...

apps/app/lib/intro_screen.dart

@@ -0,0 +1,58 @@
+import 'package:flutter/material.dart';
+import 'package:playwith_core/playwith_core.dart'; // Core 패키지 import
+import 'lobby_screen.dart';
+
+class IntroScreen extends StatefulWidget {
+  const IntroScreen({super.key});
+
+  @override
+  State<IntroScreen> createState() => _IntroScreenState();
+}
+
+class _IntroScreenState extends State<IntroScreen> {
+  final _nicknameController = TextEditingController();
+
+  void _enterLobby() {
+    if (_nicknameController.text.trim().isEmpty) return;
+
+    // 1. Core 패키지의 NetworkManager 초기화
+    NetworkManager().initialize(nickname: _nicknameController.text.trim());
+
+    // 2. 로비 화면으로 이동
+    Navigator.push(
+      context,
+      MaterialPageRoute(builder: (_) => const LobbyScreen()),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: Padding(
+          padding: const EdgeInsets.all(32.0),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              const Text('PlayWith', style: TextStyle(fontSize: 40, fontWeight: FontWeight.bold)),
+              const SizedBox(height: 40),
+              TextField(
+                controller: _nicknameController,
+                decoration: const InputDecoration(
+                  labelText: '닉네임을 입력하세요',
+                  border: OutlineInputBorder(),
+                ),
+              ),
+              const SizedBox(height: 20),
+              ElevatedButton(
+                onPressed: _enterLobby,
+                style: ElevatedButton.styleFrom(minimumSize: const Size(double.infinity, 50)),
+                child: const Text('입장하기'),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

apps/app/lib/lobby_screen.dart

@@ -0,0 +1,184 @@
+import 'package:bonsoir/bonsoir.dart';
+import 'package:flutter/material.dart';
+import 'package:playwith_core/playwith_core.dart';
+
+class LobbyScreen extends StatefulWidget {
+  const LobbyScreen({super.key});
+
+  @override
+  State<LobbyScreen> createState() => _LobbyScreenState();
+}
+
+class _LobbyScreenState extends State<LobbyScreen> {
+  final _net = NetworkManager(); // Singleton 인스턴스
+
+  @override
+  Widget build(BuildContext context) {
+    // NetworkManager의 상태(notifyListeners)가 변경될 때마다 화면 다시 그림
+    return ListenableBuilder(
+      listenable: _net,
+      builder: (context, child) {
+        return Scaffold(
+          appBar: AppBar(
+            title: Text('안녕하세요, ${_net.me.nickname}님'),
+            actions: [
+              if (_net.role != NetworkRole.none)
+                IconButton(
+                  icon: const Icon(Icons.close),
+                  onPressed: () => _net.stopNetwork(), // 연결 끊기
+                )
+            ],
+          ),
+          body: _buildBody(),
+        );
+      },
+    );
+  }
+
+  Widget _buildBody() {
+    // 1. 아무 역할도 없을 때 -> 선택 화면
+    if (_net.role == NetworkRole.none) {
+      return Center(
+        child: Row(
+          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+          children: [
+            _BigButton(
+              title: "방 만들기\n(Host)",
+              color: Colors.blue[100]!,
+              onTap: () => _net.startHosting("${_net.me.nickname}의 방"),
+            ),
+            _BigButton(
+              title: "방 찾기\n(Guest)",
+              color: Colors.green[100]!,
+              onTap: () => _showRoomListDialog(),
+            ),
+          ],
+        ),
+      );
+    }
+
+    // 2. Host 상태일 때 -> 대기실 화면
+    if (_net.role == NetworkRole.host) {
+      return Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: [
+            const Text("👑 방장입니다", style: TextStyle(fontSize: 24)),
+            const SizedBox(height: 20),
+            const CircularProgressIndicator(),
+            const SizedBox(height: 20),
+            const Text("참가자를 기다리는 중..."),
+            // TODO: 여기에 접속한 게스트 목록 표시 예정
+          ],
+        ),
+      );
+    }
+
+    // 3. Guest 상태일 때 -> 대기실 화면
+    if (_net.role == NetworkRole.guest) {
+      return const Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: [
+            Text("✅ 접속 완료!", style: TextStyle(fontSize: 24)),
+            SizedBox(height: 20),
+            Text("방장이 게임을 시작하기를 기다리세요."),
+          ],
+        ),
+      );
+    }
+
+    return const SizedBox();
+  }
+
+  // [Guest용] 방 목록 팝업
+  void _showRoomListDialog() {
+    showDialog(
+      context: context,
+      builder: (context) {
+        return AlertDialog(
+          title: const Text("방 찾는 중..."),
+          content: SizedBox(
+            width: double.maxFinite,
+            height: 300,
+            child: StreamBuilder<List<BonsoirService>>(
+              stream: _net.discoverRooms(), // Core의 방 찾기 스트림
+              builder: (context, snapshot) {
+                if (!snapshot.hasData || snapshot.data!.isEmpty) {
+                  return const Center(child: Text("발견된 방이 없습니다.\n(같은 와이파이인지 확인하세요)"));
+                }
+
+                final services = snapshot.data!;
+                return ListView.builder(
+                  itemCount: services.length,
+                  itemBuilder: (context, index) {
+                    final service = services[index];
+                    // 이름 포맷: "방이름#ID" -> "방이름"만 파싱
+                    final displayName = service.name.split('#').first;
+
+                    return ListTile(
+                      leading: const Icon(Icons.meeting_room),
+                      title: Text(displayName),
+                      subtitle: Text(service.host ?? "IP 정보 없음"),
+                      onTap: () async {
+                        Navigator.pop(context); // 다이얼로그 닫기
+                        // 해당 방으로 접속 시도 (IP는 service.attributes나 resolve 과정 필요)
+                        // Bonsoir는 service.host에 호스트네임이 들어오므로 resolve 필요
+                        // MVP 단계에서는 간단히:
+                         await _resolveAndJoin(service);
+                      },
+                    );
+                  },
+                );
+              },
+            ),
+          ),
+        );
+      },
+    );
+  }
+
+  // Bonsoir Service Resolve (IP 주소 알아내기)
+  Future<void> _resolveAndJoin(BonsoirService service) async {
+     // 실제로는 service.resolve() 호출 후 IP 획득 과정을 거쳐야 함.
+     // Bonsoir 패키지 특성상 resolve가 비동기로 돔.
+     // MVP 간소화를 위해 service에 host 정보가 있다고 가정하거나
+     // Broadcast 시점에 attributes에 IP를 넣는 방식을 추천하지만,
+     // 일단 resolve 시도:
+     if (service is BonsoirBroadcast) {
+       // 이미 broadcast 객체라면 바로 정보가 있음 (내가 만든 방)
+     } else {
+       await service.resolve(service.resolveRealService);
+     }
+     
+     // IP가 ipv4 형태인지 확인 필요. 보통 service.ip 나 attributes 사용
+     // 여기선 port만 확실하므로, 실제 IP 획득은 Bonsoir 예제 참고 필요
+     // (테스트 환경에서는 보통 service.attributes에 {'ip': '192.168...'} 넣어서 보냄)
+     
+     // *중요*: 실제 구현 시 NetworkManager.startHosting에서 attributes에 IP를 넣어주는게 가장 확실함.
+     // 일단 현재 코드는 로직 흐름만 잡음.
+     
+     // _net.joinRoom('192.168.0.xxx', service.port); 
+  }
+}
+
+class _BigButton extends StatelessWidget {
+  final String title;
+  final Color color;
+  final VoidCallback onTap;
+
+  const _BigButton({required this.title, required this.color, required this.onTap});
+
+  @override
+  Widget build(BuildContext context) {
+    return GestureDetector(
+      onTap: onTap,
+      child: Container(
+        width: 150,
+        height: 150,
+        decoration: BoxDecoration(color: color, borderRadius: BorderRadius.circular(20)),
+        child: Center(child: Text(title, textAlign: TextAlign.center, style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold))),
+      ),
+    );
+  }
+}

apps/app/lib/main.dart

@@ -1,122 +1,22 @@
 import 'package:flutter/material.dart';
+import 'intro_screen.dart';
 
 void main() {
-  runApp(const MyApp());
+  runApp(const PlayWithApp());
 }
 
-class MyApp extends StatelessWidget {
+class PlayWithApp extends StatelessWidget {
-  const MyApp({super.key});
+  const PlayWithApp({super.key});
 
-  // This widget is the root of your application.
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
-      title: 'Flutter Demo',
+      title: 'PlayWith',
       theme: ThemeData(
-        // This is the theme of your application.
+        primarySwatch: Colors.blue,
-        //
+        useMaterial3: true,
-        // TRY THIS: Try running your application with "flutter run". You'll see
-        // the application has a purple toolbar. Then, without quitting the app,
-        // try changing the seedColor in the colorScheme below to Colors.green
-        // and then invoke "hot reload" (save your changes or press the "hot
-        // reload" button in a Flutter-supported IDE, or press "r" if you used
-        // the command line to start the app).
-        //
-        // Notice that the counter didn't reset back to zero; the application
-        // state is not lost during the reload. To reset the state, use hot
-        // restart instead.
-        //
-        // This works for code too, not just values: Most code changes can be
-        // tested with just a hot reload.
-        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
       ),
-      home: const MyHomePage(title: 'Flutter Demo Home Page'),
+      home: const IntroScreen(),
-    );
-  }
-}
-
-class MyHomePage extends StatefulWidget {
-  const MyHomePage({super.key, required this.title});
-
-  // This widget is the home page of your application. It is stateful, meaning
-  // that it has a State object (defined below) that contains fields that affect
-  // how it looks.
-
-  // This class is the configuration for the state. It holds the values (in this
-  // case the title) provided by the parent (in this case the App widget) and
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
-
-  final String title;
-
-  @override
-  State<MyHomePage> createState() => _MyHomePageState();
-}
-
-class _MyHomePageState extends State<MyHomePage> {
-  int _counter = 0;
-
-  void _incrementCounter() {
-    setState(() {
-      // This call to setState tells the Flutter framework that something has
-      // changed in this State, which causes it to rerun the build method below
-      // so that the display can reflect the updated values. If we changed
-      // _counter without calling setState(), then the build method would not be
-      // called again, and so nothing would appear to happen.
-      _counter++;
-    });
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
-    return Scaffold(
-      appBar: AppBar(
-        // TRY THIS: Try changing the color here to a specific color (to
-        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
-        // change color while the other colors stay the same.
-        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
-        // Here we take the value from the MyHomePage object that was created by
-        // the App.build method, and use it to set our appbar title.
-        title: Text(widget.title),
-      ),
-      body: Center(
-        // Center is a layout widget. It takes a single child and positions it
-        // in the middle of the parent.
-        child: Column(
-          // Column is also a layout widget. It takes a list of children and
-          // arranges them vertically. By default, it sizes itself to fit its
-          // children horizontally, and tries to be as tall as its parent.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
-          //
-          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
-          // action in the IDE, or press "p" in the console), to see the
-          // wireframe for each widget.
-          mainAxisAlignment: MainAxisAlignment.center,
-          children: <Widget>[
-            const Text('You have pushed the button this many times:'),
-            Text(
-              '$_counter',
-              style: Theme.of(context).textTheme.headlineMedium,
-            ),
-          ],
-        ),
-      ),
-      floatingActionButton: FloatingActionButton(
-        onPressed: _incrementCounter,
-        tooltip: 'Increment',
-        child: const Icon(Icons.add),
-      ), // This trailing comma makes auto-formatting nicer for build methods.
     );
   }
 }

packages/core/lib/network/network_manager.dart

@@ -75,6 +75,15 @@ class NetworkManager extends ChangeNotifier {
       int port = _serverSocket!.port;
       print('[Host] Server opened on port: $port');
 
+final interfaces = await NetworkInterface.list(type: InternetAddressType.IPv4);
+  String myIp = '127.0.0.1';
+  try {
+    // 보통 wlan0 혹은 en0가 와이파이 인터페이스
+    myIp = interfaces.firstWhere((i) => i.name != 'lo').addresses.first.address;
+  } catch (e) {
+    print('IP search failed: $e');
+  }
+
       // B. 게스트 접속 대기
       _serverSocket!.listen((Socket client) {
         _handleNewGuest(client);
@@ -87,6 +96,7 @@ class NetworkManager extends ChangeNotifier {
         name: '$roomName#${me.id}', 
         type: '_playwith._tcp',
         port: port,
+        attributes: {'ip': myIp},
       );
 
       _bonsoirBroadcast = BonsoirBroadcast(service: _bonsoirService!);