From c2c7a25487a919f084e047aa9c8c5caca1cf9a48 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 7 Jan 2022 16:19:43 +0300
Subject: [PATCH] Keep reaction media in memory.

---
 Telegram/SourceFiles/data/data_message_reactions.cpp       | 7 +++++++
 Telegram/SourceFiles/data/data_message_reactions.h         | 3 +++
 .../SourceFiles/history/view/history_view_react_button.cpp | 4 +++-
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/data/data_message_reactions.cpp b/Telegram/SourceFiles/data/data_message_reactions.cpp
index c1b041fb4..715643db5 100644
--- a/Telegram/SourceFiles/data/data_message_reactions.cpp
+++ b/Telegram/SourceFiles/data/data_message_reactions.cpp
@@ -231,15 +231,22 @@ void Reactions::request() {
 			_hash = data.vhash().v;
 
 			const auto &list = data.vreactions().v;
+			const auto oldCache = base::take(_iconsCache);
 			_active.clear();
 			_available.clear();
 			_active.reserve(list.size());
 			_available.reserve(list.size());
+			_iconsCache.reserve(list.size() * 2);
+			const auto toCache = [&](not_null<DocumentData*> document) {
+				_iconsCache.emplace(document, document->createMediaView());
+			};
 			for (const auto &reaction : list) {
 				if (const auto parsed = parse(reaction)) {
 					_available.push_back(*parsed);
 					if (parsed->active) {
 						_active.push_back(*parsed);
+						toCache(parsed->appearAnimation);
+						toCache(parsed->selectAnimation);
 					}
 				}
 			}
diff --git a/Telegram/SourceFiles/data/data_message_reactions.h b/Telegram/SourceFiles/data/data_message_reactions.h
index cfa284bd1..d52146441 100644
--- a/Telegram/SourceFiles/data/data_message_reactions.h
+++ b/Telegram/SourceFiles/data/data_message_reactions.h
@@ -97,6 +97,9 @@ private:
 
 	std::vector<Reaction> _active;
 	std::vector<Reaction> _available;
+	base::flat_map<
+		not_null<DocumentData*>,
+		std::shared_ptr<Data::DocumentMedia>> _iconsCache;
 	rpl::event_stream<> _updated;
 
 	mtpRequestId _requestId = 0;
diff --git a/Telegram/SourceFiles/history/view/history_view_react_button.cpp b/Telegram/SourceFiles/history/view/history_view_react_button.cpp
index 8744d0554..5eecb615d 100644
--- a/Telegram/SourceFiles/history/view/history_view_react_button.cpp
+++ b/Telegram/SourceFiles/history/view/history_view_react_button.cpp
@@ -550,7 +550,8 @@ void Manager::loadIcons() {
 		}
 		return entry.icon;
 	};
-	// #TODO reactions rebuild list better
+	const auto selected = _selectedIcon;
+	setSelectedIcon(-1);
 	_icons.clear();
 	auto main = true;
 	for (const auto &reaction : _list) {
@@ -561,6 +562,7 @@ void Manager::loadIcons() {
 		});
 		main = false;
 	}
+	setSelectedIcon(selected < _icons.size() ? selected : -1);
 }
 
 void Manager::checkIcons() {