import { VegaSlimmer } from '../../vega-slimmer/vega-slimmer-core';
import { Nullable } from '../../types/general';
/**
 * Abstract base slimmer with shared backdrop state.
 */
export declare abstract class SharedBackdropManager extends VegaSlimmer {
  private static backdropRef;
  private static consumers;
  private static visibilityIntents;
  private static consumerCount;
  private static visibilityIntentCount;
  /**
   * Register this consumer and ensure a shared backdrop exists.
   */
  connectedCallback(): void;
  /**
   * Unregister this consumer and remove shared backdrop when last consumer disconnects.
   */
  disconnectedCallback(): void;
  /**
   * Get current backdrop element.
   *
   * @returns {Nullable<HTMLVegaBackdropElement>} Backdrop element or null.
   */
  getBackdrop(): Nullable<HTMLVegaBackdropElement>;
  /**
   * Get current connected consumer count.
   *
   * @returns {number} Consumer count.
   */
  getConsumerCount(): number;
  /**
   * Clear all shared state and remove backdrop.
   */
  clear(): void;
  /**
   * Set visibility intent for this slimmer consumer.
   *
   * @param {boolean} visible - Desired visibility.
   */
  protected setVisibilityIntent(visible: boolean): void;
  /**
   * Whether this manager type handles backdrop existence lazily (on demand).
   * Override and return `true` in derived classes that create/remove the backdrop
   * per visibility cycle instead of at connectedCallback.
   *
   * @returns {boolean} False by default — backdrop is created eagerly at connect time.
   */
  protected usesLazyBackdrop(): boolean;
  /**
   * Ensure a backdrop exists for this subclass and return it.
   *
   * @returns {HTMLVegaBackdropElement} Shared backdrop element.
   */
  private ensureBackdrop;
  /**
   * Remove the shared backdrop for this subclass from the DOM.
   */
  private removeBackdrop;
  /**
   * Sync shared backdrop `visible` based on current visibility intents.
   */
  private syncVisibility;
  /**
   * Handles visibility sync for manager types that opt into lazy backdrop lifecycle.
   * When `shouldShow` is true the backdrop is created (if needed) and made visible.
   * When `shouldShow` is false the backdrop is removed from the DOM.
   *
   * @param {boolean} shouldShow - Whether the backdrop should be visible.
   */
  private syncLazyBackdrop;
  /**
   * Reset stale static shared state when the tracked backdrop is no longer in the DOM.
   */
  private resetStaleSharedState;
  /**
   * Create a backdrop element for the specific subclass use case.
   *
   * @param {Document} doc - The document reference.
   * @returns {HTMLVegaBackdropElement} The created backdrop element.
   */
  protected abstract createBackdrop(doc: Document): HTMLVegaBackdropElement;
}