import 'reflect-metadata';

import {
    Location,
} from '@angular/common';
import {
    NavigationEnd,
    NavigationStart,
    Router,
} from '@angular/router';

import {
    ScrollToTopOnRouteChangeService,
} from './scroll-to-top-on-route-change.service';

import { Observable } from 'rxjs';

const initScrollToTopOnRouteChange = (
    router?: Router,
    window?: Window,
) => {
    return new ScrollToTopOnRouteChangeService(
        router, window,
    );
};

describe('scrollToTopOnRouteChange', () => {
    test('Scrolls to top when going to a new url', () => {
        const nextUrl = '3';
        const navStart = new NavigationStart(0, nextUrl);
        const navEnd = new NavigationEnd(0, nextUrl, nextUrl);
        const router = {
            events: Observable.create((observer) => {
                observer.next(navStart);
                observer.next(navEnd);
            }),
        } as Router;
        const location = {} as Location;
        location.subscribe = jest.fn();
        const window = {} as Window;
        window.scrollTo = jest.fn();
        const scrollToTopOnRouteChange = initScrollToTopOnRouteChange(
            router, window,
        );
        scrollToTopOnRouteChange.routeTrail = [{
            scroll: {
                x: 0,
                y: 0,
            },
            url: '1',
        }, {
            scroll: {
                x: 0,
                y: 0,
            },
            url: '2',
        }];

        scrollToTopOnRouteChange.scrollToTopOnRouteChange();

        expect(window.scrollTo).toHaveBeenCalledWith(0, 0);
    });

    test('Scrolls to the previous y when going to the previous url', () => {
        jest.useFakeTimers();
        const nextUrl = '10';
        const navStart = new NavigationStart(0, nextUrl);
        const navEnd = new NavigationEnd(0, nextUrl, nextUrl);
        const router = {
            events: Observable.create((observer) => {
                observer.next(navStart);
                observer.next(navEnd);
                jest.runAllTimers();
            }),
        } as Router;
        const location = {} as Location;
        location.subscribe = jest.fn();
        const window = {} as Window;
        window.scrollTo = jest.fn();
        const scrollToTopOnRouteChange = initScrollToTopOnRouteChange(
            router, window,
        );
        scrollToTopOnRouteChange.routeTrail = [{
            scroll: {
                x: 0,
                y: 0,
            },
            url: '10',
        }, {
            scroll: {
                x: 0,
                y: 30,
            },
            url: '20',
        }];
        jest.runAllTimers();

        scrollToTopOnRouteChange.scrollToTopOnRouteChange();

        expect(window.scrollTo).toHaveBeenCalledWith(0, 30);
    });
});