sinoMedCloud/lib/app/app.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:sino_med_cloud/core/network/network_provider.dart';
import 'package:sino_med_cloud/l10n/app_localizations.dart';
import '../core/constants/app_enum.dart';
import 'router.dart';
import 'theme.dart';

class SinoMedApp extends ConsumerStatefulWidget {
  const SinoMedApp({super.key});

  @override
  ConsumerState<SinoMedApp> createState() => _SinoMedAppState();
}

class _SinoMedAppState extends ConsumerState<SinoMedApp> {
  @override
  Widget build(BuildContext context) {
    // 监听网络状态变化并自动导航
    // ref.listen 必须在 build 方法中使用
    ref.listen(networkStatusProvider, (previous, next) {
      next.whenData((status) {
        final router = AppRouter.router;
        try {
          // 获取当前路由路径
          // 注意：如果 router 还没准备好，这里可能会报错，所以加了 try-catch
          final matchList = router.routerDelegate.currentConfiguration.matches;
          final currentLocation = matchList.isNotEmpty 
              ? matchList.last.matchedLocation 
              : router.routerDelegate.currentConfiguration.uri.path;
          
          // 判断网络是否正常（WiFi 和移动网络都视为正常）
          final isNetworkAvailable = status == NetworkStatus.wifi || status == NetworkStatus.mobile;
          
          if (isNetworkAvailable) {
            // 网络正常：如果当前在无网络页面，则返回到之前保存的页面
            if (currentLocation == '/noNetwork') {
              final previousPath = ref.read(previousPagePathProvider);
              final targetPath = previousPath ?? '/'; // 如果没有保存的页面，则返回登录页
              
              // 使用 addPostFrameCallback 避免在构建过程中导航
              WidgetsBinding.instance.addPostFrameCallback((_) {
                if (mounted) {
                  router.go(targetPath);
                  // 清除保存的页面路径
                  ref.read(previousPagePathProvider.notifier).state = null;
                }
              });
            }
            // 如果网络正常且不在无网络页面，则停留在当前页面
          } else {
            // 网络不正常（无网络）：保存当前页面并导航到无网络页面
            if (currentLocation != '/noNetwork') {
              // 保存当前页面路径（如果当前不在无网络页面）
              ref.read(previousPagePathProvider.notifier).state = currentLocation;
              
              WidgetsBinding.instance.addPostFrameCallback((_) {
                if (mounted) {
                  router.go('/noNetwork');
                }
              });
            }
          }
        } catch (e) {
          // 如果无法获取当前路由，根据网络状态直接处理
          final isNetworkAvailable = status == NetworkStatus.wifi || status == NetworkStatus.mobile;
          if (!isNetworkAvailable) {
            WidgetsBinding.instance.addPostFrameCallback((_) {
              if (mounted) {
                router.go('/noNetwork');
              }
            });
          }
        }
      });
    });

    final networkAsync = ref.watch(networkStatusProvider);

    return networkAsync.when(
      loading: () {
        // Loading 状态显示加载指示器
        return const MaterialApp(
          debugShowCheckedModeBanner: false,
          home: Scaffold(
            body: Center(child: CircularProgressIndicator()),
          ),
        );
      },
      error: (error, _) {
        return _materialApp;
      },
      data: (_) {
        return _materialApp;
      },
    );
  }

  MaterialApp get _materialApp => MaterialApp.router(
    onGenerateTitle: (context) => AppLocalizations.of(context)?.appSubtitle ?? '中方诊药云',
    theme: AppTheme.light,
    routerConfig: AppRouter.router,
    debugShowCheckedModeBanner: false,
    localizationsDelegates: AppLocalizations.localizationsDelegates,
    supportedLocales: AppLocalizations.supportedLocales,
    locale: const Locale('zh'),
  );
}