import 'dart:typed_data';

/// SPS/PPS/I帧依赖关系管理器
class FrameDependencyManager {
  Uint8List? _sps;
  Uint8List? _pps;
  final int windowSize = 10;
  final List<int> _iFrameSeqWindow = [];

  // 丢帧自愈相关
  int _dropCount = 0;
  final int dropThreshold = 10; // 可根据需要调整

  /// 重置依赖管理器（自愈）
  void reset() {
    _iFrameSeqWindow.clear();
    _dropCount = 0;
  }

  /// 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;
  int get dropCount => _dropCount;
  int get dropThresholdValue => dropThreshold;
  void updateIFrameSeq(int seq) {
    _iFrameSeqWindow.add(seq);
    if (_iFrameSeqWindow.length > windowSize) {
      _iFrameSeqWindow.removeAt(0);
    }
    _dropCount = 0; // I帧解码时重置丢帧计数
    // print('[FrameDependencyManager][调试] I帧解码成功，序号: $seq，当前I帧窗口: ${_iFrameSeqWindow.toString()}');
  }

  /// 判断指定I帧序号是否在滑动窗口内
  bool isIFrameDecoded(int? seq) {
    if (seq == null || !_iFrameSeqWindow.contains(seq)) {
      _dropCount++;
      // print('[FrameDependencyManager][调试] 当前I帧窗口: ${_iFrameSeqWindow.toString()}，待查找I帧序号: $seq');
      if (_dropCount >= dropThreshold) {
        print('[FrameDependencyManager][自愈] 连续丢帧$_dropCount次，自动reset依赖窗口');
        reset();
      }
      return false;
    }
    return true;
  }
}