import { ApplicationRef, EmbeddedViewRef, TemplateRef, ViewContainerRef } from '@angular/core';
import * as i0 from "@angular/core";
export declare class HeadwindOverlayService {
    private readonly _applicationRef;
    private _openedViewRefs;
    /**
     * By default, opening an overlay will create viewContainerRef to render overlay.
     * Once viewContainerRef is created, that is cached to this property to prevent creating multiple viewContainerRefs.
     */
    private _cachedViewContainerRef?;
    constructor(_applicationRef: ApplicationRef);
    get viewContainerRef(): ViewContainerRef;
    /**
     * Open a template as overlay
     * @param templateRef - TemplateRef to open as an overlay
     * @param onDestroy - Callback to call when destroying EmbeddedViewRef
     */
    open<C = any>(templateRef: TemplateRef<C>, onDestroy?: () => void): EmbeddedViewRef<C>;
    closeLatest(): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<HeadwindOverlayService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<HeadwindOverlayService>;
}