chatgui: fix scroll jump on refresh, force debounce, add DEBUG logs

- Same-channel refresh: save scroll pos in memory, restore from memory (no DB race)
- Force m_readDebounce->start() after loadChannel (scrollToBottom may not trigger valueChanged)
- DEBUG_DEBUG logs in updateReadPosition, saveChannelState, onMessageReceived, setChannelUnreadCount

tools/chatgui/src/channellist.cpp

@@ -245,11 +245,15 @@ void ChannelList::setChannelUnreadCount(const QString& channelId, int count) {
     for (int row = 0; row < m_model->rowCount(); row++) {
         QStandardItem* item = m_model->item(row);
         if (item && item->data(ChannelChannelIdRole).toString() == channelId) {
+            int old = item->data(ChannelUnreadCountRole).toInt();
+            DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "ChannelList::setChannelUnreadCount ch=%s %d->%d",
+                       qPrintable(channelId), old, count);
             item->setData(count, ChannelUnreadCountRole);
             emit m_model->dataChanged(m_model->index(row, 0), m_model->index(row, 0));
             return;
         }
     }
+    DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "ChannelList::setChannelUnreadCount ch=%s not found", qPrintable(channelId));
 }
 
 int ChannelList::getChannelUnreadCount(const QString& channelId) const {

tools/chatgui/src/mainwindow.cpp

@@ -327,14 +327,17 @@ void MainWindow::showSettings() {
 }
 
 void MainWindow::onMessageReceived(const char* ch_id) {
-    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "MainWindow: msg received ch=%s", ch_id);
-    SoundManager::instance()->play("msg_incoming");
     QString cid = QString::fromUtf8(ch_id);
+    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "MainWindow::onMessageReceived ch=%s cur=%s",
+               qPrintable(cid), qPrintable(m_currentChannelId));
+    SoundManager::instance()->play("msg_incoming");
     if (m_messageList) {
         if (cid == m_currentChannelId) {
             m_messageList->refresh();
         } else if (m_channelList) {
             int unread = m_channelList->getChannelUnreadCount(cid) + 1;
+            DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow::onMessageReceived increment unread ch=%s %d->%d",
+                       qPrintable(cid), unread - 1, unread);
             m_channelList->setChannelUnreadCount(cid, unread);
         }
     }

tools/chatgui/src/messagelist.cpp

@@ -23,6 +23,7 @@ extern "C" {
 #include "../transport/chat_core.h"
 #include "../../lib/u_async.h"
 #include "../../lib/mem.h"
+#include "../../lib/debug_config.h"
 }
 
 static QPixmap makeAvatar(const QColor &color, const QString &letter, int size = 36) {
@@ -176,16 +177,30 @@ MessageList::MessageList(DbManager* db, QWidget *parent)
 void MessageList::loadChannel(const QString& channelId) {
     QWidget* prevFocus = QApplication::focusWidget();
 
+    bool sameChannel = (m_currentChannelId == channelId);
+
     /* Save state of current channel before switching */
-    if (!m_currentChannelId.isEmpty() && m_currentChannelId != channelId)
-        saveChannelState();
+    if (!m_currentChannelId.isEmpty()) {
+        if (!sameChannel) {
+            saveChannelState();
+        } else {
+            QModelIndex topIdx = m_view->indexAt(QPoint(0, 0));
+            m_savedTopMsgId = topIdx.isValid() ? topIdx.data(MsgIdRole).toLongLong() : 0;
+            QScrollBar* sb = m_view->verticalScrollBar();
+            m_wasAtBottom = sb && (sb->value() >= sb->maximum());
+        }
+    }
 
     m_model->clear();
     m_avatarCache.clear();
     m_currentChannelId = channelId;
     m_readDebounce->stop();
-    m_lastReadMsgId = m_db->getUiStateInt64(
-        QStringLiteral("ch_%1_last_read").arg(channelId), 0);
+    if (!m_db || !m_db->isOpen()) return;
+
+    if (sameChannel)
+        m_lastReadMsgId = m_db->getUiStateInt64(
+            QStringLiteral("ch_%1_last_read").arg(channelId), 0);
+
     if (!m_db || !m_db->isOpen()) return;
 
     auto msgs = m_db->getMessages(channelId, 100);
@@ -211,7 +226,22 @@ void MessageList::loadChannel(const QString& channelId) {
         m_model->appendRow(item);
     }
 
-    restoreScrollPosition(channelId);
+    if (sameChannel) {
+        if (m_wasAtBottom || m_savedTopMsgId == 0)
+            m_view->scrollToBottom();
+        else
+            for (int row = 0; row < m_model->rowCount(); row++)
+                if (m_model->item(row)->data(MsgIdRole).toLongLong() == m_savedTopMsgId) {
+                    m_view->scrollTo(m_model->index(row, 0), QAbstractItemView::PositionAtTop);
+                    break;
+                }
+    } else {
+        m_lastReadMsgId = m_db->getUiStateInt64(
+            QStringLiteral("ch_%1_last_read").arg(channelId), 0);
+        restoreScrollPosition(channelId);
+    }
+
+    m_readDebounce->start();
 
     if (prevFocus)
         prevFocus->setFocus();
@@ -264,6 +294,8 @@ void MessageList::saveChannelState() {
         lastPosMsgId = topIdx.data(MsgIdRole).toLongLong();
 
     qint64 lastReadMsgId = m_lastReadMsgId;
+    DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MessageList::saveChannelState ch=%s read=%lld pos=%lld",
+                qPrintable(m_currentChannelId), (long long)lastReadMsgId, (long long)lastPosMsgId);
     if (lastReadMsgId == 0 && lastPosMsgId == 0) return;
 
     QByteArray cid = m_currentChannelId.toUtf8();
@@ -326,6 +358,11 @@ void MessageList::updateReadPosition() {
             newReadMsgId = msgId;
     }
 
+    DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG,
+        "MessageList::updateReadPosition ch=%s oldRead=%lld newRead=%lld lastVisRow=%d/%d",
+        qPrintable(m_currentChannelId), (long long)m_lastReadMsgId,
+        (long long)newReadMsgId, lastFullyVisibleRow, m_model->rowCount());
+
     if (newReadMsgId > m_lastReadMsgId) {
         m_lastReadMsgId = newReadMsgId;
 

tools/chatgui/src/messagelist.h

@@ -35,6 +35,8 @@ private:
     QHash<quint64, QColor> m_avatarCache;
     qint64                m_lastReadMsgId = 0;
     QTimer*               m_readDebounce;
+    qint64                m_savedTopMsgId = 0;
+    bool                  m_wasAtBottom = false;
 
     void saveChannelState();
     void restoreScrollPosition(const QString& channelId);