import { EventEmitter } from '@angular/core';
import { ModalWindowComponent } from '../components/modal-window.component';
/**
 * Maintains the indices of all active modal windows and reports index
 * changes to the relevant modals so that each modal can layer itself
 * accordingly with the correct z-index.
*/
export declare class ModalManagerService {
    /** Informs subscribers when the index of a modal on the stack changes */
    modalIndexChanged: EventEmitter<[ModalWindowComponent, number]>;
    /** Maintains the currently-displayed modal windows in order */
    private activeModals;
    /** Starting point for the z-index of the layered modal windows */
    startingZIndex: number;
    /**
     * Pushes the provided modal to the top of the stack, if it's not already there, and
     * returns its index so that the component knows where to place itself via z-index
     * @param modal A reference to the the modal component instance that we want to register
     */
    push(modal: ModalWindowComponent): number;
    /**
     * Removes the specified modal, if it exists.
     * @param modal The modal to remove
     */
    removeModal(modal: ModalWindowComponent): void;
}