fis_lib_measure/lib/process/unit/convert/convert.dart

import 'package:fis_measure/process/unit/convert/length.dart';
import 'package:fis_measure/process/unit/convert/speed.dart';
import 'package:fis_measure/process/unit/convert/area.dart';
import 'package:fis_measure/process/unit/convert/time.dart';
import 'package:vid/us/vid_us_unit.dart';

import 'abstract.dart';

/// 单位数值转换器
class UnitValueConverter {
  static UnitValueConverter? _ins;
  static UnitValueConverter get _singleton {
    if (_ins == null) {
      _ins = UnitValueConverter._();
      _ins!._init();
    }
    return _ins!;
  }

  UnitValueConverter._();
  final _map = <VidUsUnit, UnitMapBase>{};

  /// 转换为目标单位的值
  ///
  /// [unit] 当前单位
  ///
  /// [targetUnit] 目标单位
  ///
  /// [value] 当前单位值
  static double convert(VidUsUnit unit, VidUsUnit targetUnit, double value) {
    final result = _singleton._findUnitExt(unit)?.convert(targetUnit, value);
    return result ?? value;
  }

  UnitMapBase? _findUnitExt(VidUsUnit unit) {
    if (_map.containsKey(unit)) {
      return _map[unit];
    }
    return null;
  }

  void _init() {
    _add(LengthMap());
    _add(TimeMap());
    _add(SpeedMap());
    _add(AreaMap());
  }

  void _add(UnitMapBase item) {
    _map[item.unit] = item;
  }
}