export type ReferencePrefix = 'BK' | 'QRY';
export declare const REFERENCE_NUMBER_MAX_ATTEMPTS = 20;
export declare const DEFAULT_BOOKING_PREFIX = "BK";
export type SqlExecutor = (sql: string, params: unknown[]) => Promise<unknown[]>;
export declare function normalizeReferencePrefix(prefix: string | null | undefined, fallback: string): string;
export declare function extractReferenceDigits(reference: string | null | undefined): string | null;
export declare function allocateUniqueReferenceNumber(subject: ReferencePrefix, tenantId: string, query: SqlExecutor, displayPrefix?: string): Promise<string>;
export declare function allocateBookingNumberFromQuery(queryNumber: string | null | undefined, tenantId: string, query: SqlExecutor, displayPrefix?: string): Promise<string>;