import 'reflect-metadata';

import {
    requiredMocks,
} from './../../../../test-mocks';
requiredMocks(jest);

import {
    ChangeDetectorRef,
} from '@angular/core';

import {
    Subscription,
} from 'rxjs';

import {
    empty,
    of,
} from 'rxjs';

import {
    BackgroundImageFadeInDirective,
} from './background-image-fade-in.directive';

import {
    ImagePreloaderService,
} from './../../services/index';

const initBackgroundImageFadeInDirective = (
    imagePreloaderService?: ImagePreloaderService,
    changeDetectorRef?: ChangeDetectorRef,
) => {
    return new BackgroundImageFadeInDirective(
        imagePreloaderService,
        changeDetectorRef,
    );
};

describe('ngOnChanges', () => {
    const initNgOnChanges = (
        imagePreloaderResult?,
    ) => {
        const imagePreloaderService = {} as ImagePreloaderService;
        imagePreloaderService.load = jest.fn().mockReturnValue(
            imagePreloaderResult || of(''),
        );
        const changeDetectorRef = {} as ChangeDetectorRef;
        changeDetectorRef.markForCheck = jest.fn();
        const backgroundImageFadeInDirective =
            initBackgroundImageFadeInDirective(
                imagePreloaderService,
                changeDetectorRef,
            );
        backgroundImageFadeInDirective.backgroundImageUrl = 'testBackgroundUrl';

        return {
            backgroundImageFadeInDirective,
            changeDetectorRef,
            imagePreloaderService,
        };
    };

    test('Sets isLoaded to true', () => {
        const {
            backgroundImageFadeInDirective,
        } = initNgOnChanges(empty());

        backgroundImageFadeInDirective.ngOnChanges();

        expect(backgroundImageFadeInDirective.isLoaded).toBe(false);
    });

    test('Calls imagePreloaderService.load with the backgroundUrl', () => {
        const {
            backgroundImageFadeInDirective,
            imagePreloaderService,
        } = initNgOnChanges();

        backgroundImageFadeInDirective.ngOnChanges();

        expect(imagePreloaderService.load).toHaveBeenCalledWith(
            'testBackgroundUrl',
        );
    });

    test('Does not change hostBackgroundUrl until the image is loaded', () => {
        const {
            backgroundImageFadeInDirective,
        } = initNgOnChanges(empty());
        backgroundImageFadeInDirective.hostBackgroundUrl = null;

        backgroundImageFadeInDirective.ngOnChanges();

        expect(backgroundImageFadeInDirective.hostBackgroundUrl)
            .toBeNull();
    });

    // tslint:disable-next-line
    test('When the image is loaded sets hostBackgroundUrl to the expected url', () => {
        const {
            backgroundImageFadeInDirective,
            imagePreloaderService,
        } = initNgOnChanges();

        backgroundImageFadeInDirective.ngOnChanges();

        expect(backgroundImageFadeInDirective.hostBackgroundUrl)
            .toBe('url(testBackgroundUrl)');
    });

    // tslint:disable-next-line
    test('When the image is loaded sets isLoaded to true', () => {
        const {
            backgroundImageFadeInDirective,
        } = initNgOnChanges();

        backgroundImageFadeInDirective.ngOnChanges();

        expect(backgroundImageFadeInDirective.isLoaded)
            .toBe(true);
    });

    // tslint:disable-next-line
    test('When the image is loaded calls changeDetectorRef.markForCheck', () => {
        const {
            backgroundImageFadeInDirective,
            changeDetectorRef,
        } = initNgOnChanges();

        backgroundImageFadeInDirective.ngOnChanges();

        expect(changeDetectorRef.markForCheck).toHaveBeenCalled();
    });
});

describe('ngOnDestroy', () => {
    test('Unsubscribes from the imagePreloaderService.load observable', () => {
        const subscription = new Subscription();
        subscription.unsubscribe = jest.fn();
        const imagePreloaderObservable = of('');
        imagePreloaderObservable.subscribe = jest.fn().mockReturnValue(
            subscription,
        );
        const imagePreloaderService = {} as ImagePreloaderService;
        imagePreloaderService.load = jest.fn().mockReturnValue(
            imagePreloaderObservable,
        );
        const backgroundImageFadeInDirective =
            initBackgroundImageFadeInDirective(imagePreloaderService);
        backgroundImageFadeInDirective.ngOnChanges();

        backgroundImageFadeInDirective.ngOnDestroy();

        expect(subscription.unsubscribe).toHaveBeenCalled();
    });
});