feat: edit position chat after load history

src/chatlog/chatlog.cpp

@@ -693,7 +693,7 @@ void ChatLog::forceRelayout()
     startResizeWorker();
 }
 
-void ChatLog::checkVisibility(bool causedByScroll)
+void ChatLog::checkVisibility(bool causedWheelEvent)
 {
     if (lines.empty())
         return;
@@ -734,10 +734,10 @@ void ChatLog::checkVisibility(bool causedByScroll)
         emit firstVisibleLineChanged(visibleLines.at(0));
     }
 
-    if (causedByScroll) {
+    if (causedWheelEvent) {
         if (lowerBound != lines.cend() && lowerBound->get()->row == 0) {
             emit loadHistoryLower();
-        } else if (upperBound != lines.cend() && upperBound->get()->row >= lines.size() - 10) {
+        } else if (upperBound == lines.cend()) {
             emit loadHistoryUpper();
         }
     }
@@ -746,7 +746,7 @@ void ChatLog::checkVisibility(bool causedByScroll)
 void ChatLog::scrollContentsBy(int dx, int dy)
 {
     QGraphicsView::scrollContentsBy(dx, dy);
-    checkVisibility(true);
+    checkVisibility();
 }
 
 void ChatLog::resizeEvent(QResizeEvent* ev)
@@ -942,6 +942,12 @@ void ChatLog::focusOutEvent(QFocusEvent* ev)
     }
 }
 
+void ChatLog::wheelEvent(QWheelEvent *event)
+{
+    QGraphicsView::wheelEvent(event);
+    checkVisibility(true);
+}
+
 void ChatLog::retranslateUi()
 {
     copyAction->setText(tr("Copy"));

src/chatlog/chatlog.h

@@ -97,7 +97,7 @@ protected:
 
     void reposition(int start, int end, qreal deltaY);
     void updateSceneRect();
-    void checkVisibility(bool causedByScroll = false);
+    void checkVisibility(bool causedWheelEvent = false);
     void scrollToBottom();
     void startResizeWorker();
 
@@ -110,6 +110,7 @@ protected:
     virtual void showEvent(QShowEvent*) final override;
     virtual void focusInEvent(QFocusEvent* ev) final override;
     virtual void focusOutEvent(QFocusEvent* ev) final override;
+    virtual void wheelEvent(QWheelEvent *event) final override;
 
     void updateMultiSelectionRect();
     void updateTypingNotification();

src/widget/form/genericchatform.cpp

@@ -657,16 +657,47 @@ void GenericChatForm::loadHistory(const QDateTime &time, const LoadHistoryDialog
     chatWidget->clear();
     messages.clear();
 
-    auto begin = firstItemAfterDate(time.date(), chatLog);
-    auto end = ChatLogIdx(begin.get() + 1);
+    if (type == LoadHistoryDialog::from) {
+        loadHistoryFrom(time);
+        auto msg = messages.cbegin()->second;
+        chatWidget->scrollToLine(msg);
+    } else {
+        loadHistoryTo(time);
+    }
+}
+
+void GenericChatForm::loadHistoryTo(const QDateTime &time)
+{
+    auto end = ChatLogIdx(0);
+    if (time.isNull()) {
+        end = messages.begin()->first;
+    } else {
+        end = firstItemAfterDate(time.date(), chatLog);
+    }
+
+    auto begin = ChatLogIdx(0);
+    if (end.get() > 100) {
+        begin = ChatLogIdx(end.get() - 100);
+    }
 
     renderMessages(begin, end);
-
-    if (type == LoadHistoryDialog::from) {
-        loadHistoryUpper();
-    } else {
-        loadHistoryLower();
 }
+
+void GenericChatForm::loadHistoryFrom(const QDateTime &time)
+{
+    auto begin = ChatLogIdx(0);
+    if (time.isNull()) {
+        begin = messages.rbegin()->first;
+    } else {
+        begin = firstItemAfterDate(time.date(), chatLog);
+    }
+
+    int add = 100;
+    if (begin.get() + 100 > chatLog.getNextIdx().get()) {
+        add = chatLog.getNextIdx().get() - (begin.get() + 100);
+    }
+    auto end = ChatLogIdx(begin.get() + add);
+    renderMessages(begin, end);
 }
 
 
@@ -1023,25 +1054,14 @@ void GenericChatForm::goToCurrentDate()
 
 void GenericChatForm::loadHistoryLower()
 {
-    auto end = messages.begin()->first;
-    auto begin = ChatLogIdx(0);
-    if (end.get() > 100) {
-        begin = ChatLogIdx(end.get() - 100);
-    }
-
-    renderMessages(begin, end);
+    loadHistoryTo(QDateTime());
 }
 
 void GenericChatForm::loadHistoryUpper()
 {
-    auto begin = messages.rbegin()->first;
-
-    int add = 100;
-    if (begin.get() + 100 > chatLog.getNextIdx().get()) {
-        add = chatLog.getNextIdx().get() - (begin.get() + 100);
-    }
-    auto end = ChatLogIdx(begin.get() + add);
-    renderMessages(begin, end);
+    auto msg = messages.crbegin()->second;
+    loadHistoryFrom(QDateTime());
+    chatWidget->scrollToLine(msg);
 }
 
 void GenericChatForm::updateShowDateInfo(const ChatLine::Ptr& line)

src/widget/form/genericchatform.h

@@ -136,6 +136,8 @@ private:
     void addSystemDateMessage(const QDate& date);
     QDateTime getTime(const ChatLine::Ptr& chatLine) const;
     void loadHistory(const QDateTime& time, const LoadHistoryDialog::LoadType type);
+    void loadHistoryTo(const QDateTime& time);
+    void loadHistoryFrom(const QDateTime& time);
 
 protected:
     ChatMessage::Ptr createMessage(const ToxPk& author, const QString& message,