import { ZIndexLayer, ZIndexContext, ContextTrackingConfig } from './types';
/**
 * Registration for a z-index allocation.
 */
export interface ZIndexRegistration {
    /** Unique registration ID */
    id: string;
    /** The element being registered */
    element: Element;
    /** Assigned layer */
    layer: ZIndexLayer;
    /** Assigned z-index value */
    zIndex: number;
    /** Priority within layer (higher = on top) */
    priority: number;
    /** Registration timestamp */
    registeredAt: number;
}
/**
 * Options for z-index registration.
 */
export interface ZIndexRegistrationOptions {
    /** Layer to register in */
    layer?: ZIndexLayer;
    /** Priority within layer (default: 0) */
    priority?: number;
    /** Whether to auto-increment within layer */
    autoIncrement?: boolean;
}
/**
 * Callback for z-index changes.
 */
export type ZIndexChangeCallback = (registration: ZIndexRegistration) => void;
/**
 * Manages z-index values across the application.
 *
 * @remarks
 * Provides a centralized system for z-index management that prevents
 * conflicts and ensures consistent layering behavior.
 *
 * @example
 * ```typescript
 * const manager = ZIndexManager.getInstance();
 *
 * // Register an element in the modal layer
 * const reg = manager.register(element, { layer: 'modal' });
 *
 * // Apply the z-index
 * element.style.zIndex = String(reg.zIndex);
 *
 * // When done:
 * manager.unregister(reg.id);
 * ```
 */
export declare class ZIndexManager {
    private static instance;
    /** Map of registration IDs to registrations */
    private readonly registrations;
    /** Map of elements to their registration IDs */
    private readonly elementToId;
    /** Map of layers to their registration IDs (ordered by z-index) */
    private readonly layerRegistrations;
    /** Current offset within each layer */
    private readonly layerOffsets;
    /** Change callbacks */
    private readonly changeCallbacks;
    /** Configuration */
    private readonly config;
    /** Registration ID counter */
    private registrationIdCounter;
    /**
     * Creates a new ZIndexManager instance.
     */
    private constructor();
    /**
     * Gets the singleton instance.
     */
    static getInstance(config?: Partial<ContextTrackingConfig>): ZIndexManager;
    /**
     * Resets the singleton instance.
     */
    static resetInstance(): void;
    /**
     * Registers an element for z-index management.
     *
     * @param element - Element to register
     * @param options - Registration options
     * @returns Registration object
     */
    register(element: Element, options?: ZIndexRegistrationOptions): ZIndexRegistration;
    /**
     * Unregisters an element.
     *
     * @param idOrElement - Registration ID or element to unregister
     */
    unregister(idOrElement: string | Element): void;
    /**
     * Updates an existing registration.
     *
     * @param id - Registration ID
     * @param options - New options
     * @returns Updated registration or null
     */
    update(id: string, options: Partial<ZIndexRegistrationOptions>): ZIndexRegistration | null;
    /**
     * Gets the registration for an element.
     *
     * @param element - Element to look up
     * @returns Registration or null
     */
    getRegistration(element: Element): ZIndexRegistration | null;
    /**
     * Gets all registrations in a layer.
     *
     * @param layer - Layer to query
     * @returns Array of registrations (sorted by z-index)
     */
    getLayerRegistrations(layer: ZIndexLayer): ZIndexRegistration[];
    /**
     * Gets the z-index for a layer.
     *
     * @param layer - Layer to query
     * @returns Base z-index for the layer
     */
    getLayerZIndex(layer: ZIndexLayer): number;
    /**
     * Gets the z-index context for an element.
     *
     * @param element - Element to query
     * @returns Z-index context
     */
    getZIndexContext(element: Element): ZIndexContext;
    /**
     * Gets the next available z-index in a layer.
     *
     * @param layer - Layer to query
     * @returns Next z-index value
     */
    getNextZIndex(layer: ZIndexLayer): number;
    /**
     * Gets the highest z-index currently in use in a layer.
     *
     * @param layer - Layer to query
     * @returns Highest z-index or base layer z-index
     */
    getHighestZIndex(layer: ZIndexLayer): number;
    /**
     * Subscribes to z-index changes.
     *
     * @param callback - Change callback
     * @returns Unsubscribe function
     */
    onChange(callback: ZIndexChangeCallback): () => void;
    /**
     * Brings an element to the front of its layer.
     *
     * @param element - Element to bring to front
     */
    bringToFront(element: Element): void;
    /**
     * Sends an element to the back of its layer.
     *
     * @param element - Element to send to back
     */
    sendToBack(element: Element): void;
    /**
     * Clears all registrations.
     */
    clear(): void;
    /**
     * Generates a unique registration ID.
     */
    private generateId;
    /**
     * Sorts registrations within a layer by z-index.
     */
    private sortLayer;
    /**
     * Rebalances z-index values within a layer.
     */
    private rebalanceLayer;
    /**
     * Notifies change callbacks.
     */
    private notifyChange;
    /**
     * Finds the stacking context root for an element.
     */
    private findStackingContextRoot;
    /**
     * Checks if an element creates a stacking context.
     */
    private createsStackingContext;
}
/**
 * Gets the z-index manager instance.
 */
export declare function getZIndexManager(): ZIndexManager;
/**
 * Registers an element for z-index management.
 *
 * @param element - Element to register
 * @param options - Registration options
 * @returns Registration object
 */
export declare function registerZIndex(element: Element, options?: ZIndexRegistrationOptions): ZIndexRegistration;
/**
 * Unregisters an element from z-index management.
 *
 * @param idOrElement - Registration ID or element
 */
export declare function unregisterZIndex(idOrElement: string | Element): void;
/**
 * Gets the z-index for a specific layer.
 *
 * @param layer - Layer to query
 * @returns Z-index value
 */
export declare function getLayerZIndex(layer: ZIndexLayer): number;
/**
 * Brings an element to the front of its layer.
 *
 * @param element - Element to bring to front
 */
export declare function bringToFront(element: Element): void;
/**
 * Sends an element to the back of its layer.
 *
 * @param element - Element to send to back
 */
export declare function sendToBack(element: Element): void;