PilotVault/Fly App/lib/fly/state/live_stream_state.dart

import 'package:flutter/foundation.dart';

import 'parse.dart';

/// RTMP live streaming (plan P9), from the bridge's `liveStream` events. The
/// stream is app-level in the SDK, so it is not cleared on disconnect: the
/// next event says whether it survived.
class LiveStreamState extends ChangeNotifier {
  bool streaming = false;

  /// The last `OnLiveChangeListener` status: `STREAMING`, `STOPPED`, `ERROR`, or null.
  String? status;
  String? url;
  int videoKbps = 0;
  int audioKbps = 0;
  double fps = 0;

  /// How long it has been streaming, as the SDK counts it.
  int seconds = 0;

  /// Frames waiting to be sent; a growing cache means the uplink cannot keep up.
  int cacheSize = 0;
  String? error;

  /// The uplink is behind (more than ~2 s of video cached).
  bool get congested => streaming && cacheSize > 60;

  void apply(Map<String, dynamic> e) {
    streaming = asBool(e['streaming']) ?? false;
    status = asString(e['status']);
    url = asString(e['url']);
    videoKbps = asInt(e['videoKbps']) ?? 0;
    audioKbps = asInt(e['audioKbps']) ?? 0;
    fps = finite(e['fps']) ?? 0;
    seconds = asInt(e['seconds']) ?? 0;
    cacheSize = asInt(e['cacheSize']) ?? 0;
    error = asString(e['error']);
    notifyListeners();
  }

  /// `1:05`, `1:02:09`.
  String get elapsedLabel {
    final int h = seconds ~/ 3600, m = (seconds % 3600) ~/ 60, s = seconds % 60;
    final String ss = s.toString().padLeft(2, '0');
    return h > 0 ? '$h:${m.toString().padLeft(2, '0')}:$ss' : '$m:$ss';
  }

  /// `2.4 Mbps`, `850 kbps`.
  String get bitrateLabel {
    final int total = videoKbps + audioKbps;
    return total >= 1000 ? '${(total / 1000).toStringAsFixed(1)} Mbps' : '$total kbps';
  }
}

/// The aircraft's own video player (plan P9 in-FPV playback), from
/// `mediaPlayback` events.
@immutable
class MediaPlayback {
  const MediaPlayback({this.index = -1, this.status = 'STOPPED', this.position = 0});

  factory MediaPlayback.fromEvent(Map<String, dynamic> e) => MediaPlayback(
        index: asInt(e['index']) ?? -1,
        status: asString(e['status']) ?? 'UNKNOWN',
        position: finite(e['position']) ?? 0,
      );

  /// Index of the playing file in the last `mediaList`, or -1.
  final int index;

  /// `PLAYING`, `PAUSED`, `STOPPED` or `UNKNOWN`.
  final String status;

  /// Seconds into the file.
  final double position;

  bool get playing => status == 'PLAYING';
  bool get paused => status == 'PAUSED';

  @override
  bool operator ==(Object other) =>
      other is MediaPlayback && other.index == index && other.status == status && other.position == position;

  @override
  int get hashCode => Object.hash(index, status, position);
}

/// The stream address with its key hidden (the last path segment is the
/// platform's secret): `rtmp://a.rtmp.youtube.com/live2/•••x9`.
String maskStreamUrl(String url) {
  final int slash = url.lastIndexOf('/');
  if (slash < 0 || slash < url.indexOf('://') + 3 || slash == url.length - 1) return url;
  final String key = url.substring(slash + 1);
  final String tail = key.length > 4 ? key.substring(key.length - 2) : '';
  return '${url.substring(0, slash + 1)}•••$tail';
}

/// Whether [url] is an address the SDK will stream to.
bool validStreamUrl(String url) {
  final Uri? u = Uri.tryParse(url.trim());
  return u != null && (u.scheme == 'rtmp' || u.scheme == 'rtmps') && u.host.isNotEmpty && u.pathSegments.where((String s) => s.isNotEmpty).isNotEmpty;
}