In the viewer remember which story was opened.

Telegram/SourceFiles/media/stories/media_stories_controller.cpp

@@ -673,6 +673,7 @@ void Controller::rebuildFromContext(
 				_showingUnreadSources = source && (source->readTill < id);
 			}
 			rebuildCachedSourcesList(sources, (i - begin(sources)));
+			_cachedSourcesList[_cachedSourceIndex].shownId = storyId.story;
 			showSiblings(&user->session());
 			if (int(sources.end() - i) < kPreloadUsersCount) {
 				stories.loadMore(list);
@@ -980,13 +981,13 @@ void Controller::showSiblings(not_null<Main::Session*> session) {
 		session,
 		(_cachedSourceIndex > 0
 			? _cachedSourcesList[_cachedSourceIndex - 1]
-			: PeerId()));
+			: CachedSource()));
 	showSibling(
 		_siblingRight,
 		session,
 		(_cachedSourceIndex + 1 < _cachedSourcesList.size()
 			? _cachedSourcesList[_cachedSourceIndex + 1]
-			: PeerId()));
+			: CachedSource()));
 }
 
 void Controller::hideSiblings() {
@@ -997,16 +998,16 @@ void Controller::hideSiblings() {
 void Controller::showSibling(
 		std::unique_ptr<Sibling> &sibling,
 		not_null<Main::Session*> session,
-		PeerId peerId) {
-	if (!peerId) {
+		CachedSource cached) {
+	if (!cached) {
 		sibling = nullptr;
 		return;
 	}
-	const auto source = session->data().stories().source(peerId);
+	const auto source = session->data().stories().source(cached.peerId);
 	if (!source) {
 		sibling = nullptr;
-	} else if (!sibling || !sibling->shows(*source)) {
-		sibling = std::make_unique<Sibling>(this, *source);
+	} else if (!sibling || !sibling->shows(*source, cached.shownId)) {
+		sibling = std::make_unique<Sibling>(this, *source, cached.shownId);
 	}
 }
 
@@ -1301,12 +1302,18 @@ void Controller::rebuildCachedSourcesList(
 
 	// Remove removed.
 	_cachedSourcesList.erase(ranges::remove_if(_cachedSourcesList, [&](
-			PeerId id) {
-		return !ranges::contains(lists, id, &Data::StoriesSourceInfo::id);
+			CachedSource source) {
+		return !ranges::contains(
+			lists,
+			source.peerId,
+			&Data::StoriesSourceInfo::id);
 	}), end(_cachedSourcesList));
 
 	// Find current, full rebuild if can't find.
-	const auto i = ranges::find(_cachedSourcesList, currentPeerId);
+	const auto i = ranges::find(
+		_cachedSourcesList,
+		currentPeerId,
+		&CachedSource::peerId);
 	if (i == end(_cachedSourcesList)) {
 		_cachedSourcesList.clear();
 	} else {
@@ -1320,17 +1327,24 @@ void Controller::rebuildCachedSourcesList(
 				|| (info.unreadCount > 0)
 				|| (info.id == currentPeerId);
 		};
+		const auto mapper = [](const Data::StoriesSourceInfo &info) {
+			return CachedSource{ info.id };
+		};
 		_cachedSourcesList = lists
 			| ranges::views::filter(predicate)
-			| ranges::views::transform(&Data::StoriesSourceInfo::id)
+			| ranges::views::transform(mapper)
 			| ranges::to_vector;
-		_cachedSourceIndex = ranges::find(_cachedSourcesList, currentPeerId)
-			- begin(_cachedSourcesList);
+		_cachedSourceIndex = ranges::find(
+			_cachedSourcesList,
+			currentPeerId,
+			&CachedSource::peerId
+		) - begin(_cachedSourcesList);
 	} else if (ranges::equal(
 			lists,
 			_cachedSourcesList,
 			ranges::equal_to(),
-			&Data::StoriesSourceInfo::id)) {
+			&Data::StoriesSourceInfo::id,
+			&CachedSource::peerId)) {
 		// No rebuild needed.
 	} else {
 		// All that go before the current push to front.
@@ -1338,10 +1352,13 @@ void Controller::rebuildCachedSourcesList(
 			const auto &info = lists[--before];
 			if (_showingUnreadSources && !info.unreadCount) {
 				continue;
-			} else if (!ranges::contains(_cachedSourcesList, info.id)) {
+			} else if (!ranges::contains(
+					_cachedSourcesList,
+					info.id,
+					&CachedSource::peerId)) {
 				_cachedSourcesList.insert(
 					begin(_cachedSourcesList),
-					info.id);
+					{ info.id });
 				++_cachedSourceIndex;
 			}
 		}
@@ -1352,8 +1369,11 @@ void Controller::rebuildCachedSourcesList(
 			const auto &info = lists[after];
 			if (_showingUnreadSources && !info.unreadCount) {
 				continue;
-			} else if (!ranges::contains(_cachedSourcesList, info.id)) {
-				_cachedSourcesList.push_back(info.id);
+			} else if (!ranges::contains(
+					_cachedSourcesList,
+					info.id,
+					&CachedSource::peerId)) {
+				_cachedSourcesList.push_back({ info.id });
 			}
 		}
 	}

Telegram/SourceFiles/media/stories/media_stories_controller.h

@@ -177,6 +177,14 @@ private:
 			const StoriesList &,
 			const StoriesList &) = default;
 	};
+	struct CachedSource {
+		PeerId peerId = 0;
+		StoryId shownId = 0;
+
+		explicit operator bool() const {
+			return peerId != 0;
+		}
+	};
 	class PhotoPlayback;
 	class Unsupported;
 
@@ -198,7 +206,7 @@ private:
 	void showSibling(
 		std::unique_ptr<Sibling> &sibling,
 		not_null<Main::Session*> session,
-		PeerId peerId);
+		CachedSource cached);
 
 	void subjumpTo(int index);
 	void checkWaitingFor();
@@ -264,7 +272,7 @@ private:
 	bool _started = false;
 	bool _viewed = false;
 
-	std::vector<PeerId> _cachedSourcesList;
+	std::vector<CachedSource> _cachedSourcesList;
 	int _cachedSourceIndex = -1;
 	bool _showingUnreadSources = false;
 

Telegram/SourceFiles/media/stories/media_stories_sibling.cpp

@@ -33,6 +33,17 @@ constexpr auto kSiblingFadeOver = 0.4;
 constexpr auto kSiblingNameOpacity = 0.8;
 constexpr auto kSiblingNameOpacityOver = 1.;
 
+[[nodiscard]] StoryId LookupShownId(
+		const Data::StoriesSource &source,
+		StoryId suggestedId) {
+	const auto i = suggestedId
+		? source.ids.lower_bound(Data::StoryIdDates{ suggestedId })
+		: end(source.ids);
+	return (i != end(source.ids) && i->id == suggestedId)
+		? suggestedId
+		: source.toOpen().id;
+}
+
 } // namespace
 
 class Sibling::Loader {
@@ -229,9 +240,10 @@ bool Sibling::LoaderVideo::updateAfterGoodCheck() {
 
 Sibling::Sibling(
 	not_null<Controller*> controller,
-	const Data::StoriesSource &source)
+	const Data::StoriesSource &source,
+	StoryId suggestedId)
 : _controller(controller)
-, _id{ source.user->id, source.ids.front().id }
+, _id{ source.user->id, LookupShownId(source, suggestedId) }
 , _peer(source.user) {
 	checkStory();
 	_goodShown.stop();
@@ -288,10 +300,14 @@ not_null<PeerData*> Sibling::peer() const {
 	return _peer;
 }
 
-bool Sibling::shows(const Data::StoriesSource &source) const {
-	Expects(!source.ids.empty());
-
-	return _id == FullStoryId{ source.user->id, source.ids.front().id };
+bool Sibling::shows(
+		const Data::StoriesSource &source,
+		StoryId suggestedId) const {
+	const auto fullId = FullStoryId{
+		source.user->id,
+		LookupShownId(source, suggestedId),
+	};
+	return (_id == fullId);
 }
 
 SiblingView Sibling::view(const SiblingLayout &layout, float64 over) {

Telegram/SourceFiles/media/stories/media_stories_sibling.h

@@ -26,12 +26,15 @@ class Sibling final : public base::has_weak_ptr {
 public:
 	Sibling(
 		not_null<Controller*> controller,
-		const Data::StoriesSource &source);
+		const Data::StoriesSource &source,
+		StoryId suggestedId);
 	~Sibling();
 
 	[[nodiscard]] FullStoryId shownId() const;
 	[[nodiscard]] not_null<PeerData*> peer() const;
-	[[nodiscard]] bool shows(const Data::StoriesSource &source) const;
+	[[nodiscard]] bool shows(
+		const Data::StoriesSource &source,
+		StoryId suggestedId) const;
 
 	[[nodiscard]] SiblingView view(
 		const SiblingLayout &layout,