Phase 2 scaffold: mitra online status & pairing logic

Add mitra online/offline status with heartbeat-based auto-offline,
customer-mitra pairing via Valkey pub/sub blast, session management,
and control center dashboard with real-time stats.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client_app/lib/core/api/api_client.dart

@@ -2,7 +2,7 @@ import 'package:dio/dio.dart';
 import 'package:firebase_auth/firebase_auth.dart';
 
 class ApiClient {
-  static const String _baseUrl = String.fromEnvironment(
+  static const String baseUrl = String.fromEnvironment(
     'API_BASE_URL',
     defaultValue: 'https://api.halobestie.com',
   );
@@ -10,7 +10,7 @@ class ApiClient {
   late final Dio _dio;
 
   ApiClient() {
-    _dio = Dio(BaseOptions(baseUrl: _baseUrl));
+    _dio = Dio(BaseOptions(baseUrl: baseUrl));
     _dio.interceptors.add(InterceptorsWrapper(
       onRequest: (options, handler) async {
         final user = FirebaseAuth.instance.currentUser;

client_app/lib/core/pairing/pairing_bloc.dart

@@ -0,0 +1,173 @@
+import 'dart:async';
+import 'dart:convert';
+import 'package:dio/dio.dart';
+import 'package:equatable/equatable.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import '../api/api_client.dart';
+
+// Events
+abstract class PairingEvent extends Equatable {
+  @override
+  List<Object?> get props => [];
+}
+
+class RequestPairing extends PairingEvent {}
+class CancelPairing extends PairingEvent {}
+
+class _PairingStatusUpdate extends PairingEvent {
+  final Map<String, dynamic> data;
+  _PairingStatusUpdate(this.data);
+  @override
+  List<Object?> get props => [data];
+}
+
+class _PairingTimeout extends PairingEvent {}
+
+// States
+abstract class PairingState extends Equatable {
+  @override
+  List<Object?> get props => [];
+}
+
+class PairingInitial extends PairingState {}
+class PairingSearching extends PairingState {
+  final String sessionId;
+  PairingSearching(this.sessionId);
+  @override
+  List<Object?> get props => [sessionId];
+}
+
+class PairingBestieFound extends PairingState {
+  final String sessionId;
+  final String mitraName;
+  PairingBestieFound({required this.sessionId, required this.mitraName});
+  @override
+  List<Object?> get props => [sessionId, mitraName];
+}
+
+class PairingActive extends PairingState {
+  final String sessionId;
+  final String mitraName;
+  PairingActive({required this.sessionId, required this.mitraName});
+  @override
+  List<Object?> get props => [sessionId, mitraName];
+}
+
+class PairingNoBestie extends PairingState {}
+class PairingCancelled extends PairingState {}
+
+class PairingError extends PairingState {
+  final String message;
+  PairingError(this.message);
+  @override
+  List<Object?> get props => [message];
+}
+
+// Bloc
+class PairingBloc extends Bloc<PairingEvent, PairingState> {
+  final ApiClient apiClient;
+  Timer? _timeoutTimer;
+  StreamSubscription? _sseSubscription;
+
+  PairingBloc({required this.apiClient}) : super(PairingInitial()) {
+    on<RequestPairing>(_onRequestPairing);
+    on<CancelPairing>(_onCancelPairing);
+    on<_PairingStatusUpdate>(_onStatusUpdate);
+    on<_PairingTimeout>(_onTimeout);
+  }
+
+  Future<void> _onRequestPairing(RequestPairing event, Emitter<PairingState> emit) async {
+    try {
+      final response = await apiClient.post('/api/client/chat/request');
+      final data = response['data'] as Map<String, dynamic>;
+      final sessionId = data['id'] as String;
+
+      emit(PairingSearching(sessionId));
+
+      // Start 60s local timeout as a safety net
+      _timeoutTimer = Timer(const Duration(seconds: 60), () {
+        add(_PairingTimeout());
+      });
+
+      // Listen to SSE for status updates
+      _listenToSSE(sessionId);
+    } on DioException catch (e) {
+      final code = e.response?.data?['error']?['code'];
+      if (code == 'NO_MITRA_AVAILABLE') {
+        emit(PairingNoBestie());
+      } else if (code == 'ALREADY_ACTIVE') {
+        emit(PairingError('Kamu sudah memiliki sesi aktif.'));
+      } else {
+        emit(PairingError('Gagal memulai. Coba lagi.'));
+      }
+    }
+  }
+
+  void _listenToSSE(String sessionId) {
+    final dio = Dio(BaseOptions(baseUrl: ApiClient.baseUrl));
+    // SSE endpoint — use responseType stream
+    dio.get(
+      '/api/client/chat/request/$sessionId/status',
+      options: Options(responseType: ResponseType.stream),
+    ).then((response) {
+      final stream = response.data.stream as Stream<List<int>>;
+      _sseSubscription = stream
+          .transform(utf8.decoder)
+          .transform(const LineSplitter())
+          .where((line) => line.startsWith('data: '))
+          .map((line) => jsonDecode(line.substring(6)) as Map<String, dynamic>)
+          .listen(
+            (data) => add(_PairingStatusUpdate(data)),
+            onError: (_) {},
+          );
+    }).catchError((_) {});
+  }
+
+  Future<void> _onStatusUpdate(_PairingStatusUpdate event, Emitter<PairingState> emit) async {
+    final data = event.data;
+    final type = data['type'] as String?;
+
+    if (type == 'paired') {
+      _cleanup();
+      final mitraName = data['mitra_display_name'] as String? ?? 'Bestie';
+      final sessionId = data['session_id'] as String;
+      emit(PairingBestieFound(sessionId: sessionId, mitraName: mitraName));
+
+      // Brief delay then transition to active
+      await Future.delayed(const Duration(seconds: 2));
+      emit(PairingActive(sessionId: sessionId, mitraName: mitraName));
+    } else if (type == 'expired') {
+      _cleanup();
+      emit(PairingNoBestie());
+    }
+  }
+
+  Future<void> _onCancelPairing(CancelPairing event, Emitter<PairingState> emit) async {
+    if (state is PairingSearching) {
+      final sessionId = (state as PairingSearching).sessionId;
+      try {
+        await apiClient.post('/api/client/chat/request/$sessionId/cancel');
+      } catch (_) {}
+      _cleanup();
+      emit(PairingCancelled());
+    }
+  }
+
+  Future<void> _onTimeout(_PairingTimeout event, Emitter<PairingState> emit) async {
+    _cleanup();
+    emit(PairingNoBestie());
+  }
+
+  void _cleanup() {
+    _timeoutTimer?.cancel();
+    _timeoutTimer = null;
+    _sseSubscription?.cancel();
+    _sseSubscription = null;
+  }
+
+  @override
+  Future<void> close() {
+    _cleanup();
+    return super.close();
+  }
+}

client_app/lib/features/chat/screens/bestie_found_screen.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:go_router/go_router.dart';
+import '../../../core/pairing/pairing_bloc.dart';
+
+class BestieFoundScreen extends StatelessWidget {
+  final String sessionId;
+  final String mitraName;
+
+  const BestieFoundScreen({
+    super.key,
+    required this.sessionId,
+    required this.mitraName,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return BlocListener<PairingBloc, PairingState>(
+      listener: (context, state) {
+        if (state is PairingActive) {
+          context.go('/chat/session/${state.sessionId}', extra: state.mitraName);
+        }
+      },
+      child: Scaffold(
+        body: Center(
+          child: Padding(
+            padding: const EdgeInsets.all(32),
+            child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: [
+                const Icon(Icons.check_circle, size: 80, color: Colors.green),
+                const SizedBox(height: 24),
+                const Text(
+                  'Bestie ditemukan!',
+                  style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
+                ),
+                const SizedBox(height: 8),
+                Text(
+                  'Menghubungkan kamu ke $mitraName',
+                  textAlign: TextAlign.center,
+                  style: const TextStyle(fontSize: 16, color: Colors.grey),
+                ),
+                const SizedBox(height: 24),
+                const CircularProgressIndicator(),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

client_app/lib/features/chat/screens/no_bestie_screen.dart

@@ -0,0 +1,39 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+
+class NoBestieScreen extends StatelessWidget {
+  const NoBestieScreen({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: Padding(
+          padding: const EdgeInsets.all(32),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              const Icon(Icons.sentiment_dissatisfied, size: 80, color: Colors.orange),
+              const SizedBox(height: 24),
+              const Text(
+                'Bestie belum tersedia',
+                style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
+              ),
+              const SizedBox(height: 8),
+              const Text(
+                'Maaf, semua Bestie sedang sibuk. Coba lagi nanti ya.',
+                textAlign: TextAlign.center,
+                style: TextStyle(fontSize: 16, color: Colors.grey),
+              ),
+              const SizedBox(height: 48),
+              ElevatedButton(
+                onPressed: () => context.go('/home'),
+                child: const Text('Kembali'),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

client_app/lib/features/chat/screens/searching_screen.dart

@@ -0,0 +1,55 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:go_router/go_router.dart';
+import '../../../core/pairing/pairing_bloc.dart';
+
+class SearchingScreen extends StatelessWidget {
+  const SearchingScreen({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return BlocListener<PairingBloc, PairingState>(
+      listener: (context, state) {
+        if (state is PairingBestieFound) {
+          context.go('/chat/found', extra: {
+            'sessionId': state.sessionId,
+            'mitraName': state.mitraName,
+          });
+        } else if (state is PairingNoBestie) {
+          context.go('/chat/no-bestie');
+        } else if (state is PairingCancelled) {
+          context.go('/home');
+        }
+      },
+      child: Scaffold(
+        body: Center(
+          child: Padding(
+            padding: const EdgeInsets.all(32),
+            child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: [
+                const CircularProgressIndicator(),
+                const SizedBox(height: 32),
+                const Text(
+                  'Mencari Bestie...',
+                  style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
+                ),
+                const SizedBox(height: 8),
+                const Text(
+                  'Tunggu sebentar ya, kami sedang mencarikan Bestie untukmu',
+                  textAlign: TextAlign.center,
+                  style: TextStyle(fontSize: 16, color: Colors.grey),
+                ),
+                const SizedBox(height: 48),
+                OutlinedButton(
+                  onPressed: () => context.read<PairingBloc>().add(CancelPairing()),
+                  child: const Text('Batalkan'),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

client_app/lib/features/chat/screens/session_active_screen.dart

@@ -0,0 +1,82 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:go_router/go_router.dart';
+import '../../../core/api/api_client.dart';
+
+class SessionActiveScreen extends StatelessWidget {
+  final String sessionId;
+  final String mitraName;
+
+  const SessionActiveScreen({
+    super.key,
+    required this.sessionId,
+    required this.mitraName,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Sesi Aktif'),
+        automaticallyImplyLeading: false,
+      ),
+      body: Center(
+        child: Padding(
+          padding: const EdgeInsets.all(32),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              const Icon(Icons.chat_bubble, size: 80, color: Colors.blue),
+              const SizedBox(height: 24),
+              Text(
+                'Terhubung dengan $mitraName',
+                style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 8),
+              const Text(
+                'Sesi chat akan tersedia di fase berikutnya.',
+                textAlign: TextAlign.center,
+                style: TextStyle(fontSize: 14, color: Colors.grey),
+              ),
+              const SizedBox(height: 48),
+              ElevatedButton(
+                style: ElevatedButton.styleFrom(backgroundColor: Colors.red),
+                onPressed: () => _endSession(context),
+                child: const Text('Akhiri Sesi', style: TextStyle(color: Colors.white)),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+
+  Future<void> _endSession(BuildContext context) async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('Akhiri Sesi?'),
+        content: const Text('Apakah kamu yakin ingin mengakhiri sesi ini?'),
+        actions: [
+          TextButton(onPressed: () => Navigator.of(ctx).pop(false), child: const Text('Batal')),
+          TextButton(onPressed: () => Navigator.of(ctx).pop(true), child: const Text('Ya, Akhiri')),
+        ],
+      ),
+    );
+
+    if (confirmed == true && context.mounted) {
+      try {
+        final apiClient = context.read<ApiClient>();
+        await apiClient.post('/api/client/chat/session/$sessionId/end');
+        if (context.mounted) context.go('/home');
+      } catch (_) {
+        if (context.mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('Gagal mengakhiri sesi. Coba lagi.')),
+          );
+        }
+      }
+    }
+  }
+}

client_app/lib/features/home/home_screen.dart

@@ -1,39 +1,66 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:go_router/go_router.dart';
 import '../../core/auth/auth_bloc.dart';
+import '../../core/pairing/pairing_bloc.dart';
 
-/// Phase 1 placeholder — will be replaced in Phase 2 with chat/session features.
 class HomeScreen extends StatelessWidget {
   const HomeScreen({super.key});
 
   @override
   Widget build(BuildContext context) {
-    return BlocBuilder<AuthBloc, AuthState>(
-      builder: (context, state) {
-        final displayName = state is AuthAuthenticated
-            ? state.profile['display_name'] as String
-            : state is AuthAnonymous
-                ? state.displayName
-                : '';
-
-        return Scaffold(
-          appBar: AppBar(
-            title: const Text('Halo Bestie'),
-            actions: [
-              IconButton(
-                icon: const Icon(Icons.logout),
-                onPressed: () => context.read<AuthBloc>().add(LogoutRequested()),
-              ),
-            ],
-          ),
-          body: Center(
-            child: Text(
-              'Halo, $displayName!',
-              style: const TextStyle(fontSize: 24),
-            ),
-          ),
-        );
+    return BlocListener<PairingBloc, PairingState>(
+      listener: (context, state) {
+        if (state is PairingSearching) {
+          context.go('/chat/searching');
+        } else if (state is PairingNoBestie) {
+          context.go('/chat/no-bestie');
+        } else if (state is PairingError) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            SnackBar(content: Text(state.message)),
+          );
+        }
       },
+      child: BlocBuilder<AuthBloc, AuthState>(
+        builder: (context, state) {
+          final displayName = state is AuthAuthenticated
+              ? state.profile['display_name'] as String
+              : state is AuthAnonymous
+                  ? state.displayName
+                  : '';
+
+          return Scaffold(
+            appBar: AppBar(
+              title: const Text('Halo Bestie'),
+              actions: [
+                IconButton(
+                  icon: const Icon(Icons.logout),
+                  onPressed: () => context.read<AuthBloc>().add(LogoutRequested()),
+                ),
+              ],
+            ),
+            body: Center(
+              child: Padding(
+                padding: const EdgeInsets.all(32),
+                child: Column(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  children: [
+                    Text('Halo, $displayName!', style: const TextStyle(fontSize: 24)),
+                    const SizedBox(height: 48),
+                    ElevatedButton(
+                      style: ElevatedButton.styleFrom(
+                        padding: const EdgeInsets.symmetric(horizontal: 48, vertical: 16),
+                      ),
+                      onPressed: () => context.read<PairingBloc>().add(RequestPairing()),
+                      child: const Text('Mulai Curhat', style: TextStyle(fontSize: 18)),
+                    ),
+                  ],
+                ),
+              ),
+            ),
+          );
+        },
+      ),
     );
   }
 }

client_app/lib/main.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'core/api/api_client.dart';
 import 'core/auth/auth_bloc.dart';
+import 'core/pairing/pairing_bloc.dart';
 import 'firebase_options.dart';
 import 'router.dart';
 
@@ -17,8 +18,13 @@ class App extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return BlocProvider(
-      create: (_) => AuthBloc(apiClient: ApiClient())..add(AppStarted()),
+    final apiClient = ApiClient();
+    return MultiBlocProvider(
+      providers: [
+        BlocProvider(create: (_) => AuthBloc(apiClient: apiClient)..add(AppStarted())),
+        BlocProvider(create: (_) => PairingBloc(apiClient: apiClient)),
+        RepositoryProvider.value(value: apiClient),
+      ],
       child: BlocBuilder<AuthBloc, AuthState>(
         builder: (context, state) {
           return MaterialApp.router(

client_app/lib/router.dart

@@ -7,6 +7,10 @@ import 'features/auth/screens/register_screen.dart';
 import 'features/auth/screens/otp_screen.dart';
 import 'features/auth/screens/force_register_screen.dart';
 import 'features/home/home_screen.dart';
+import 'features/chat/screens/searching_screen.dart';
+import 'features/chat/screens/bestie_found_screen.dart';
+import 'features/chat/screens/no_bestie_screen.dart';
+import 'features/chat/screens/session_active_screen.dart';
 
 GoRouter buildRouter(AuthBloc authBloc) {
   return GoRouter(
@@ -30,6 +34,21 @@ GoRouter buildRouter(AuthBloc authBloc) {
       GoRoute(path: '/auth/otp', builder: (context, state) => OtpScreen(phone: state.extra as String)),
       GoRoute(path: '/auth/force-register', builder: (_, __) => const ForceRegisterScreen()),
       GoRoute(path: '/home', builder: (_, __) => const HomeScreen()),
+      GoRoute(path: '/chat/searching', builder: (_, __) => const SearchingScreen()),
+      GoRoute(path: '/chat/found', builder: (context, state) {
+        final extra = state.extra as Map<String, dynamic>;
+        return BestieFoundScreen(
+          sessionId: extra['sessionId'] as String,
+          mitraName: extra['mitraName'] as String,
+        );
+      }),
+      GoRoute(path: '/chat/no-bestie', builder: (_, __) => const NoBestieScreen()),
+      GoRoute(path: '/chat/session/:sessionId', builder: (context, state) {
+        return SessionActiveScreen(
+          sessionId: state.pathParameters['sessionId']!,
+          mitraName: state.extra as String? ?? 'Bestie',
+        );
+      }),
     ],
   );
 }