Fix stuck unread messages by storing state events in the db

This may increase the db size by a factor of 1000 in the worst case and
it will need some fixes, when we decide to not show some events in the
timeline, but it should work for now.

src/Cache.cpp

@@ -43,9 +43,9 @@ static lmdb::val NEXT_BATCH_KEY("next_batch");
 static lmdb::val OLM_ACCOUNT_KEY("olm_account");
 static lmdb::val CACHE_FORMAT_VERSION_KEY("cache_format_version");
 
-constexpr size_t MAX_RESTORED_MESSAGES = 30;
+constexpr size_t MAX_RESTORED_MESSAGES = 30'000;
 
-constexpr auto DB_SIZE = 32UL * 1024UL * 1024UL * 1024ULL; // 32 GB
+constexpr auto DB_SIZE = 32ULL * 1024ULL * 1024ULL * 1024ULL; // 32 GB
 constexpr auto MAX_DBS = 8092UL;
 
 //! Cache databases and their format.
@@ -915,16 +915,17 @@ Cache::calculateRoomReadStatus(const std::string &room_id)
         auto txn = lmdb::txn::begin(env_);
 
         // Get last event id on the room.
-        const auto last_event_id = getLastMessageInfo(txn, room_id).event_id;
+        const auto last_event_id = getLastEventId(txn, room_id);
         const auto localUser     = utils::localUser().toStdString();
 
-        if (last_event_id.isEmpty())
-                return false;
-
         txn.commit();
 
+        if (last_event_id.empty())
+                return false;
+
         // Retrieve all read receipts for that event.
-        const auto receipts = readReceipts(last_event_id, QString::fromStdString(room_id));
+        const auto receipts =
+          readReceipts(QString::fromStdString(last_event_id), QString::fromStdString(room_id));
 
         if (receipts.size() == 0)
                 return true;
@@ -1258,6 +1259,7 @@ Cache::getTimelineMentions()
 mtx::responses::Timeline
 Cache::getTimelineMessages(lmdb::txn &txn, const std::string &room_id)
 {
+        // TODO(nico): Limit the messages returned by this maybe?
         auto db = getMessagesDb(txn, room_id);
 
         mtx::responses::Timeline timeline;
@@ -1325,6 +1327,31 @@ Cache::roomInfo(bool withInvites)
         return result;
 }
 
+std::string
+Cache::getLastEventId(lmdb::txn &txn, const std::string &room_id)
+{
+        auto db = getMessagesDb(txn, room_id);
+
+        if (db.size(txn) == 0)
+                return {};
+
+        std::string timestamp, msg;
+
+        auto cursor = lmdb::cursor::open(txn, db);
+        while (cursor.get(timestamp, msg, MDB_NEXT)) {
+                auto obj = json::parse(msg);
+
+                if (obj.count("event") == 0)
+                        continue;
+
+                cursor.close();
+                return obj["event"]["event_id"];
+        }
+        cursor.close();
+
+        return {};
+}
+
 DescInfo
 Cache::getLastMessageInfo(lmdb::txn &txn, const std::string &room_id)
 {
@@ -1336,13 +1363,14 @@ Cache::getLastMessageInfo(lmdb::txn &txn, const std::string &room_id)
         std::string timestamp, msg;
 
         QSettings settings;
-        auto local_user = settings.value("auth/user_id").toString();
+        const auto local_user = utils::localUser();
 
         auto cursor = lmdb::cursor::open(txn, db);
         while (cursor.get(timestamp, msg, MDB_NEXT)) {
                 auto obj = json::parse(msg);
 
-                if (obj.count("event") == 0)
+                if (obj.count("event") == 0 || !(obj["event"]["type"] == "m.room.message" ||
+                                                 obj["event"]["type"] == "m.sticker"))
                         continue;
 
                 mtx::events::collections::TimelineEvent event;
@@ -1937,9 +1965,6 @@ Cache::saveTimelineMessages(lmdb::txn &txn,
         using namespace mtx::events::state;
 
         for (const auto &e : res.events) {
-                if (isStateEvent(e))
-                        continue;
-
                 if (std::holds_alternative<RedactionEvent<msg::Redaction>>(e))
                         continue;
 

src/Cache_p.h

@@ -250,6 +250,7 @@ private:
         QString getInviteRoomTopic(lmdb::txn &txn, lmdb::dbi &statesdb);
         QString getInviteRoomAvatarUrl(lmdb::txn &txn, lmdb::dbi &statesdb, lmdb::dbi &membersdb);
 
+        std::string getLastEventId(lmdb::txn &txn, const std::string &room_id);
         DescInfo getLastMessageInfo(lmdb::txn &txn, const std::string &room_id);
         void saveTimelineMessages(lmdb::txn &txn,
                                   const std::string &room_id,

src/Utils.cpp

@@ -17,6 +17,7 @@
 
 #include "Cache.h"
 #include "Config.h"
+#include "MatrixClient.h"
 
 using TimelineEvent = mtx::events::collections::TimelineEvents;
 
@@ -44,8 +45,7 @@ createDescriptionInfo(const Event &event, const QString &localUser, const QStrin
 QString
 utils::localUser()
 {
-        QSettings settings;
-        return settings.value("auth/user_id").toString();
+        return QString::fromStdString(http::client()->user_id().to_string());
 }
 
 QString