import 'package:energy/algorithms/energy.dart';
import 'package:test/test.dart';

void main() {
  const double oneTon = 1000.0; // kg
  const double tenToStop = 50000.0; // J
  const double oneTonTenMetersDown = 98100.0; // J

  group('energy', () {
    test('none', () {
      expect(freedEnergy(oneTon, 0, 0, 0, 0), 0);
      expect(freedEnergy(oneTon, 0, 0, 20, 20), 0);
    });
    group('potential', () {
      test('10 m down', () {
        expect(freedEnergy(oneTon, 10, 0, 0, 0), oneTonTenMetersDown);
        expect(freedPotential(oneTon, 10, 0), oneTonTenMetersDown);
      });
      test('10 m up', () {
        expect(freedEnergy(oneTon, 0, 10, 0, 0), -oneTonTenMetersDown);
        expect(freedPotential(oneTon, 0, 10), -oneTonTenMetersDown);
      });
      test('20 m down', () {
        expect(freedEnergy(oneTon, 2 * 10, 0, 0, 0), 2 * oneTonTenMetersDown);
        expect(potential(oneTon, 2 * 10), 2 * oneTonTenMetersDown);
      });
    });

    group('kinetic', () {
      test('10 to 0', () {
        expect(freedEnergy(oneTon, 0, 0, 10, 0), tenToStop);
        expect(freedKinetic(oneTon, 10, 0), tenToStop);
      });
      test('0 to 10', () {
        expect(freedEnergy(oneTon, 0, 0, 0, 10), -tenToStop);
        expect(freedKinetic(oneTon, 0, 10), -tenToStop);
      });
      test('20 to 0', () {
        expect(freedEnergy(oneTon, 0, 0, 20, 0), 4 * tenToStop);
        expect(freedKinetic(oneTon, 20, 0), 4 * tenToStop);
      });
    });

    group('sum', () {
      test('10 down & 10 to 0', () {
        expect(
            freedEnergy(oneTon, 10, 0, 10, 0), oneTonTenMetersDown + tenToStop);
      });
      test('10 up & 0 to 10', () {
        expect(
            freedEnergy(oneTon, 0, 10, 0, 10), -(tenToStop + oneTonTenMetersDown));
      });

      test('10 down & 0 to 10', () {
        expect(
            freedEnergy(oneTon, 10, 0, 0, 10), oneTonTenMetersDown - tenToStop);
      });
      test('10 up & 10 to 0', () {
        expect(
            freedEnergy(oneTon, 0, 10, 10, 0), tenToStop - oneTonTenMetersDown);
      });
    });
  });
}