kryz-go-flutter/lib/casting_business_object.dart

import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';

enum CastingStatus { unavailable, idle, connecting, connected, error }

enum CastingPlaybackStatus { unknown, stopped, buffering, playing }

class CastingBusinessObject extends ChangeNotifier {
  static const MethodChannel _methodChannel = MethodChannel(
    'kryz_go_flutter/casting/methods',
  );
  static const EventChannel _eventChannel = EventChannel(
    'kryz_go_flutter/casting/events',
  );

  StreamSubscription<dynamic>? _eventSubscription;
  CastingStatus _status = CastingStatus.unavailable;
  CastingPlaybackStatus _playbackStatus = CastingPlaybackStatus.unknown;
  String? _connectedDeviceName;
  String? _lastError;
  
  /// Callback for when native side requests local audio to stop
  VoidCallback? onStopLocalAudioRequested;

  CastingStatus get status => _status;
  CastingPlaybackStatus get playbackStatus => _playbackStatus;
  String? get connectedDeviceName => _connectedDeviceName;
  String? get lastError => _lastError;

  bool get isSupportedOnThisPlatform {
    if (kIsWeb) {
      return false;
    }

    return defaultTargetPlatform == TargetPlatform.iOS ||
        defaultTargetPlatform == TargetPlatform.android;
  }

  bool get isConnected => _status == CastingStatus.connected;
  bool get isPlaying => _playbackStatus == CastingPlaybackStatus.playing;
  bool get isBuffering => _playbackStatus == CastingPlaybackStatus.buffering;
  bool get isStopped => _playbackStatus == CastingPlaybackStatus.stopped;

  Future<void> initialize() async {
    if (!isSupportedOnThisPlatform) {
      _setStatus(CastingStatus.unavailable);
      return;
    }

    _eventSubscription?.cancel();
    _eventSubscription = _eventChannel.receiveBroadcastStream().listen(
      _handleEvent,
      onError: (Object error) {
        _lastError = error.toString();
        _setStatus(CastingStatus.error);
      },
    );

    // Set up handler for native method calls (e.g., stopLocalAudio)
    _methodChannel.setMethodCallHandler(_handleMethodCall);

    await refreshStatus();
  }

  Future<void> refreshStatus() async {
    if (!isSupportedOnThisPlatform) {
      _setStatus(CastingStatus.unavailable);
      return;
    }

    try {
      final dynamic status = await _methodChannel.invokeMethod<dynamic>(
        'getStatus',
      );
      _handleEvent(status);
    } on PlatformException catch (error) {
      _lastError = error.message ?? error.code;
      _setStatus(CastingStatus.error);
    }
  }

  Future<void> showDevicePicker({
    bool autoplay = false,
    String? streamUrl,
    String? title,
    String? subtitle,
  }) async {
    if (!isSupportedOnThisPlatform) {
      _setStatus(CastingStatus.unavailable);
      return;
    }

    if (defaultTargetPlatform == TargetPlatform.android) {
      _setStatus(CastingStatus.connecting);
    }

    try {
      await _methodChannel.invokeMethod<void>('showDevicePicker', {
        'autoplay': autoplay,
        'streamUrl': streamUrl,
        'title': title,
        'subtitle': subtitle,
      });
    } on PlatformException catch (error) {
      _lastError = error.message ?? error.code;
      _setStatus(CastingStatus.error);
    }
  }

  Future<void> startCastingLiveStream({
    required String streamUrl,
    required String title,
    required String subtitle,
  }) async {
    if (!isSupportedOnThisPlatform) {
      _setStatus(CastingStatus.unavailable);
      return;
    }

    try {
      await _methodChannel.invokeMethod<void>('startCastingLiveStream', {
        'streamUrl': streamUrl,
        'title': title,
        'subtitle': subtitle,
      });
    } on PlatformException catch (error) {
      _lastError = error.message ?? error.code;
      // Do NOT set status to error here — native emits its own status events.
      // Overriding status from Dart corrupts the UI when native considers the
      // session still connected (e.g. during a retry after a race condition).
      rethrow;
    }
  }

  Future<void> disconnect() async {
    if (!isSupportedOnThisPlatform) {
      _setStatus(CastingStatus.unavailable);
      return;
    }

    try {
      await _methodChannel.invokeMethod<void>('disconnect');
    } on PlatformException catch (error) {
      _lastError = error.message ?? error.code;
      _setStatus(CastingStatus.error);
    }
  }

  Future<void> stopPlayback() async {
    if (!isSupportedOnThisPlatform) {
      _setStatus(CastingStatus.unavailable);
      return;
    }

    try {
      await _methodChannel.invokeMethod<void>('stopCastingPlayback');
    } on PlatformException catch (error) {
      _lastError = error.message ?? error.code;
      _setStatus(CastingStatus.error);
    }
  }

  void _handleEvent(dynamic event) {
    if (event is! Map) {
      return;
    }

    final String? status = event['status'] as String?;
    final String? playbackStatus = event['playbackStatus'] as String?;
    final String? deviceName = event['deviceName'] as String?;
    final String? message = event['message'] as String?;

    if (deviceName != null && deviceName.isNotEmpty) {
      _connectedDeviceName = deviceName;
    } else if (status != 'connected') {
      _connectedDeviceName = null;
    }

    if (message != null && message.isNotEmpty) {
      _lastError = message;
    }

    _setPlaybackStatus(_parsePlaybackStatus(playbackStatus));

    switch (status) {
      case 'idle':
        _setStatus(CastingStatus.idle);
        break;
      case 'connecting':
        _setStatus(CastingStatus.connecting);
        break;
      case 'connected':
        _setStatus(CastingStatus.connected);
        break;
      case 'error':
        _setStatus(CastingStatus.error);
        break;
      case 'unavailable':
      default:
        _setStatus(CastingStatus.unavailable);
        break;
    }
  }

  void _setStatus(CastingStatus status) {
    if (_status == status) {
      return;
    }

    _status = status;
    notifyListeners();
  }

  CastingPlaybackStatus _parsePlaybackStatus(String? playbackStatus) {
    switch (playbackStatus) {
      case 'playing':
        return CastingPlaybackStatus.playing;
      case 'buffering':
        return CastingPlaybackStatus.buffering;
      case 'stopped':
        return CastingPlaybackStatus.stopped;
      default:
        return CastingPlaybackStatus.unknown;
    }
  }

  void _setPlaybackStatus(CastingPlaybackStatus status) {
    if (_playbackStatus == status) {
      return;
    }

    _playbackStatus = status;
    notifyListeners();
  }

  @override
  void dispose() {
    _eventSubscription?.cancel();
    super.dispose();
  }

  /// Handles method calls from native code
  Future<dynamic> _handleMethodCall(MethodCall call) async {
    switch (call.method) {
      case 'stopLocalAudio':
        onStopLocalAudioRequested?.call();
        return null;
      case 'stopAudioService':
        // Stop the audio service directly (called when transferring to cast)
        onStopLocalAudioRequested?.call();
        return null;
      case 'resumeLocalAudio':
        // Audio service is resuming after cast disconnect; no action needed on Flutter side
        return null;
      default:
        return null;
    }
  }
}