госы_автобус_dart

enum PassengerGender { male, female }

class BusPriceCounter {
  double countPrice({
    required double distance,
    required int age,
    required PassengerGender gender,
    bool hasBenefit = false,
  }) {
    final discountCoeff = _countDiscountCoeff(
      age: age,
      gender: gender,
      hasBenefit: hasBenefit,
    );
    final distancePrice = _countDistancePrice(distance);
    return discountCoeff * distancePrice;
  }

  double _countDiscountCoeff({
    required int age,
    required PassengerGender gender,
    bool hasBenefit = false,
  }) {
    if (hasBenefit || age <= 3) {
      return 0;
    }
    if (7 <= age && age <= 18) {
      return 0.5;
    }

    if (gender == PassengerGender.male && age >= 65 ||
        gender == PassengerGender.female && age >= 60) {
      return 0.5;
    }
    return 1;
  }

  double _countDistancePrice(double distance) {
    if (distance <= 20) {
      return 100;
    }
    if (distance > 20 && distance <= 100) {
      return 150;
    }
    if (distance > 100 && distance <= 200) {
      return 200;
    }
    return 400;
  }
}

void main() {
  final counter = BusPriceCounter();

  // Example usage
  final price1 = counter.countPrice(
    distance: 15,
    age: 25,
    gender: PassengerGender.male,
  );
  print('Price 1: $price1'); // Expected: 100.0

  final price2 = counter.countPrice(
    distance: 50,
    age: 10,
    gender: PassengerGender.female,
  );
  print('Price 2: $price2'); // Expected: 75.0

  final price3 = counter.countPrice(
    distance: 150,
    age: 70,
    gender: PassengerGender.male,
  );
  print('Price 3: $price3'); // Expected: 100.0

  final price4 = counter.countPrice(
    distance: 300,
    age: 5,
    gender: PassengerGender.female,
  );
  print('Price 4: $price4'); // Expected: 0.0

  final price5 = counter.countPrice(
    distance: 80,
    age: 30,
    gender: PassengerGender.female,
    hasBenefit: true,
  );
  print('Price 5: $price5'); // Expected: 0.0

  final price6 = counter.countPrice(
    distance: 250,
    age: 40,
    gender: PassengerGender.male,
  );
  print('Price 6: $price6'); // Expected: 400.0
}