import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

/// 页面覆盖导航栏返回按钮的 Provider。
/// 页面在 build 中设置：`ref.read(pageBackProvider.notifier).state = () => _doPop();`
final pageBackProvider = StateProvider<VoidCallback?>((ref) => null);

/// NavBar 配置——纯数据类，由路由层在 AppScaffold.navConfig 中声明式传入。
///
/// 不再需要 Provider 中转：AppScaffold 直接消费，同步渲染，无延迟。
class NavBarConfig {
  final String title;
  final bool showBack;
  final bool showRight;
  final Widget? rightWidget;
  final VoidCallback? onBack;
  final IconData? leadingIcon;

  const NavBarConfig({
    this.title = '',
    this.showBack = false,
    this.showRight = false,
    this.rightWidget,
    this.onBack,
    this.leadingIcon,
  });

  /// 根页面默认配置（无返回按钮）
  static const home = NavBarConfig(title: '', showBack: false);
  static const messages = NavBarConfig(title: '', showBack: false);
  static const profile = NavBarConfig(title: '', showBack: false);
}