From 6e1285bb0e1f1d2b4aa443c72521c9b1f3255bfb Mon Sep 17 00:00:00 2001
From: Konstantinos Sideris <sideris.konstantin@gmail.com>
Date: Sat, 7 Oct 2017 20:50:32 +0300
Subject: [PATCH] Prevent FOUC

---
 include/ChatPage.h            |  1 +
 include/TimelineView.h        |  9 +++++++++
 include/TimelineViewManager.h |  3 +++
 src/ChatPage.cc               | 13 +++++++++++--
 src/TimelineViewManager.cc    | 10 ++++++++++
 5 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/include/ChatPage.h b/include/ChatPage.h
index f64d9589..0a6d303b 100644
--- a/include/ChatPage.h
+++ b/include/ChatPage.h
@@ -96,6 +96,7 @@ private:
         TextInputWidget *text_input_;
         TypingDisplay *typingDisplay_;
 
+        QTimer *consensusTimer_;
         QTimer *sync_timer_;
         int sync_interval_;
 
diff --git a/include/TimelineView.h b/include/TimelineView.h
index 4b5a2f77..9b81485d 100644
--- a/include/TimelineView.h
+++ b/include/TimelineView.h
@@ -97,6 +97,9 @@ public slots:
         // Add old events at the top of the timeline.
         void addBackwardsEvents(const QString &room_id, const RoomMessages &msgs);
 
+        // Whether or not the initial batch has been loaded.
+        bool hasLoaded();
+
 signals:
         void updateLastTimelineMessage(const QString &user, const DescInfo &info);
 
@@ -163,3 +166,9 @@ TimelineView::isDuplicate(const QString &event_id)
 {
         return eventIds_.contains(event_id);
 }
+
+inline bool
+TimelineView::hasLoaded()
+{
+        return scroll_layout_->count() > 1 || isTimelineFinished;
+}
diff --git a/include/TimelineViewManager.h b/include/TimelineViewManager.h
index 35dcac5a..91fda996 100644
--- a/include/TimelineViewManager.h
+++ b/include/TimelineViewManager.h
@@ -47,6 +47,9 @@ public:
         void sync(const Rooms &rooms);
         void clearAll();
 
+        // Check if all the timelines have been loaded.
+        bool hasLoaded() const;
+
         static QString chooseRandomColor();
         static QString displayName(const QString &userid);
 
diff --git a/src/ChatPage.cc b/src/ChatPage.cc
index dbffc6d0..d3f60494 100644
--- a/src/ChatPage.cc
+++ b/src/ChatPage.cc
@@ -213,6 +213,15 @@ ChatPage::ChatPage(QSharedPointer<MatrixClient> client, QWidget *parent)
                 this,
                 SLOT(removeRoom(const QString &)));
 
+        consensusTimer_ = new QTimer(this);
+        connect(consensusTimer_, &QTimer::timeout, this, [=]() {
+                if (view_manager_->hasLoaded()) {
+                        // Remove the spinner overlay.
+                        emit contentLoaded();
+                        consensusTimer_->stop();
+                }
+        });
+
         AvatarProvider::init(client);
 }
 
@@ -554,8 +563,8 @@ ChatPage::loadStateFromCache()
         // Initialize room list from the restored state and settings.
         room_list_->setInitialRooms(settingsManager_, state_manager_);
 
-        // Remove the spinner overlay.
-        emit contentLoaded();
+        // Check periodically if the timelines have been loaded.
+        consensusTimer_->start(500);
 
         sync_timer_->start(sync_interval_);
 }
diff --git a/src/TimelineViewManager.cc b/src/TimelineViewManager.cc
index 1969ae5b..9f8137fc 100644
--- a/src/TimelineViewManager.cc
+++ b/src/TimelineViewManager.cc
@@ -256,3 +256,13 @@ TimelineViewManager::displayName(const QString &userid)
 
         return userid;
 }
+
+bool
+TimelineViewManager::hasLoaded() const
+{
+        for (const auto &view : views_)
+                if (!view->hasLoaded())
+                        return false;
+
+        return true;
+}