import { greet } from './fixtures/greet.js';
import { getTimeOfDay } from './fixtures/get-time-of-day.js';
import * as getTimeOfDayModule from './fixtures/get-time-of-day.js';

// Suite
// -----------------------------------------------------------------------------
describe(`Example Tests`, function() {
  // Tests
  // ---------------------------------------------------------------------------
  describe('Jest & JSDOM basics', function() {
    test('dom manipulation (jsdom)', () => {
      const testText = 'This is a test';
      const testHTML = `<h1>Test</h1><p>${testText}</p>`;

      // Inject HTML
      document.body.innerHTML = testHTML;

      // Add class to <body> element and verify
      document.body.classList.add('foo');

      // Test HTML
      expect(document.body.getAttribute('class')).toEqual('foo');
      expect(document.body.textContent).toMatch(/Test/);
      expect(document.querySelectorAll('p')).toHaveLength(1);
      expect(document.querySelector('p').textContent).toBe(testText);
      expect(document.querySelector('table')).toBeNull();
    });

    // Snapshot Testing
    // https://jestjs.io/docs/en/snapshot-testing
    test('snapshot (jsdom)', () => {
      const testText = 'This is a test';
      const testHTML = `<h1>Test</h1><p>${testText}</p>`;

      // Inject HTML
      document.body.innerHTML = testHTML;

      // Add class to <body> element and verify
      document.body.classList.add('foo');

      const documentHTML = document.documentElement.outerHTML;

      // Test snapshots
      expect(documentHTML).toMatchSnapshot(); // See __snapshots__
      expect(documentHTML).toMatchInlineSnapshot(
        `"<html><head></head><body class=\\"foo\\"><h1>Test</h1><p>This is a test</p></body></html>"`
      );
    });
  });

  describe('Fake Timers', function() {
    test('data & time', () => {
      const fakeDate = new Date().setHours(1);

      jest.useFakeTimers('modern');
      jest.setSystemTime(fakeDate);

      const timeOfDay = getTimeOfDay();

      expect(timeOfDay).toBe('morning');
    });
  });

  describe('Mocks & Spys', function() {
    test('mock import/require dependency using jest.fn()', () => {
      const testModule = require('./fixtures/get-time-of-day.js');
      const { greet: testGreet } = require('./fixtures/greet.js');

      testModule.getTimeOfDay = jest.fn(() => 'day');

      const timeOfDay = testModule.getTimeOfDay();
      const greeting = testGreet('John');

      expect(timeOfDay).toBe('day');
      expect(greeting).toBe(`Good day, John!`);
    });

    test('mock import/require dependency using jest.doMock()', () => {
      const mockModulePath = './fixtures/get-time-of-day.js';

      jest.doMock(mockModulePath, () => ({
        __esModule: true,
        getTimeOfDay: jest.fn(() => 'night'),
      }));

      const mockGetTimeOfDay = require(mockModulePath).getTimeOfDay;
      const { greet: testGreet } = require('./fixtures/greet.js');

      const timeOfDay = mockGetTimeOfDay();
      const greeting = testGreet('John');

      expect(timeOfDay).toBe('night');
      expect(greeting).toBe(`Good night, John!`);
    });

    test('spy on native method using jest.spyOn()', () => {
      // Replace Math.random() implementation to return fixed value
      jest.spyOn(Math, 'random').mockImplementation(() => 0.1);

      expect(Math.random()).toEqual(0.1);
      expect(Math.random()).toEqual(0.1);
      expect(Math.random()).toEqual(0.1);
    });

    test('spy on import/require dependency using jest.spyOn()', () => {
      jest
        .spyOn(getTimeOfDayModule, 'getTimeOfDay')
        .mockImplementation(() => 'night');

      const timeOfDay = getTimeOfDay();
      const greeting = greet('John');

      expect(timeOfDay).toBe('night');
      expect(greeting).toBe(`Good night, John!`);
    });
  });
});
