Support hashtags with mentions.

Telegram/SourceFiles/data/data_message_reaction_id.cpp

@@ -40,6 +40,25 @@ std::vector<ReactionId> SearchTagsFromQuery(
 	return result;
 }
 
+HashtagWithUsername HashtagWithUsernameFromQuery(QStringView query) {
+	const auto match = TextUtilities::RegExpHashtag(true).match(query);
+	if (match.hasMatch()) {
+		const auto username = match.capturedView(2).mid(1).toString();
+		const auto offset = int(match.capturedLength(1));
+		const auto full = int(query.size());
+		const auto length = full
+			- int(username.size())
+			- 1
+			- offset
+			- int(match.capturedLength(3));
+		if (!username.isEmpty() && length > 0 && offset + length <= full) {
+			const auto hashtag = query.mid(offset, length).toString();
+			return { hashtag, username };
+		}
+	}
+	return {};
+}
+
 QString ReactionEntityData(const ReactionId &id) {
 	if (id.empty()) {
 		return {};

Telegram/SourceFiles/data/data_message_reaction_id.h

@@ -65,6 +65,13 @@ struct MessageReaction {
 [[nodiscard]] std::vector<ReactionId> SearchTagsFromQuery(
 	const QString &query);
 
+struct HashtagWithUsername {
+	QString hashtag;
+	QString username;
+};
+[[nodiscard]] HashtagWithUsername HashtagWithUsernameFromQuery(
+	QStringView query);
+
 [[nodiscard]] QString ReactionEntityData(const ReactionId &id);
 
 [[nodiscard]] ReactionId ReactionFromMTP(const MTPReaction &reaction);

Telegram/SourceFiles/mainwidget.cpp

@@ -43,6 +43,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "window/window_history_hider.h"
 #include "window/window_controller.h"
 #include "window/window_peer_menu.h"
+#include "window/window_session_controller_link_info.h"
 #include "window/themes/window_theme.h"
 #include "chat_helpers/bot_command.h"
 #include "chat_helpers/tabbed_selector.h" // TabbedSelector::refreshStickers
@@ -744,6 +745,15 @@ void MainWidget::hideSingleUseKeyboard(FullMsgId replyToId) {
 }
 
 void MainWidget::searchMessages(const QString &query, Dialogs::Key inChat) {
+	const auto complex = Data::HashtagWithUsernameFromQuery(query);
+	if (!complex.username.isEmpty()) {
+		_controller->showPeerByLink(Window::PeerByLinkInfo{
+			.usernameOrId = complex.username,
+			.text = complex.hashtag,
+			.resolveType = Window::ResolveType::HashtagSearch,
+		});
+		return;
+	}
 	auto tags = Data::SearchTagsFromQuery(query);
 	if (_dialogs) {
 		auto state = Dialogs::SearchState{

Telegram/SourceFiles/storage/storage_account.cpp

@@ -2722,7 +2722,9 @@ std::optional<RecentHashtagPack> Account::saveRecentHashtags(
 	auto found = false;
 	auto m = QRegularExpressionMatch();
 	auto recent = getPack();
-	for (auto i = 0, next = 0; (m = TextUtilities::RegExpHashtag(false).match(text, i)).hasMatch(); i = next) {
+	for (auto i = 0, next = 0
+		; (m = TextUtilities::RegExpHashtag(false).match(text, i)).hasMatch()
+		; i = next) {
 		i = m.capturedStart();
 		next = m.capturedEnd();
 		if (m.hasMatch()) {

Telegram/SourceFiles/window/window_session_controller.cpp

@@ -580,6 +580,8 @@ void SessionNavigation::showPeerByLinkResolved(
 			params);
 	} else if (resolveType == ResolveType::Profile) {
 		showPeerInfo(peer, params);
+	} else if (resolveType == ResolveType::HashtagSearch) {
+		searchMessages(info.text, peer->owner().history(peer));
 	} else if (peer->isForum() && resolveType != ResolveType::Boost) {
 		const auto itemId = info.messageId;
 		if (!itemId) {

Telegram/SourceFiles/window/window_session_controller_link_info.h

@@ -19,6 +19,7 @@ enum class ResolveType {
 	BotStart,
 	AddToGroup,
 	AddToChannel,
+	HashtagSearch,
 	ShareGame,
 	Mention,
 	Boost,