move breadcrumb controller to right dir

port info on server start

app/lib/breadcrumb_page/breadcrumb_controller.dart

@@ -0,0 +1,62 @@
+import 'package:flutter/widgets.dart';
+
+class _BreadCrumbNode {
+  String name;
+  Widget widget;
+  _BreadCrumbNode? next;
+
+  _BreadCrumbNode(this.name, this.widget);
+}
+
+class BreadCrumbController extends ChangeNotifier {
+  final Widget defaultRoute;
+  final String rootName;
+
+  late final _BreadCrumbNode _rootPage =
+      _BreadCrumbNode(rootName, defaultRoute);
+  late Widget _currentpage = _rootPage.widget;
+
+  void pushPage(Widget widget, String name) {
+    _findPage(null, _rootPage).next = _BreadCrumbNode(name, widget);
+    _currentpage = widget;
+    notifyListeners();
+  }
+
+  void switchPage(String name) {
+    final pageNode = _findPage(name, _rootPage);
+    _currentpage = pageNode.widget;
+    // hope for garbage collector to free the floating items (;
+    pageNode.next = null;
+    notifyListeners();
+  }
+
+  List<String> getNames() {
+    return _genNameList(_rootPage);
+  }
+
+  Widget getCurrentPage() {
+    return _currentpage;
+  }
+
+  _BreadCrumbNode _findPage(String? name, _BreadCrumbNode node) {
+    if (node.name == name) {
+      return node;
+    }
+
+    if (node.next != null) {
+      return _findPage(name, node.next!);
+    } else {
+      return node;
+    }
+  }
+
+  List<String> _genNameList(_BreadCrumbNode node) {
+    if (node.next != null) {
+      return _genNameList(node.next!)..insert(0, node.name);
+    } else {
+      return [node.name];
+    }
+  }
+
+  BreadCrumbController(this.defaultRoute, this.rootName);
+}

app/lib/breadcrumb_page/breadcrumb_page.dart

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_breadcrumb/flutter_breadcrumb.dart';
 import 'package:provider/provider.dart';
 
-import '../breadcrumb_controller.dart';
+import 'breadcrumb_controller.dart';
 
 class BreadCrumbPage extends StatefulWidget {
   const BreadCrumbPage(