feat: watch together recent rooms, plex usernames, action toasts, shorter codes

close #855

lib/watch_together/services/recent_rooms_service.dart

@@ -0,0 +1,78 @@
+import 'dart:convert';
+
+import '../../services/settings_service.dart';
+
+class RecentRoom {
+  final String code;
+  final String? name;
+  final DateTime lastUsed;
+
+  const RecentRoom({required this.code, this.name, required this.lastUsed});
+
+  Map<String, dynamic> toJson() => {
+        'code': code,
+        if (name != null) 'name': name,
+        'lastUsed': lastUsed.millisecondsSinceEpoch,
+      };
+
+  factory RecentRoom.fromJson(Map<String, dynamic> json) => RecentRoom(
+        code: json['code'] as String,
+        name: json['name'] as String?,
+        lastUsed: DateTime.fromMillisecondsSinceEpoch(json['lastUsed'] as int),
+      );
+
+  RecentRoom copyWith({String? code, String? name, DateTime? lastUsed, bool clearName = false}) => RecentRoom(
+        code: code ?? this.code,
+        name: clearName ? null : (name ?? this.name),
+        lastUsed: lastUsed ?? this.lastUsed,
+      );
+}
+
+class RecentRoomsService {
+  static const int _maxRooms = 20;
+
+  static List<RecentRoom> getRecentRooms() {
+    final json = SettingsService.instanceOrNull?.getRecentRooms();
+    if (json == null) return [];
+    try {
+      final list = jsonDecode(json) as List<dynamic>;
+      final rooms = list.map((e) => RecentRoom.fromJson(e as Map<String, dynamic>)).toList();
+      rooms.sort((a, b) => b.lastUsed.compareTo(a.lastUsed));
+      return rooms;
+    } catch (_) {
+      return [];
+    }
+  }
+
+  static Future<void> _save(List<RecentRoom> rooms) async {
+    rooms.sort((a, b) => b.lastUsed.compareTo(a.lastUsed));
+    if (rooms.length > _maxRooms) rooms.removeRange(_maxRooms, rooms.length);
+    await SettingsService.instanceOrNull?.setRecentRooms(jsonEncode(rooms.map((r) => r.toJson()).toList()));
+  }
+
+  static Future<void> addOrUpdateRoom(String code, {String? name}) async {
+    final rooms = getRecentRooms();
+    final index = rooms.indexWhere((r) => r.code == code);
+    if (index >= 0) {
+      rooms[index] = rooms[index].copyWith(lastUsed: DateTime.now(), name: name ?? rooms[index].name);
+    } else {
+      rooms.add(RecentRoom(code: code, name: name, lastUsed: DateTime.now()));
+    }
+    await _save(rooms);
+  }
+
+  static Future<void> removeRoom(String code) async {
+    final rooms = getRecentRooms();
+    rooms.removeWhere((r) => r.code == code);
+    await _save(rooms);
+  }
+
+  static Future<void> renameRoom(String code, String? name) async {
+    final rooms = getRecentRooms();
+    final index = rooms.indexWhere((r) => r.code == code);
+    if (index >= 0) {
+      rooms[index] = rooms[index].copyWith(name: name, clearName: name == null);
+      await _save(rooms);
+    }
+  }
+}

lib/watch_together/services/watch_together_peer_service.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:math';
 
 import 'package:uuid/uuid.dart';
 import '../../utils/future_extensions.dart';
@@ -98,9 +99,11 @@ class WatchTogetherPeerService with KeepaliveMixin {
   /// List of connected peer IDs
   List<String> get connectedPeers => _connectedPeers.toList();
 
-  /// Generate a short, readable session ID
-  String _generateSessionId() {
-    return const Uuid().v4().substring(0, 8).toUpperCase();
+  /// Generate a short, readable session ID (5 alphanumeric chars)
+  static String _generateSessionId() {
+    const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
+    final random = Random.secure();
+    return String.fromCharCodes(List.generate(5, (_) => chars.codeUnitAt(random.nextInt(chars.length))));
   }
 
   /// Connect to the relay WebSocket and set up the message listener.
@@ -308,13 +311,14 @@ class WatchTogetherPeerService with KeepaliveMixin {
   /// Create a new session as host
   ///
   /// Returns the session ID that others can use to join.
-  Future<String> createSession() async {
+  /// If [sessionId] is provided, uses that instead of generating a new one.
+  Future<String> createSession({String? sessionId}) async {
     if (_channel != null) {
       await disconnect();
     }
 
     _isHost = true;
-    _sessionId = _generateSessionId();
+    _sessionId = sessionId?.toUpperCase() ?? _generateSessionId();
     _myPeerId = 'wt-$_sessionId';
     _reconnectAttempts = 0;
 
@@ -380,6 +384,20 @@ class WatchTogetherPeerService with KeepaliveMixin {
     }
   }
 
+  /// Try to join a session; if it doesn't exist, create it as host.
+  ///
+  /// Returns `true` if the user became the host (room was empty).
+  Future<bool> joinOrCreateSession(String sessionId) async {
+    try {
+      await joinSession(sessionId);
+      return false; // joined as guest
+    } on PeerError catch (e) {
+      if (e.type != PeerErrorType.serverError) rethrow;
+      await createSession(sessionId: sessionId);
+      return true; // created as host
+    }
+  }
+
   /// Broadcast a message to all connected peers
   void broadcast(SyncMessage message) {
     final payload = message.toJson();