Overwrite undo history

app/assets/javascripts/lib/text_utility.js.coffee

@@ -3,11 +3,14 @@
   w.gl.text ?= {}
   w.gl.text.undoManager ?= {}
 
+  gl.text.randomString = -> Math.random().toString(36).substring(7)
+
   gl.text.replaceRange = (s, start, end, substitute) ->
     s.substring(0, start) + substitute + s.substring(end);
 
   gl.text.wrap = (textArea, tag) ->
     $textArea = $(textArea)
+    oldVal = $textArea.val()
     $textArea.focus()
     textArea = $textArea.get(0)
     selObj = window.getSelection()
@@ -18,10 +21,12 @@
         textArea.selectionStart,
         textArea.selectionEnd,
         (tag+selObj.toString()+tag))
-    $textArea.data('old-val', text).val(replaceWith);
+    $textArea.data('old-val', text).val(replaceWith)
+    gl.text.undoManager.addUndo(oldVal, $textArea.val())
 
   gl.text.prepend = (textArea, tag) ->
     $textArea = $(textArea)
+    oldVal = $textArea.val()
     $textArea.focus()
     textArea = $textArea.get(0)
     selObj = window.getSelection()
@@ -36,12 +41,45 @@
       ("#{lineBreak}#{tag} #{selObj.toString()} \n")
     )
     $textArea.data('old-val', text).val(replaceWith);
-    # $textArea.val(replaceWith)
+    gl.text.undoManager.addUndo(oldVal, $textArea.val())
+
+  gl.text.undoManager.history = {}
+  gl.text.undoManager.undoHistory = {}
+
+  gl.text.undoManager.addUniqueIfNotExists = ($ta) ->
+    unique = $ta.attr('data-unique')
+    if not unique?
+      unique = gl.text.randomString()
+      $ta.attr('data-unique', unique)
+      gl.text.undoManager.history[unique] = []
+      gl.text.undoManager.undoHistory[unique] = []
+    unique
+
+  gl.text.undoManager.addUndo = (oldVal, newVal) ->
+    $thisTextarea = $('textarea:focus')
+    unique = gl.text.undoManager.addUniqueIfNotExists($thisTextarea)
+    gl.text.undoManager.history[unique].push({
+      oldVal: oldVal,
+      newVal: newVal
+    })
 
   gl.text.undoManager.undo = () ->
+    $thisTextarea = $('textarea:focus')
+    unique = gl.text.undoManager.addUniqueIfNotExists($thisTextarea)
+    if not gl.text.undoManager.history[unique].length
+      return
+    latestChange = gl.text.undoManager.history[unique].pop()
+    gl.text.undoManager.undoHistory[unique].push(latestChange)
+    $thisTextarea.val(latestChange.oldVal)
 
+  gl.text.undoManager.redo = () ->
+    $thisTextarea = $('textarea:focus')
+    unique = gl.text.undoManager.addUniqueIfNotExists($thisTextarea)
+    if not gl.text.undoManager.undoHistory[unique].length
+      return
 
   gl.text.addListeners = () ->
+    console.log('addListeners')
     self = @
     $('.js-md').on 'click', ->
       $this = $(@)
@@ -61,12 +99,14 @@
           $this.data('md-tag')
         )
 
-    $(window).on 'keydown', (e) ->
+    $(window).on 'keydown', (e) =>
       if e.ctrlKey or e.metaKey
         if String.fromCharCode(e.which).toLowerCase() is 'z' and !e.shiftKey
           e.preventDefault()
+          self.undoManager.undo()
         else if ((String.fromCharCode(e.which).toLowerCase() is 'z' and e.shiftKey) or (String.fromCharCode(e.which).toLowerCase() is 'y'))
           e.preventDefault()
+          self.undoManager.redo()
 
   gl.text.removeListeners = () ->
     $('js-md.btn-bold').off()

app/views/projects/issues/_discussion.html.haml

@@ -5,3 +5,9 @@
 
 #notes
   = render 'projects/notes/notes_with_form'
+
+:javascript
+  $(function(){
+    gl.text.removeListeners();
+    gl.text.addListeners();
+  })
\ No newline at end of file