Initial support for streamed bot responses.

Telegram/CMakeLists.txt

@@ -952,6 +952,8 @@ PRIVATE
     history/history_inner_widget.h
     history/history_location_manager.cpp
     history/history_location_manager.h
+    history/history_streamed_drafts.cpp
+    history/history_streamed_drafts.h
     history/history_translation.cpp
     history/history_translation.h
     history/history_unread_things.cpp

Telegram/SourceFiles/api/api_updates.cpp

@@ -51,6 +51,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/history.h"
 #include "history/history_item.h"
 #include "history/history_item_helpers.h"
+#include "history/history_streamed_drafts.h"
 #include "history/history_unread_things.h"
 #include "core/application.h"
 #include "storage/storage_account.h"
@@ -1096,6 +1097,9 @@ void Updates::handleSendActionUpdate(
 	const auto from = (fromId == session().userPeerId())
 		? session().user().get()
 		: session().data().peerLoaded(fromId);
+	const auto when = requestingDifference()
+		? 0
+		: base::unixtime::now();
 	if (action.type() == mtpc_speakingInGroupCallAction) {
 		handleSpeakingInCall(peer, fromId, from);
 	}
@@ -1109,11 +1113,10 @@ void Updates::handleSendActionUpdate(
 		handleEmojiInteraction(peer, qs(data.vemoticon()));
 		return;
 	} else if (action.type() == mtpc_sendMessageTextDraftAction) {
+		const auto &data = action.c_sendMessageTextDraftAction();
+		history->streamedDrafts().apply(rootId, fromId, when, data);
 		return;
 	}
-	const auto when = requestingDifference()
-		? 0
-		: base::unixtime::now();
 	session().data().sendActionManager().registerFor(
 		history,
 		rootId,

Telegram/SourceFiles/history/history.cpp

@@ -15,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/history_item.h"
 #include "history/history_item_components.h"
 #include "history/history_item_helpers.h"
+#include "history/history_streamed_drafts.h"
 #include "history/history_translation.h"
 #include "history/history_unread_things.h"
 #include "core/ui_integration.h"
@@ -3749,6 +3750,13 @@ void History::checkLocalMessages() {
 	}
 }
 
+HistoryStreamedDrafts &History::streamedDrafts() {
+	if (!_streamedDrafts) {
+		_streamedDrafts = std::make_unique<HistoryStreamedDrafts>(this);
+	}
+	return *_streamedDrafts;
+}
+
 HistoryItem *History::joinedMessageInstance() const {
 	return _joinedMessage;
 }
@@ -3907,6 +3915,7 @@ void History::clear(ClearType type, bool markEmpty) {
 	_unreadBarView = nullptr;
 	_firstUnreadView = nullptr;
 	removeJoinedMessage();
+	base::take(_streamedDrafts);
 
 	forgetScrollState();
 	blocks.clear();

Telegram/SourceFiles/history/history.h

@@ -23,6 +23,7 @@ class HistoryItem;
 struct HistoryItemCommonFields;
 struct HistoryMessageMarkupData;
 class HistoryMainElementDelegateMixin;
+class HistoryStreamedDrafts;
 struct LanguageId;
 
 namespace Data {
@@ -91,6 +92,8 @@ public:
 	[[nodiscard]] const Data::HistoryMessages &messages() const;
 	[[nodiscard]] Data::HistoryMessages *maybeMessages();
 
+	[[nodiscard]] HistoryStreamedDrafts &streamedDrafts();
+
 	[[nodiscard]] HistoryItem *joinedMessageInstance() const;
 	void checkLocalMessages();
 	void removeJoinedMessage();
@@ -641,6 +644,7 @@ private:
 	std::unordered_set<std::unique_ptr<HistoryItem>> _items;
 
 	std::unique_ptr<Data::HistoryMessages> _messages;
+	std::unique_ptr<HistoryStreamedDrafts> _streamedDrafts;
 
 	// This almost always is equal to _lastMessage. The only difference is
 	// for a group that migrated to a supergroup. Then _lastMessage can

Telegram/SourceFiles/history/history_streamed_drafts.cpp

@@ -0,0 +1,59 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "history/history_streamed_drafts.h"
+
+#include "api/api_text_entities.h"
+#include "data/data_session.h"
+#include "history/history.h"
+#include "history/history_item.h"
+
+HistoryStreamedDrafts::HistoryStreamedDrafts(not_null<History*> history)
+: _history(history) {
+}
+
+HistoryStreamedDrafts::~HistoryStreamedDrafts() {
+	for (const auto &[rootId, draft] : base::take(_drafts)) {
+		draft.message->destroy();
+	}
+}
+
+void HistoryStreamedDrafts::apply(
+		MsgId rootId,
+		PeerId fromId,
+		TimeId when,
+		const MTPDsendMessageTextDraftAction &data) {
+	const auto now = crl::now();
+	const auto text = Api::ParseTextWithEntities(
+		&_history->session(),
+		data.vtext());
+	const auto randomId = data.vrandom_id().v;
+	const auto i = _drafts.find(rootId);
+	if (i != end(_drafts)) {
+		if (when && i->second.randomId == randomId) {
+			i->second.message->setText(text);
+			i->second.updated = now;
+			return;
+		}
+		i->second.message->destroy();
+		_drafts.erase(i);
+	}
+	if (!when) {
+		return;
+	}
+	_drafts.emplace(rootId, Draft{
+		.message = _history->addNewLocalMessage({
+			.id = _history->owner().nextLocalMessageId(),
+			.flags = MessageFlag::Local,
+			.from = fromId,
+			.replyTo = { .topicRootId = rootId },
+			.date = when,
+		}, text, MTP_messageMediaEmpty()),
+		.randomId = randomId,
+		.updated = now,
+	});
+}

Telegram/SourceFiles/history/history_streamed_drafts.h

@@ -0,0 +1,33 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+class History;
+
+class HistoryStreamedDrafts final {
+public:
+	explicit HistoryStreamedDrafts(not_null<History*> history);
+	~HistoryStreamedDrafts();
+
+	void apply(
+		MsgId rootId,
+		PeerId fromId,
+		TimeId when,
+		const MTPDsendMessageTextDraftAction &data);
+
+private:
+	struct Draft {
+		not_null<HistoryItem*> message;
+		uint64 randomId = 0;
+		crl::time updated = 0;
+	};
+
+	const not_null<History*> _history;
+	base::flat_map<MsgId, Draft> _drafts;
+
+};