From 4e9a52343f52cc8d22b22fb9f66cfc011ee002e2 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 28 Jan 2022 17:11:38 +0300
Subject: [PATCH] Process unread reactions to unknown messages.

---
 Telegram/SourceFiles/api/api_updates.cpp      |  3 ++
 .../data/data_message_reactions.cpp           | 30 +++++++++++++++++++
 .../SourceFiles/data/data_message_reactions.h |  5 ++++
 Telegram/SourceFiles/data/data_session.cpp    |  1 +
 4 files changed, 39 insertions(+)

diff --git a/Telegram/SourceFiles/api/api_updates.cpp b/Telegram/SourceFiles/api/api_updates.cpp
index 9359a0d73..f2f3ea1f5 100644
--- a/Telegram/SourceFiles/api/api_updates.cpp
+++ b/Telegram/SourceFiles/api/api_updates.cpp
@@ -31,6 +31,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_folder.h"
 #include "data/data_scheduled_messages.h"
 #include "data/data_send_action.h"
+#include "data/data_message_reactions.h"
 #include "chat_helpers/emoji_interactions.h"
 #include "lang/lang_cloud_manager.h"
 #include "history/history.h"
@@ -1632,6 +1633,8 @@ void Updates::feedUpdate(const MTPUpdate &update) {
 				d.vmsg_id().v);
 			if (item) {
 				item->updateReactions(&d.vreactions());
+			} else if (Data::Reactions::HasUnread(d.vreactions())) {
+				history->owner().histories().requestDialogEntry(history);
 			}
 		}
 	} break;
diff --git a/Telegram/SourceFiles/data/data_message_reactions.cpp b/Telegram/SourceFiles/data/data_message_reactions.cpp
index 80c8a7d1a..9eeccff72 100644
--- a/Telegram/SourceFiles/data/data_message_reactions.cpp
+++ b/Telegram/SourceFiles/data/data_message_reactions.cpp
@@ -14,6 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_app_config.h"
 #include "data/data_user.h"
 #include "data/data_session.h"
+#include "data/data_histories.h"
 #include "data/data_changes.h"
 #include "data/data_document.h"
 #include "data/data_document_media.h"
@@ -472,6 +473,35 @@ bool Reactions::sending(not_null<HistoryItem*> item) const {
 	return _sentRequests.contains(item->fullId());
 }
 
+bool Reactions::HasUnread(const MTPMessageReactions &data) {
+	return data.match([&](const MTPDmessageReactions &data) {
+		if (const auto &recent = data.vrecent_reactions()) {
+			for (const auto &one : recent->v) {
+				if (one.match([&](const MTPDmessagePeerReaction &data) {
+					return data.is_unread();
+				})) {
+					return true;
+				}
+			}
+		}
+		return false;
+	});
+}
+
+void Reactions::CheckUnknownForUnread(
+		not_null<Session*> owner,
+		const MTPMessage &message) {
+	message.match([&](const MTPDmessage &data) {
+		if (data.vreactions() && HasUnread(*data.vreactions())) {
+			const auto peerId = peerFromMTP(data.vpeer_id());
+			if (const auto history = owner->historyLoaded(peerId)) {
+				owner->histories().requestDialogEntry(history);
+			}
+		}
+	}, [](const auto &) {
+	});
+}
+
 MessageReactions::MessageReactions(not_null<HistoryItem*> item)
 : _item(item) {
 }
diff --git a/Telegram/SourceFiles/data/data_message_reactions.h b/Telegram/SourceFiles/data/data_message_reactions.h
index 2ab784c91..555828dad 100644
--- a/Telegram/SourceFiles/data/data_message_reactions.h
+++ b/Telegram/SourceFiles/data/data_message_reactions.h
@@ -68,6 +68,11 @@ public:
 
 	void updateAllInHistory(not_null<PeerData*> peer, bool enabled);
 
+	[[nodiscard]] static bool HasUnread(const MTPMessageReactions &data);
+	static void CheckUnknownForUnread(
+		not_null<Session*> owner,
+		const MTPMessage &message);
+
 private:
 	struct ImageSet {
 		QImage bottomInfo;
diff --git a/Telegram/SourceFiles/data/data_session.cpp b/Telegram/SourceFiles/data/data_session.cpp
index a138442e8..34b435a6a 100644
--- a/Telegram/SourceFiles/data/data_session.cpp
+++ b/Telegram/SourceFiles/data/data_session.cpp
@@ -1872,6 +1872,7 @@ void Session::updateEditedMessage(const MTPMessage &data) {
 		return message(peerFromMTP(data.vpeer_id()), data.vid().v);
 	});
 	if (!existing) {
+		Reactions::CheckUnknownForUnread(this, data);
 		return;
 	}
 	if (existing->isLocalUpdateMedia() && data.type() == mtpc_message) {