import 'dart:math';

import 'package:flutter/material.dart';

class EnergyBilanceModel extends ChangeNotifier {

  double _startVelocity = 0;
  double _endVelocity = 0;
  double _startHeight = 0;
  double _endHeight = 0;

  double _weight = 0;

  static const double _gravity = 9.81; //in m/s^2

  double get deltaVelocity => _endVelocity - _startVelocity;
  double get deltaHeight => _endHeight - _startHeight;

  double get potentialEnergy => _weight * _gravity * deltaHeight;
  double get kineticEnergy => _weight * pow(deltaVelocity, 2) / 2;

  void setStartVelocity(double v){
    _startVelocity = v;
    notifyListeners();
  }

  void setEndVelocity(double v){
    _endVelocity = v;
    notifyListeners();
  }

  void setStartHeight(double h){
    _startHeight = h;
    notifyListeners();
  }

  void setEndHeight(double h){
    _endHeight = h;
    notifyListeners();
  }

  void setWeight(double m){
    _weight = m;
    notifyListeners();
  }
}