import { blink } from './blink';
import { sineOut } from 'svelte/easing';

const internals = {
  response: null
};

describe('blink', () => {

  test('it has a default delay of 0ms', () => {

    const response = blink(document.createElement('div'), {});

    expect(response.delay).toBe(0);
  });

  test('it allows delay to be overridden', () => {

    const response = blink(document.createElement('div'), {
      delay: 300
    });

    expect(response.delay).toBe(300);
  });

  test('it has a default duration of 400ms', () => {

    const response = blink(document.createElement('div'), {});

    expect(response.duration).toBe(400);
  });

  test('it allows delay to be overridden', () => {

    const response = blink(document.createElement('div'), {
      duration: 999
    });

    expect(response.duration).toBe(999);
  });

  test('it uses sineOut as the default easing function', () => {

    const response = blink(document.createElement('div'), {});

    expect(response.easing).toBe(sineOut);
  });

  test('it allows easing function to be overridden', () => {

    const response = blink(document.createElement('div'), {
      easing: () => 'excellent'
    });

    expect(response.easing()).toBe('excellent');
  });

  describe('css animation function', () => {

    beforeEach(() => {

      const div = document.createElement('div');
      div.style.width = '100px';
      div.style.height = '200px';
      internals.response = blink(div, {});
    });

    test('It starts with with zeroed width and height', () => {

      const css = internals.response.css(0, 1);
      expect(css).toContain('width: 0px');
      expect(css).toContain('height: 0px');
    });

    test('It grows to full height and 0 width in first 20%', () => {

      const css = internals.response.css(0.2, 0.8);
      expect(css).toContain('width: 0px');
      expect(css).toContain('height: 200px');
    });

    test('It expands to full height by the end', () => {

      const css = internals.response.css(1, 0);
      expect(css).toContain('width: 100px');
      expect(css).toContain('height: 200px');
    });

    test('It keeps element vertically centered by adjusting the margin', () => {

      const css = internals.response.css(0.1, 0.9);
      expect(css).toContain('margin: 50px 50px');
      expect(css).toContain('height: 100px');
    });

    test('It keeps element horizontally centered by adjusting the margin', () => {

      const css = internals.response.css(0.6, 0.4);
      expect(css).toContain('margin: 0px 25px');
      expect(css).toContain('width: 50px');
    });
  });
});