import 'package:flutter/material.dart';

/// 认证页统一框架：SafeArea + 滚动 + 水平 padding 24 + 键盘避让（设计规范 §6.2）。
///
/// 登录 / 注册 / 找回密码共用。[appBar] 供注册页传入透明返回栏；
/// 键盘弹出时内容可滚动，防止溢出。
class AuthScaffold extends StatelessWidget {
  const AuthScaffold({required this.child, super.key, this.appBar});

  final Widget child;
  final PreferredSizeWidget? appBar;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: appBar,
      body: SafeArea(
        child: LayoutBuilder(
          builder: (context, constraints) {
            return SingleChildScrollView(
              padding: const EdgeInsets.symmetric(horizontal: 24),
              child: ConstrainedBox(
                constraints: BoxConstraints(minHeight: constraints.maxHeight),
                child: child,
              ),
            );
          },
        ),
      ),
    );
  }
}