import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { timer, Observable, BehaviorSubject } from 'rxjs';
import { includes, isEqual } from 'lodash';

@Injectable({
  providedIn: 'root'
})

export class CardService {
  private pollInstance: Observable<number>;
  private card: IContactlessCard = undefined;
  private pollingEnabled = true;

  public listen: BehaviorSubject<any> = new BehaviorSubject(undefined);

  constructor(private http: HttpClient) {
    this.pollInstance = timer(1000);
  }

  private handleCardRemovedEvent = () => {
    this.card = undefined;
    console.log('Card removed from reader');
  }

  private handleCardDetectedEvent = (response) => {
    console.log('Card detected');
    this.card = response;
    this.listen.next({
      card: this.card
    });
  }

  private handleCardStilPresentEvent = () => {
    console.log('Card still present');
  }

  private restartPoll = () => {
    if (this.pollingEnabled) {
      this.pollInstance.subscribe(() => {
        this.pollCardStatus();
      });
    }
  }

  public pollCardStatus = () => {
    console.log('pollCardStatus...');
    this.pollingEnabled = true;
    this.http.get('http://someendpoint:1234/card').subscribe((response: any) => {
      if (!response) {
        if (this.card) {
          this.handleCardRemovedEvent();
        }

        this.restartPoll();
        return;
      }

      if (!isEqual(this.card, response)) {
        this.handleCardDetectedEvent(response);
      } else {
        this.handleCardStilPresentEvent();
      }

      this.restartPoll();
    }, (error) => {
      this.restartPoll();
    });
  }

  public stopPolling = () => {
    console.log('Card polling cancelled');
    this.pollingEnabled = false;
  }

}

import { CardService } from './card.service';
import { TestBed, getTestBed, fakeAsync, tick } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';

describe('CardService Tests:', () => {
  let cardService: CardService;
  let injector: TestBed;
  let httpMock: HttpTestingController;
  let req;

  const mockCardResponse = {
    'type': 'SOME_CARD',
    'uid': 'xxx-111-222-ZZZ'
  };

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      providers: [CardService]
    });
    injector = getTestBed();
    cardService = injector.get(CardService);
    httpMock = injector.get(HttpTestingController);
  });

  afterEach(() => {
    httpMock.verify();
  });

  describe('when polling for card status changes', () => {
    beforeEach(() => {
      cardService.pollCardStatus();
      req = httpMock.expectOne('http://someendpoint:1234/card');
        expect(req.request.method).toBe('GET');
    });
    describe('and a new card is detected', () => {
      beforeEach(() => {
        req.flush(mockCardResponse);
      });
      it('should be able inspect the card details from the card service listen subject', () => {
        cardService.listen.subscribe((cardEvent) => {
          expect(cardEvent.card).toBe(mockCardResponse);
        });
      });
    });
  });
});

import { CardService } from './card.service';
import { TestBed, getTestBed, fakeAsync, tick } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';

describe('CardService Tests:', () => {
  let cardService: CardService;
  let injector: TestBed;
  let httpMock: HttpTestingController;
  let req;

  const mockCardResponse = {
    'type': 'SOME_CARD',
    'uid': 'xxx-111-222-ZZZ'
  };

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      providers: [CardService]
    });
    injector = getTestBed();
    cardService = injector.get(CardService);
    httpMock = injector.get(HttpTestingController);
  });

  afterEach(() => {
    httpMock.verify();
  });

  describe('when polling for card status changes', () => {
    beforeEach(() => {
      cardService.pollCardStatus();
      req = httpMock.expectOne('http://someendpoint:1234/card');
        expect(req.request.method).toBe('GET');
    });
    describe('and a new card is detected', () => {
      beforeEach(() => {
        req.flush(mockCardResponse);
      });
      it('should be able inspect the card details from the card service listen subject', () => {
        cardService.listen.subscribe((cardEvent) => {
          expect(cardEvent.card).toBe(mockCardResponse);
        });
      });
            describe('and the same card is detected on the next poll response', () => {
        beforeEach(() => {
          req = httpMock.expectOne('http://localhost:8080/services/card');
          expect(req.request.method).toBe('GET');
          req.flush(itsoCardResponse);
        });
        it('should log a message to say the same card is still present', ) => {
          expect(console.log).toHaveBeenCalledWith('Card still present');
        });
      });
    });
  });
});