From 641364c105cffd24f82391a90e37531937d31c28 Mon Sep 17 00:00:00 2001
From: Konstantinos Sideris <sideris.konstantin@gmail.com>
Date: Fri, 31 Aug 2018 10:47:27 +0300
Subject: [PATCH] Handle some more edge cases in timeline

---
 src/ChatPage.cpp              | 10 ++++++++--
 src/timeline/TimelineView.cpp | 30 +++++++++++++++++++++++++++---
 src/timeline/TimelineView.h   |  2 ++
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/ChatPage.cpp b/src/ChatPage.cpp
index 4bb7b497..9596d561 100644
--- a/src/ChatPage.cpp
+++ b/src/ChatPage.cpp
@@ -1110,9 +1110,15 @@ ChatPage::createRoom(const mtx::requests::CreateRoom &req)
         http::client()->create_room(
           req, [this](const mtx::responses::CreateRoom &res, mtx::http::RequestErr err) {
                   if (err) {
+                          const auto err_code   = mtx::errors::to_string(err->matrix_error.errcode);
+                          const auto error      = err->matrix_error.error;
+                          const int status_code = static_cast<int>(err->status_code);
+
+                          nhlog::net()->warn(
+                            "failed to create room: {} {} ({})", error, err_code, status_code);
+
                           emit showNotification(
-                            tr("Room creation failed: %1")
-                              .arg(QString::fromStdString(err->matrix_error.error)));
+                            tr("Room creation failed: %1").arg(QString::fromStdString(error)));
                           return;
                   }
 
diff --git a/src/timeline/TimelineView.cpp b/src/timeline/TimelineView.cpp
index 6eb553e8..a77bae6a 100644
--- a/src/timeline/TimelineView.cpp
+++ b/src/timeline/TimelineView.cpp
@@ -164,11 +164,19 @@ TimelineView::sliderMoved(int position)
         }
 }
 
+bool
+TimelineView::isStartOfTimeline(const mtx::responses::Messages &msgs)
+{
+        return (msgs.chunk.size() == 0 && (msgs.end.empty() || msgs.end == msgs.start));
+}
+
 void
 TimelineView::addBackwardsEvents(const mtx::responses::Messages &msgs)
 {
         // We've reached the start of the timline and there're no more messages.
-        if (msgs.end.empty() || ((msgs.end == msgs.start) && msgs.chunk.size() == 0)) {
+        if (isStartOfTimeline(msgs)) {
+                nhlog::ui()->info("[{}] start of timeline reached, no more messages to fetch",
+                                  room_id_.toStdString());
                 isTimelineFinished = true;
                 return;
         }
@@ -562,6 +570,13 @@ TimelineView::init()
 void
 TimelineView::getMessages()
 {
+        if (prev_batch_token_.isEmpty()) {
+                nhlog::ui()->info("[{}] start of timeline reached, prev_batch token is empty",
+                                  room_id_.toStdString());
+                isTimelineFinished = true;
+                return;
+        }
+
         mtx::http::MessagesOpts opts;
         opts.room_id = room_id_.toStdString();
         opts.from    = prev_batch_token_.toStdString();
@@ -829,13 +844,22 @@ TimelineView::sendNextPendingMessage()
 void
 TimelineView::notifyForLastEvent()
 {
-        auto lastItem          = scroll_layout_->itemAt(scroll_layout_->count() - 1);
+        if (scroll_layout_->count() == 0) {
+                nhlog::ui()->error("notifyForLastEvent called with empty timeline");
+                return;
+        }
+
+        auto lastItem = scroll_layout_->itemAt(scroll_layout_->count() - 1);
+
+        if (!lastItem)
+                return;
+
         auto *lastTimelineItem = qobject_cast<TimelineItem *>(lastItem->widget());
 
         if (lastTimelineItem)
                 emit updateLastTimelineMessage(room_id_, lastTimelineItem->descriptionMessage());
         else
-                nhlog::ui()->warn("cast to TimelineView failed: {}", room_id_.toStdString());
+                nhlog::ui()->warn("cast to TimelineItem failed: {}", room_id_.toStdString());
 }
 
 void
diff --git a/src/timeline/TimelineView.h b/src/timeline/TimelineView.h
index 0d18c7fe..46facd7e 100644
--- a/src/timeline/TimelineView.h
+++ b/src/timeline/TimelineView.h
@@ -169,6 +169,8 @@ private:
 
         //! Mark our own widgets as read if they have more than one receipt.
         void displayReadReceipts(std::vector<TimelineEvent> events);
+        //! Determine if the start of the timeline is reached from the response of /messages.
+        bool isStartOfTimeline(const mtx::responses::Messages &msgs);
 
         QWidget *relativeWidget(QWidget *item, int dt) const;