())
+						&& (view->hasVisibleText() || mediaHasTextForCopy)) {
 						const auto translate = mediaHasTextForCopy
 							? (HistoryView::TransribedText(item)
 								.append('\n')
@@ -3925,6 +3934,7 @@ void HistoryInner::notifyIsBotChanged() {
 
 void HistoryInner::notifyMigrateUpdated() {
 	_migrated = _history->migrateFrom();
+	_migrated->translateTo(_history->translatedTo());
 }
 
 void HistoryInner::applyDragSelection() {

Telegram/SourceFiles/history/history_inner_widget.h

@@ -31,6 +31,7 @@ enum class CursorState : char;
 enum class PointState : char;
 class EmptyPainter;
 class Element;
+class TranslateTracker;
 } // namespace HistoryView
 
 namespace HistoryView::Reactions {
@@ -445,6 +446,7 @@ private:
 
 	std::unique_ptr<BotAbout> _botAbout;
 	std::unique_ptr<HistoryView::EmptyPainter> _emptyPainter;
+	std::unique_ptr<HistoryView::TranslateTracker> _translateTracker;
 
 	mutable History *_curHistory = nullptr;
 	mutable int _curBlock = 0;

Telegram/SourceFiles/history/history_item.cpp

@@ -78,6 +78,25 @@ constexpr auto kPinnedMessageTextLimit = 16;
 
 using ItemPreview = HistoryView::ItemPreview;
 
+[[nodiscard]] bool IsOnlyEmojiAndSpaces(const QString &text) {
+	if (text.isEmpty()) {
+		return true;
+	}
+	auto emoji = 0;
+	auto start = text.data();
+	const auto end = start + text.size();
+	while (start < end) {
+		if (start->isSpace()) {
+			++start;
+		} else if (Ui::Emoji::Find(start, end, &emoji)) {
+			start += emoji;
+		} else {
+			return false;
+		}
+	}
+	return true;
+}
+
 } // namespace
 
 void HistoryItem::HistoryItem::Destroyer::operator()(HistoryItem *value) {
@@ -2006,6 +2025,94 @@ std::optional<QString> HistoryItem::errorTextForForward(
 	return {};
 }
 
+const HistoryMessageTranslation *HistoryItem::translation() const {
+	return Get<HistoryMessageTranslation>();
+}
+
+bool HistoryItem::translationShowRequiresCheck(LanguageId to) const {
+	// Check if a call to translationShowRequiresRequest(to) is not a no-op.
+	if (!to) {
+		if (const auto translation = Get<HistoryMessageTranslation>()) {
+			return (!translation->failed && translation->text.empty())
+				|| translation->used;
+		}
+		return false;
+	} else if (const auto translation = Get<HistoryMessageTranslation>()) {
+		if (translation->to == to) {
+			return !translation->used && !translation->text.empty();
+		}
+		return true;
+	} else {
+		return true;
+	}
+}
+
+bool HistoryItem::translationShowRequiresRequest(LanguageId to) {
+	// When changing be sure to reflect in translationShowRequiresCheck(to).
+	if (!to) {
+		if (const auto translation = Get<HistoryMessageTranslation>()) {
+			if (!translation->failed && translation->text.empty()) {
+				Assert(!translation->used);
+				RemoveComponents(HistoryMessageTranslation::Bit());
+			} else {
+				translationToggle(translation, false);
+			}
+		}
+		return false;
+	} else if (const auto translation = Get<HistoryMessageTranslation>()) {
+		if (translation->to == to) {
+			translationToggle(translation, true);
+			return false;
+		}
+		translationToggle(translation, false);
+		translation->to = to;
+		translation->requested = true;
+		translation->failed = false;
+		translation->text = {};
+		return true;
+	} else {
+		AddComponents(HistoryMessageTranslation::Bit());
+		const auto added = Get<HistoryMessageTranslation>();
+		added->to = to;
+		added->requested = true;
+		return true;
+	}
+}
+
+void HistoryItem::translationToggle(
+		not_null<HistoryMessageTranslation*> translation,
+		bool used) {
+	if (translation->used != used && !translation->text.empty()) {
+		translation->used = used;
+		_history->owner().requestItemTextRefresh(this);
+		_history->owner().updateDependentMessages(this);
+	}
+}
+
+void HistoryItem::translationDone(LanguageId to, TextWithEntities result) {
+	const auto set = [&](not_null<HistoryMessageTranslation*> translation) {
+		if (result.empty()) {
+			translation->failed = true;
+		} else {
+			translation->text = std::move(result);
+			if (_history->translatedTo() == to) {
+				translationToggle(translation, true);
+			}
+		}
+	};
+	if (const auto translation = Get<HistoryMessageTranslation>()) {
+		if (translation->to == to && translation->text.empty()) {
+			translation->requested = false;
+			set(translation);
+		}
+	} else {
+		AddComponents(HistoryMessageTranslation::Bit());
+		const auto added = Get<HistoryMessageTranslation>();
+		added->to = to;
+		set(added);
+	}
+}
+
 bool HistoryItem::canReact() const {
 	if (!isRegular() || isService()) {
 		return false;
@@ -2180,14 +2287,31 @@ MsgId HistoryItem::idOriginal() const {
 	return id;
 }
 
-TextWithEntities HistoryItem::originalText() const {
-	return isService() ? TextWithEntities() : _text;
+const TextWithEntities &HistoryItem::originalText() const {
+	static const auto kEmpty = TextWithEntities();
+	return isService() ? kEmpty : _text;
 }
 
-TextWithEntities HistoryItem::originalTextWithLocalEntities() const {
-	return isService()
-		? TextWithEntities()
-		: withLocalEntities(originalText());
+const TextWithEntities &HistoryItem::translatedText() const {
+	if (isService()) {
+		static const auto kEmpty = TextWithEntities();
+		return kEmpty;
+	} else if (const auto translation = this->translation()
+		; translation
+		&& translation->used
+		&& (translation->to == history()->translatedTo())) {
+		return translation->text;
+	} else {
+		return originalText();
+	}
+}
+
+TextWithEntities HistoryItem::translatedTextWithLocalEntities() const {
+	if (isService()) {
+		return {};
+	} else {
+		return withLocalEntities(translatedText());
+	}
 }
 
 TextForMimeData HistoryItem::clipboardText() const {
@@ -2595,6 +2719,7 @@ void HistoryItem::setText(const TextWithEntities &textWithEntities) {
 void HistoryItem::setTextValue(TextWithEntities text) {
 	const auto had = !_text.empty();
 	_text = std::move(text);
+	RemoveComponents(HistoryMessageTranslation::Bit());
 	if (had) {
 		history()->owner().requestItemTextRefresh(this);
 	}
@@ -2658,7 +2783,7 @@ ItemPreview HistoryItem::toPreview(ToPreviewOptions options) const {
 		if (_media) {
 			return _media->toPreview(options);
 		} else if (!emptyText()) {
-			return { .text = _text };
+			return { .text = options.translated ? translatedText() : _text };
 		}
 		return {};
 	}();
@@ -2705,6 +2830,7 @@ TextWithEntities HistoryItem::inReplyText() const {
 		return toPreview({
 			.hideSender = true,
 			.generateImages = false,
+			.translated = true,
 		}).text;
 	}
 	auto result = notificationText();
@@ -4256,7 +4382,7 @@ PreparedServiceText HistoryItem::preparePinnedText() {
 		result.links.push_back(fromLink());
 		result.links.push_back(pinned->lnk);
 		if (mediaText.isEmpty()) {
-			auto original = pinned->msg->originalText();
+			auto original = pinned->msg->translatedText();
 			auto cutAt = 0;
 			auto limit = kPinnedMessageTextLimit;
 			auto size = original.text.size();
@@ -4544,6 +4670,23 @@ crl::time HistoryItem::getSelfDestructIn(crl::time now) {
 	return 0;
 }
 
+void HistoryItem::cacheOnlyEmojiAndSpaces(bool only) {
+	_flags |= MessageFlag::OnlyEmojiAndSpacesSet;
+	if (only) {
+		_flags |= MessageFlag::OnlyEmojiAndSpaces;
+	} else {
+		_flags &= ~MessageFlag::OnlyEmojiAndSpaces;
+	}
+}
+
+bool HistoryItem::isOnlyEmojiAndSpaces() const {
+	if (!(_flags & MessageFlag::OnlyEmojiAndSpacesSet)) {
+		const_cast<HistoryItem*>(this)->cacheOnlyEmojiAndSpaces(
+			IsOnlyEmojiAndSpaces(_text.text));
+	}
+	return (_flags & MessageFlag::OnlyEmojiAndSpaces);
+}
+
 void HistoryItem::setupChatThemeChange() {
 	if (const auto user = history()->peer->asUser()) {
 		auto link = std::make_shared<LambdaClickHandler>([=](

Telegram/SourceFiles/history/history_item.h

@@ -21,10 +21,12 @@ struct HistoryMessageReply;
 struct HistoryMessageViews;
 struct HistoryMessageMarkupData;
 struct HistoryMessageReplyMarkup;
+struct HistoryMessageTranslation;
 struct HistoryServiceDependentData;
 enum class HistorySelfDestructType;
 struct PreparedServiceText;
 class ReplyKeyboard;
+struct LanguageId;
 
 namespace base {
 template <typename Enum>
@@ -259,6 +261,8 @@ public:
 	[[nodiscard]] bool definesReplyKeyboard() const;
 	[[nodiscard]] ReplyMarkupFlags replyKeyboardFlags() const;
 
+	void cacheOnlyEmojiAndSpaces(bool only);
+	[[nodiscard]] bool isOnlyEmojiAndSpaces() const;
 	[[nodiscard]] bool hasSwitchInlineButton() const {
 		return _flags & MessageFlag::HasSwitchInlineButton;
 	}
@@ -358,8 +362,9 @@ public:
 	// Example: "[link1-start]You:[link1-end] [link1-start]Photo,[link1-end] caption text"
 	[[nodiscard]] ItemPreview toPreview(ToPreviewOptions options) const;
 	[[nodiscard]] TextWithEntities inReplyText() const;
-	[[nodiscard]] TextWithEntities originalText() const;
-	[[nodiscard]] TextWithEntities originalTextWithLocalEntities() const;
+	[[nodiscard]] const TextWithEntities &originalText() const;
+	[[nodiscard]] const TextWithEntities &translatedText() const;
+	[[nodiscard]] TextWithEntities translatedTextWithLocalEntities() const;
 	[[nodiscard]] const std::vector<ClickHandlerPtr> &customTextLinks() const;
 	[[nodiscard]] TextForMimeData clipboardText() const;
 
@@ -397,6 +402,10 @@ public:
 	[[nodiscard]] bool requiresSendInlineRight() const;
 	[[nodiscard]] std::optional<QString> errorTextForForward(
 		not_null<Data::Thread*> to) const;
+	[[nodiscard]] const HistoryMessageTranslation *translation() const;
+	[[nodiscard]] bool translationShowRequiresCheck(LanguageId to) const;
+	bool translationShowRequiresRequest(LanguageId to);
+	void translationDone(LanguageId to, TextWithEntities result);
 
 	[[nodiscard]] bool canReact() const;
 	enum class ReactionSource {
@@ -542,6 +551,9 @@ private:
 	void setupChatThemeChange();
 	void setupTTLChange();
 
+	void translationToggle(
+		not_null<HistoryMessageTranslation*> translation,
+		bool used);
 	void setSelfDestruct(HistorySelfDestructType type, int ttlSeconds);
 
 	TextWithEntities fromLinkText() const;

Telegram/SourceFiles/history/history_item_components.h

@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "data/data_cloud_file.h"
 #include "history/history_item.h"
+#include "spellcheck/spellcheck_types.h" // LanguageId.
 #include "ui/empty_userpic.h"
 #include "ui/effects/animations.h"
 #include "ui/chat/message_bubble.h"
@@ -258,6 +259,15 @@ struct HistoryMessageReply
 
 };
 
+struct HistoryMessageTranslation
+	: public RuntimeComponent<HistoryMessageTranslation, HistoryItem> {
+	TextWithEntities text;
+	LanguageId to;
+	bool requested = false;
+	bool failed = false;
+	bool used = false;
+};
+
 struct HistoryMessageReplyMarkup
 	: public RuntimeComponent<HistoryMessageReplyMarkup, HistoryItem> {
 	using Button = HistoryMessageMarkupButton;

Telegram/SourceFiles/history/history_translation.cpp

@@ -0,0 +1,51 @@
+/*
+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 "history/history_translation.h"
+
+#include "data/data_changes.h"
+#include "history/history.h"
+#include "main/main_session.h"
+
+namespace {
+
+using UpdateFlag = Data::HistoryUpdate::Flag;
+
+} // namespace
+
+HistoryTranslation::HistoryTranslation(
+	not_null<History*> history,
+	const LanguageId &offerFrom)
+: _history(history) {
+	this->offerFrom(offerFrom);
+}
+
+void HistoryTranslation::offerFrom(LanguageId id) {
+	if (_offerFrom == id) {
+		return;
+	}
+	_offerFrom = id;
+	auto &changes = _history->session().changes();
+	changes.historyUpdated(_history, UpdateFlag::TranslateFrom);
+}
+
+LanguageId HistoryTranslation::offeredFrom() const {
+	return _offerFrom;
+}
+
+void HistoryTranslation::translateTo(LanguageId id) {
+	if (_translatedTo == id) {
+		return;
+	}
+	_translatedTo = id;
+	auto &changes = _history->session().changes();
+	changes.historyUpdated(_history, UpdateFlag::TranslatedTo);
+}
+
+LanguageId HistoryTranslation::translatedTo() const {
+	return _translatedTo;
+}

Telegram/SourceFiles/history/history_translation.h

@@ -0,0 +1,32 @@
+/*
+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 "spellcheck/spellcheck_types.h"
+
+class History;
+
+class HistoryTranslation final {
+public:
+	HistoryTranslation(
+		not_null<History*> history,
+		const LanguageId &offerFrom);
+
+	void offerFrom(LanguageId id);
+	[[nodiscard]] LanguageId offeredFrom() const;
+
+	void translateTo(LanguageId id);
+	[[nodiscard]] LanguageId translatedTo() const;
+
+private:
+	const not_null<History*> _history;
+
+	LanguageId _offerFrom;
+	LanguageId _translatedTo;
+
+};

Telegram/SourceFiles/history/history_widget.cpp

@@ -102,6 +102,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/view/history_view_item_preview.h"
 #include "history/view/history_view_requests_bar.h"
 #include "history/view/history_view_sticker_toast.h"
+#include "history/view/history_view_translate_bar.h"
 #include "history/view/media/history_view_media.h"
 #include "profile/profile_block_group_members.h"
 #include "info/info_memento.h"
@@ -1488,6 +1489,9 @@ void HistoryWidget::orderWidgets() {
 	if (_pinnedBar) {
 		_pinnedBar->raise();
 	}
+	if (_translateBar) {
+		_translateBar->raise();
+	}
 	if (_requestsBar) {
 		_requestsBar->raise();
 	}
@@ -2093,6 +2097,7 @@ void HistoryWidget::showHistory(
 		_history->showAtMsgId = _showAtMsgId;
 
 		destroyUnreadBarOnClose();
+		_translateBar = nullptr;
 		_pinnedBar = nullptr;
 		_pinnedTracker = nullptr;
 		_groupCallBar = nullptr;
@@ -2238,6 +2243,7 @@ void HistoryWidget::showHistory(
 
 		_updateHistoryItems.cancel();
 
+		setupTranslateBar();
 		setupPinnedTracker();
 		setupGroupCallBar();
 		setupRequestsBar();
@@ -3966,6 +3972,9 @@ void HistoryWidget::showAnimated(
 	show();
 	_topBar->finishAnimating();
 	_cornerButtons.finishAnimations();
+	if (_translateBar) {
+		_translateBar->finishAnimating();
+	}
 	if (_pinnedBar) {
 		_pinnedBar->finishAnimating();
 	}
@@ -4029,6 +4038,9 @@ void HistoryWidget::doneShow() {
 	_preserveScrollTop = true;
 	preloadHistoryIfNeeded();
 	updatePinnedViewer();
+	if (_translateBar) {
+		_translateBar->finishAnimating();
+	}
 	if (_pinnedBar) {
 		_pinnedBar->finishAnimating();
 	}
@@ -5320,7 +5332,12 @@ void HistoryWidget::updateControlsGeometry() {
 		_requestsBar->move(0, requestsTop);
 		_requestsBar->resizeToWidth(width());
 	}
-	const auto pinnedBarTop = requestsTop + (_requestsBar ? _requestsBar->height() : 0);
+	const auto translateTop = requestsTop + (_requestsBar ? _requestsBar->height() : 0);
+	if (_translateBar) {
+		_translateBar->move(0, translateTop);
+		_translateBar->resizeToWidth(width());
+	}
+	const auto pinnedBarTop = translateTop + (_translateBar ? _translateBar->height() : 0);
 	if (_pinnedBar) {
 		_pinnedBar->move(0, pinnedBarTop);
 		_pinnedBar->resizeToWidth(width());
@@ -5499,6 +5516,9 @@ void HistoryWidget::updateHistoryGeometry(
 	}
 
 	auto newScrollHeight = height() - _topBar->height();
+	if (_translateBar) {
+		newScrollHeight -= _translateBar->height();
+	}
 	if (_pinnedBar) {
 		newScrollHeight -= _pinnedBar->height();
 	}
@@ -6229,6 +6249,40 @@ void HistoryWidget::checkLastPinnedClickedIdReset(
 	}
 }
 
+void HistoryWidget::setupTranslateBar() {
+	Expects(_history != nullptr);
+
+	_translateBar = std::make_unique<HistoryView::TranslateBar>(
+		this,
+		_history);
+
+	controller()->adaptive().oneColumnValue(
+	) | rpl::start_with_next([=, raw = _translateBar.get()](bool one) {
+		raw->setShadowGeometryPostprocess([=](QRect geometry) {
+			if (!one) {
+				geometry.setLeft(geometry.left() + st::lineWidth);
+			}
+			return geometry;
+		});
+	}, _translateBar->lifetime());
+
+	_translateBarHeight = 0;
+	_translateBar->heightValue(
+	) | rpl::start_with_next([=](int height) {
+		_topDelta = _preserveScrollTop ? 0 : (height - _translateBarHeight);
+		_translateBarHeight = height;
+		updateHistoryGeometry();
+		updateControlsGeometry();
+		_topDelta = 0;
+	}, _translateBar->lifetime());
+
+	orderWidgets();
+
+	if (_showAnimation) {
+		_translateBar->hide();
+	}
+}
+
 void HistoryWidget::setupPinnedTracker() {
 	Expects(_history != nullptr);
 

Telegram/SourceFiles/history/history_widget.h

@@ -91,6 +91,7 @@ class TopBarWidget;
 class ContactStatus;
 class Element;
 class PinnedTracker;
+class TranslateBar;
 class ComposeSearch;
 namespace Controls {
 class RecordLock;
@@ -494,6 +495,7 @@ private:
 	void updateReplyEditText(not_null<HistoryItem*> item);
 
 	void updatePinnedViewer();
+	void setupTranslateBar();
 	void setupPinnedTracker();
 	void checkPinnedBarState();
 	void clearHidingPinnedBar();
@@ -638,6 +640,9 @@ private:
 
 	object_ptr<Ui::IconButton> _fieldBarCancel;
 
+	std::unique_ptr<HistoryView::TranslateBar> _translateBar;
+	int _translateBarHeight = 0;
+
 	std::unique_ptr<HistoryView::PinnedTracker> _pinnedTracker;
 	std::unique_ptr<Ui::PinnedBar> _pinnedBar;
 	std::unique_ptr<Ui::PinnedBar> _hidingPinnedBar;

Telegram/SourceFiles/history/view/history_view_context_menu.cpp

@@ -66,6 +66,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/application.h"
 #include "main/main_session.h"
 #include "main/main_session_settings.h"
+#include "spellcheck/spellcheck_types.h"
 #include "apiwrap.h"
 #include "styles/style_chat.h"
 #include "styles/style_menu_icons.h"
@@ -1058,7 +1059,8 @@ base::unique_qptr<Ui::PopupMenu> FillContextMenu(
 					.append('\n')
 					.append(item->originalText()))
 				: item->originalText();
-			if (!translate.text.isEmpty()
+			if ((!item->translation() || !item->history()->translatedTo())
+				&& !translate.text.isEmpty()
 				&& !Ui::SkipTranslate(translate)) {
 				result->addAction(tr::lng_context_translate(tr::now), [=] {
 					if (const auto item = owner->message(itemId)) {

Telegram/SourceFiles/history/view/history_view_element.cpp

@@ -652,6 +652,18 @@ const Ui::Text::String &Element::text() const {
 	return _text;
 }
 
+OnlyEmojiAndSpaces Element::isOnlyEmojiAndSpaces() const {
+	if (data()->Has<HistoryMessageTranslation>()) {
+		return OnlyEmojiAndSpaces::No;
+	} else if (!_text.isEmpty() || data()->originalText().empty()) {
+		return _text.isOnlyEmojiAndSpaces()
+			? OnlyEmojiAndSpaces::Yes
+			: OnlyEmojiAndSpaces::No;
+	} else {
+		return OnlyEmojiAndSpaces::Unknown;
+	}
+}
+
 int Element::textHeightFor(int textWidth) {
 	validateText();
 	if (_textWidth != textWidth) {
@@ -837,7 +849,7 @@ void Element::validateText() {
 		};
 		_text.setMarkedText(
 			st::messageTextStyle,
-			item->originalTextWithLocalEntities(),
+			item->translatedTextWithLocalEntities(),
 			Ui::ItemTextOptions(item),
 			context);
 		if (!text.empty() && _text.isEmpty()) {

Telegram/SourceFiles/history/view/history_view_element.h

@@ -58,6 +58,12 @@ enum class Context : char {
 	ContactPreview
 };
 
+enum class OnlyEmojiAndSpaces : char {
+	Unknown,
+	Yes,
+	No,
+};
+
 class Element;
 class ElementDelegate {
 public:
@@ -309,6 +315,8 @@ public:
 	[[nodiscard]] Ui::Text::IsolatedEmoji isolatedEmoji() const;
 	[[nodiscard]] Ui::Text::OnlyCustomEmoji onlyCustomEmoji() const;
 
+	[[nodiscard]] OnlyEmojiAndSpaces isOnlyEmojiAndSpaces() const;
+
 	// For blocks context this should be called only from recountAttachToPreviousInBlocks().
 	void setAttachToPrevious(bool attachToNext, Element *previous = nullptr);
 

Telegram/SourceFiles/history/view/history_view_item_preview.h

@@ -37,6 +37,7 @@ struct ToPreviewOptions {
 	bool generateImages = true;
 	bool ignoreGroup = false;
 	bool ignoreTopic = true;
+	bool translated = false;
 };
 
 } // namespace HistoryView

Telegram/SourceFiles/history/view/history_view_replies_section.cpp

@@ -295,17 +295,6 @@ RepliesWidget::RepliesWidget(
 		searchInTopic();
 	}, _topBar->lifetime());
 
-	if (_rootView) {
-		_rootView->raise();
-	}
-	if (_pinnedBar) {
-		_pinnedBar->raise();
-	}
-	if (_topicReopenBar) {
-		_topicReopenBar->bar().raise();
-	}
-	_topBarShadow->raise();
-
 	controller->adaptive().value(
 	) | rpl::start_with_next([=] {
 		updateAdaptiveLayout();
@@ -426,6 +415,9 @@ void RepliesWidget::orderWidgets() {
 	if (_pinnedBar) {
 		_pinnedBar->raise();
 	}
+	if (_topicReopenBar) {
+		_topicReopenBar->bar().raise();
+	}
 	_topBarShadow->raise();
 	_composeControls->raisePanels();
 }

Telegram/SourceFiles/history/view/history_view_translate_bar.cpp

@@ -0,0 +1,197 @@
+/*
+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 "history/view/history_view_translate_bar.h"
+
+#include "boxes/translate_box.h" // Ui::LanguageName.
+#include "core/application.h"
+#include "core/core_settings.h"
+#include "data/data_changes.h"
+#include "history/history.h"
+#include "main/main_session.h"
+#include "spellcheck/spellcheck_types.h"
+#include "ui/widgets/buttons.h"
+#include "ui/widgets/labels.h"
+#include "ui/widgets/shadow.h"
+#include "styles/style_chat.h"
+
+#include <QtGui/QtEvents>
+
+namespace HistoryView {
+
+TranslateBar::TranslateBar(
+	not_null<QWidget*> parent,
+	not_null<History*> history)
+: _wrap(parent, object_ptr<Ui::FlatButton>(
+	parent,
+	QString(),
+	st::historyComposeButton))
+, _shadow(std::make_unique<Ui::PlainShadow>(_wrap.parentWidget())) {
+	_wrap.hide(anim::type::instant);
+	_shadow->hide();
+
+	setup(history);
+}
+
+TranslateBar::~TranslateBar() = default;
+
+void TranslateBar::updateControlsGeometry(QRect wrapGeometry) {
+	const auto hidden = _wrap.isHidden() || !wrapGeometry.height();
+	if (_shadow->isHidden() != hidden) {
+		_shadow->setVisible(!hidden);
+	}
+}
+
+void TranslateBar::setShadowGeometryPostprocess(
+		Fn<QRect(QRect)> postprocess) {
+	_shadowGeometryPostprocess = std::move(postprocess);
+	updateShadowGeometry(_wrap.geometry());
+}
+
+void TranslateBar::updateShadowGeometry(QRect wrapGeometry) {
+	const auto regular = QRect(
+		wrapGeometry.x(),
+		wrapGeometry.y() + wrapGeometry.height(),
+		wrapGeometry.width(),
+		st::lineWidth);
+	_shadow->setGeometry(_shadowGeometryPostprocess
+		? _shadowGeometryPostprocess(regular)
+		: regular);
+}
+
+void TranslateBar::setup(not_null<History*> history) {
+	_wrap.geometryValue(
+	) | rpl::start_with_next([=](QRect rect) {
+		updateShadowGeometry(rect);
+	updateControlsGeometry(rect);
+	}, _wrap.lifetime());
+
+	const auto button = static_cast<Ui::FlatButton*>(_wrap.entity());
+	button->setClickedCallback([=] {
+		const auto to = history->translatedTo()
+			? LanguageId()
+			: Core::App().settings().translateTo();
+		history->translateTo(to);
+		if (const auto migrated = history->migrateFrom()) {
+			migrated->translateTo(to);
+		}
+	});
+
+	const auto label = Ui::CreateChild<Ui::FlatLabel>(
+		button,
+		st::historyTranslateLabel);
+	const auto icon = Ui::CreateChild<Ui::RpWidget>(button);
+	label->setAttribute(Qt::WA_TransparentForMouseEvents);
+	icon->setAttribute(Qt::WA_TransparentForMouseEvents);
+	icon->resize(st::historyTranslateIcon.size());
+	icon->paintRequest() | rpl::start_with_next([=] {
+		auto p = QPainter(icon);
+		st::historyTranslateIcon.paint(p, 0, 0, icon->width());
+	}, icon->lifetime());
+	const auto settings = Ui::CreateChild<Ui::IconButton>(
+		button,
+		st::historyTranslateSettings);
+	const auto updateLabelGeometry = [=] {
+		const auto full = _wrap.width() - icon->width();
+		const auto skip = st::semiboldFont->spacew * 2;
+		const auto natural = label->naturalWidth();
+		const auto top = [&] {
+			return (_wrap.height() - label->height()) / 2;
+		};
+		if (natural <= full - 2 * (settings->width() + skip)) {
+			label->resizeToWidth(natural);
+			label->moveToRight((full - label->width()) / 2, top());
+		} else {
+			const auto available = full - settings->width() - 2 * skip;
+			label->resizeToWidth(std::min(natural, available));
+			label->moveToRight(settings->width() + skip, top());
+		}
+		icon->move(
+			label->x() - icon->width(),
+			(_wrap.height() - icon->height()) / 2);
+	};
+
+	_wrap.sizeValue() | rpl::start_with_next([=](QSize size) {
+		settings->moveToRight(0, 0, size.width());
+		updateLabelGeometry();
+	}, lifetime());
+
+	rpl::combine(
+		Core::App().settings().translateToValue(),
+		history->session().changes().historyFlagsValue(
+			history,
+			(Data::HistoryUpdate::Flag::TranslatedTo
+				| Data::HistoryUpdate::Flag::TranslateFrom))
+	) | rpl::map([=](LanguageId to, const auto&) {
+		return history->translatedTo()
+			? u"Show Original"_q
+			: history->translateOfferedFrom()
+			? u"Translate to "_q + Ui::LanguageName(to.locale())
+			: QString();
+	}) | rpl::distinct_until_changed(
+	) | rpl::start_with_next([=](QString phrase) {
+		_shouldBeShown = !phrase.isEmpty();
+		if (_shouldBeShown) {
+			label->setText(phrase);
+			updateLabelGeometry();
+		}
+		if (!_forceHidden) {
+			_wrap.toggle(_shouldBeShown, anim::type::normal);
+		}
+	}, lifetime());
+}
+
+void TranslateBar::show() {
+	if (!_forceHidden) {
+		return;
+	}
+	_forceHidden = false;
+	if (_shouldBeShown) {
+		_wrap.show(anim::type::instant);
+		_shadow->show();
+	}
+}
+
+void TranslateBar::hide() {
+	if (_forceHidden) {
+		return;
+	}
+	_forceHidden = true;
+	_wrap.hide(anim::type::instant);
+	_shadow->hide();
+}
+
+void TranslateBar::raise() {
+	_wrap.raise();
+	_shadow->raise();
+}
+
+void TranslateBar::finishAnimating() {
+	_wrap.finishAnimating();
+}
+
+void TranslateBar::move(int x, int y) {
+	_wrap.move(x, y);
+}
+
+void TranslateBar::resizeToWidth(int width) {
+	_wrap.entity()->resizeToWidth(width);
+}
+
+int TranslateBar::height() const {
+	return !_forceHidden
+		? _wrap.height()
+		: _shouldBeShown
+		? st::historyReplyHeight
+		: 0;
+}
+
+rpl::producer<int> TranslateBar::heightValue() const {
+	return _wrap.heightValue();
+}
+
+} // namespace Ui

Telegram/SourceFiles/history/view/history_view_translate_bar.h

@@ -0,0 +1,55 @@
+/*
+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 "ui/wrap/slide_wrap.h"
+
+class History;
+struct LanguageId;
+
+namespace Ui {
+class PlainShadow;
+} // namespace Ui
+
+namespace HistoryView {
+
+class TranslateBar final {
+public:
+	TranslateBar(not_null<QWidget*> parent, not_null<History*> history);
+	~TranslateBar();
+
+	void show();
+	void hide();
+	void raise();
+	void finishAnimating();
+
+	void setShadowGeometryPostprocess(Fn<QRect(QRect)> postprocess);
+
+	void move(int x, int y);
+	void resizeToWidth(int width);
+	[[nodiscard]] int height() const;
+	[[nodiscard]] rpl::producer<int> heightValue() const;
+
+	[[nodiscard]] rpl::lifetime &lifetime() {
+		return _wrap.lifetime();
+	}
+
+private:
+	void setup(not_null<History*> history);
+	void updateShadowGeometry(QRect wrapGeometry);
+	void updateControlsGeometry(QRect wrapGeometry);
+
+	Ui::SlideWrap<> _wrap;
+	std::unique_ptr<Ui::PlainShadow> _shadow;
+	Fn<QRect(QRect)> _shadowGeometryPostprocess;
+	bool _shouldBeShown = false;
+	bool _forceHidden = false;
+
+};
+
+} // namespace HistoryView

Telegram/SourceFiles/history/view/history_view_translate_tracker.cpp

@@ -0,0 +1,351 @@
+/*
+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 "history/view/history_view_translate_tracker.h"
+
+#include "apiwrap.h"
+#include "api/api_text_entities.h"
+#include "core/application.h"
+#include "core/core_settings.h"
+#include "data/data_changes.h"
+#include "data/data_peer_values.h" // Data::AmPremiumValue.
+#include "data/data_session.h"
+#include "history/history.h"
+#include "history/history_item.h"
+#include "history/history_item_components.h"
+#include "history/view/history_view_element.h"
+#include "main/main_session.h"
+#include "spellcheck/spellcheck_types.h"
+#include "spellcheck/platform/platform_language.h"
+
+namespace HistoryView {
+namespace {
+
+constexpr auto kEnoughForRecognition = 10;
+constexpr auto kEnoughForTranslation = 6;
+constexpr auto kRequestLengthLimit = 24 * 1024;
+constexpr auto kRequestCountLimit = 20;
+
+} // namespace
+
+struct TranslateTracker::ItemForRecognize {
+	uint64 generation = 0;
+	MaybeLanguageId id;
+};
+
+TranslateTracker::TranslateTracker(not_null<History*> history)
+: _history(history)
+, _limit(kEnoughForRecognition) {
+	setup();
+}
+
+TranslateTracker::~TranslateTracker() {
+	cancelToRequest();
+	cancelSentRequest();
+}
+
+rpl::producer<bool> TranslateTracker::trackingLanguage() const {
+	return _trackingLanguage.value();
+}
+
+void TranslateTracker::setup() {
+	const auto peer = _history->peer;
+	const auto session = &_history->session();
+	peer->updateFull();
+
+	auto translationEnabled = session->changes().peerFlagsValue(
+		peer,
+		Data::PeerUpdate::Flag::TranslationDisabled
+	) | rpl::map([=] {
+		return peer->translationFlag() == PeerData::TranslationFlag::Enabled;
+	}) | rpl::distinct_until_changed();
+
+	_trackingLanguage = Data::AmPremiumValue(&_history->session());
+
+	_trackingLanguage.value(
+	) | rpl::start_with_next([=](bool tracking) {
+		_trackingLifetime.destroy();
+		if (tracking) {
+			recognizeCollected();
+			trackSkipLanguages();
+		} else {
+			checkRecognized({});
+			_history->translateTo({});
+			if (const auto migrated = _history->migrateFrom()) {
+				migrated->translateTo({});
+			}
+		}
+	}, _lifetime);
+}
+
+bool TranslateTracker::enoughForRecognition() const {
+	return _itemsForRecognize.size() >= kEnoughForRecognition;
+}
+
+void TranslateTracker::startBunch() {
+	_addedInBunch = 0;
+	++_generation;
+}
+
+void TranslateTracker::add(
+		not_null<Element*> view,
+		LanguageId translatedTo) {
+	const auto item = view->data();
+	const auto only = view->isOnlyEmojiAndSpaces();
+	if (only != OnlyEmojiAndSpaces::Unknown) {
+		item->cacheOnlyEmojiAndSpaces(only == OnlyEmojiAndSpaces::Yes);
+	}
+	add(item, translatedTo, false);
+}
+
+void TranslateTracker::add(
+		not_null<HistoryItem*> item,
+		LanguageId translatedTo) {
+	add(item, translatedTo, false);
+}
+
+void TranslateTracker::add(
+		not_null<HistoryItem*> item,
+		LanguageId translatedTo,
+		bool skipDependencies) {
+	Expects(_addedInBunch >= 0);
+
+	if (item->out()
+		|| item->isService()
+		|| !item->isRegular()
+		|| item->isOnlyEmojiAndSpaces()) {
+		return;
+	}
+	if (item->translationShowRequiresCheck(translatedTo)) {
+		_switchTranslations[item] = translatedTo;
+	}
+	if (!skipDependencies) {
+		if (const auto reply = item->Get<HistoryMessageReply>()) {
+			if (const auto to = reply->replyToMsg.get()) {
+				add(to, translatedTo, true);
+			}
+		}
+	}
+	const auto id = item->fullId();
+	const auto i = _itemsForRecognize.find(id);
+	if (i != end(_itemsForRecognize)) {
+		i->second.generation = _generation;
+		return;
+	}
+	const auto &text = item->originalText().text;
+	_itemsForRecognize.emplace(id, ItemForRecognize{
+		.generation = _generation,
+		.id = (_trackingLanguage.current()
+			? Platform::Language::Recognize(text)
+			: MaybeLanguageId{ text }),
+	});
+	++_addedInBunch;
+}
+
+void TranslateTracker::switchTranslation(
+		not_null<HistoryItem*> item,
+		LanguageId id) {
+	if (item->translationShowRequiresRequest(id)) {
+		_itemsToRequest.emplace(
+			item->fullId(),
+			ItemToRequest{ item->originalText().text.size() });
+	}
+}
+
+void TranslateTracker::finishBunch() {
+	if (_addedInBunch > 0) {
+		accumulate_max(_limit, _addedInBunch + kEnoughForRecognition);
+		_addedInBunch = -1;
+		applyLimit();
+		if (_trackingLanguage.current()) {
+			checkRecognized();
+		}
+	}
+	requestSome();
+	if (!_switchTranslations.empty()) {
+		auto switching = base::take(_switchTranslations);
+		for (const auto &[item, id] : switching) {
+			switchTranslation(item, id);
+		}
+		_switchTranslations = std::move(switching);
+		_switchTranslations.clear();
+	}
+}
+
+void TranslateTracker::cancelToRequest() {
+	if (!_itemsToRequest.empty()) {
+		const auto owner = &_history->owner();
+		for (const auto &[id, entry] : base::take(_itemsToRequest)) {
+			if (const auto item = owner->message(id)) {
+				item->translationShowRequiresRequest({});
+			}
+		}
+	}
+}
+
+void TranslateTracker::cancelSentRequest() {
+	if (_requestId) {
+		const auto owner = &_history->owner();
+		for (const auto &id : base::take(_requested)) {
+			if (const auto item = owner->message(id)) {
+				item->translationShowRequiresRequest({});
+			}
+		}
+		_history->session().api().request(base::take(_requestId)).cancel();
+	}
+}
+
+void TranslateTracker::requestSome() {
+	if (_requestId || _itemsToRequest.empty()) {
+		return;
+	}
+	const auto to = _history->translatedTo();
+	if (!to) {
+		cancelToRequest();
+		return;
+	}
+	_requested.clear();
+	_requested.reserve(_itemsToRequest.size());
+	const auto session = &_history->session();
+	const auto peerId = _itemsToRequest.back().first.peer;
+	auto peer = (peerId == _history->peer->id)
+		? _history->peer
+		: session->data().peer(peerId);
+	auto length = 0;
+	auto list = QVector<MTPint>();
+	list.reserve(_itemsToRequest.size());
+	for (auto i = _itemsToRequest.end(); i != _itemsToRequest.begin();) {
+		if ((--i)->first.peer != peerId) {
+			break;
+		}
+		length += i->second.length;
+		_requested.push_back(i->first);
+		list.push_back(MTP_int(i->first.msg));
+		i = _itemsToRequest.erase(i);
+		if (list.size() >= kRequestCountLimit
+			|| length >= kRequestLengthLimit) {
+			break;
+		}
+	}
+	using Flag = MTPmessages_TranslateText::Flag;
+	_requestId = session->api().request(MTPmessages_TranslateText(
+		MTP_flags(Flag::f_peer | Flag::f_id),
+		peer->input,
+		MTP_vector<MTPint>(list),
+		MTPVector<MTPTextWithEntities>(),
+		MTP_string(to.locale().name().mid(0, 2))
+	)).done([=](const MTPmessages_TranslatedText &result) {
+		requestDone(to, result.data().vresult().v);
+	}).fail([=] {
+		requestDone(to, {});
+	}).send();
+}
+
+void TranslateTracker::requestDone(
+		LanguageId to,
+		const QVector<MTPTextWithEntities> &list) {
+	auto index = 0;
+	const auto session = &_history->session();
+	const auto owner = &session->data();
+	for (const auto &id : base::take(_requested)) {
+		if (const auto item = owner->message(id)) {
+			const auto data = (index >= list.size())
+				? nullptr
+				: &list[index].data();
+			auto text = data ? TextWithEntities{
+				qs(data->vtext()),
+				Api::EntitiesFromMTP(session, data->ventities().v)
+			} : TextWithEntities();
+			item->translationDone(to, std::move(text));
+		}
+		++index;
+	}
+	_requestId = 0;
+	requestSome();
+}
+
+void TranslateTracker::applyLimit() {
+	const auto generationProjection = [](const auto &pair) {
+		return pair.second.generation;
+	};
+	const auto owner = &_history->owner();
+
+	// Erase starting with oldest generation till items count is not too big.
+	while (_itemsForRecognize.size() > _limit) {
+		const auto oldest = ranges::min_element(
+			_itemsForRecognize,
+			ranges::less(),
+			generationProjection
+		)->second.generation;
+		for (auto i = begin(_itemsForRecognize)
+			; i != end(_itemsForRecognize);) {
+			if (i->second.generation == oldest) {
+				if (const auto j = _itemsToRequest.find(i->first)
+					; j != end(_itemsToRequest)) {
+					if (const auto item = owner->message(i->first)) {
+						item->translationShowRequiresRequest({});
+					}
+					_itemsToRequest.erase(j);
+				}
+				i = _itemsForRecognize.erase(i);
+			} else {
+				++i;
+			}
+		}
+	}
+}
+
+void TranslateTracker::recognizeCollected() {
+	const auto owner = &_history->owner();
+	for (auto &[id, entry] : _itemsForRecognize) {
+		if (const auto text = std::get_if<QString>(&entry.id)) {
+			entry.id = Platform::Language::Recognize(*text);
+		}
+	}
+}
+
+void TranslateTracker::trackSkipLanguages() {
+	Core::App().settings().skipTranslationLanguagesValue(
+	) | rpl::start_with_next([=](const std::vector<LanguageId> &skip) {
+		checkRecognized(skip);
+	}, _trackingLifetime);
+}
+
+void TranslateTracker::checkRecognized() {
+	checkRecognized(Core::App().settings().skipTranslationLanguages());
+}
+
+void TranslateTracker::checkRecognized(const std::vector<LanguageId> &skip) {
+	if (!_trackingLanguage.current()) {
+		_history->translateOfferFrom({});
+		return;
+	}
+	auto languages = base::flat_map<LanguageId, int>();
+	for (const auto &[id, entry] : _itemsForRecognize) {
+		if (const auto id = std::get_if<LanguageId>(&entry.id)) {
+			if (*id && !ranges::contains(skip, *id)) {
+				++languages[*id];
+			}
+		}
+	}
+	using namespace base;
+	const auto count = int(_itemsForRecognize.size());
+	constexpr auto p = &flat_multi_map_pair_type<LanguageId, int>::second;
+	const auto threshold = (count > kEnoughForRecognition)
+		? (count * kEnoughForTranslation / kEnoughForRecognition)
+		: _allLoaded
+		? std::min(count, kEnoughForTranslation)
+		: kEnoughForTranslation;
+	if (ranges::accumulate(languages, 0, ranges::plus(), p) >= threshold) {
+		_history->translateOfferFrom(
+			ranges::max_element(languages, ranges::less(), p)->first);
+	} else {
+		_history->translateOfferFrom({});
+	}
+}
+
+} // namespace HistoryView

Telegram/SourceFiles/history/view/history_view_translate_tracker.h

@@ -0,0 +1,76 @@
+/*
+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
+
+class History;
+class HistoryItem;
+struct LanguageId;
+
+namespace HistoryView {
+
+class Element;
+
+class TranslateTracker final {
+public:
+	explicit TranslateTracker(not_null<History*> history);
+	~TranslateTracker();
+
+	[[nodiscard]] bool enoughForRecognition() const;
+	void startBunch();
+	void add(not_null<Element*> view, LanguageId translatedTo);
+	void add(not_null<HistoryItem*> item, LanguageId translatedTo);
+	void finishBunch();
+
+	[[nodiscard]] rpl::producer<bool> trackingLanguage() const;
+
+private:
+	using MaybeLanguageId = std::variant<QString, LanguageId>;
+	struct ItemForRecognize;
+	struct ItemToRequest {
+		int length = 0;
+	};
+
+	void setup();
+	void add(
+		not_null<HistoryItem*> item,
+		LanguageId translatedTo,
+		bool skipDependencies);
+	void recognizeCollected();
+	void trackSkipLanguages();
+	void checkRecognized();
+	void checkRecognized(const std::vector<LanguageId> &skip);
+	void applyLimit();
+	void requestSome();
+	void cancelToRequest();
+	void cancelSentRequest();
+	void switchTranslation(not_null<HistoryItem*> item, LanguageId id);
+
+	void requestDone(
+		LanguageId to,
+		const QVector<MTPTextWithEntities> &list);
+
+	const not_null<History*> _history;
+	rpl::variable<bool> _trackingLanguage = false;
+	base::flat_map<FullMsgId, ItemForRecognize> _itemsForRecognize;
+	uint64 _generation = 0;
+	int _limit = 0;
+	int _addedInBunch = -1;
+	bool _allLoaded = false;
+
+	base::flat_map<not_null<HistoryItem*>, LanguageId> _switchTranslations;
+	base::flat_map<FullMsgId, ItemToRequest> _itemsToRequest;
+	std::vector<FullMsgId> _requested;
+	mtpRequestId _requestId = 0;
+
+	rpl::lifetime _trackingLifetime;
+	rpl::lifetime _lifetime;
+
+};
+
+} // namespace HistoryView
+

Telegram/SourceFiles/history/view/media/history_view_media.cpp

@@ -305,7 +305,7 @@ Ui::Text::String Media::createCaption(not_null<HistoryItem*> item) const {
 	};
 	result.setMarkedText(
 		st::messageTextStyle,
-		item->originalTextWithLocalEntities(),
+		item->translatedTextWithLocalEntities(),
 		Ui::ItemTextOptions(item),
 		context);
 	FillTextWithAnimatedSpoilers(_parent, result);

Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp

@@ -2300,7 +2300,7 @@ void OverlayWidget::refreshCaption() {
 			return;
 		}
 	}
-	const auto caption = _message->originalText();
+	const auto caption = _message->translatedText();
 	if (caption.text.isEmpty()) {
 		return;
 	}

Telegram/SourceFiles/ui/chat/chat.style

@@ -1257,3 +1257,19 @@ historyHasCustomEmoji: FlatLabel(defaultFlatLabel) {
 	minWidth: 80px;
 }
 historyHasCustomEmojiPosition: point(12px, 4px);
+
+historyTranslateLabel: FlatLabel(defaultFlatLabel) {
+	style: semiboldTextStyle;
+	textFg: windowActiveTextFg;
+	minWidth: 80px;
+}
+historyTranslateIcon: icon{{ "menu/translate", windowActiveTextFg }};
+historyTranslateSettings: IconButton(defaultIconButton) {
+	width: 46px;
+	height: 46px;
+	icon: icon{{ "menu/customize", windowActiveTextFg }};
+	iconOver: icon{{ "menu/customize", windowActiveTextFg }};
+	rippleAreaPosition: point(4px, 4px);
+	rippleAreaSize: 38px;
+	ripple: defaultRippleAnimation;
+}

Telegram/lib_spellcheck

@@ -1 +1 @@
-Subproject commit cf59ca87b761ab5bbd80be02a61cd38a70142898
+Subproject commit e5ac664fe397d5874a244bbbc8a7b266223cb88b

Telegram/lib_ui

@@ -1 +1 @@
-Subproject commit 43e9128014c5239a6732ae34bdfe007efb9692c8
+Subproject commit f2e698f2209a86c133261196275ca98273c7a4dc