import { Injectable, NgZone } from '@angular/core';
import { removeItem } from '../../common/utils';

@Injectable({
  providedIn: 'root',
})
export class IntervalUpdateService {
  private interval: any;
  private actions: (() => void)[] = [];
  constructor(private zone: NgZone) {
  }
  subscribe(action: () => void) {
    this.actions.push(action);

    if (!this.interval) {
      this.zone.runOutsideAngular(() => {
        this.interval = setInterval(() => {
          this.actions.forEach(a => a());
        }, 1000 * 10);
      });
    }

    return () => {
      removeItem(this.actions, action);

      if (this.actions.length === 0) {
        clearInterval(this.interval);
        this.interval = undefined;
      }
    };
  }
  toggle(action: () => void) {
    let unsubscribe: (() => void) | undefined;

    return (on: boolean) => {
      if (on && !unsubscribe) {
        unsubscribe = this.subscribe(action);
      } else if (!on && unsubscribe) {
        unsubscribe();
        unsubscribe = undefined;
      }
    };
  }
}