import { Observable, BehaviorSubject } from 'rxjs';
import { SizeService } from './responsive.interfaces';

const getWindowSize = () => {
    return {
        height: window.innerHeight,
        width: window.innerWidth
    };
};

export class WindowSizeService implements SizeService {
    size: Observable<{width: number, height: number}>;

    constructor() {
        let windowSize = new BehaviorSubject(getWindowSize());
        this.size = windowSize.asObservable().distinctUntilChanged();

        Observable.fromEvent(window, 'resize')
            .map(getWindowSize)
            .subscribe(windowSize);
    }
}