import {inject, TestBed} from '@angular/core/testing';

import {InputComponentManagerService} from './input-component-manager.service';
import {Step} from './step';

describe('InputComponentManagerService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [InputComponentManagerService]
    });
  });

  it('should be created', inject([InputComponentManagerService], (service: InputComponentManagerService) => {
    expect(service).toBeTruthy();
  }));

  it('should create a component if requesting the first one',
    inject([InputComponentManagerService], (service: InputComponentManagerService) => {
      const firstStep: Step = service.getFirst();
      expect(firstStep).toBeTruthy();
      expect(service.getFirst()).toBe(firstStep);
      expect(service.getAllComponents().length).toEqual(1);
    })
  );

  it('must not add a null Step', inject([InputComponentManagerService], (service: InputComponentManagerService) => {
    expect(() => service.register(null)).toThrowError();
    expect(service.getAllComponents().length).toEqual(0);
  }));

  it('must not add an undefined Step', inject([InputComponentManagerService], (service: InputComponentManagerService) => {
    expect(() => service.register(undefined)).toThrowError();
    expect(service.getAllComponents().length).toEqual(0);
  }));

  it('should register new Steps', inject([InputComponentManagerService], (service: InputComponentManagerService) => {
    service.register(new Step(99));
    expect(service.getAllComponents().length).toEqual(1);
    service.register(new Step(100));
    expect(service.getAllComponents().length).toEqual(2);
  }));

  it('should return a new step if the next step doesn\'t exist',
    inject([InputComponentManagerService], (service: InputComponentManagerService) => {
      // arrange
      const firstStep: Step = new Step(0);
      service.register(firstStep);

      // act
      const nextStep: Step = service.getNext(firstStep);

      // assert
      expect(service.getAllComponents().length).toEqual(2);
      expect(nextStep.index).toEqual(1);
    })
  );

  it('should return the next step if requested', inject([InputComponentManagerService], (service: InputComponentManagerService) => {
    // arrange
    const firstStep: Step = new Step(0);
    const nextStep: Step = new Step(1);
    service.register(firstStep);
    service.register(nextStep);

    // act
    const requestedStep: Step = service.getNext(firstStep);
    // assert
    expect(service.getAllComponents().length).toEqual(2);
    expect(requestedStep).toEqual(nextStep);
  }));
});