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

import { ApiService } from './api.service';
import {HttpClientTestingModule, HttpTestingController} from '@angular/common/http/testing';
import {HttpClient} from '@angular/common/http';
import {of} from 'rxjs/internal/observable/of';

describe('ApiService', () => {
  let service: ApiService;
  const httpClientMock = {
    get: () => {},
    post: () => {},
    put: () => {},
    delete: () => {},
  } as any;
  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      providers: [
        {provide: String, useValue: ''},
        {provide: HttpClient, useValue: httpClientMock}
      ]
    });
    service = TestBed.inject(ApiService);
  });

  it('should be created', () => {
    expect(service).toBeTruthy();
  });

  it('should call through to the httpClient when various REST calls are made', () => {
    const postSpy = spyOn(httpClientMock, 'post').and.returnValue(of({}));
    const getSpy = spyOn(httpClientMock, 'get').and.returnValue(of({}));
    const putSpy = spyOn(httpClientMock, 'put').and.returnValue(of({}));
    const deleteSpy = spyOn(httpClientMock, 'delete').and.returnValue(of({}));

    expect(postSpy).toHaveBeenCalledTimes(0);
    expect(getSpy).toHaveBeenCalledTimes(0);
    expect(putSpy).toHaveBeenCalledTimes(0);

    service.create('snacks');
    service.getAll();
    service.get('candy');
    service.update({foo: 'bar'}, '1234', '2');
    service.delete('candy');

    expect(postSpy).toHaveBeenCalledTimes(1);
    expect(getSpy).toHaveBeenCalledTimes(2);
    expect(putSpy).toHaveBeenCalledTimes(1);
    expect(deleteSpy).toHaveBeenCalledTimes(1);
  });

  it('should call update without a version tag', fakeAsync(() => {
    spyOn(httpClientMock, 'put').and.returnValue(of('put was called!'));
    service.update({foo: '123'}, 'foo')
      .subscribe(value => expect(value).toBe('put was called!'));
  }));
  it('should not put if resource is empty', fakeAsync(() => {
    service.update(null, 'foo')
      .subscribe(value => expect(value).toBe('Empty resource, nothing to put'));
  }));
});