♻️ Reorganize index management on worker code (#6477)

* ♻️ Factor index management out of app.worker.impl

* 💄 Fix silly spacing

* 💄 Lint

frontend/src/app/worker/index.cljs

@@ -0,0 +1,34 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) KALEIDOS INC
+
+(ns app.worker.index
+  "Page index management within the worker."
+  (:require
+   [app.common.data.macros :as dm]
+   [app.common.files.changes :as ch]
+   [app.worker.impl :as impl]
+   [okulary.core :as l]))
+
+(defonce state (l/atom {:pages-index {}}))
+
+(defmethod impl/handler :index/initialize-page-index
+  [{:keys [page] :as message}]
+  (swap! state update :pages-index assoc (:id page) page)
+  (impl/handler (assoc message :cmd :selection/initialize-page-index))
+  (impl/handler (assoc message :cmd :snaps/initialize-page-index)))
+
+(defmethod impl/handler :index/update-page-index
+  [{:keys [page-id changes] :as message}]
+
+  (let [old-page (dm/get-in @state [:pages-index page-id])
+        new-page (-> state
+                     (swap! ch/process-changes changes false)
+                     (dm/get-in [:pages-index page-id]))
+        message (assoc message
+                       :old-page old-page
+                       :new-page new-page)]
+    (impl/handler (assoc message :cmd :selection/update-page-index))
+    (impl/handler (assoc message :cmd :snaps/update-page-index))))