From aee7197c435c44399c4bcfd6ed1c87763b726cb7 Mon Sep 17 00:00:00 2001
From: Joffrey JAFFEUX <j.jaffeux@gmail.com>
Date: Fri, 19 Jan 2024 22:49:14 +0100
Subject: [PATCH] FIX: correctly save scroll position in channel (#25345)

Due to an incorrect test the previous service was incorrectly implementing the map, and was most importantly not deleting the state when reaching bottom.
---
 .../discourse/components/chat-channel.gjs          |  2 +-
 .../services/chat-channel-scroll-positions.js      | 14 +++++++++-----
 plugins/chat/spec/system/chat_channel_spec.rb      |  8 +++++++-
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/plugins/chat/assets/javascripts/discourse/components/chat-channel.gjs b/plugins/chat/assets/javascripts/discourse/components/chat-channel.gjs
index 87eddf7955f..f93fe4c88e0 100644
--- a/plugins/chat/assets/javascripts/discourse/components/chat-channel.gjs
+++ b/plugins/chat/assets/javascripts/discourse/components/chat-channel.gjs
@@ -497,7 +497,7 @@ export default class ChatChannel extends Component {
 
     if (state.atBottom) {
       this.fetchMoreMessages({ direction: FUTURE });
-      this.chatChannelScrollPositions.remove(this.args.channel.id);
+      this.chatChannelScrollPositions.delete(this.args.channel.id);
     } else {
       this.chatChannelScrollPositions.set(
         this.args.channel.id,
diff --git a/plugins/chat/assets/javascripts/discourse/services/chat-channel-scroll-positions.js b/plugins/chat/assets/javascripts/discourse/services/chat-channel-scroll-positions.js
index 9a4888c7608..70602e94fa5 100644
--- a/plugins/chat/assets/javascripts/discourse/services/chat-channel-scroll-positions.js
+++ b/plugins/chat/assets/javascripts/discourse/services/chat-channel-scroll-positions.js
@@ -5,13 +5,17 @@ import { TrackedMap } from "@ember-compat/tracked-built-ins";
 export default class ChatChannelScrollPositions extends Service {
   @tracked positions = new TrackedMap();
 
-  add(channelId, position) {
-    this.positions.set(channelId, position);
+  get(id) {
+    return this.positions.get(id);
   }
 
-  remove(channelId) {
-    if (this.positions.has(channelId)) {
-      this.positions.delete(channelId);
+  set(id, position) {
+    this.positions.set(id, position);
+  }
+
+  delete(id) {
+    if (this.positions.has(id)) {
+      this.positions.delete(id);
     }
   }
 }
diff --git a/plugins/chat/spec/system/chat_channel_spec.rb b/plugins/chat/spec/system/chat_channel_spec.rb
index 1acbb05eb9b..37b7d66406e 100644
--- a/plugins/chat/spec/system/chat_channel_spec.rb
+++ b/plugins/chat/spec/system/chat_channel_spec.rb
@@ -375,7 +375,13 @@ RSpec.describe "Chat channel", type: :system do
       sidebar_page.open_channel(channel_2)
       sidebar_page.open_channel(channel_1)
 
-      expect(channel_page.messages).to have_message(id: channel_1.chat_messages[2].id)
+      expect(channel_page.messages).to have_no_message(id: channel_1.chat_messages[49].id)
+
+      find(".chat-scroll-to-bottom__button.visible").click
+      sidebar_page.open_channel(channel_2)
+      sidebar_page.open_channel(channel_1)
+
+      expect(channel_page.messages).to have_message(id: channel_1.chat_messages[49].id)
     end
   end
 end