From c10588a7dc248e427a6191841a68410f98904ac2 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 30 Nov 2017 16:50:13 +0400
Subject: [PATCH] Merge group-supergroup history in jump-to-date.

Fixes #4094.
---
 Telegram/SourceFiles/apiwrap.cpp              | 44 +++++++++++++---
 Telegram/SourceFiles/apiwrap.h                |  6 +++
 .../SourceFiles/window/window_controller.cpp  | 50 ++++++++++++++-----
 3 files changed, 82 insertions(+), 18 deletions(-)

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index 31b403edc2..88dbc7332d 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -1960,7 +1960,11 @@ void ApiWrap::applyUpdateNoPtsCheck(const MTPUpdate &update) {
 	}
 }
 
-void ApiWrap::jumpToDate(not_null<PeerData*> peer, const QDate &date) {
+template <typename Callback>
+void ApiWrap::requestMessageAfterDate(
+		not_null<PeerData*> peer,
+		const QDate &date,
+		Callback &&callback) {
 	// API returns a message with date <= offset_date.
 	// So we request a message with offset_date = desired_date - 1 and add_offset = -1.
 	// This should give us the first message with date >= desired_date.
@@ -1980,7 +1984,11 @@ void ApiWrap::jumpToDate(not_null<PeerData*> peer, const QDate &date) {
 		MTP_int(maxId),
 		MTP_int(minId),
 		MTP_int(historyHash)
-	)).done([peer](const MTPmessages_Messages &result) {
+	)).done([
+		peer,
+		offsetDate,
+		callback = std::forward<Callback>(callback)
+	](const MTPmessages_Messages &result) {
 		auto getMessagesList = [&result, peer]() -> const QVector<MTPMessage>* {
 			auto handleMessages = [](auto &messages) {
 				App::feedUsers(messages.vusers);
@@ -2011,15 +2019,39 @@ void ApiWrap::jumpToDate(not_null<PeerData*> peer, const QDate &date) {
 		if (auto list = getMessagesList()) {
 			App::feedMsgs(*list, NewMessageExisting);
 			for (auto &message : *list) {
-				auto id = idFromMessage(message);
-				Ui::showPeerHistory(peer, id);
-				return;
+				if (dateFromMessage(message) >= offsetDate) {
+					callback(idFromMessage(message));
+					return;
+				}
 			}
 		}
-		Ui::showPeerHistory(peer, ShowAtUnreadMsgId);
+		callback(ShowAtUnreadMsgId);
 	}).send();
 }
 
+void ApiWrap::jumpToDate(not_null<PeerData*> peer, const QDate &date) {
+	if (auto channel = peer->migrateTo()) {
+		jumpToDate(channel, date);
+		return;
+	}
+	auto jumpToDateInPeer = [peer, date, this] {
+		requestMessageAfterDate(peer, date, [peer](MsgId resultId) {
+			Ui::showPeerHistory(peer, resultId);
+		});
+	};
+	if (auto chat = peer->migrateFrom()) {
+		requestMessageAfterDate(chat, date, [=](MsgId resultId) {
+			if (resultId) {
+				Ui::showPeerHistory(chat, resultId);
+			} else {
+				jumpToDateInPeer();
+			}
+		});
+	} else {
+		jumpToDateInPeer();
+	}
+}
+
 void ApiWrap::preloadEnoughUnreadMentions(not_null<History*> history) {
 	auto fullCount = history->getUnreadMentionsCount();
 	auto loadedCount = history->getUnreadMentionsLoadedCount();
diff --git a/Telegram/SourceFiles/apiwrap.h b/Telegram/SourceFiles/apiwrap.h
index 2fb0273c5c..efca429c3e 100644
--- a/Telegram/SourceFiles/apiwrap.h
+++ b/Telegram/SourceFiles/apiwrap.h
@@ -216,6 +216,12 @@ private:
 	void saveChatAdmins(not_null<ChatData*> chat);
 	void sendSaveChatAdminsRequests(not_null<ChatData*> chat);
 
+	template <typename Callback>
+	void requestMessageAfterDate(
+		not_null<PeerData*> peer,
+		const QDate &date,
+		Callback &&callback);
+
 	int applyAffectedHistory(
 		not_null<PeerData*> peer,
 		const MTPmessages_AffectedHistory &result);
diff --git a/Telegram/SourceFiles/window/window_controller.cpp b/Telegram/SourceFiles/window/window_controller.cpp
index 0a25a91075..7645531792 100644
--- a/Telegram/SourceFiles/window/window_controller.cpp
+++ b/Telegram/SourceFiles/window/window_controller.cpp
@@ -280,7 +280,10 @@ void Controller::showJumpToDate(not_null<PeerData*> peer, QDate requestedDate) {
 		}
 		return QDate::currentDate();
 	};
-	auto maxPeerDate = [peer] {
+	auto maxPeerDate = [](not_null<PeerData*> peer) {
+		if (auto channel = peer->migrateTo()) {
+			peer = channel;
+		}
 		if (auto history = App::historyLoaded(peer)) {
 			if (!history->lastMsgDate.isNull()) {
 				return history->lastMsgDate.date();
@@ -288,22 +291,45 @@ void Controller::showJumpToDate(not_null<PeerData*> peer, QDate requestedDate) {
 		}
 		return QDate::currentDate();
 	};
-	auto minPeerDate = [peer] {
-		if (auto history = App::historyLoaded(peer)) {
-			if (history->loadedAtTop()) {
-				if (history->isEmpty()) {
-					return QDate::currentDate();
+	auto minPeerDate = [](not_null<PeerData*> peer) {
+		const auto startDate = [] {
+			// Telegram was launched in August 2013 :)
+			return QDate(2013, 8, 1);
+		};
+		if (auto chat = peer->migrateFrom()) {
+			if (auto history = App::historyLoaded(chat)) {
+				if (history->loadedAtTop()) {
+					if (!history->isEmpty()) {
+						return history->blocks.front()->items.front()->date.date();
+					}
+				} else {
+					return startDate();
 				}
-				return history->blocks.front()->items.front()->date.date();
 			}
 		}
-		return QDate(2013, 8, 1); // Telegram was launched in August 2013 :)
+		if (auto history = App::historyLoaded(peer)) {
+			if (history->loadedAtTop()) {
+				if (!history->isEmpty()) {
+					return history->blocks.front()->items.front()->date.date();
+				}
+				return QDate::currentDate();
+			}
+		}
+		return startDate();
 	};
-	auto highlighted = requestedDate.isNull() ? currentPeerDate() : requestedDate;
+	auto highlighted = requestedDate.isNull()
+		? currentPeerDate()
+		: requestedDate;
 	auto month = highlighted;
-	auto box = Box<CalendarBox>(month, highlighted, [this, peer](const QDate &date) { Auth().api().jumpToDate(peer, date); });
-	box->setMinDate(minPeerDate());
-	box->setMaxDate(maxPeerDate());
+	auto callback = [this, peer](const QDate &date) {
+		Auth().api().jumpToDate(peer, date);
+	};
+	auto box = Box<CalendarBox>(
+		month,
+		highlighted,
+		std::move(callback));
+	box->setMinDate(minPeerDate(peer));
+	box->setMaxDate(maxPeerDate(peer));
 	Ui::show(std::move(box));
 }