fis_lib_vid/lib/data_host/web/shell.dart

part of 'data_host.dart';

class _VidDataHostShell implements VidDataHostInterface {
  _VidDataHostShell(this.url);

  static PlatformService get _platform => VidDataHostEnv.platformGetter!.call();

  VidUsProbe? _probe;
  int? _frameCount;

  @override
  final String url;

  @override
  int get frameCount => _frameCount!;

  @override
  VidUsProbe get probe => _probe!;

  @override
  Future<VidUsImageData?> getData() async => null;

  @override
  Future<VidDataHostLoadInfo?> load() async {
    final rst = await _platform.loadVid(url);
    if (!rst.isSuccess) return null;

    final buffer = const Base64Decoder().convert(rst.probeBase64!);
    final probe = VidUsProbe.fromBytes(buffer);
    _probe = probe;
    _frameCount = rst.frameCount;

    final info = VidDataHostLoadInfo(probe);
    return info;
  }

  @override
  Future<VidUsImage?> getFrame<TProcessor extends VidFrameProcessor>(
    int index, {
    List<TProcessor>? processors,
  }) async {
    final rpcProcessors = _convert2RpcProcessors(processors);
    final rst = await _platform.getVidFrame(GetVidFrameRequest(
      index: index,
      processors: rpcProcessors,
    ));
    if (!rst.isSuccess) return null;

    final buffer = const Base64Decoder().convert(rst.frameBase64!);
    final frame = VidUsImage.fromBytes(buffer);
    return frame;
  }

  @override
  Future<void> release() async {
    _platform.releaseVid();
  }

  List<TOut>? _convert2RpcProcessors<TIn extends VidFrameProcessor,
      TOut extends VidFrameProcessorBase>(List<TIn>? processors) {
    if (processors == null || processors.isEmpty) return null;

    final result = <TOut>[];
    for (final processor in processors) {
      final converted = _convert2RpcProcessor<TIn, TOut>(processor);
      if (converted != null) {
        result.add(converted);
      }
    }
    return result;
  }

  TOut? _convert2RpcProcessor<TIn extends VidFrameProcessor,
      TOut extends VidFrameProcessorBase>(TIn processor) {
    if (processor is VidBrightnessProcessor) {
      return VidFrameBrightnessProcessor(processor.brightness) as TOut;
    }
    if (processor is VidContrastProcessor) {
      return VidFrameContrastProcessor(processor.contrast) as TOut;
    }
    return null;
  }
}