/*!
 * Copyright (c) 2026-present, Okta, Inc. and/or its affiliates. All rights reserved.
 * The Okta software accompanied by this notice is provided pursuant to the Apache License, Version 2.0 (the "License.")
 *
 * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 * See the License for the specific language governing permissions and limitations under the License.
 */
import { type UnsubscribeMessageSubscription } from "./tools/createMessageBus.js";
export type CloseBackdrop = () => void;
export type OpenBackdropArgs = {
    backdropId: string;
    /**
     * The z-index the overlay renders at. A higher layer paints above a lower one no matter which opened first, so it decides the order before opening order does.
     */
    layer: number;
};
export type CloseBackdropArgs = Pick<OpenBackdropArgs, "backdropId">;
export type BackdropStack = {
    /**
     * The ids of every open backdrop, bottom first: by layer, then by opening order. The last one is on top. The array keeps its identity until the stack changes, so it is safe to return from a `useSyncExternalStore` snapshot.
     */
    getOpenBackdropIds: () => readonly string[];
    /**
     * Put a backdrop on top of every open backdrop in its layer. Returns the function that takes it back off.
     */
    openBackdrop: (args: OpenBackdropArgs) => CloseBackdrop;
    subscribeToOpenBackdropIds: (listener: () => void) => UnsubscribeMessageSubscription;
};
/**
 * Create a stack of open backdrops, so stacked overlays can agree on which one paints.
 */
export declare const createBackdropStack: () => BackdropStack;
/**
 * The one stack every Odyssey overlay in this bundle shares.
 */
export declare const defaultBackdropStack: BackdropStack;
//# sourceMappingURL=backdropStack.d.ts.map