Fix scroll behavior and prevent history loading when the conversation is empty

app/Widgets/Chat/Chat.php

@@ -1012,7 +1012,8 @@ class Chat extends \Movim\Widget\Base
             ->first();
 
         if ($contextMessage) {
-            $this->ajaxGetHistory($jid, $contextMessage->published, muc: $contextMessage->isMuc(), prepend: false, tryMam: false, clear: true);
+            $this->rpc('MovimTpl.fill', '#' . cleanupId($jid) . '-conversation', '');
+            $this->ajaxGetHistory($jid, $contextMessage->published, muc: $contextMessage->isMuc(), prepend: false, tryMam: false);
             $this->rpc('Chat.scrollAndBlinkMessageMid', $mid);
             $this->rpc('MovimUtils.addClass', '#chat_widget .contained', 'history');
         }
@@ -1024,7 +1025,7 @@ class Chat extends \Movim\Widget\Base
      * @param string jid
      * @param string time
      */
-    public function ajaxGetHistory(string $jid, ?string $date = null, bool $muc = false, bool $prepend = true, bool $tryMam = true, ?bool $clear = false)
+    public function ajaxGetHistory(string $jid, ?string $date = null, bool $muc = false, bool $prepend = true, bool $tryMam = true)
     {
         if (!validateJid($jid)) return;
 
@@ -1048,10 +1049,6 @@ class Chat extends \Movim\Widget\Base
                 $this->prepareMessage($message);
             }
 
-            if ($clear) {
-                $this->rpc('MovimTpl.fill', '#' . cleanupId($jid) . '-conversation', '');
-            }
-
             $this->rpc('Chat.appendMessagesWrapper', $this->_wrapper, $prepend);
             $this->_wrapper = [];
         }

app/Widgets/Chat/chat.js

@@ -658,10 +658,11 @@ var Chat = {
     },
     setScrollBehaviour: function () {
         var discussion = Chat.getDiscussion();
-        if (discussion == null) return;
+        if (!discussion) return;
 
         discussion.onscroll = function () {
-            if (this.scrollTop < 1) {
+            // Don't get more history the conversation is already empty
+            if (discussion.querySelector('.conversation').innerHTML != '' && this.scrollTop < 100) {
                 Chat.getHistory(true);
             }
 
@@ -672,7 +673,7 @@ var Chat = {
     },
     setScroll: function () {
         var discussion = Chat.getDiscussion();
-        if (discussion == null) return;
+        if (!discussion) return;
 
         Chat.lastHeight = discussion.scrollHeight;
         Chat.lastScroll = discussion.scrollTop + discussion.clientHeight;
@@ -700,7 +701,7 @@ var Chat = {
     },
     scrollTotally: function () {
         var discussion = Chat.getDiscussion();
-        if (discussion == null) return;
+        if (!discussion) return;
 
         discussion.scrollTop = discussion.scrollHeight;
     },
@@ -722,7 +723,7 @@ var Chat = {
     },
     scrollToSeparator: function () {
         var discussion = Chat.getDiscussion();
-        if (discussion == null) return;
+        if (!discussion) return;
 
         var separator = discussion.querySelector('.separator');
         if (separator) {
@@ -1273,6 +1274,8 @@ var Chat = {
     appendDate: function (date, prepend) {
         var list = document.querySelector('#chat_widget > div ul.conversation');
 
+        if (!list) return;
+
         dateNode = Chat.date.cloneNode(true);
         dateNode.querySelector('p').innerHTML = date;
         dateNode.id = MovimUtils.cleanupId(date);