enhance: way better cursor restore for undo/redo

This commits records both the start pos (user starts to type) and end
pos (before transaction), because the user always wants undo to move
the cursor back to the start position and redo to the end position.

src/main/frontend/handler/editor.cljs

@@ -2917,6 +2917,10 @@
           hashtag? (or (surround-by? input "#" " ")
                        (surround-by? input "#" :end)
                        (= key "#"))]
+      (when (and (not @(:editor/start-pos @state/state))
+                 (not (and key (string/starts-with? key "Arrow"))))
+        (state/set-state! :editor/start-pos pos))
+
       (cond
         (and (contains? #{"ArrowLeft" "ArrowRight"} key)
              (contains? #{:property-search :property-value-search} (state/get-editor-action)))

src/main/frontend/handler/history.cljs

@@ -8,13 +8,13 @@
             [goog.dom :as gdom]))
 
 (defn restore-cursor!
-  [{:keys [last-edit-block container pos]}]
+  [{:keys [last-edit-block container pos end-pos]} undo?]
   (when (and container last-edit-block)
     #_:clj-kondo/ignore
     (when-let [container (gdom/getElement container)]
       (when-let [block-uuid (:block/uuid last-edit-block)]
         (when-let [block (db/pull [:block/uuid block-uuid])]
-          (editor/edit-block! block pos
+          (editor/edit-block! block (if undo? pos end-pos)
                               (:block/uuid block)
                               {:custom-content (:block/content block)}))))))
 

src/main/frontend/modules/editor/undo_redo.cljs

@@ -133,41 +133,13 @@
       (pop-undo))
     (pop-undo)))
 
-(defn- get-next-tx-editor-cursor
-  [tx-id]
-  (let [result (->> (sort (keys @(:history/tx->editor-cursor @state/state)))
-                    (split-with #(not= % tx-id))
-                    second)]
-    (when (> (count result) 1)
-      (when-let [next-tx-id (nth result 1)]
-        (get @(get @state/state :history/tx->editor-cursor) next-tx-id)))))
-
-(defn- get-previous-tx-id
-  [tx-id]
-  (let [result (->> (sort (keys @(:history/tx->editor-cursor @state/state)))
-                    (split-with #(not= % tx-id))
-                    first)]
-    (when (>= (count result) 1)
-      (last result))))
-
-(defn- get-previous-tx-editor-cursor
-  [tx-id]
-  (when-let [prev-tx-id (get-previous-tx-id tx-id)]
-    (get @(get @state/state :history/tx->editor-cursor) prev-tx-id)))
-
 (defn undo
   []
   (when-let [e (smart-pop-undo)]
     (let [{:keys [txs tx-meta tx-id]} e
           new-txs (get-txs false txs)
           current-editor-cursor (get @(get @state/state :history/tx->editor-cursor) tx-id)
-          save-block? (= (:outliner-op tx-meta) :save-block)
-          prev-editor-cursor (get-previous-tx-editor-cursor tx-id)
-          editor-cursor (if (and save-block?
-                                 (= (:block/uuid (:last-edit-block prev-editor-cursor))
-                                    (:block/uuid (state/get-edit-block))))
-                          prev-editor-cursor
-                          current-editor-cursor)]
+          editor-cursor current-editor-cursor]
       (push-redo e)
       (transact! new-txs (merge {:undo? true}
                                 tx-meta))
@@ -181,10 +153,7 @@
   []
   (when-let [{:keys [txs tx-meta tx-id] :as e} (smart-pop-redo)]
     (let [new-txs (get-txs true txs)
-          current-editor-cursor (get @(get @state/state :history/tx->editor-cursor) tx-id)
-          editor-cursor (if (= (:outliner-op tx-meta) :save-block)
-                          current-editor-cursor
-                          (get-next-tx-editor-cursor tx-id))]
+          current-editor-cursor (get @(get @state/state :history/tx->editor-cursor) tx-id)]
       (push-undo e)
       (transact! new-txs (merge {:redo? true}
                                 tx-meta))
@@ -192,7 +161,7 @@
         (state/pub-event! [:whiteboard/redo e]))
       (assoc e
              :txs-op new-txs
-             :editor-cursor editor-cursor))))
+             :editor-cursor current-editor-cursor))))
 
 (defn toggle-undo-redo-mode!
   []

src/main/frontend/modules/outliner/pipeline.cljs

@@ -56,8 +56,8 @@
                          (fn [m] (assoc m tx-id editor-cursor)))))
 
 (defn restore-cursor-and-app-state!
-  [{:keys [editor-cursor app-state]}]
-  (history/restore-cursor! editor-cursor)
+  [{:keys [editor-cursor app-state]} undo?]
+  (history/restore-cursor! editor-cursor undo?)
   (history/restore-app-state! app-state))
 
 (defn invoke-hooks
@@ -101,9 +101,11 @@
 
           (when-let [state (:ui/restore-cursor-state @state/state)]
             (when (or undo? redo?)
-              (restore-cursor-and-app-state! state)
+              (restore-cursor-and-app-state! state undo?)
               (state/set-state! :ui/restore-cursor-state nil)))
 
+          (state/set-state! :editor/start-pos nil)
+
           (when (and state/lsp-enabled?
                      (seq blocks)
                      (<= (count blocks) 1000))

src/main/frontend/state.cljs

@@ -117,6 +117,7 @@
 
       :config                                {}
       :block/component-editing-mode?         false
+      :editor/start-pos                      (atom nil)
       :editor/op                             (atom nil)
       :editor/latest-op                      (atom nil)
       :editor/hidden-editors                 #{} ;; page names
@@ -1260,7 +1261,8 @@ Similar to re-frame subscriptions"
     (when container
       {:last-edit-block edit-block
        :container       (gobj/get container "id")
-       :pos             (or (cursor/pos (gdom/getElement edit-input-id))
+       :pos             @(:editor/start-pos @state)
+       :end-pos         (or (cursor/pos (gdom/getElement edit-input-id))
                             (count (:block/content edit-block)))})))
 
 (defn clear-edit!