/** The slice of the singleton modal this controller reads and writes. */
export interface OwnableModal {
    /** Monotonic per-open token; bumped each time a caller claims the singleton. */
    generation: number;
    onBackdrop: (() => void) | null;
    /** Invoked on the current owner when a newer open claims the modal. */
    onSupersede: (() => void) | null;
}
export interface ModalOwnership {
    /** True while this open still owns the singleton modal. */
    owns(): boolean;
    /**
     * Settle this open exactly once. `action` (the owner-only DOM hide plus the
     * promise resolve/reject) runs only if this open still owns the modal and has
     * not already settled - a superseded or already-settled open is a no-op.
     * Returns whether `action` ran.
     */
    settleOwned(action: () => void): boolean;
}
/**
 * Claim the singleton modal for a fresh open. Any earlier open that never settled
 * is superseded: the generation is bumped first (so the prior open's `owns()`
 * turns false and its late callbacks can no longer touch the modal we now own),
 * then its supersede hook is invoked so its promise rejects.
 *
 * @param onSuperseded rejects THIS open's promise when a later open supersedes it.
 */
export declare function claimModalOpen(m: OwnableModal, onSuperseded: () => void): ModalOwnership;