From 3da733520db0080c0bccd76038e7965982263027 Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Mon, 9 Oct 2023 05:09:23 +0300
Subject: [PATCH] Added API support to request list of public forwards for
 single message.

---
 Telegram/SourceFiles/api/api_statistics.cpp | 101 ++++++++++++++++++++
 Telegram/SourceFiles/api/api_statistics.h   |  29 ++++++
 2 files changed, 130 insertions(+)

diff --git a/Telegram/SourceFiles/api/api_statistics.cpp b/Telegram/SourceFiles/api/api_statistics.cpp
index aeddce54a..5ca74ab1c 100644
--- a/Telegram/SourceFiles/api/api_statistics.cpp
+++ b/Telegram/SourceFiles/api/api_statistics.cpp
@@ -10,6 +10,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "apiwrap.h"
 #include "data/data_channel.h"
 #include "data/data_peer.h"
+#include "data/data_session.h"
+#include "history/history.h"
 #include "main/main_session.h"
 #include "statistics/statistics_data_deserialize.h"
 
@@ -287,4 +289,103 @@ Data::SupergroupStatistics Statistics::supergroupStats() const {
 	return _supergroupStats;
 }
 
+PublicForwards::PublicForwards(
+	not_null<ChannelData*> channel,
+	FullMsgId fullId)
+: _channel(channel)
+, _fullId(fullId)
+, _api(&channel->session().api().instance()) {
+}
+
+void PublicForwards::request(
+		const OffsetToken &token,
+		Fn<void(Slice)> done) {
+	if (_requestId) {
+		return;
+	}
+	const auto offsetPeer = _channel->owner().peer(token.fullId.peer);
+	const auto tlOffsetPeer = offsetPeer
+		? offsetPeer->input
+		: MTP_inputPeerEmpty();
+	constexpr auto kLimit = tl::make_int(100);
+	_requestId = _api.request(MTPstats_GetMessagePublicForwards(
+		_channel->inputChannel,
+		MTP_int(_fullId.msg),
+		MTP_int(token.rate),
+		tlOffsetPeer,
+		MTP_int(token.fullId.msg),
+		kLimit
+	)).done([=, channel = _channel](const MTPmessages_Messages &result) {
+		using Messages = QVector<FullMsgId>;
+		_requestId = 0;
+
+		auto nextToken = OffsetToken();
+		const auto process = [&](const MTPVector<MTPMessage> &messages) {
+			auto result = Messages();
+			for (const auto &message : messages.v) {
+				const auto msgId = IdFromMessage(message);
+				const auto peerId = PeerFromMessage(message);
+				const auto lastDate = DateFromMessage(message);
+				if (const auto peer = channel->owner().peerLoaded(peerId)) {
+					if (lastDate) {
+						channel->owner().addNewMessage(
+							message,
+							MessageFlags(),
+							NewMessageType::Existing);
+						nextToken.fullId = { peerId, msgId };
+						result.push_back(nextToken.fullId);
+					}
+				}
+			}
+			return result;
+		};
+
+		auto allLoaded = false;
+		auto fullCount = 0;
+		auto messages = result.match([&](const MTPDmessages_messages &data) {
+			channel->owner().processUsers(data.vusers());
+			channel->owner().processChats(data.vchats());
+			auto list = process(data.vmessages());
+			allLoaded = true;
+			fullCount = list.size();
+			return list;
+		}, [&](const MTPDmessages_messagesSlice &data) {
+			channel->owner().processUsers(data.vusers());
+			channel->owner().processChats(data.vchats());
+			auto list = process(data.vmessages());
+
+			if (const auto nextRate = data.vnext_rate()) {
+				const auto rateUpdated = (nextRate->v != token.rate);
+				if (rateUpdated) {
+					nextToken.rate = nextRate->v;
+				} else {
+					allLoaded = true;
+				}
+			}
+			fullCount = data.vcount().v;
+			return list;
+		}, [&](const MTPDmessages_channelMessages &data) {
+			channel->owner().processUsers(data.vusers());
+			channel->owner().processChats(data.vchats());
+			auto list = process(data.vmessages());
+			allLoaded = true;
+			fullCount = data.vcount().v;
+			return list;
+		}, [&](const MTPDmessages_messagesNotModified &) {
+			allLoaded = true;
+			return Messages();
+		});
+
+		_lastTotal = std::max(_lastTotal, fullCount);
+		done({
+			.list = std::move(messages),
+			.total = _lastTotal,
+			.allLoaded = allLoaded,
+			.token = nextToken,
+		});
+	}).fail([=] {
+		_requestId = 0;
+	}).send();
+}
+
 } // namespace Api
diff --git a/Telegram/SourceFiles/api/api_statistics.h b/Telegram/SourceFiles/api/api_statistics.h
index 76df8bc49..e3a282c96 100644
--- a/Telegram/SourceFiles/api/api_statistics.h
+++ b/Telegram/SourceFiles/api/api_statistics.h
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/sender.h"
 
 class ApiWrap;
+class ChannelData;
 class PeerData;
 
 namespace Api {
@@ -40,4 +41,32 @@ private:
 
 };
 
+class PublicForwards final {
+public:
+	struct OffsetToken final {
+		int rate = 0;
+		FullMsgId fullId;
+	};
+
+	struct Slice {
+		QVector<FullMsgId> list;
+		int total = 0;
+		bool allLoaded = false;
+		OffsetToken token;
+	};
+
+	explicit PublicForwards(not_null<ChannelData*> channel, FullMsgId fullId);
+
+	void request(const OffsetToken &token, Fn<void(Slice)> done);
+
+private:
+	const not_null<ChannelData*> _channel;
+	const FullMsgId _fullId;
+	mtpRequestId _requestId = 0;
+	int _lastTotal = 0;
+
+	MTP::Sender _api;
+
+};
+
 } // namespace Api