Add jump-to-end button to chat preview.

Telegram/SourceFiles/data/data_history_messages.cpp

@@ -189,7 +189,8 @@ rpl::producer<MessagesSlice> HistoryMessagesViewer(
 	};
 	const auto messageId = (aroundId.fullId.msg == ShowAtUnreadMsgId)
 		? computeUnreadAroundId()
-		: (aroundId.fullId.msg == ShowAtTheEndMsgId)
+		: ((aroundId.fullId.msg == ShowAtTheEndMsgId)
+			|| (aroundId == MaxMessagePosition))
 		? (ServerMaxMsgId - 1)
 		: (aroundId.fullId.peer == history->peer->id)
 		? aroundId.fullId.msg

Telegram/SourceFiles/history/view/history_view_chat_preview.cpp

@@ -19,6 +19,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_thread.h"
 #include "history/view/reactions/history_view_reactions_button.h"
+#include "history/view/history_view_corner_buttons.h"
 #include "history/view/history_view_list_widget.h"
 #include "history/history.h"
 #include "history/history_item.h"
@@ -52,7 +53,8 @@ namespace {
 
 class Item final
 	: public Ui::Menu::ItemBase
-	, private HistoryView::ListDelegate {
+	, private ListDelegate
+	, private CornerButtonsDelegate {
 public:
 	Item(not_null<Ui::RpWidget*> parent, not_null<Data::Thread*> thread);
 
@@ -73,6 +75,7 @@ private:
 	void setupHistory();
 	void updateInnerVisibleArea();
 
+	// ListDelegate delegate.
 	Context listContext() override;
 	bool listScrollTo(int top, bool syntetic = true) override;
 	void listCancelRequest() override;
@@ -164,6 +167,16 @@ private:
 		std::unique_ptr<QMimeData> data,
 		Fn<void()> finished) override;
 
+	// CornerButtonsDelegate delegate.
+	void cornerButtonsShowAtPosition(
+		Data::MessagePosition position) override;
+	Data::Thread *cornerButtonsThread() override;
+	FullMsgId cornerButtonsCurrentId() override;
+	bool cornerButtonsIgnoreVisibility() override;
+	std::optional<bool> cornerButtonsDownShown() override;
+	bool cornerButtonsUnreadMayBeShown() override;
+	bool cornerButtonsHas(CornerButtonType type) override;
+
 	const not_null<QAction*> _dummyAction;
 	const not_null<Main::Session*> _session;
 	const not_null<Data::Thread*> _thread;
@@ -176,7 +189,8 @@ private:
 	const std::unique_ptr<Ui::ElasticScroll> _scroll;
 	const std::unique_ptr<Ui::FlatButton> _markRead;
 
-	QPointer<HistoryView::ListWidget> _inner;
+	QPointer<ListWidget> _inner;
+	std::unique_ptr<CornerButtons> _cornerButtons;
 	rpl::event_stream<ChatPreviewAction> _actions;
 
 	QImage _bg;
@@ -446,11 +460,16 @@ void Item::setupHistory() {
 		this,
 		_session,
 		static_cast<ListDelegate*>(this)));
+	_cornerButtons = std::make_unique<CornerButtons>(
+		_scroll.get(),
+		_chatStyle.get(),
+		static_cast<CornerButtonsDelegate*>(this));
 
 	_markRead->shownValue() | rpl::start_with_next([=](bool shown) {
 		const auto top = _top->height();
 		const auto bottom = shown ? _markRead->height() : 0;
 		_scroll->setGeometry(rect().marginsRemoved({ 0, top, 0, bottom }));
+		_cornerButtons->updatePositions();
 	}, _markRead->lifetime());
 
 	_scroll->scrolls(
@@ -495,6 +514,7 @@ void Item::paintEvent(QPaintEvent *e) {
 void Item::updateInnerVisibleArea() {
 	const auto scrollTop = _scroll->scrollTop();
 	_inner->setVisibleTopBottom(scrollTop, scrollTop + _scroll->height());
+	_cornerButtons->updateJumpDownVisibility();
 }
 
 Context Item::listContext() {
@@ -592,18 +612,28 @@ MessagesBarData Item::listMessagesBar(
 		return {};
 	}
 
+	auto skipped = false;
 	const auto hidden = _replies && (repliesTill < 2);
 	for (auto i = 0, count = int(elements.size()); i != count; ++i) {
 		const auto item = elements[i]->data();
-		if (!item->isRegular()
-			|| item->out()
-			|| (_replies && !item->replyToId())) {
+		if (!item->isRegular() || (_replies && !item->replyToId())) {
 			continue;
 		}
 		const auto inHistory = (item->history() == _history);
-		if ((_replies && item->id > repliesTill)
+		const auto unread = (_replies && item->id > repliesTill)
 			|| (migratedTill && (inHistory || item->id > migratedTill))
-			|| (historyTill && inHistory && item->id > historyTill)) {
+			|| (historyTill && inHistory && item->id > historyTill);
+		if (!unread) {
+			skipped = true;
+		}
+		if (item->out()) {
+			continue;
+		}
+		if (unread) {
+			if (!skipped) {
+				// Don't show jumping unread bar if scrolling up from bottom.
+				return {};
+			}
 			return {
 				.bar = {
 					.element = elements[i],
@@ -800,6 +830,46 @@ void Item::listLaunchDrag(
 	Fn<void()> finished) {
 }
 
+void Item::cornerButtonsShowAtPosition(Data::MessagePosition position) {
+	if (position == Data::UnreadMessagePosition) {
+		position = Data::MaxMessagePosition;
+	}
+	_inner->showAtPosition(
+		position,
+		{},
+		_cornerButtons->doneJumpFrom(position.fullId, {}, true));
+}
+
+Data::Thread *Item::cornerButtonsThread() {
+	return _thread;
+}
+
+FullMsgId Item::cornerButtonsCurrentId() {
+	return {};
+}
+
+bool Item::cornerButtonsIgnoreVisibility() {
+	return false;
+}
+
+std::optional<bool> Item::cornerButtonsDownShown() {
+	const auto top = _scroll->scrollTop() + st::historyToDownShownAfter;
+	if (top < _scroll->scrollTopMax()) {
+		return true;
+	} else if (_inner->loadedAtBottomKnown()) {
+		return !_inner->loadedAtBottom();
+	}
+	return std::nullopt;
+}
+
+bool Item::cornerButtonsUnreadMayBeShown() {
+	return _inner->loadedAtBottomKnown();
+}
+
+bool Item::cornerButtonsHas(CornerButtonType type) {
+	return (type == CornerButtonType::Down);
+}
+
 } // namespace
 
 ChatPreview MakeChatPreview(

Telegram/SourceFiles/history/view/history_view_corner_buttons.cpp

@@ -7,9 +7,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "history/view/history_view_corner_buttons.h"
 
-#include "ui/widgets/scroll_area.h"
 #include "ui/chat/chat_style.h"
 #include "ui/controls/jump_down_button.h"
+#include "ui/widgets/elastic_scroll.h"
+#include "ui/widgets/scroll_area.h"
 #include "base/qt/qt_key_modifiers.h"
 #include "history/history.h"
 #include "history/history_item.h"
@@ -33,17 +34,41 @@ CornerButtons::CornerButtons(
 	not_null<Ui::ScrollArea*> parent,
 	not_null<const Ui::ChatStyle*> st,
 	not_null<CornerButtonsDelegate*> delegate)
-: _scroll(parent)
+: CornerButtons(
+	parent,
+	[=](QEvent *e) { return parent->viewportEvent(e); },
+	st,
+	delegate) {
+}
+
+CornerButtons::CornerButtons(
+	not_null<Ui::ElasticScroll*> parent,
+	not_null<const Ui::ChatStyle*> st,
+	not_null<CornerButtonsDelegate*> delegate)
+: CornerButtons(
+	parent,
+	[=](QEvent *e) { return parent->viewportEvent(e); },
+	st,
+	delegate) {
+}
+
+CornerButtons::CornerButtons(
+	not_null<QWidget*> parent,
+	Fn<bool(QEvent*)> scrollViewportEvent,
+	not_null<const Ui::ChatStyle*> st,
+	not_null<CornerButtonsDelegate*> delegate)
+: _parent(parent)
+, _scrollViewportEvent(std::move(scrollViewportEvent))
 , _delegate(delegate)
 , _down(
 	parent,
-	st->value(parent->lifetime(), st::historyToDown))
+	st->value(_stLifetime, st::historyToDown))
 , _mentions(
 	parent,
-	st->value(parent->lifetime(), st::historyUnreadMentions))
+	st->value(_stLifetime, st::historyUnreadMentions))
 , _reactions(
 		parent,
-		st->value(parent->lifetime(), st::historyUnreadReactions)) {
+		st->value(_stLifetime, st::historyUnreadReactions)) {
 	_down.widget->addClickHandler([=] { downClick(); });
 	_mentions.widget->addClickHandler([=] { mentionsClick(); });
 	_reactions.widget->addClickHandler([=] { reactionsClick(); });
@@ -68,7 +93,7 @@ bool CornerButtons::eventFilter(QObject *o, QEvent *e) {
 		&& (o == _down.widget
 			|| o == _mentions.widget
 			|| o == _reactions.widget)) {
-		return _scroll->viewportEvent(e);
+		return _scrollViewportEvent(e);
 	}
 	return QObject::eventFilter(o, e);
 }
@@ -200,9 +225,7 @@ void CornerButtons::showAt(MsgId id) {
 	}
 }
 
-void CornerButtons::updateVisibility(
-		CornerButtonType type,
-		bool shown) {
+void CornerButtons::updateVisibility(Type type, bool shown) {
 	auto &button = buttonByType(type);
 	if (button.shown != shown) {
 		button.shown = shown;
@@ -291,7 +314,7 @@ void CornerButtons::updatePositions() {
 			historyDownShown);
 		_down.widget->moveToRight(
 			st::historyToDownPosition.x(),
-			_scroll->height() - top);
+			_parent->height() - top);
 	}
 	{
 		const auto right = anim::interpolate(
@@ -302,7 +325,7 @@ void CornerButtons::updatePositions() {
 			0,
 			_down.widget->height() + skip,
 			historyDownShown);
-		const auto top = _scroll->height()
+		const auto top = _parent->height()
 			- _mentions.widget->height()
 			- st::historyToDownPosition.y()
 			- shift;
@@ -321,7 +344,7 @@ void CornerButtons::updatePositions() {
 			0,
 			_mentions.widget->height() + skip,
 			unreadMentionsShown);
-		const auto top = _scroll->height()
+		const auto top = _parent->height()
 			- _reactions.widget->height()
 			- st::historyToDownPosition.y()
 			- shift;
@@ -355,7 +378,7 @@ Fn<void(bool found)> CornerButtons::doneJumpFrom(
 		}
 		if (!found && !ignoreMessageNotFound) {
 			Ui::Toast::Show(
-				_scroll.get(),
+				_parent.get(),
 				tr::lng_message_not_found(tr::now));
 		}
 	};

Telegram/SourceFiles/history/view/history_view_corner_buttons.h

@@ -17,6 +17,7 @@ struct FullMsgId;
 namespace Ui {
 class ChatStyle;
 class ScrollArea;
+class ElasticScroll;
 class JumpDownButton;
 } // namespace Ui
 
@@ -61,6 +62,10 @@ public:
 		not_null<Ui::ScrollArea*> parent,
 		not_null<const Ui::ChatStyle*> st,
 		not_null<CornerButtonsDelegate*> delegate);
+	CornerButtons(
+		not_null<Ui::ElasticScroll*> parent,
+		not_null<const Ui::ChatStyle*> st,
+		not_null<CornerButtonsDelegate*> delegate);
 
 	using Type = CornerButtonType;
 
@@ -91,6 +96,12 @@ public:
 		bool ignoreMessageNotFound = false);
 
 private:
+	CornerButtons(
+		not_null<QWidget*> parent,
+		Fn<bool(QEvent*)> scrollViewportEvent,
+		not_null<const Ui::ChatStyle*> st,
+		not_null<CornerButtonsDelegate*> delegate);
+
 	bool eventFilter(QObject *o, QEvent *e) override;
 
 	void computeCurrentReplyReturn();
@@ -99,9 +110,12 @@ private:
 	[[nodiscard]] History *lookupHistory() const;
 	void showAt(MsgId id);
 
-	const not_null<Ui::ScrollArea*> _scroll;
+	const not_null<QWidget*> _parent;
+	const Fn<bool(QEvent*)> _scrollViewportEvent;
 	const not_null<CornerButtonsDelegate*> _delegate;
 
+	rpl::lifetime _stLifetime;
+
 	CornerButton _down;
 	CornerButton _mentions;
 	CornerButton _reactions;