Track and display unread count in discussions.

Telegram/SourceFiles/api/api_updates.cpp

@@ -2094,17 +2094,18 @@ void Updates::feedUpdate(const MTPUpdate &update) {
 		const auto msgId = d.vtop_msg_id().v;
 		const auto readTillId = d.vread_max_id().v;
 		const auto item = session().data().message(channelId, msgId);
+		const auto unreadCount = std::nullopt;
 		if (item) {
-			item->setRepliesInboxReadTill(readTillId);
+			item->setRepliesInboxReadTill(readTillId, unreadCount);
 			if (const auto post = item->lookupDiscussionPostOriginal()) {
-				post->setRepliesInboxReadTill(readTillId);
+				post->setRepliesInboxReadTill(readTillId, unreadCount);
 			}
 		}
 		if (const auto broadcastId = d.vbroadcast_id()) {
 			if (const auto post = session().data().message(
 					broadcastId->v,
 					d.vbroadcast_post()->v)) {
-				post->setRepliesInboxReadTill(readTillId);
+				post->setRepliesInboxReadTill(readTillId, unreadCount);
 			}
 		}
 	} break;

Telegram/SourceFiles/data/data_changes.h

@@ -134,16 +134,17 @@ struct MessageUpdate {
 	enum class Flag : uint32 {
 		None = 0,
 
-		Edited           = (1U << 0),
-		Destroyed        = (1U << 1),
-		DialogRowRepaint = (1U << 2),
-		DialogRowRefresh = (1U << 3),
-		NewAdded         = (1U << 4),
-		ReplyMarkup      = (1U << 5),
-		BotCallbackSent  = (1U << 6),
-		NewMaybeAdded    = (1U << 7),
+		Edited             = (1U << 0),
+		Destroyed          = (1U << 1),
+		DialogRowRepaint   = (1U << 2),
+		DialogRowRefresh   = (1U << 3),
+		NewAdded           = (1U << 4),
+		ReplyMarkup        = (1U << 5),
+		BotCallbackSent    = (1U << 6),
+		NewMaybeAdded      = (1U << 7),
+		RepliesUnreadCount = (1U << 8),
 
-		LastUsedBit      = (1U << 7),
+		LastUsedBit        = (1U << 7),
 	};
 	using Flags = base::flags<Flag>;
 	friend inline constexpr auto is_flag_type(Flag) { return true; }

Telegram/SourceFiles/data/data_replies_list.cpp

@@ -101,6 +101,15 @@ rpl::producer<MessagesSlice> RepliesList::source(
 		_partLoaded.events(
 		) | rpl::start_with_next(pushDelayed, lifetime);
 
+		_history->session().data().channelDifferenceTooLong(
+		) | rpl::filter([=](not_null<ChannelData*> channel) {
+			if (_history->peer != channel || !_skippedAfter.has_value()) {
+				return false;
+			}
+			_skippedAfter = std::nullopt;
+			return true;
+		}) | rpl::start_with_next(pushDelayed, lifetime);
+
 		push();
 		return lifetime;
 	};
@@ -169,6 +178,64 @@ rpl::producer<int> RepliesList::fullCount() const {
 	return _fullCount.value() | rpl::filter_optional();
 }
 
+std::optional<int> RepliesList::fullUnreadCountAfter(
+		MsgId readTillId,
+		MsgId wasReadTillId,
+		std::optional<int> wasUnreadCountAfter) const {
+	Expects(readTillId >= wasReadTillId);
+
+	readTillId = std::max(readTillId, _rootId);
+	wasReadTillId = std::max(wasReadTillId, _rootId);
+	const auto backLoaded = (_skippedBefore == 0);
+	const auto frontLoaded = (_skippedAfter == 0);
+	const auto fullLoaded = backLoaded && frontLoaded;
+	const auto allUnread = (readTillId == _rootId)
+		|| (fullLoaded && _list.empty());
+	const auto countIncoming = [&](auto from, auto till) {
+		auto &owner = _history->owner();
+		const auto channelId = _history->channelId();
+		auto count = 0;
+		for (auto i = from; i != till; ++i) {
+			if (!owner.message(channelId, *i)->out()) {
+				++count;
+			}
+		}
+		return count;
+	};
+	if (allUnread && fullLoaded) {
+		// Should not happen too often unless the list is empty.
+		return countIncoming(begin(_list), end(_list));
+	} else if (frontLoaded && !_list.empty() && readTillId >= _list.front()) {
+		// Always "count by local data" if read till the end.
+		return 0;
+	} else if (wasReadTillId == readTillId) {
+		// Otherwise don't recount the same value over and over.
+		return wasUnreadCountAfter;
+	} else if (frontLoaded && !_list.empty() && readTillId >= _list.back()) {
+		// And count by local data if it is available and read-till changed.
+		return countIncoming(
+			begin(_list),
+			ranges::lower_bound(_list, readTillId, std::greater<>()));
+	} else if (_list.empty()) {
+		return std::nullopt;
+	} else if (wasUnreadCountAfter.has_value()
+		&& (frontLoaded || readTillId <= _list.front())
+		&& (backLoaded || wasReadTillId >= _list.back())) {
+		// Count how many were read since previous value.
+		const auto from = ranges::lower_bound(
+			_list,
+			readTillId,
+			std::greater<>());
+		const auto till = ranges::lower_bound(
+			from,
+			end(_list),
+			wasReadTillId,
+			std::greater<>());
+		return std::max(*wasUnreadCountAfter - countIncoming(from, till), 0);
+	}
+	return std::nullopt;
+}
+
 void RepliesList::injectRootMessageAndReverse(not_null<Viewer*> viewer) {
 	injectRootMessage(viewer);
 	ranges::reverse(viewer->slice.ids);

Telegram/SourceFiles/data/data_replies_list.h

@@ -31,6 +31,11 @@ public:
 
 	[[nodiscard]] rpl::producer<int> fullCount() const;
 
+	[[nodiscard]] std::optional<int> fullUnreadCountAfter(
+		MsgId readTillId,
+		MsgId wasReadTillId,
+		std::optional<int> wasUnreadCountAfter) const;
+
 private:
 	struct Viewer;
 

Telegram/SourceFiles/history/history_item.h

@@ -223,7 +223,9 @@ public:
 	[[nodiscard]] virtual MsgId repliesInboxReadTill() const {
 		return MsgId(0);
 	}
-	virtual void setRepliesInboxReadTill(MsgId readTillId) {
+	virtual void setRepliesInboxReadTill(
+		MsgId readTillId,
+		std::optional<int> unreadCount) {
 	}
 	[[nodiscard]] virtual MsgId computeRepliesInboxReadTillFull() const {
 		return MsgId(0);
@@ -316,7 +318,10 @@ public:
 	}
 	virtual void clearReplies() {
 	}
-	virtual void changeRepliesCount(int delta, PeerId replier) {
+	virtual void changeRepliesCount(
+		int delta,
+		PeerId replier,
+		std::optional<bool> unread) {
 	}
 	virtual void setReplyToTop(MsgId replyToTop) {
 	}

Telegram/SourceFiles/history/history_item_components.h

@@ -49,6 +49,7 @@ struct HistoryMessageViews : public RuntimeComponent<HistoryMessageViews, Histor
 	MsgId repliesInboxReadTillId = 0;
 	MsgId repliesOutboxReadTillId = 0;
 	MsgId repliesMaxId = 0;
+	int repliesUnreadCount = -1; // unknown
 	ChannelId commentsMegagroupId = 0;
 	MsgId commentsRootId = 0;
 };

Telegram/SourceFiles/history/history_message.cpp

@@ -816,16 +816,30 @@ MsgId HistoryMessage::repliesInboxReadTill() const {
 	return 0;
 }
 
-void HistoryMessage::setRepliesInboxReadTill(MsgId readTillId) {
+void HistoryMessage::setRepliesInboxReadTill(
+		MsgId readTillId,
+		std::optional<int> unreadCount) {
 	if (const auto views = Get<HistoryMessageViews>()) {
 		const auto newReadTillId = std::max(readTillId, 1);
-		if (newReadTillId > views->repliesInboxReadTillId) {
+		const auto ignore = (newReadTillId < views->repliesInboxReadTillId);
+		if (ignore) {
+			return;
+		}
+		const auto changed = (newReadTillId > views->repliesInboxReadTillId);
+		if (changed) {
 			const auto wasUnread = repliesAreComments() && areRepliesUnread();
 			views->repliesInboxReadTillId = newReadTillId;
 			if (wasUnread && !areRepliesUnread()) {
 				history()->owner().requestItemRepaint(this);
 			}
 		}
+		const auto wasUnreadCount = (views->repliesUnreadCount >= 0)
+			? std::make_optional(views->repliesUnreadCount)
+			: std::nullopt;
+		if (unreadCount != wasUnreadCount
+			&& (changed || unreadCount.has_value())) {
+			setUnreadRepliesCount(views, unreadCount.value_or(-1));
+		}
 	}
 }
 
@@ -1808,10 +1822,27 @@ void HistoryMessage::refreshRepliesText(
 	}
 }
 
-void HistoryMessage::changeRepliesCount(int delta, PeerId replier) {
+void HistoryMessage::changeRepliesCount(
+		int delta,
+		PeerId replier,
+		std::optional<bool> unread) {
 	const auto views = Get<HistoryMessageViews>();
 	const auto limit = HistoryMessageViews::kMaxRecentRepliers;
-	if (!views || views->replies.count < 0) {
+	if (!views) {
+		return;
+	}
+
+	// Update unread count.
+	if (!unread) {
+		setUnreadRepliesCount(views, -1);
+	} else if (views->repliesUnreadCount >= 0 && *unread) {
+		setUnreadRepliesCount(
+			views,
+			std::max(views->repliesUnreadCount + delta, 0));
+	}
+
+	// Update full count.
+	if (views->replies.count < 0) {
 		return;
 	}
 	views->replies.count = std::max(views->replies.count + delta, 0);
@@ -1830,6 +1861,19 @@ void HistoryMessage::changeRepliesCount(int delta, PeerId replier) {
 	refreshRepliesText(views);
 }
 
+void HistoryMessage::setUnreadRepliesCount(
+		not_null<HistoryMessageViews*> views,
+		int count) {
+	// Track unread count in discussion forwards, not in the channel posts.
+	if (views->repliesUnreadCount == count || views->commentsMegagroupId) {
+		return;
+	}
+	views->repliesUnreadCount = count;
+	history()->session().changes().messageUpdated(
+		this,
+		Data::MessageUpdate::Flag::RepliesUnreadCount);
+}
+
 void HistoryMessage::setReplyToTop(MsgId replyToTop) {
 	const auto reply = Get<HistoryMessageReply>();
 	if (!reply
@@ -1877,19 +1921,23 @@ void HistoryMessage::changeReplyToTopCounter(
 	if (!top) {
 		return;
 	}
-	const auto changeFor = [&](not_null<HistoryItem*> item) {
-		if (const auto from = displayFrom()) {
-			item->changeRepliesCount(delta, from->id);
-			return;
-		}
-		item->changeRepliesCount(delta, PeerId());
-	};
+	auto unread = out() ? std::make_optional(false) : std::nullopt;
 	if (const auto views = top->Get<HistoryMessageViews>()) {
 		if (views->commentsMegagroupId) {
 			// This is a post in channel, we don't track its replies.
 			return;
 		}
+		if (views->repliesInboxReadTillId > 0) {
+			unread = !out() && (id > views->repliesInboxReadTillId);
+		}
 	}
+	const auto changeFor = [&](not_null<HistoryItem*> item) {
+		if (const auto from = displayFrom()) {
+			item->changeRepliesCount(delta, from->id, unread);
+		} else {
+			item->changeRepliesCount(delta, PeerId(), unread);
+		}
+	};
 	changeFor(top);
 	if (const auto original = top->lookupDiscussionPostOriginal()) {
 		changeFor(original);

Telegram/SourceFiles/history/history_message.h

@@ -133,7 +133,10 @@ public:
 	void setForwardsCount(int count) override;
 	void setReplies(const MTPMessageReplies &data) override;
 	void clearReplies() override;
-	void changeRepliesCount(int delta, PeerId replier) override;
+	void changeRepliesCount(
+		int delta,
+		PeerId replier,
+		std::optional<bool> unread) override;
 	void setReplyToTop(MsgId replyToTop) override;
 	void setPostAuthor(const QString &author) override;
 	void setRealId(MsgId newId) override;
@@ -181,7 +184,9 @@ public:
 	[[nodiscard]] bool externalReply() const override;
 
 	[[nodiscard]] MsgId repliesInboxReadTill() const override;
-	void setRepliesInboxReadTill(MsgId readTillId) override;
+	void setRepliesInboxReadTill(
+		MsgId readTillId,
+		std::optional<int> unreadCount) override;
 	[[nodiscard]] MsgId computeRepliesInboxReadTillFull() const override;
 	[[nodiscard]] MsgId repliesOutboxReadTill() const override;
 	void setRepliesOutboxReadTill(MsgId readTillId) override;
@@ -250,6 +255,9 @@ private:
 	void refreshRepliesText(
 		not_null<HistoryMessageViews*> views,
 		bool forceResize = false);
+	void setUnreadRepliesCount(
+		not_null<HistoryMessageViews*> views,
+		int count);
 
 	static void FillForwardedInfo(
 		CreateConfig &config,

Telegram/SourceFiles/history/view/history_view_pinned_section.h

@@ -160,7 +160,6 @@ private:
 	bool _scrollDownIsShown = false;
 	object_ptr<Ui::HistoryDownButton> _scrollDown;
 
-	Data::MessagesSlice _lastSlice;
 	int _messagesCount = -1;
 
 };

Telegram/SourceFiles/history/view/history_view_replies_section.cpp

@@ -247,16 +247,24 @@ RepliesWidget::RepliesWidget(
 			data.progress);
 	}, lifetime());
 
+	using MessageUpdateFlag = Data::MessageUpdate::Flag;
 	_history->session().changes().messageUpdates(
-		Data::MessageUpdate::Flag::Destroyed
+		MessageUpdateFlag::Destroyed
+		| MessageUpdateFlag::RepliesUnreadCount
 	) | rpl::start_with_next([=](const Data::MessageUpdate &update) {
-		if (update.item == _root) {
-			_root = nullptr;
-			updatePinnedVisibility();
-			controller->showBackFromStack();
-		}
-		while (update.item == _replyReturn) {
-			calculateNextReplyReturn();
+		if (update.flags & MessageUpdateFlag::Destroyed) {
+			if (update.item == _root) {
+				_root = nullptr;
+				updatePinnedVisibility();
+				controller->showBackFromStack();
+			}
+			while (update.item == _replyReturn) {
+				calculateNextReplyReturn();
+			}
+			return;
+		} else if ((update.item == _root)
+			&& (update.flags & MessageUpdateFlag::RepliesUnreadCount)) {
+			refreshUnreadCountBadge();
 		}
 	}, lifetime());
 
@@ -302,12 +310,15 @@ void RepliesWidget::sendReadTillRequest() {
 	_readRequestPending = false;
 	const auto api = &_history->session().api();
 	api->request(base::take(_readRequestId)).cancel();
+
 	_readRequestId = api->request(MTPmessages_ReadDiscussion(
 		_root->history()->peer->input,
 		MTP_int(_root->id),
 		MTP_int(_root->computeRepliesInboxReadTillFull())
-	)).done([=](const MTPBool &) {
-	}).send();
+	)).done(crl::guard(this, [=](const MTPBool &) {
+		_readRequestId = 0;
+		reloadUnreadCountIfNeeded();
+	})).send();
 }
 
 void RepliesWidget::setupRoot() {
@@ -317,6 +328,7 @@ void RepliesWidget::setupRoot() {
 			_root = lookupRoot();
 			if (_root) {
 				_areComments = computeAreComments();
+				refreshUnreadCountBadge();
 				if (_readRequestPending) {
 					sendReadTillRequest();
 				}
@@ -370,6 +382,19 @@ bool RepliesWidget::computeAreComments() const {
 	return _root && _root->isDiscussionPost();
 }
 
+std::optional<int> RepliesWidget::computeUnreadCount() const {
+	if (!_root) {
+		return std::nullopt;
+	}
+	const auto views = _root->Get<HistoryMessageViews>();
+	if (!views) {
+		return std::nullopt;
+	}
+	return (views->repliesUnreadCount >= 0)
+		? std::make_optional(views->repliesUnreadCount)
+		: std::nullopt;
+}
+
 void RepliesWidget::setupComposeControls() {
 	auto slowmodeSecondsLeft = session().changes().peerFlagsValue(
 		_history->peer,
@@ -1143,6 +1168,7 @@ void RepliesWidget::setupScrollDownButton() {
 	_scrollDown->setClickedCallback([=] {
 		scrollDownClicked();
 	});
+	refreshUnreadCountBadge();
 	base::install_event_filter(_scrollDown, [=](not_null<QEvent*> event) {
 		if (event->type() != QEvent::Wheel) {
 			return base::EventFilterResult::Continue;
@@ -1154,6 +1180,56 @@ void RepliesWidget::setupScrollDownButton() {
 	updateScrollDownVisibility();
 }
 
+void RepliesWidget::refreshUnreadCountBadge() {
+	if (!_root) {
+		return;
+	} else if (const auto count = computeUnreadCount()) {
+		_scrollDown->setUnreadCount(*count);
+	} else if (!_readRequestPending
+		&& !_readRequestTimer.isActive()
+		&& !_readRequestId) {
+		reloadUnreadCountIfNeeded();
+	}
+}
+
+void RepliesWidget::reloadUnreadCountIfNeeded() {
+	const auto views = _root ? _root->Get<HistoryMessageViews>() : nullptr;
+	if (!views || views->repliesUnreadCount >= 0) {
+		return;
+	} else if (views->repliesInboxReadTillId
+		< _root->computeRepliesInboxReadTillFull()) {
+		_readRequestTimer.callOnce(0);
+	} else if (!_reloadUnreadCountRequestId) {
+		const auto session = &_history->session();
+		const auto fullId = _root->fullId();
+		const auto apply = [session, fullId](int readTill, int unreadCount) {
+			if (const auto root = session->data().message(fullId)) {
+				root->setRepliesInboxReadTill(readTill, unreadCount);
+				if (const auto post = root->lookupDiscussionPostOriginal()) {
+					post->setRepliesInboxReadTill(readTill, unreadCount);
+				}
+			}
+		};
+		const auto weak = Ui::MakeWeak(this);
+		_reloadUnreadCountRequestId = session->api().request(
+			MTPmessages_GetDiscussionMessage(
+				_history->peer->input,
+				MTP_int(_rootId))
+		).done([=](const MTPmessages_DiscussionMessage &result) {
+			if (weak) {
+				_reloadUnreadCountRequestId = 0;
+			}
+			result.match([&](const MTPDmessages_discussionMessage &data) {
+				session->data().processUsers(data.vusers());
+				session->data().processChats(data.vchats());
+				apply(
+					data.vread_inbox_max_id().value_or_empty(),
+					data.vunread_count().v);
+			});
+		}).send();
+	}
+}
+
 void RepliesWidget::scrollDownClicked() {
 	if (QGuiApplication::keyboardModifiers() == Qt::ControlModifier) {
 		showAtEnd();
@@ -1692,11 +1768,21 @@ void RepliesWidget::readTill(not_null<HistoryItem*> item) {
 	}
 	const auto was = _root->computeRepliesInboxReadTillFull();
 	const auto now = item->id;
-	const auto fast = item->out();
-	if (was < now) {
-		_root->setRepliesInboxReadTill(now);
+	if (now < was) {
+		return;
+	}
+	const auto views = _root->Get<HistoryMessageViews>();
+	const auto wasReadTillId = views ? views->repliesInboxReadTillId : 0;
+	const auto wasUnreadCount = views ? views->repliesUnreadCount : -1;
+	const auto unreadCount = _replies->fullUnreadCountAfter(
+		now,
+		wasReadTillId,
+		wasUnreadCount);
+	const auto fast = item->out() || !unreadCount.has_value();
+	if (was < now || (fast && now == was)) {
+		_root->setRepliesInboxReadTill(now, unreadCount);
 		if (const auto post = _root->lookupDiscussionPostOriginal()) {
-			post->setRepliesInboxReadTill(now);
+			post->setRepliesInboxReadTill(now, unreadCount);
 		}
 		if (!_readRequestTimer.isActive()) {
 			_readRequestTimer.callOnce(fast ? 0 : kReadRequestTimeout);

Telegram/SourceFiles/history/view/history_view_replies_section.h

@@ -198,6 +198,7 @@ private:
 	[[nodiscard]] MsgId replyToId() const;
 	[[nodiscard]] HistoryItem *lookupRoot() const;
 	[[nodiscard]] bool computeAreComments() const;
+	[[nodiscard]] std::optional<int> computeUnreadCount() const;
 	void orderWidgets();
 
 	void pushReplyReturn(not_null<HistoryItem*> item);
@@ -208,6 +209,8 @@ private:
 	void recountChatWidth();
 	void replyToMessage(FullMsgId itemId);
 	void refreshTopBarActiveChat();
+	void refreshUnreadCountBadge();
+	void reloadUnreadCountIfNeeded();
 
 	void uploadFile(const QByteArray &fileContent, SendMediaType type);
 	bool confirmSendingFiles(
@@ -276,13 +279,13 @@ private:
 	bool _scrollDownIsShown = false;
 	object_ptr<Ui::HistoryDownButton> _scrollDown;
 
-	Data::MessagesSlice _lastSlice;
 	bool _choosingAttach = false;
 
 	base::Timer _readRequestTimer;
 	bool _readRequestPending = false;
 	mtpRequestId _readRequestId = 0;
 
+	mtpRequestId _reloadUnreadCountRequestId = 0;
 	bool _loaded = false;
 
 };

Telegram/SourceFiles/window/window_session_controller.cpp

@@ -399,7 +399,8 @@ void SessionNavigation::showRepliesForMessage(
 					item->setRepliesMaxId(maxId->v);
 				}
 				item->setRepliesInboxReadTill(
-					data.vread_inbox_max_id().value_or_empty());
+					data.vread_inbox_max_id().value_or_empty(),
+					data.vunread_count().v);
 				item->setRepliesOutboxReadTill(
 					data.vread_outbox_max_id().value_or_empty());
 				const auto post = _session->data().message(channelId, rootId);
@@ -409,7 +410,8 @@ void SessionNavigation::showRepliesForMessage(
 						post->setRepliesMaxId(maxId->v);
 					}
 					post->setRepliesInboxReadTill(
-						data.vread_inbox_max_id().value_or_empty());
+						data.vread_inbox_max_id().value_or_empty(),
+						data.vunread_count().v);
 					post->setRepliesOutboxReadTill(
 						data.vread_outbox_max_id().value_or_empty());
 				}