import 'dart:math' as math;
import 'package:fis_measure/configs/patient.dart';
import 'package:fis_measure/interfaces/enums/species.dart';
import 'package:fis_measure/utils/number.dart';

class ObstetricsFormulas {
  ObstetricsFormulas._();
  static final IObstetricsFormulaStrategy _singleton =
      GlobalPatientConfig.speciesType == SpeciesType.mouse
          ? BaseObstetricsFormulas()
          : AnimalsObstetricsFormulas();

  static double gsMean(double d1, double d2, double d3) =>
      _singleton.gsMean(d1, d2, d3);
  static double gsMax(double d1, double d2, double d3) =>
      _singleton.gsMax(d1, d2, d3);
}

abstract class IObstetricsFormulaStrategy {
  double gsMean(double d1, double d2, double d3);
  double gsMax(double d1, double d2, double d3);
}

class BaseObstetricsFormulas implements IObstetricsFormulaStrategy {
  /// (D1 + D2 + D3)/3.0
  ///
  /// return Unit cm
  ///
  /// [d1] Unit cm
  ///
  /// [d2] Unit cm
  ///
  /// [d3] Unit cm
  @override
  double gsMean(double d1, double d2, double d3) {
    double mean = double.nan;
    if (!NumUtil.almostEquals(d1, 0) &&
        !NumUtil.almostEquals(d2, 0) &&
        !NumUtil.almostEquals(d3, 0)) {
      mean = (d1 + d2 + d3) / 3;
    }
    return mean;
  }

  ///Max(D1, D2, D3)
  @override
  double gsMax(double d1, double d2, double d3) {
    double max = double.nan;
    if (!(NumUtil.almostEquals(d1, 0) &&
        NumUtil.almostEquals(d2, 0) &&
        NumUtil.almostEquals(d3, 0))) {
      max = math.max(d1, math.max(d2, d3));
    }
    return max;
  }
}

class AnimalsObstetricsFormulas extends BaseObstetricsFormulas {}