From fe0d579d565ce9a3312bd17c11dec13d199fd317 Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Thu, 8 Nov 2018 12:06:39 +0100
Subject: [PATCH] Cursor improvements in pad (Beta)

---
 www/common/cursor.js | 26 ++++++++++++++++++++++++++
 www/pad/inner.js     | 17 ++++++++++-------
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/www/common/cursor.js b/www/common/cursor.js
index e72585bb8..b19c02850 100644
--- a/www/common/cursor.js
+++ b/www/common/cursor.js
@@ -124,6 +124,7 @@ define([
 
         cursor.pushDelta = function (oldVal, newVal) {
             if (oldVal === newVal) { return; }
+
             var commonStart = 0;
             while (oldVal.charAt(commonStart) === newVal.charAt(commonStart)) {
                 commonStart++;
@@ -156,6 +157,31 @@ define([
             };
         };
 
+        cursor.transformRange = function (cursorRange, ops) {
+            var transformCursor = function (cursor, op) {
+                if (!op) { return cursor; }
+
+                var pos = op.offset;
+                var remove = op.toRemove;
+                var insert = op.toInsert.length;
+                if (typeof cursor === 'undefined') { return; }
+                if (typeof remove === 'number' && pos < cursor) {
+                    cursor -= Math.min(remove, cursor - pos);
+                }
+                if (typeof insert === 'number' && pos < cursor) {
+                    cursor += insert;
+                }
+                return cursor;
+            };
+            var c = cursorRange.offset;
+            if (Array.isArray(ops)) {
+                for (var i = ops.length - 1; i >= 0; i--) {
+                    c = transformCursor(c, ops[i]);
+                }
+                cursorRange.offset = c;
+            }
+        };
+
         cursor.brFix = function () {
             cursor.update();
             var start = Range.start;
diff --git a/www/pad/inner.js b/www/pad/inner.js
index 7df4b45f9..40f2f5906 100644
--- a/www/pad/inner.js
+++ b/www/pad/inner.js
@@ -318,20 +318,23 @@ define([
 
                 if (!frame) { return; }
 
-                if (typeof info.diff.oldValue === 'string' && typeof info.diff.newValue === 'string') {
-                    var pushes = cursor.pushDelta(info.diff.oldValue, info.diff.newValue);
+                if (frame && typeof info.diff.oldValue === 'string' && typeof info.diff.newValue === 'string') {
+                    //var pushes = cursor.pushDelta(info.diff.oldValue, info.diff.newValue);
+                    var ops = ChainPad.Diff.diff(info.diff.oldValue, info.diff.newValue);
 
                     if (frame & 1) {
                         // push cursor start if necessary
-                        if (pushes.commonStart < cursor.Range.start.offset) {
+                        cursor.transformRange(cursor.Range.start, ops);
+                        /*if (pushes.commonStart < cursor.Range.start.offset) {
                             cursor.Range.start.offset += pushes.delta;
-                        }
+                        }*/
                     }
                     if (frame & 2) {
                         // push cursor end if necessary
-                        if (pushes.commonStart < cursor.Range.end.offset) {
+                        cursor.transformRange(cursor.Range.end, ops);
+                        /*if (pushes.commonStart < cursor.Range.end.offset) {
                             cursor.Range.end.offset += pushes.delta;
-                        }
+                        }*/
                     }
                 }
             },
@@ -698,7 +701,7 @@ define([
         // terminate the test like `test.cancel()`
         window.easyTest = function () {
             cursor.update();
-            var start = cursor.Range.start;
+            //var start = cursor.Range.start;
             //var test = TypingTest.testInput(inner, start.el, start.offset, framework.localChange);
             var test = TypingTest.testInput2(editor);
             framework.localChange();