import type { ContextOptions, DateArg } from "./types.ts";
/**
 * The {@link subISOWeekYears} function options.
 */
export interface SubISOWeekYearsOptions<DateType extends Date = Date>
  extends ContextOptions<DateType> {}
/**
 * @name subISOWeekYears
 * @category ISO Week-Numbering Year Helpers
 * @summary Subtract the specified number of ISO week-numbering years from the given date.
 *
 * @description
 * Subtract the specified number of ISO week-numbering years from the given date.
 *
 * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
 *
 * @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
 * @typeParam ResultDate - The result `Date` type, it is the type returned from the context function if it is passed, or inferred from the arguments.
 *
 * @param date - The date to be changed
 * @param amount - The amount of ISO week-numbering years to be subtracted.
 * @param options - The options
 *
 * @returns The new date with the ISO week-numbering years subtracted
 *
 * @example
 * // Subtract 5 ISO week-numbering years from 1 September 2014:
 * const result = subISOWeekYears(new Date(2014, 8, 1), 5)
 * //=> Mon Aug 31 2009 00:00:00
 */
export declare function subISOWeekYears<
  DateType extends Date,
  ResultDate extends Date = DateType,
>(
  date: DateArg<DateType>,
  amount: number,
  options?: SubISOWeekYearsOptions<ResultDate> | undefined,
): ResultDate;
