export class SubscriptionObject {
  subscribedPropsDic: any = {};
  public readyForUpdate: boolean = false;
  private handler: (() => void) | undefined;

  constructor(
    public value: any,
    private onSubscribe: (
      prop: string | number | symbol,
      subcriptionInstance: SubscriptionObject,
    ) => void,
    private onDestroy: (subcriptionInstance: SubscriptionObject) => void,
  ) {
    const instance = this;
    const subscriptionProxyHandler: ProxyHandler<any> = {
      get: function (target, name) {
        if (!instance.subscribedPropsDic[name]) instance.subscribeTo(name);
        return target[name];
      },
    };
    this.value = new Proxy(value, subscriptionProxyHandler);
  }

  private subscribeTo = (prop: string | number | symbol) => {
    this.subscribedPropsDic[prop] = true;
    this.onSubscribe(prop, this);
  };

  public destroy = () => {
    this.onDestroy(this);
  };

  public setHandler(fn: () => void) {
    this.handler = fn;
  }

  public update() {
    if (this.handler) this.handler();
    this.readyForUpdate = false;
  }
}