From c04f3a704800144948fbe114a33f56fd95384517 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 19 Feb 2020 17:49:49 +0400
Subject: [PATCH] Don't replace local with server last message.

---
 Telegram/SourceFiles/history/history.cpp      | 33 ++++++++++---------
 Telegram/SourceFiles/history/history.h        |  1 +
 .../SourceFiles/history/history_widget.cpp    | 19 -----------
 3 files changed, 19 insertions(+), 34 deletions(-)

diff --git a/Telegram/SourceFiles/history/history.cpp b/Telegram/SourceFiles/history/history.cpp
index 247b9893d..15834f0d4 100644
--- a/Telegram/SourceFiles/history/history.cpp
+++ b/Telegram/SourceFiles/history/history.cpp
@@ -1937,8 +1937,8 @@ void History::setFolder(
 		not_null<Data::Folder*> folder,
 		HistoryItem *folderDialogItem) {
 	setFolderPointer(folder);
-	if (folderDialogItem && _lastMessage != folderDialogItem) {
-		setLastMessage(folderDialogItem);
+	if (folderDialogItem) {
+		setLastServerMessage(folderDialogItem);
 	}
 }
 
@@ -2369,16 +2369,19 @@ void History::clearSharedMedia() {
 	//}
 }
 
+void History::setLastServerMessage(HistoryItem *item) {
+	if (_lastMessage
+		&& *_lastMessage
+		&& !IsServerMsgId((*_lastMessage)->id)
+		&& (!item || (*_lastMessage)->date() > item->date())) {
+		return;
+	}
+	setLastMessage(item);
+}
+
 void History::setLastMessage(HistoryItem *item) {
-	if (_lastMessage) {
-		if (*_lastMessage == item) {
-			return;
-		} else if (*_lastMessage
-			&& item
-			&& !IsServerMsgId((*_lastMessage)->id)
-			&& (*_lastMessage)->date() > item->date()) {
-			return;
-		}
+	if (_lastMessage && *_lastMessage == item) {
+		return;
 	}
 	_lastMessage = item;
 	if (peer->migrateTo()) {
@@ -2766,12 +2769,12 @@ void History::applyDialogTopMessage(MsgId topMessageId) {
 			channelId(),
 			topMessageId);
 		if (const auto item = owner().message(itemId)) {
-			setLastMessage(item);
+			setLastServerMessage(item);
 		} else {
-			setLastMessage(nullptr);
+			setLastServerMessage(nullptr);
 		}
 	} else {
-		setLastMessage(nullptr);
+		setLastServerMessage(nullptr);
 	}
 	if (clearUnreadOnClientSide()) {
 		setUnreadCount(0);
@@ -3167,7 +3170,7 @@ void History::clear(ClearType type) {
 			setUnreadCount(0);
 		}
 		if (type == ClearType::DeleteChat) {
-			setLastMessage(nullptr);
+			setLastServerMessage(nullptr);
 		} else if (_lastMessage && *_lastMessage) {
 			if (IsServerMsgId((*_lastMessage)->id)) {
 				(*_lastMessage)->applyEditionToHistoryCleared();
diff --git a/Telegram/SourceFiles/history/history.h b/Telegram/SourceFiles/history/history.h
index 47d833970..9385c6da7 100644
--- a/Telegram/SourceFiles/history/history.h
+++ b/Telegram/SourceFiles/history/history.h
@@ -455,6 +455,7 @@ private:
 	// After adding a new history slice check lastMessage / loadedAtBottom.
 	void checkLastMessage();
 	void setLastMessage(HistoryItem *item);
+	void setLastServerMessage(HistoryItem *item);
 
 	void refreshChatListMessage();
 	void setChatListMessage(HistoryItem *item);
diff --git a/Telegram/SourceFiles/history/history_widget.cpp b/Telegram/SourceFiles/history/history_widget.cpp
index ea4701bd3..d34e0cc13 100644
--- a/Telegram/SourceFiles/history/history_widget.cpp
+++ b/Telegram/SourceFiles/history/history_widget.cpp
@@ -145,22 +145,6 @@ void ActivateWindow(not_null<Window::SessionController*> controller) {
 	Ui::ActivateWindowDelayed(window);
 }
 
-bool ShowHistoryEndInsteadOfUnread(
-		not_null<Data::Session*> session,
-		PeerId peerId) {
-	// Ignore unread messages in case of unread changelogs.
-	// We must show this history at end for the changelog to be visible.
-	if (peerId != PeerData::kServiceNotificationsId) {
-		return false;
-	}
-	const auto history = session->history(peerId);
-	if (!history->unreadCount()) {
-		return false;
-	}
-	const auto last = history->lastMessage();
-	return (last != nullptr) && !IsServerMsgId(last->id);
-}
-
 object_ptr<Ui::FlatButton> SetupDiscussButton(
 		not_null<QWidget*> parent,
 		not_null<Window::SessionController*> controller) {
@@ -1646,9 +1630,6 @@ void HistoryWidget::showHistory(
 	const auto startBot = (showAtMsgId == ShowAndStartBotMsgId);
 	if (startBot) {
 		showAtMsgId = ShowAtTheEndMsgId;
-	} else if ((showAtMsgId == ShowAtUnreadMsgId)
-		&& ShowHistoryEndInsteadOfUnread(&session().data(), peerId)) {
-		showAtMsgId = ShowAtTheEndMsgId;
 	}
 
 	clearHighlightMessages();