From c63f1f045236c0de6a144e3334ccea2473d3724a Mon Sep 17 00:00:00 2001
From: James Graham <james.h.graham@protonmail.com>
Date: Mon, 15 May 2023 19:11:44 +0000
Subject: [PATCH] Cache last event

Cache the last room event so that the room list can be sorted on startup

Fixes network/neochat#88 \
BUG: 455042
---
 src/neochatroom.cpp | 44 ++++++++++++++++++++++++++++++++++++++++++++
 src/neochatroom.h   |  4 ++++
 2 files changed, 48 insertions(+)

diff --git a/src/neochatroom.cpp b/src/neochatroom.cpp
index 63614f050..e6f003c00 100644
--- a/src/neochatroom.cpp
+++ b/src/neochatroom.cpp
@@ -52,6 +52,8 @@
 #include "filetransferpseudojob.h"
 #include "texthandler.h"
 
+#include <KConfig>
+#include <KConfigGroup>
 #ifndef Q_OS_ANDROID
 #include <KIO/Job>
 #endif
@@ -73,6 +75,22 @@ NeoChatRoom::NeoChatRoom(Connection *connection, QString roomId, JoinState joinS
 
     connect(this, &Room::aboutToAddHistoricalMessages, this, &NeoChatRoom::readMarkerLoadedChanged);
 
+    // Load cached event if available.
+    KConfig dataResource("data", KConfig::SimpleConfig, QStandardPaths::AppDataLocation);
+    KConfigGroup eventCacheGroup(&dataResource, "EventCache");
+
+    if (eventCacheGroup.hasKey(id())) {
+        auto eventJson = QJsonDocument::fromJson(eventCacheGroup.readEntry(id(), QByteArray())).object();
+        if (!eventJson.isEmpty()) {
+            auto event = loadEvent<RoomEvent>(eventJson);
+
+            if (event != nullptr) {
+                m_cachedEvent = std::move(event);
+            }
+        }
+    }
+    connect(this, &Room::addedMessages, this, &NeoChatRoom::cacheLastEvent);
+
     connect(this, &Quotient::Room::eventsHistoryJobChanged, this, &NeoChatRoom::lastActiveTimeChanged);
 
     connect(this, &Room::joinStateChanged, this, [this](JoinState oldState, JoinState newState) {
@@ -300,9 +318,32 @@ const RoomEvent *NeoChatRoom::lastEvent() const
         }
 #endif
     }
+
+    if (m_cachedEvent != nullptr) {
+        return std::to_address(m_cachedEvent);
+    }
+
     return nullptr;
 }
 
+void NeoChatRoom::cacheLastEvent()
+{
+    auto event = lastEvent();
+    if (event != nullptr) {
+        KConfig dataResource("data", KConfig::SimpleConfig, QStandardPaths::AppDataLocation);
+        KConfigGroup eventCacheGroup(&dataResource, "EventCache");
+
+        auto eventJson = QJsonDocument(event->fullJson()).toJson();
+        eventCacheGroup.writeEntry(id(), eventJson);
+
+        auto uniqueEvent = loadEvent<RoomEvent>(event->fullJson());
+
+        if (event != nullptr) {
+            m_cachedEvent = std::move(uniqueEvent);
+        }
+    }
+}
+
 bool NeoChatRoom::lastEventIsSpoiler() const
 {
     if (auto event = lastEvent()) {
@@ -378,6 +419,9 @@ void NeoChatRoom::countChanged()
 QDateTime NeoChatRoom::lastActiveTime()
 {
     if (timelineSize() == 0) {
+        if (m_cachedEvent != nullptr) {
+            return m_cachedEvent->originTimestamp();
+        }
         return QDateTime();
     }
 
diff --git a/src/neochatroom.h b/src/neochatroom.h
index 14a380038..3b5fdb190 100644
--- a/src/neochatroom.h
+++ b/src/neochatroom.h
@@ -774,6 +774,8 @@ private:
     QCoro::Task<void> doDeleteMessagesByUser(const QString &user, QString reason);
     QCoro::Task<void> doUploadFile(QUrl url, QString body = QString());
 
+    std::unique_ptr<Quotient::RoomEvent> m_cachedEvent;
+
     QString m_chatBoxText;
     QString m_editText;
     QString m_chatBoxReplyId;
@@ -790,6 +792,8 @@ private Q_SLOTS:
     void countChanged();
     void updatePushNotificationState(QString type);
 
+    void cacheLastEvent();
+
 Q_SIGNALS:
     void cachedInputChanged();
     void busyChanged();