fis_lib_vid_ext/lib/vid_extended_data.dart

import 'dart:typed_data';

import 'package:vid/us/vid_us_data_reader.dart';
import 'package:vid/us/vid_us_image_data.dart';

import 'vid_tag.dart';
import 'vid_value.dart';
import 'vid_value_element.dart';

extension VidExtendedDataExt on VidUsImageData {
  /// 获取结构化扩展数据
  VidExtendedData? getStructExtendedData() {
    return VidExtendedData.fromBytes(extendedData);
  }
}

/// vid文件扩展数据实体
class VidExtendedData {
  /// version tag
  static VidTag get versionTag => VidTag("Vid", "Version");

  /// version num
  static VidIntegerValueElement get versionValue => VidIntegerValueElement(1);

  late final Map<VidTag, IVidValue> data;

  VidExtendedData(Map<VidTag, IVidValue> tv) {
    data = tv;
    add(versionTag, versionValue);
  }

  void add(VidTag key, IVidValue value) {
    data[key] = value;
  }

  static VidExtendedData? fromBytes(Uint8List bytes) {
    if (bytes.isEmpty) return null;
    try {
      final reader = VidUsDataReader(bytes);
      final count = reader.readInt();
      if (count <= 0 || count > bytes.length) return null;

      final Map<VidTag, IVidValue> map = {};
      for (int cursor = 0; cursor < count; cursor++) {
        final key = reader.readString();
        final keys = key.split(',');
        if (keys.length != 3) {
          return null;
        }

        final vidTag = VidTag(keys[0], keys[1]);
        final valueStr = reader.readString();
        final valueTypeName = keys[2].toLowerCase();
        final valueType = ValueType.values
            .firstWhere((e) => e.name.toLowerCase() == valueTypeName);
        final vidValue = _convertStr2ValEle(valueType, valueStr);
        map[vidTag] = vidValue;
      }
      return VidExtendedData(map);
    } catch (e) {}
    return null;
  }

  static IVidValue _convertStr2ValEle(ValueType type, String value) {
    switch (type) {
      case ValueType.string:
        return VidStringValueElement(value);
      case ValueType.double:
        return VidDoubleValueElement(double.parse(value));
      case ValueType.float:
        return VidFloatValueElement(double.parse(value));
      case ValueType.integer:
        return VidIntegerValueElement(int.parse(value));
      case ValueType.long:
        return VidLongValueElement(int.parse(value));
      case ValueType.uint:
        return VidUintValueElement(int.parse(value));
      case ValueType.ulong:
        return VidUlongValueElement(int.parse(value));
      case ValueType.ushort:
        return VidUshortValueElement(int.parse(value));
      case ValueType.byte:
        return VidByteValueElement(int.parse(value));
      case ValueType.short:
        return VidShortValueElement(int.parse(value));
    }
  }
}