UnityView(
  config: const UnityConfig(sceneName: 'GameScene'),
  placeholder: const Center(child: CircularProgressIndicator()),
  onReady: (bridge) {
    bridge.send(UnityMessage.command('StartGame'));
  },
  onMessage: (message) {
    if (message.type == 'score_updated') {
      // handle score
    }
  },
)

abstract class UnityBridge {
  UnityLifecycleState get currentState;
  bool get isReady;

  // Streams
  Stream<UnityMessage> get messageStream;
  Stream<UnityPerformanceStats> get performanceStream;  // 2.0.0
  Stream<UnityEvent> get eventStream;
  Stream<SceneInfo> get sceneStream;
  Stream<UnityLifecycleState> get lifecycleStream;

  // Sending (JSON)
  Future<void> send(UnityMessage message);
  Future<void> sendWhenReady(UnityMessage message);

  // Sending (binary, 2.0.0)
  Future<void> sendBinary(UnityMessage message);
  Future<void> sendBinaryWhenReady(UnityMessage message);

  // Lifecycle
  Future<void> initialize();
  Future<void> pause();
  Future<void> resume();
  Future<void> unload();
  Future<void> dispose();
}

const UnityMessage({
  required this.type,
  this.data,
  this.gameObject = 'FlutterBridge',
  this.method = 'ReceiveMessage',
});

factory UnityMessage.command(String action, [Map<String, dynamic>? data]);
factory UnityMessage.to(String gameObject, String method, [Map<String, dynamic>? data]);
factory UnityMessage.routed(String target, String method, [Map<String, dynamic>? data]);
factory UnityMessage.fromJson(String jsonString);

// Command to Unity
final msg = UnityMessage.command('LoadScene', {'name': 'Level1'});

// Event from Unity
final event = UnityMessage.fromJson('{"type":"scene_loaded","data":"Level1"}');

const UnityConfig({
  this.sceneName = 'MainScene',
  this.fullscreen = false,
  this.unloadOnDispose = true,
  this.hideStatusBar = false,
  this.runImmediately = true,
  this.targetFrameRate = 60,
  this.platformViewMode = PlatformViewMode.hybridComposition,
  this.transparentBackground = false,
  this.arMode = UnityArMode.none,
});

factory UnityConfig.fullscreen({String sceneName = 'MainScene', bool transparentBackground = false});
factory UnityConfig.embedded({String sceneName = 'MainScene', bool transparentBackground = false});
factory UnityConfig.ar({String sceneName = 'MainScene', UnityArMode mode = UnityArMode.overlay});

enum UnityArMode { none, passthrough, overlay }

Stream<UnityMessage> get messageStream;
Stream<UnityPerformanceStats> get performanceStream;  // 2.0.0
Stream<UnityEvent> get eventStream;
Stream<SceneInfo> get sceneStream;
Stream<UnityLifecycleState> get lifecycleStream;

enum UnityLifecycleState {
  uninitialized,
  initializing,
  ready,
  paused,
  resumed,
  disposed,
}

StreamingController({
  required UnityBridge bridge,
  required String manifestUrl,
  UnityAssetLoader? assetLoader,  // defaults to UnityAddressablesLoader
  http.Client? httpClient,
  CacheManager? cacheManager,
})

public class PlayerController : MonoBehaviour
{
    [UnityKitMethod]               // callable as "Jump"
    public void Jump() { /* ... */ }

    [UnityKitMethod("move")]       // callable as "move"
    public void Move(MovePayload p) { /* p deserialized from JSON */ }

    void OnEnable()  => MessageRouter.RegisterMethods("player", this);
    void OnDisable() => MessageRouter.Unregister("player");
}

using UnityKit;

public class EnemyManager : FlutterMonoBehaviour
{
    protected override void OnFlutterMessage(string method, string data)
    {
        switch (method)
        {
            case "SpawnWave":
                // parse data, spawn enemies
                break;
            case "Reset":
                // reset game state
                break;
        }
    }

    private void OnWaveCleared()
    {
        // Direct send
        SendToFlutter("wave_cleared", "{\"wave\": 3}");

        // Batched send (via MessageBatcher component on FlutterBridge)
        SendToFlutterBatched("score_updated", "{\"score\": 1500}");
    }
}