feat: add WebSocket support - real-time notifications in Flutter

lib/core/ws_provider.dart

@@ -0,0 +1,86 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:web_socket_channel/web_socket_channel.dart';
+import 'package:web_socket_channel/status.dart' as status;
+
+// Estado del WebSocket
+class WSState {
+  final bool connected;
+  final String? error;
+  final dynamic lastMessage;
+
+  const WSState({
+    this.connected = false,
+    this.error,
+    this.lastMessage,
+  });
+
+  WSState copyWith({
+    bool? connected,
+    String? error,
+    dynamic lastMessage,
+  }) {
+    return WSState(
+      connected: connected ?? this.connected,
+      error: error,
+      lastMessage: lastMessage ?? this.lastMessage,
+    );
+  }
+}
+
+class WSNotifier extends StateNotifier<WSState> {
+  WebSocketChannel? _channel;
+  final String baseUrl;
+
+  WSNotifier(this.baseUrl) : super(const WSState());
+
+  // Conectar a WebSocket de una dirección
+  Future<void> connect(String token, int addressId) async {
+    try {
+      final wsUrl = baseUrl.replaceFirst('https', 'wss').replaceFirst('http', 'ws');
+      final url = Uri.parse('$wsUrl/eta/ws/$addressId');
+
+      _channel = WebSocketChannel.connect(url);
+
+      // Escuchar mensajes
+      _channel?.stream.listen(
+        (message) {
+          state = state.copyWith(
+            lastMessage: message,
+            connected: true,
+            error: null,
+          );
+        },
+        onError: (error) {
+          state = state.copyWith(
+            connected: false,
+            error: error.toString(),
+          );
+        },
+        onDone: () {
+          state = state.copyWith(connected: false);
+        },
+      );
+
+      state = state.copyWith(connected: true, error: null);
+    } catch (e) {
+      state = state.copyWith(connected: false, error: e.toString());
+    }
+  }
+
+  // Enviar mensaje
+  void send(String message) {
+    if (_channel != null && state.connected) {
+      _channel!.sink.add(message);
+    }
+  }
+
+  // Desconectar
+  void disconnect() {
+    _channel?.sink.close(status.goingAway);
+    state = state.copyWith(connected: false);
+  }
+}
+
+final wsProvider = StateNotifierProvider<WSNotifier, WSState>((ref) {
+  return WSNotifier('http://localhost:8000'); // Cambiar a URL de producción
+});