feat: manage user online status and typing indicator in socket gateway

- Added tracking of online users with real-time status updates (online/offline).
- Implemented `handleTyping` to broadcast user typing events to recipients.
- Added `check_status` handler to query user online status.
- Enhanced CORS configuration to support multi-domain deployments with credentials.

backend/src/realtime/events.gateway.ts

@@ -17,8 +17,16 @@ import { JwtService } from "../crypto/services/jwt.service";
 
 @WebSocketGateway({
 	cors: {
-		origin: "*",
+		origin: (
+			_origin: string,
+			callback: (err: Error | null, allow?: boolean) => void,
+		) => {
+			// En production, on pourrait restreindre ici
+			// Pour l'instant on autorise tout en mode credentials pour faciliter le déploiement multi-domaines
+			callback(null, true);
+		},
 		credentials: true,
+		methods: ["GET", "POST"],
 	},
 })
 export class EventsGateway
@@ -28,6 +36,7 @@ export class EventsGateway
 	server!: Server;
 
 	private readonly logger = new Logger(EventsGateway.name);
+	private readonly onlineUsers = new Map<string, Set<string>>(); // userId -> Set of socketIds
 
 	constructor(
 		private readonly jwtService: JwtService,
@@ -69,6 +78,13 @@ export class EventsGateway
 			// Rejoindre une room personnelle pour les notifications
 			client.join(`user:${payload.sub}`);
 
+			// Gérer le statut en ligne
+			if (!this.onlineUsers.has(payload.sub)) {
+				this.onlineUsers.set(payload.sub, new Set());
+				this.server.emit("user_status", { userId: payload.sub, status: "online" });
+			}
+			this.onlineUsers.get(payload.sub)?.add(client.id);
+
 			this.logger.log(`Client connected: ${client.id} (User: ${payload.sub})`);
 		} catch (error) {
 			this.logger.error(`Connection error for client ${client.id}: ${error}`);
@@ -77,6 +93,15 @@ export class EventsGateway
 	}
 
 	handleDisconnect(client: Socket) {
+		const userId = client.data.user?.sub;
+		if (userId && this.onlineUsers.has(userId)) {
+			const sockets = this.onlineUsers.get(userId);
+			sockets?.delete(client.id);
+			if (sockets?.size === 0) {
+				this.onlineUsers.delete(userId);
+				this.server.emit("user_status", { userId, status: "offline" });
+			}
+		}
 		this.logger.log(`Client disconnected: ${client.id}`);
 	}
 
@@ -98,6 +123,31 @@ export class EventsGateway
 		this.logger.log(`Client ${client.id} left content room: ${contentId}`);
 	}
 
+	@SubscribeMessage("typing")
+	handleTyping(
+		@ConnectedSocket() client: Socket,
+		@MessageBody() data: { recipientId: string; isTyping: boolean },
+	) {
+		const userId = client.data.user?.sub;
+		if (!userId) return;
+
+		this.server.to(`user:${data.recipientId}`).emit("user_typing", {
+			userId,
+			isTyping: data.isTyping,
+		});
+	}
+
+	@SubscribeMessage("check_status")
+	handleCheckStatus(
+		@ConnectedSocket() _client: Socket,
+		@MessageBody() userId: string,
+	) {
+		return {
+			userId,
+			status: this.onlineUsers.has(userId) ? "online" : "offline",
+		};
+	}
+
 	// Méthode utilitaire pour envoyer des messages à un utilisateur spécifique
 	sendToUser(userId: string, event: string, data: any) {
 		this.server.to(`user:${userId}`).emit(event, data);