Add metrics

lib/spinify.dart

@@ -15,6 +15,7 @@ export 'package:spinify/src/model/exception.dart';
 export 'package:spinify/src/model/history.dart';
 export 'package:spinify/src/model/jwt.dart';
 export 'package:spinify/src/model/message.dart';
+export 'package:spinify/src/model/metrics.dart';
 export 'package:spinify/src/model/presence.dart';
 export 'package:spinify/src/model/presence_stats.dart';
 export 'package:spinify/src/model/publication.dart';

lib/src/client/spinify.dart

@@ -15,6 +15,7 @@ import 'package:spinify/src/model/event.dart';
 import 'package:spinify/src/model/exception.dart';
 import 'package:spinify/src/model/history.dart';
 import 'package:spinify/src/model/message.dart';
+import 'package:spinify/src/model/metrics.dart';
 import 'package:spinify/src/model/presence.dart';
 import 'package:spinify/src/model/presence_stats.dart';
 import 'package:spinify/src/model/publication.dart';
@@ -65,7 +66,8 @@ final class Spinify extends SpinifyBase
         SpinifyPresenceMixin,
         SpinifyHistoryMixin,
         SpinifyRPCMixin,
-        SpinifyQueueMixin {
+        SpinifyQueueMixin,
+        SpinifyMetricsMixin {
   /// {@macro spinify}
   Spinify([SpinifyConfig? config]) : super(config ?? SpinifyConfig.byDefault());
 
@@ -713,6 +715,42 @@ base mixin SpinifyRPCMixin on SpinifyBase, SpinifyErrorsMixin {
   }
 }
 
+/// Responsible for metrics.
+/// {@nodoc}
+@internal
+base mixin SpinifyMetricsMixin on SpinifyBase {
+  int _connectsTotal = 0, _connectsSuccessful = 0;
+
+  @override
+  Future<void> connect(String url) async {
+    _connectsTotal++;
+    return super.connect(url);
+  }
+
+  @override
+  void _onConnected(SpinifyState$Connected state) {
+    super._onConnected(state);
+    _connectsSuccessful++;
+  }
+
+  /// Get metrics of Spinify client.
+  @override
+  SpinifyMetrics get metrics {
+    final timestamp = DateTime.now().toUtc();
+    final wsMetrics = _transport.metrics;
+    return SpinifyMetrics(
+      timestamp: timestamp,
+      lastUrl: wsMetrics.lastUrl,
+      reconnects: (successful: _connectsSuccessful, total: _connectsTotal),
+      state: state,
+      receivedCount: wsMetrics.receivedCount,
+      receivedSize: wsMetrics.receivedSize,
+      transferredCount: wsMetrics.transferredCount,
+      transferredSize: wsMetrics.transferredSize,
+    );
+  }
+}
+
 /// Mixin responsible for queue.
 /// SHOULD BE LAST MIXIN.
 /// {@nodoc}

lib/src/client/spinify_interface.dart

@@ -5,6 +5,7 @@ import 'dart:async';
 import 'package:spinify/src/client/state.dart';
 import 'package:spinify/src/client/states_stream.dart';
 import 'package:spinify/src/model/history.dart';
+import 'package:spinify/src/model/metrics.dart';
 import 'package:spinify/src/model/presence.dart';
 import 'package:spinify/src/model/presence_stats.dart';
 import 'package:spinify/src/model/pushes_stream.dart';
@@ -22,7 +23,8 @@ abstract interface class ISpinify
         ISpinifyClientSubscriptionsManager,
         ISpinifyPresenceOwner,
         ISpinifyHistoryOwner,
-        ISpinifyRemoteProcedureCall {
+        ISpinifyRemoteProcedureCall,
+        ISpinifyMetricsOwner {
   /// Connect to the server.
   /// [url] is a URL of endpoint.
   Future<void> connect(String url);
@@ -128,3 +130,9 @@ abstract interface class ISpinifyRemoteProcedureCall {
   /// Send arbitrary RPC and wait for response.
   Future<List<int>> rpc(String method, List<int> data);
 }
+
+/// Spinify metrics interface.
+abstract interface class ISpinifyMetricsOwner {
+  /// Get metrics of Spinify client.
+  SpinifyMetrics get metrics;
+}

lib/src/model/metrics.dart

@@ -0,0 +1,67 @@
+import 'package:meta/meta.dart';
+import 'package:spinify/src/client/state.dart';
+
+/// {@template metrics}
+/// Metrics of Spinify client.
+/// {@endtemplate}
+/// {@category Client}
+/// {@category Entity}
+@immutable
+final class SpinifyMetrics implements Comparable<SpinifyMetrics> {
+  /// {@macro metrics}
+  const SpinifyMetrics({
+    required this.timestamp,
+    required this.state,
+    required this.transferredSize,
+    required this.receivedSize,
+    required this.reconnects,
+    required this.transferredCount,
+    required this.receivedCount,
+    required this.lastUrl,
+  });
+
+  /// Timestamp of the metrics.
+  final DateTime timestamp;
+
+  /// The current state of the client.
+  final SpinifyState state;
+
+  /// The total number of bytes sent.
+  final BigInt transferredSize;
+
+  /// The total number of bytes received.
+  final BigInt receivedSize;
+
+  /// The total number of times the connection has been re-established.
+  final ({int successful, int total}) reconnects;
+
+  /// The total number of messages sent.
+  final BigInt transferredCount;
+
+  /// The total number of messages received.
+  final BigInt receivedCount;
+
+  /// The last URL used to connect.
+  final String? lastUrl;
+
+  @override
+  int compareTo(SpinifyMetrics other) => timestamp.compareTo(other.timestamp);
+
+  /// Convert metrics to JSON.
+  Map<String, Object?> toJson() => <String, Object?>{
+        'timestamp': timestamp,
+        'state': state.toJson(),
+        'reconnects': <String, int>{
+          'successful': reconnects.successful,
+          'total': reconnects.total,
+        },
+        'transferredSize': transferredSize,
+        'receivedSize': receivedSize,
+        'transferredCount': transferredCount,
+        'receivedCount': receivedCount,
+        'lastUrl': lastUrl,
+      };
+
+  @override
+  String toString() => 'SpinifyMetrics{}';
+}

lib/src/transport/transport_interface.dart

@@ -12,6 +12,7 @@ import 'package:spinify/src/subscription/server_subscription_manager.dart';
 import 'package:spinify/src/subscription/subcibed_on_channel.dart';
 import 'package:spinify/src/subscription/subscription_config.dart';
 import 'package:spinify/src/util/notifier.dart';
+import 'package:ws/ws.dart';
 
 /// Class responsible for sending and receiving data from the server.
 /// {@nodoc}
@@ -29,6 +30,10 @@ abstract interface class ISpinifyTransport {
   /// {@nodoc}
   abstract final SpinifyListenable<SpinifyEvent> events;
 
+  /// Get web socket metrics.
+  /// {@nodoc}
+  WebSocketMetrics get metrics;
+
   /// Connect to the server.
   /// [url] is a URL of endpoint.
   /// [subs] is a list of server-side subscriptions to subscribe on connect.

lib/src/transport/ws_protobuf_transport.dart

@@ -75,6 +75,9 @@ abstract base class SpinifyWSPBTransportBase implements ISpinifyTransport {
   final SpinifyChangeNotifier<SpinifyEvent> events =
       SpinifyChangeNotifier<SpinifyEvent>();
 
+  @override
+  WebSocketMetrics get metrics => _webSocket.metrics;
+
   /// Init transport, override this method to add custom logic.
   /// {@nodoc}
   @protected