From 3176c3dc8c84bd4a0a12aceda0dfe0b427736a96 Mon Sep 17 00:00:00 2001
From: Sebastian Wolf <sebastian@ygriega.de>
Date: Tue, 2 Feb 2021 22:05:24 +0100
Subject: [PATCH] Chat page: Adjust initial scroll position, honoring #243

---
 qml/pages/ChatPage.qml | 10 +++++++++-
 src/chatmodel.cpp      | 12 ++++++++++++
 src/chatmodel.h        |  1 +
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/qml/pages/ChatPage.qml b/qml/pages/ChatPage.qml
index 045b72b..54ba6e9 100644
--- a/qml/pages/ChatPage.qml
+++ b/qml/pages/ChatPage.qml
@@ -443,7 +443,6 @@ Page {
                 chatModel.initialize(chatInformation);
 
                 pageStack.pushAttached(Qt.resolvedUrl("ChatInformationPage.qml"), { "chatInformation" : chatInformation, "privateChatUserInformation": chatPartnerInformation, "groupInformation": chatGroupInformation, "chatOnlineMemberCount": chatOnlineMemberCount});
-                chatPage.isInitialized = true;
 
                 if(doSendBotStartMessage) {
                     tdLibWrapper.sendBotStartMessage(chatInformation.id, chatInformation.id, sendBotStartMessageParameter, "")
@@ -595,6 +594,9 @@ Page {
         onMessagesIncrementalUpdate: {
             Debug.log("Incremental update received. View now has ", chatView.count, " messages, view is on index ", modelIndex, ", own messages were read before index ", lastReadSentIndex);
             chatView.lastReadSentIndex = lastReadSentIndex;
+            if (!chatPage.isInitialized) {
+                chatView.scrollToIndex(modelIndex);
+            }
             chatViewCooldownTimer.restart();
         }
         onNotificationSettingsUpdated: {
@@ -925,6 +927,12 @@ Page {
                     onTriggered: {
                         Debug.log("[ChatPage] Cooldown completed...");
                         chatView.inCooldown = false;
+
+                        if (!chatPage.isInitialized) {
+                            Debug.log("Page is initialized!");
+                            chatPage.isInitialized = true;
+                            chatView.handleScrollPositionChanged();
+                        }
                     }
                 }
 
diff --git a/src/chatmodel.cpp b/src/chatmodel.cpp
index 68695a3..7a38a31 100644
--- a/src/chatmodel.cpp
+++ b/src/chatmodel.cpp
@@ -403,6 +403,7 @@ void ChatModel::handleMessagesReceived(const QVariantList &messages, int totalCo
         this->inReload = false;
         int listInboxPosition = this->calculateLastKnownMessageId();
         int listOutboxPosition = this->calculateLastReadSentMessageId();
+        listInboxPosition = this->calculateScrollPosition(listInboxPosition);
         if (this->inIncrementalUpdate) {
             this->inIncrementalUpdate = false;
             emit messagesIncrementalUpdate(listInboxPosition, listOutboxPosition);
@@ -443,6 +444,7 @@ void ChatModel::handleMessagesReceived(const QVariantList &messages, int totalCo
                 this->inReload = false;
                 int listInboxPosition = this->calculateLastKnownMessageId();
                 int listOutboxPosition = this->calculateLastReadSentMessageId();
+                listInboxPosition = this->calculateScrollPosition(listInboxPosition);
                 if (this->inIncrementalUpdate) {
                     this->inIncrementalUpdate = false;
                     emit messagesIncrementalUpdate(listInboxPosition, listOutboxPosition);
@@ -779,6 +781,16 @@ int ChatModel::calculateLastReadSentMessageId()
     return listOutboxPosition;
 }
 
+int ChatModel::calculateScrollPosition(int listInboxPosition)
+{
+    LOG("Calculating new scroll position, current:" << listInboxPosition << ", list size:" << this->messages.size());
+    if ((this->messages.size() - 1) > listInboxPosition) {
+        return listInboxPosition + 1;
+    } else {
+        return listInboxPosition;
+    }
+}
+
 bool ChatModel::isMostRecentMessageLoaded()
 {
     // Need to check if we can actually add messages (only possible if the previously latest messages are loaded)
diff --git a/src/chatmodel.h b/src/chatmodel.h
index 30ce20f..7424346 100644
--- a/src/chatmodel.h
+++ b/src/chatmodel.h
@@ -85,6 +85,7 @@ private:
     QVariantMap enhanceMessage(const QVariantMap &message);
     int calculateLastKnownMessageId();
     int calculateLastReadSentMessageId();
+    int calculateScrollPosition(int listInboxPosition);
     bool isMostRecentMessageLoaded();
 
 private: