enhance: undo redo use patches instead of full text

src/main/frontend/diff.cljs

@@ -1,15 +1,34 @@
 (ns frontend.diff
   (:require [clojure.string :as string]
             ["diff" :as jsdiff]
+            ["diff-match-patch" :as diff-match-patch]
             [goog.object :as gobj]
             [lambdaisland.glogi :as log]
             [cljs-bean.core :as bean]))
 
+;; TODO: replace with diff-match-patch
 (defn diff
   [s1 s2]
   (-> ((gobj/get jsdiff "diffLines") s1 s2)
       bean/->clj))
 
+(defonce dmp (diff-match-patch.))
+
+(defn diffs
+  [s1 s2]
+  (.diff_main dmp s1 s2 true))
+
+(defn get-patches
+  [s1 s2 diffs]
+  (.patch_make dmp s1 s2 diffs))
+
+(defn apply-patches!
+  [text patches]
+  (if (seq patches)
+    (let [result (.patch_apply dmp patches text)]
+      (nth result 0))
+    text))
+
 ;; (find-position "** hello _w_" "hello w")
 (defn find-position
   [markup text]
@@ -32,6 +51,6 @@
 
           :else
           (recur r1 t2 (inc i1) i2))))
-      (catch js/Error e
-        (log/error :diff/find-position {:error e})
-        (count markup))))
+    (catch js/Error e
+      (log/error :diff/find-position {:error e})
+      (count markup))))