Coverted part of the "variable" plugin

app/code/core/Mage/Adminhtml/Block/Cms/Block/Edit.php

@@ -40,7 +40,7 @@ public function __construct()
         $this->_formScripts[] = "
             function toggleEditor() {
                 if (tinymce.get('block_content') === null) {
-                    tinymce.init({selector: 'textarea#block_content', branding: false, promotion: false, plugins: 'lists advlist directionality image link media nonbreaking preview quickbars'});
+                    tinymce.init({selector: 'textarea#block_content', branding: false, promotion: false, plugins: 'lists advlist directionality image link media nonbreaking preview quickbars openmagevariable'});
                 } else {
                     tinymce.get('block_content').remove();
                 }

app/code/core/Mage/Adminhtml/Block/Cms/Page/Edit.php

@@ -106,7 +106,7 @@ protected function _prepareLayout()
         $this->_formScripts[] = "
             function toggleEditor() {
                 if (tinymce.get('page_content') === null) {
-                    tinymce.init({selector: 'textarea#page_content', branding: false, promotion: false, plugins: 'lists advlist directionality image link media nonbreaking preview quickbars'});
+                    tinymce.init({selector: 'textarea#page_content', branding: false, promotion: false, plugins: 'lists advlist directionality image link media nonbreaking preview quickbars openmagevariable'});
                 } else {
                     tinymce.get('page_content').remove();
                 }

app/code/core/Mage/Core/Model/Variable/Config.php

@@ -34,7 +34,7 @@ public function getWysiwygPluginSettings($config)
             'search' => ['html_id'],
             'subject' => 'MagentovariablePlugin.loadChooser(\'' . $this->getVariablesWysiwygActionUrl() . '\', \'{{html_id}}\');'
         ];
-        $variableWysiwygPlugin = [['name' => 'magentovariable',
+        $variableWysiwygPlugin = [['name' => 'openmagevariable',
             'src' => $this->getWysiwygJsPluginSrc(),
             'options' => [
                 'title' => Mage::helper('adminhtml')->__('Insert Variable...'),
@@ -54,7 +54,7 @@ public function getWysiwygPluginSettings($config)
      */
     public function getWysiwygJsPluginSrc()
     {
-        return Mage::getBaseUrl('js') . 'mage/adminhtml/wysiwyg/tiny_mce/plugins/magentovariable/editor_plugin.js';
+        return Mage::getBaseUrl('js') . 'mage/adminhtml/wysiwyg/tiny_mce/plugins/openmagevariable/editor_plugin.js';
     }
 
     /**

app/code/core/Mage/Widget/Model/Widget/Config.php

@@ -30,7 +30,7 @@ class Mage_Widget_Model_Widget_Config extends Varien_Object
     public function getPluginSettings($config)
     {
         return [
-            'widget_plugin_src'   => Mage::getBaseUrl('js') . 'mage/adminhtml/wysiwyg/tiny_mce/plugins/magentowidget/editor_plugin.js',
+            'widget_plugin_src'   => Mage::getBaseUrl('js') . 'mage/adminhtml/wysiwyg/tiny_mce/plugins/openmagewidget/editor_plugin.js',
             'widget_images_url'   => $this->getPlaceholderImagesBaseUrl(),
             'widget_placeholders' => $this->getAvailablePlaceholderFilenames(),
             'widget_window_url'   => $this->getWidgetWindowUrl($config)

js/mage/adminhtml/wysiwyg/tiny_mce/plugins/magentovariable/editor_plugin.js → js/mage/adminhtml/wysiwyg/tinymce/plugins/openmagevariable/editor_plugin.js

@@ -12,18 +12,16 @@
  * @license     https://opensource.org/licenses/afl-3.0.php  Academic Free License (AFL 3.0)
  */
 
-tinymce.PluginManager.add('OpenMageVariablePlugin', (ed, url) => {
-    ed.addCommand('mceMagentovariable', function() {
-        var pluginSettings = ed.settings.magentoPluginsOptions.get('magentovariable');
-        MagentovariablePlugin.setEditor(ed);
-        MagentovariablePlugin.loadChooser(pluginSettings.url, null);
-    });
-
-    // Register Widget plugin button
-    ed.addButton('magentovariable', {
-        title : 'magentovariable.insert_variable',
-        cmd : 'mceMagentovariable',
-        image : url + '/img/icon.gif'
+tinymce.PluginManager.add('openmagevariable', (ed, url) => {
+    //TODO: the button doesn't show on the toolbar
+    ed.ui.registry.addButton('openmagevariable', {
+        text: 'Insert Variable',
+        onAction: () => {
+            //TODO: the code of this method needs to be converted to tinymce6
+            var pluginSettings = ed.settings.magentoPluginsOptions.get('openmagevariable');
+            openmagevariable.setEditor(ed);
+            openmagevariable.loadChooser(pluginSettings.url, null);
+        }
     });
 
     return {

js/mage/adminhtml/wysiwyg/tiny_mce/plugins/magentowidget/editor_plugin.js → js/mage/adminhtml/wysiwyg/tinymce/plugins/openmagewidget/editor_plugin.js

@@ -12,7 +12,7 @@
  * @license     https://opensource.org/licenses/afl-3.0.php  Academic Free License (AFL 3.0)
  */
 
-tinymce.PluginManager.add('OpenMageWidgetPlugin', (ed, url) => {
+tinymce.PluginManager.add('openmagewidget', (ed, url) => {
     ed.addCommand('mceMagentowidget', function() {
         widgetTools.openDialog(ed.settings.magentowidget_url + 'widget_target_id/' + ed.getElement().id + '/');
     });