Fill reply history windows at boundaries and preserve read position

tools/chatgui/db/db_manager.cpp

@@ -239,6 +239,7 @@ static MessageRow readMessage(sqlite3_stmt* stmt, quint64 myId) {
     m.id = sqlite3_column_int64(stmt, 0); m.authorNodeId = (quint64)sqlite3_column_int64(stmt, 1);
     const auto json = QJsonDocument::fromJson(DbManager::colBlob(stmt, 2)).object();
     m.contentType = json.value("ct").toString("text/plain"); m.data = json.value("d").toString().toUtf8();
+    if (m.contentType.isEmpty()) m.contentType = "text/plain";
     const QByteArray reply = json.value("reply_to").toString().toLatin1();
     if (!reply.isEmpty()) {
         m.replyTo = QByteArray::fromHex(reply);
@@ -255,21 +256,30 @@ static MessageRow readMessage(sqlite3_stmt* stmt, quint64 myId) {
 /* Окно вокруг оригинала выбирается одним SQL snapshot, включая одинаковые timestamp. */
 QList<MessageRow> DbManager::getMessages(const QString& chId, int limit, const QByteArray& around) const {
     QList<MessageRow> list;
+    if (!around.isEmpty() && (around.size() != 32 || limit <= 0)) {
+        GUI_ERROR("history: invalid anchor/window bytes=%d limit=%d", int(around.size()), limit); return list;
+    }
     QString sql = QStringLiteral(
         "SELECT id, node_id, data, timestamp, chain_hash, author_signature, local_attrs, message_id"
-        " FROM \"%1\" ORDER BY timestamp DESC, author_signature DESC LIMIT ?1 OFFSET "
-        "max(0,(SELECT count(*) FROM \"%1\" n JOIN \"%1\" a ON a.message_id=?2 "
-        "WHERE (n.timestamp,n.author_signature)>(a.timestamp,a.author_signature)) - ?1/2)").arg(msgTableName(chId));
+        " FROM \"%1\" ORDER BY timestamp DESC, author_signature DESC LIMIT ?1").arg(msgTableName(chId));
+    if (!around.isEmpty()) sql += QStringLiteral(
+        " OFFSET min(max(0,(SELECT count(*) FROM \"%1\" n JOIN \"%1\" a ON a.message_id=?2 "
+        "WHERE (n.timestamp,n.author_signature)>(a.timestamp,a.author_signature)) - ?1/2),"
+        "max(0,(SELECT count(*) FROM \"%1\")-?1))").arg(msgTableName(chId));
     sqlite3_stmt* stmt = prepareOrNull(sql.toUtf8().constData());
     if (!stmt) return list;
     sqlite3_bind_int(stmt, 1, limit);
-    sqlite3_bind_blob(stmt, 2, around.constData(), around.size(), SQLITE_TRANSIENT);
+    if (!around.isEmpty()) sqlite3_bind_blob(stmt, 2, around.constData(), around.size(), SQLITE_TRANSIENT);
     uint64_t myId = 0;
     { sqlite3_stmt* ms = prepareOrNull("SELECT node_id FROM local_identity WHERE id=1");
       if (ms) { if (sqlite3_step(ms) == SQLITE_ROW) myId = (uint64_t)sqlite3_column_int64(ms, 0); sqlite3_finalize(ms); } }
-    while (sqlite3_step(stmt) == SQLITE_ROW) {
+    int rc;
+    while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
         list.prepend(readMessage(stmt, myId));
     }
+    if (rc != SQLITE_DONE) GUI_ERROR("history: read failed ch=%s rc=%d", qPrintable(chId), rc);
+    if (!around.isEmpty()) GUI_DEBUG("history: window loaded ch=%s anchor=%s rows=%d limit=%d",
+                                    qPrintable(chId), around.toHex().constData(), int(list.size()), limit);
     sqlite3_finalize(stmt);
     return list;
 }

tools/chatgui/src/messagelist.cpp

@@ -676,8 +676,6 @@ void MessageList::loadChannel(const QString& channelId) {
     QWidget* prevFocus = QApplication::focusWidget();
 
     bool sameChannel = (m_currentChannelId == channelId);
-    if (!sameChannel) m_historyAnchor.clear();
-    m_view->setHistoricalWindow(!m_historyAnchor.isEmpty());
 
     /* Save state of current channel before switching */
     if (!m_currentChannelId.isEmpty()) {
@@ -699,6 +697,8 @@ void MessageList::loadChannel(const QString& channelId) {
         }
     }
 
+    if (!sameChannel) m_historyAnchor.clear();
+    m_view->setHistoricalWindow(!m_historyAnchor.isEmpty());
     m_model->clear();
     m_avatarCache.clear();
     if (m_currentChannelId != channelId) { m_feedback.clear(); m_pendingPoll.clear(); }
@@ -869,6 +869,7 @@ void MessageList::refresh() {
 }
 
 void MessageList::saveChannelState() {
+    if (!m_historyAnchor.isEmpty()) return; // Просмотр цитаты сохраняет прежнюю позицию чтения свежей истории.
     if (m_currentChannelId.isEmpty() || m_model->rowCount() == 0) return;
 
     QScrollBar* sb = m_view->verticalScrollBar();
@@ -922,6 +923,7 @@ void MessageList::reloadLocalNicks() {
         quint64 nid = v.value<quint64>();
         item->setData(authorName(nid), MsgAuthorRole);
     }
+    if (!isDmChannel(m_currentChannelId)) refreshReplies();
     m_view->viewport()->update();
 }
 
@@ -947,6 +949,7 @@ void MessageList::restoreScrollPosition(const QString& channelId) {
 }
 
 void MessageList::updateReadPosition() {
+    if (!m_historyAnchor.isEmpty()) return;
     if (m_currentChannelId.isEmpty() || m_model->rowCount() == 0) return;
 
     int vpHeight = m_view->viewport()->height();