FIX: Do not lose admin sidebar when opening chat drawer (#26235)

This commit fixes an issue where the following happens:

1. You open /admin as a member of the admin_sidebar_enabled_groups
1. You then click the chat icon in the header when you prefer to have
   drawer open, or if you just minimise chat into drawer after it opens
   fullscreen
1. You lose the admin sidebar panel, and are reset instead to the main
   panel

Also included is a bit of refactoring to make it so the forcing of
admin sidebar state is in one place.

app/assets/javascripts/admin/addon/routes/admin-revamp.js

@@ -1,5 +1,5 @@
 import { service } from "@ember/service";
-import { ADMIN_PANEL, MAIN_PANEL } from "discourse/lib/sidebar/panels";
+import { MAIN_PANEL } from "discourse/lib/sidebar/panels";
 import DiscourseURL from "discourse/lib/url";
 import DiscourseRoute from "discourse/routes/discourse";
 import I18n from "discourse-i18n";
@@ -8,6 +8,7 @@ export default class AdminRoute extends DiscourseRoute {
   @service siteSettings;
   @service currentUser;
   @service sidebarState;
+  @service adminSidebarStateManager;
 
   titleToken() {
     return I18n.t("admin_title");
@@ -18,9 +19,9 @@ export default class AdminRoute extends DiscourseRoute {
       return DiscourseURL.redirectTo("/admin");
     }
 
-    this.sidebarState.setPanel(ADMIN_PANEL);
-    this.sidebarState.setSeparatedMode();
-    this.sidebarState.hideSwitchPanelButtons();
+    this.adminSidebarStateManager.maybeForceAdminSidebar({
+      onlyIfAlreadyActive: false,
+    });
 
     this.controllerFor("application").setProperties({
       showTop: false,
@@ -29,8 +30,10 @@ export default class AdminRoute extends DiscourseRoute {
 
   deactivate(transition) {
     this.controllerFor("application").set("showTop", true);
-    if (!transition?.to.name.startsWith("admin")) {
-      this.sidebarState.setPanel(MAIN_PANEL);
+    if (this.adminSidebarStateManager.currentUserUsingAdminSidebar) {
+      if (!transition?.to.name.startsWith("admin")) {
+        this.sidebarState.setPanel(MAIN_PANEL);
+      }
     }
   }
 }

app/assets/javascripts/admin/addon/routes/admin.js

@@ -1,7 +1,7 @@
 import { tracked } from "@glimmer/tracking";
 import { service } from "@ember/service";
 import PreloadStore from "discourse/lib/preload-store";
-import { ADMIN_PANEL, MAIN_PANEL } from "discourse/lib/sidebar/panels";
+import { MAIN_PANEL } from "discourse/lib/sidebar/panels";
 import DiscourseRoute from "discourse/routes/discourse";
 import I18n from "discourse-i18n";
 
@@ -18,11 +18,9 @@ export default class AdminRoute extends DiscourseRoute {
   }
 
   activate() {
-    if (this.currentUser.use_admin_sidebar) {
-      this.sidebarState.setPanel(ADMIN_PANEL);
-      this.sidebarState.setSeparatedMode();
-      this.sidebarState.hideSwitchPanelButtons();
-    }
+    this.adminSidebarStateManager.maybeForceAdminSidebar({
+      onlyIfAlreadyActive: false,
+    });
 
     this.controllerFor("application").setProperties({
       showTop: false,
@@ -39,7 +37,7 @@ export default class AdminRoute extends DiscourseRoute {
   deactivate(transition) {
     this.controllerFor("application").set("showTop", true);
 
-    if (this.currentUser.use_admin_sidebar) {
+    if (this.adminSidebarStateManager.currentUserUsingAdminSidebar) {
       if (!transition?.to.name.startsWith("admin")) {
         this.sidebarState.setPanel(MAIN_PANEL);
       }

app/assets/javascripts/admin/addon/services/admin-sidebar-state-manager.js

@@ -1,10 +1,14 @@
 import { tracked } from "@glimmer/tracking";
-import Service from "@ember/service";
+import Service, { service } from "@ember/service";
 import { TrackedObject } from "@ember-compat/tracked-built-ins";
 import KeyValueStore from "discourse/lib/key-value-store";
+import { ADMIN_PANEL } from "discourse/lib/sidebar/panels";
 
 export default class AdminSidebarStateManager extends Service {
+  @service sidebarState;
+  @service currentUser;
   @tracked keywords = new TrackedObject();
+
   STORE_NAMESPACE = "discourse_admin_sidebar_experiment_";
 
   store = new KeyValueStore(this.STORE_NAMESPACE);
@@ -16,4 +20,36 @@ export default class AdminSidebarStateManager extends Service {
   set navConfig(value) {
     this.store.setObject({ key: "navConfig", value });
   }
+
+  get currentUserUsingAdminSidebar() {
+    return this.currentUser?.use_admin_sidebar;
+  }
+
+  maybeForceAdminSidebar(opts = {}) {
+    opts.onlyIfAlreadyActive ??= true;
+
+    const isAdminSidebarActive =
+      this.sidebarState.currentPanel?.key === ADMIN_PANEL;
+
+    if (!this.currentUserUsingAdminSidebar) {
+      return false;
+    }
+
+    if (!opts.onlyIfAlreadyActive) {
+      return this.#forceAdminSidebar();
+    }
+
+    if (isAdminSidebarActive) {
+      return this.#forceAdminSidebar();
+    } else {
+      return false;
+    }
+  }
+
+  #forceAdminSidebar() {
+    this.sidebarState.setPanel(ADMIN_PANEL);
+    this.sidebarState.setSeparatedMode();
+    this.sidebarState.hideSwitchPanelButtons();
+    return true;
+  }
 }