import { Injectable, OnDestroy } from '@angular/core';
import { map, debounceTime } from 'rxjs/operators';
import { Subscription, fromEvent } from 'rxjs';

interface Action {
	id: string;
	action: () => any;
}

@Injectable({
	providedIn: 'root'
})


export class ResizeContentService implements OnDestroy {

	private subscription: Subscription;
	private listOfCallbacks: Action[] = [];


	constructor() {
			const resizeEvent = fromEvent(window, 'resize');
			this.subscription = (resizeEvent.pipe(map(() => {
			}), debounceTime(50)).subscribe(() => {
				this.listOfCallbacks.forEach(f => f.action());
				})
		);
		}

	registerCallback(id: string, action: any) {
		const actionToBePerformed: Action = { id: id, action: action};
		this.listOfCallbacks.push(actionToBePerformed);
	}

	destroyCallback(id: string): void {
		const filteredList = this.listOfCallbacks.filter(action => action.id !== id);
		this.listOfCallbacks = filteredList;
	}

	ngOnDestroy(): void {
		this.subscription.unsubscribe();
	}

}