import {Injectable} from "@angular/core";
import {Event} from "../../../common/event/Event";

@Injectable()
export class OverlayService {

  OnOverlayChange = new Event<boolean>();
  private scrollWidth: number = null;

  public showOverlay() {

    //disable scrolling
    document.getElementsByTagName('body')[0].style.overflow = 'hidden';
    this.OnOverlayChange.trigger(true);
  }

  public hideOverlay() {

    document.getElementsByTagName('body')[0].style.overflowY = 'scroll';
    this.OnOverlayChange.trigger(false);
  }

  getScrollbarWidth() {
    if (this.scrollWidth == null) {


      let outer = document.createElement("div");
      outer.style.visibility = "hidden";
      outer.style.width = "100px";
      outer.style.msOverflowStyle = "scrollbar"; // needed for WinJS apps

      document.body.appendChild(outer);

      let widthNoScroll = outer.offsetWidth;
      // force scrollbars
      outer.style.overflow = "scroll";

      // add innerdiv
      let inner = document.createElement("div");
      inner.style.width = "100%";
      outer.appendChild(inner);

      let widthWithScroll = inner.offsetWidth;

      // remove divs
      outer.parentNode.removeChild(outer);
      this.scrollWidth = widthNoScroll - widthWithScroll;
    }

    return this.scrollWidth;
  }

  getPhantomScrollbarWidth() {
    if (document.getElementsByTagName('body')[0].style.overflow == 'hidden') {
      return this.getScrollbarWidth();
    }
    return 0;
  }

}