migrate: riverpod + freezed (#870)

lib/data/provider/virtual_keyboard.dart

@@ -1,56 +1,63 @@
-import 'package:flutter/widgets.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:server_box/data/res/store.dart';
 import 'package:xterm/core.dart';
 
-class VirtKeyProvider extends TerminalInputHandler with ChangeNotifier {
-  VirtKeyProvider();
+part 'virtual_keyboard.g.dart';
+part 'virtual_keyboard.freezed.dart';
 
-  bool _ctrl = false;
-  bool get ctrl => _ctrl;
-  set ctrl(bool value) {
-    if (value != _ctrl) {
-      _ctrl = value;
-      notifyListeners();
+@freezed
+abstract class VirtKeyState with _$VirtKeyState {
+  const factory VirtKeyState({
+    @Default(false) final bool ctrl,
+    @Default(false) final bool alt,
+    @Default(false) final bool shift,
+  }) = _VirtKeyState;
+}
+
+@riverpod
+class VirtKeyboard extends _$VirtKeyboard implements TerminalInputHandler {
+  @override
+  VirtKeyState build() {
+    return const VirtKeyState();
+  }
+
+  bool get ctrl => state.ctrl;
+  bool get alt => state.alt;
+  bool get shift => state.shift;
+
+  void setCtrl(bool value) {
+    if (value != state.ctrl) {
+      state = state.copyWith(ctrl: value);
     }
   }
 
-  bool _alt = false;
-  bool get alt => _alt;
-  set alt(bool value) {
-    if (value != _alt) {
-      _alt = value;
-      notifyListeners();
+  void setAlt(bool value) {
+    if (value != state.alt) {
+      state = state.copyWith(alt: value);
     }
   }
 
-  bool _shift = false;
-  bool get shift => _shift;
-  set shift(bool value) {
-    if (value != _shift) {
-      _shift = value;
-      notifyListeners();
+  void setShift(bool value) {
+    if (value != state.shift) {
+      state = state.copyWith(shift: value);
     }
   }
 
   void reset(TerminalKeyboardEvent e) {
-    if (e.ctrl) {
-      ctrl = false;
-    }
-    if (e.alt) {
-      alt = false;
-    }
-    if (e.shift) {
-      shift = false;
-    }
-    notifyListeners();
+    state = state.copyWith(
+      ctrl: e.ctrl ? false : state.ctrl,
+      alt: e.alt ? false : state.alt,
+      shift: e.shift ? false : state.shift,
+    );
   }
 
   @override
   String? call(TerminalKeyboardEvent event) {
     final e = event.copyWith(
-      ctrl: event.ctrl || ctrl,
-      alt: event.alt || alt,
-      shift: event.shift || shift,
+      ctrl: event.ctrl || state.ctrl,
+      alt: event.alt || state.alt,
+      shift: event.shift || state.shift,
     );
     if (Stores.setting.sshVirtualKeyAutoOff.fetch()) {
       reset(e);