feat: add message_received socket handler to notify senders of delivery status

src/messages/messages.gateway.ts

@@ -323,6 +323,45 @@ export class MessagesGateway implements OnGatewayConnection, OnGatewayDisconnect
     });
   }
 
+  /**
+   * Acknowledge message delivery from receiver client.
+   * Called by mobile/web when `new_message` is received via socket so the
+   * sender gets a real-time double-tick regardless of Redis presence state.
+   */
+  @SubscribeMessage('message_received')
+  async handleMessageReceived(
+    @ConnectedSocket() client: AuthenticatedSocket,
+    @MessageBody() data: { messageId: string; conversationId: string },
+  ) {
+    if (!client.userId || !data?.messageId) return { error: 'Invalid request' };
+
+    try {
+      // Verify the receiver is actually a participant of this conversation
+      const message = await this.prisma.message.findUnique({
+        where: { id: data.messageId },
+        select: { id: true, senderId: true, conversationId: true, status: true },
+      });
+
+      if (!message) return { error: 'Message not found' };
+      // Don't mark sender's own message as delivered
+      if (message.senderId === client.userId) return { success: false };
+      // Already delivered or read — no-op
+      if (message.status !== 'SENT') return { success: true };
+
+      const updated = await this.messagesService.markMessageDelivered(message.id);
+      const deliveredEvent = {
+        messageId: message.id,
+        conversationId: message.conversationId,
+        deliveredAt: (updated.deliveredAt ?? new Date()).toISOString(),
+      };
+      this.sendToUser(message.senderId, 'message_delivered', deliveredEvent);
+      return { success: true };
+    } catch (error) {
+      this.logger.warn(`message_received ack failed for ${client.userId}: ${error.message}`);
+      return { error: 'Failed to ack delivery' };
+    }
+  }
+
   /**
    * Mark messages as read
    */