import 'dart:math';

import 'package:diameter/models/settings.dart';

class Utils {
  // static double roundToDecimalPlaces(double value, int precision) {
  //   double mod = pow(10.0, precision).toDouble();
  //   return ((value * mod).round().toDouble() / mod);
  // }

  static double roundToMultipleOfBase(double value, double base) {
    double result = value;
    if (base != 0) {
      double remainder = value % base;
      int precision = Utils.getFractionDigitsLength(base);
      
      if (remainder != 0) {
        result = Utils.addDoublesWithPrecision(result, -remainder, precision);
        if (remainder > (base / 2)) {
          result = Utils.addDoublesWithPrecision(result, base, precision);
        }
      }
    }

    return result;
  }

  static double addDoublesWithPrecision(double a, double b, int precision) {
    double mod = pow(10.0, precision).toDouble();
    double difference = (a * mod) + (b * mod);

    if (mod != 0) {
      return difference.round() / mod;
    }

    return difference.round().toDouble();
  }

  static int getFractionDigitsLength(double value) {
    final fractionDigits = value.toString().split('.');
    return fractionDigits[1] == '0' ? 0 : fractionDigits[1].length;
  }

  static String toStringMatchingTemplateFractionPrecision(
      double value, double template) {
    final precision = getFractionDigitsLength(template);
    return value.toStringAsFixed(precision);
  }

  static double convertMgPerDlToMmolPerL(int mgPerDl, {double step = 0.01}) {
    return Utils.roundToMultipleOfBase(mgPerDl * 0.0555, step);
  }

  static int convertMmolPerLToMgPerDl(double mmolPerL) {
    return (mmolPerL * 18.018).round();
  }

  static double calculateCarbs(double carbsRatio, double portionSize,
      {double step = 0.01}) {
    return Utils.roundToMultipleOfBase(carbsRatio * portionSize / 100, step);
  }

  static double calculateCarbsRatio(double carbsPerPortion, double portionSize,
      {double step = 0.01}) {
    return portionSize > 0
        ? Utils.roundToMultipleOfBase(carbsPerPortion * 100 / portionSize, step)
        : 0;
  }

  static double calculatePortionSize(double carbsRatio, double carbsPerPortion,
      {double step = 0.01}) {
    return carbsRatio > 0
        ? Utils.roundToMultipleOfBase(carbsPerPortion * 100 / carbsRatio, step)
        : 0;
  }

  static String displayGlucose({int? mgPerDl, double? mmolPerL}) {
    return '${Settings.glucoseMeasurement == GlucoseMeasurement.mgPerDl ? (mgPerDl ?? '') : (mmolPerL ?? '')}';
  }

  static String displayGlucoseWithSuffix({int? mgPerDl, double? mmolPerL}) {
    return '${Utils.displayGlucose(mgPerDl: mgPerDl, mmolPerL: mmolPerL)} ${Settings.glucoseMeasurementSuffix}';
  }

  static String displayNutritionAmount(double amount,
      {bool cutExtraDigits = false}) {
    final value = cutExtraDigits && Utils.getFractionDigitsLength(amount) == 0
        ? amount.toInt().toString()
        : amount;
    return '$value${Settings.nutritionMeasurementSuffix}';
  }
}