import 'dart:typed_data';

/// SPS/PPS/I帧依赖关系管理器
class FrameDependencyManager {
  Uint8List? _sps;
  Uint8List? _pps;
  final int windowSize = 30;
  final List<int> _iFrameSeqWindow = [];

  /// 更新SPS缓存
  void updateSps(Uint8List sps) {
    _sps = sps;
  }
  /// 更新PPS缓存
  void updatePps(Uint8List pps) {
    _pps = pps;
  }
  Uint8List? get sps => _sps;
  Uint8List? get pps => _pps;

  /// 判断是否有可用I帧
  bool get hasIFrame => _iFrameSeqWindow.isNotEmpty;
  int? get lastIFrameSeq => _iFrameSeqWindow.isNotEmpty ? _iFrameSeqWindow.last : null;
  void updateIFrameSeq(int seq) {
    _iFrameSeqWindow.add(seq);
    if (_iFrameSeqWindow.length > windowSize) {
      _iFrameSeqWindow.removeAt(0);
    }
  }

  /// 判断指定I帧序号是否在滑动窗口内
  bool isIFrameDecoded(int? seq) {
    return seq != null && _iFrameSeqWindow.contains(seq);
  }
}