import type { Any, AnyObject, Callback, Options, SortSpec } from "../../types";
import { TimeUnit } from "../expression/date/_internal";
export type Boundary = "current" | "unbounded" | number;
export interface WindowOutputOption {
    readonly documents?: [Boundary, Boundary];
    readonly range?: [Boundary, Boundary];
    readonly unit?: TimeUnit;
}
export interface SetWindowFieldsInput {
    readonly partitionBy?: Any;
    readonly sortBy: SortSpec;
    readonly output: Record<string, {
        [x: string]: Any;
        window?: WindowOutputOption;
    }>;
}
export interface WindowOperatorInput {
    readonly parentExpr: SetWindowFieldsInput;
    readonly inputExpr: Any;
    readonly documentNumber: number;
    readonly field: string;
}
export type WindowTimeUnit = Exclude<TimeUnit, "year" | "quarter" | "month">;
/** used for testing only. check that the collection and optional key is cached */
export declare const cached: (xs: AnyObject[]) => boolean;
/**
 * A utility function that manages memoization for window operators.
 * It caches intermediate results for a given collection and field,
 * and ensures proper cleanup after processing.
 *
 * @template T - The type of the cached value.
 * @template R - The return type of the callback function.
 * @param collection - The collection of documents being processed.
 * @param expr - The window operator input containing metadata such as the field name and document number.
 * @param initialize - A callback function that computes and returns the cached value for the field.
 * @param fn - A callback function that processes the cached value and returns the result.
 * @returns The result of the `fn` callback function.
 * @throws Any errors thrown by the `fn` callback function.
 */
export declare function withMemo<T = Any, R = Any>(collection: AnyObject[], expr: Pick<WindowOperatorInput, "field" | "documentNumber">, initialize: Callback<T>, fn: Callback<R, T>): R;
/** Returns the position of a document in the $setWindowFields stage partition. */
export declare function rank(_: AnyObject, collection: AnyObject[], expr: WindowOperatorInput, options: Options, dense: boolean): Any;