Provide an accessor for the form widget of the Settings controller (#5212)

Co-authored-by: Luke Towers <github@luketowers.ca>

modules/system/controllers/Settings.php

@@ -2,6 +2,8 @@
 
 use Lang;
 use Flash;
+use Config;
+use Request;
 use Backend;
 use BackendMenu;
 use System\Classes\SettingsManager;
@@ -139,6 +141,22 @@ class Settings extends Controller
         return $this->formWidget->render($options);
     }
 
+    /**
+     * Returns the form widget used by this behavior.
+     *
+     * @return \Backend\Widgets\Form
+     */
+    public function formGetWidget()
+    {
+        if (is_null($this->formWidget)) {
+            $item = $this->findSettingItem();
+            $model = $this->createModel($item);
+            $this->initWidgets($model);
+        }
+
+        return $this->formWidget;
+    }
+
     /**
      * Prepare the widgets used by this action
      * Model $model
@@ -169,10 +187,22 @@ class Settings extends Controller
     }
 
     /**
-     * Locates a setting item for a module or plugin
+     * Locates a setting item for a module or plugin.
+     *
+     * If none of the parameters are provided, they will be auto-guessed from the URL.
+     *
+     * @param string|null $author
+     * @param string|null $plugin
+     * @param string|null $code
+     *
+     * @return array
      */
-    protected function findSettingItem($author, $plugin, $code)
+    protected function findSettingItem($author = null, $plugin = null, $code = null)
     {
+        if (is_null($author) || is_null($plugin)) {
+            [$author, $plugin, $code] = $this->guessSettingItem();
+        }
+
         $manager = SettingsManager::instance();
 
         $moduleOwner = $author;
@@ -187,4 +217,23 @@ class Settings extends Controller
 
         return $item;
     }
+
+    /**
+     * Guesses the requested setting item from the current URL segments provided by the Request object.
+     *
+     * @return array
+     */
+    protected function guessSettingItem()
+    {
+        $segments = Request::segments();
+
+        if (!empty(Config::get('cms.backendUri', 'backend'))) {
+            array_splice($segments, 0, 4);
+        } else {
+            array_splice($segments, 0, 3);
+        }
+
+        // Ensure there's at least 3 segments
+        return array_pad($segments, 3, null);
+    }
 }