school-attendance/lib/main_client_app.dart

// 🚪 앱 진입점. Firebase/백그라운드 감시 서비스 초기화 후 로그인 화면으로 시작한다.
// 실제 화면 구현은 lib/screens/ 폴더, 공통 설정은 lib/config.dart 참고.
import 'dart:io';
import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';
import 'config.dart';
import 'function/session_store.dart';
import 'pocket_watch_service.dart';
import 'theme/app_palette.dart';
import 'ui/login_screen.dart';
import 'ui/main_dashboard.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
  await printFCMToken();
  if (!kIsWeb && Platform.isAndroid) {
    await initializePocketWatchService();
  }
  runApp(const SchoolAttendanceApp());
}

class SchoolAttendanceApp extends StatelessWidget {
  const SchoolAttendanceApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: '$schoolName 학생 도우미',
      theme: ThemeData(
        useMaterial3: true,
        scaffoldBackgroundColor: AppPalette.mist,
        colorScheme:
            ColorScheme.fromSeed(
              seedColor: AppPalette.ink,
              brightness: Brightness.light,
            ).copyWith(
              primary: AppPalette.ink,
              onPrimary: AppPalette.paper,
              secondary: AppPalette.ink,
              onSecondary: AppPalette.paper,
              surface: AppPalette.paper,
              onSurface: AppPalette.ink,
            ),
      ),
      home: const _StartupGate(), // 🚪 저장된 로그인이 있으면 대시보드로, 없으면 로그인 화면으로.
    );
  }
}

/// 🔐 "로그인 유지" 진입점. 기기에 저장된 세션이 있는지 확인하는 동안 잠깐 로딩을 보여주고,
/// 있으면 로그인 화면 없이 바로 대시보드로, 없으면 로그인 화면으로 보낸다.
class _StartupGate extends StatefulWidget {
  const _StartupGate();

  @override
  State<_StartupGate> createState() => _StartupGateState();
}

class _StartupGateState extends State<_StartupGate> {
  SavedSession? _session;
  bool _checked = false;

  @override
  void initState() {
    super.initState();
    _checkSession();
  }

  Future<void> _checkSession() async {
    final session = await SessionStore.load();
    if (!mounted) return;
    setState(() {
      _session = session;
      _checked = true;
    });
  }

  @override
  Widget build(BuildContext context) {
    if (!_checked) {
      return Scaffold(
        backgroundColor: AppPalette.mist,
        body: const Center(child: CircularProgressIndicator()),
      );
    }
    final session = _session;
    if (session != null) {
      return MainDashboard(
        userId: session.userId,
        userName: session.userName,
        role: session.role,
        isDeviceMatched: session.isDeviceMatched,
      );
    }
    return const LoginScreen();
  }
}