Use Websocket to update number of unread notifications

lib/helpers/events_helper.dart

@@ -9,6 +9,13 @@ import 'package:event_bus/event_bus.dart';
 /// Main WebSocket closed
 class WSClosedEvent {}
 
+/// New number of notifications
+class NewNumberNotifsEvent {
+  final int newNum;
+
+  NewNumberNotifsEvent(this.newNum);
+}
+
 class EventsHelper {
   static EventBus _mgr = EventBus();
 

lib/helpers/websocket_helper.dart

@@ -1,6 +1,9 @@
+import 'dart:convert';
+
 import 'package:comunic/helpers/events_helper.dart';
 import 'package:comunic/models/api_request.dart';
 import 'package:comunic/models/config.dart';
+import 'package:comunic/models/ws_message.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
 
 /// User web socket helper
@@ -40,7 +43,10 @@ class WebSocketHelper {
 
     _ws.stream.listen(
       // When we got data
-          (onData) => print("WS New data: $onData"),
+          (data) {
+        print("WS New data: $data");
+        _processMessage(data.toString());
+      },
 
       // Print errors on console
       onError: (e, stack) {
@@ -55,4 +61,31 @@ class WebSocketHelper {
       },
     );
   }
+
+  /// Process incoming message
+  static _processMessage(String msgStr) {
+    try {
+      final msg = WsMessage.fromJSON(jsonDecode(msgStr));
+
+      if (!msg.hasId)
+        _processUnattendedMessage(msg);
+      else
+        throw Exception("Do not know how to process attended message!");
+    } catch (e, stack) {
+      print("WS could not process message: $e");
+      print(stack);
+    }
+  }
+
+  /// Process an unattended message
+  static _processUnattendedMessage(WsMessage msg) {
+    switch (msg.title) {
+      case "number_notifs":
+        EventsHelper.emit(NewNumberNotifsEvent(msg.data));
+        break;
+
+      default:
+        throw Exception("Unknown message type: ${msg.title}");
+    }
+  }
 }

lib/models/count_unread_notifications.dart

@@ -3,8 +3,8 @@
 /// @author Pierre Hubert
 
 class CountUnreadNotifications {
-  final int notifications;
-  final int conversations;
+  int notifications;
+  int conversations;
 
   CountUnreadNotifications({
     this.notifications,

lib/models/ws_message.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/widgets.dart';
+
+/// WebSocket message
+///
+/// @author Pierre Hubert
+
+class WsMessage {
+  final String id;
+  final String title;
+  final dynamic data;
+
+  const WsMessage({
+    @required this.id,
+    @required this.title,
+    @required this.data,
+  })  : assert(id != null),
+        assert(title != null);
+
+  /// Construct a message from a JSON document (messages coming from the server)
+  static WsMessage fromJSON(final Map<dynamic, dynamic> m) {
+    return WsMessage(id: m["id"], title: m["title"], data: m["data"]);
+  }
+
+  bool get hasId => this.id != null && this.id.isNotEmpty;
+}

lib/ui/widgets/navbar_widget.dart

@@ -1,3 +1,4 @@
+import 'package:comunic/helpers/events_helper.dart';
 import 'package:comunic/helpers/notifications_helper.dart';
 import 'package:comunic/models/count_unread_notifications.dart';
 import 'package:comunic/ui/widgets/safe_state.dart';
@@ -113,8 +114,7 @@ class ComunicAppBar extends StatefulWidget implements PreferredSizeWidget {
   final OnSelectMenuAction onTap;
   final BarCallbackActions selectedAction;
 
-  const ComunicAppBar(
-      {Key key, @required this.onTap, @required this.selectedAction})
+  const ComunicAppBar({Key key, @required this.onTap, @required this.selectedAction})
       : assert(onTap != null),
         super(key: key);
 
@@ -126,12 +126,17 @@ class ComunicAppBar extends StatefulWidget implements PreferredSizeWidget {
 }
 
 class _ComunicAppBarState extends SafeState<ComunicAppBar> {
-  CountUnreadNotifications _unreadNotifications;
+  var _unreadNotifications =
+  CountUnreadNotifications(notifications: 0, conversations: 0);
 
   @override
   void initState() {
     _refreshCountUnread();
     super.initState();
+
+    // Listen to notifications number update
+    this.listenChangeState<NewNumberNotifsEvent>(
+            (d) => _unreadNotifications.notifications = d.newNum);
   }
 
   void _refreshCountUnread() async {

lib/ui/widgets/safe_state.dart

@@ -8,7 +8,6 @@ import 'package:flutter/material.dart';
 /// @author Pierre HUBERT
 
 abstract class SafeState<T extends StatefulWidget> extends State<T> {
-
   final _subscriptions = List<StreamSubscription>();
 
   @override
@@ -21,8 +20,7 @@ abstract class SafeState<T extends StatefulWidget> extends State<T> {
 
   @override
   void setState(fn) {
-    if(mounted)
-      super.setState(fn);
+    if (mounted) super.setState(fn);
   }
 
   /// Register to a new subscription
@@ -30,4 +28,14 @@ abstract class SafeState<T extends StatefulWidget> extends State<T> {
   void listen<T>(void onEvent(T event)) {
     _subscriptions.add(EventsHelper.on<T>(onEvent));
   }
+
+  /// Register to a new subscription
+  ///
+  /// Callback will we called inside of setState
+  @protected
+  void listenChangeState<T>(void onEvent(T event)) {
+    _subscriptions.add(EventsHelper.on<T>((d) {
+      setState(() => onEvent(d));
+    }));
+  }
 }