import getWeek from '../getWeek/index'
import toDate from '../toDate/index'
import toInteger from '../_lib/toInteger/index'
import requiredArgs from '../_lib/requiredArgs/index'
/**
* @name setWeek
* @category Week Helpers
* @summary Set the local week to the given date.
*
* @description
* Set the local week to the given date, saving the weekday number.
* The exact calculation depends on the values of
* `options.weekStartsOn` (which is the index of the first day of the week)
* and `options.firstWeekContainsDate` (which is the day of January, which is always in
* the first week of the week-numbering year)
*
* Week numbering: https://en.wikipedia.org/wiki/Week#Week_numbering
*
* ### v2.0.0 breaking changes:
*
* - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
*
* @param {Date|Number} date - the date to be changed
* @param {Number} week - the week of the new date
* @param {Object} [options] - an object with options.
* @param {Locale} [options.locale=defaultLocale] - the locale object. See [Locale]{@link https://date-fns.org/docs/Locale}
* @param {0|1|2|3|4|5|6} [options.weekStartsOn=0] - the index of the first day of the week (0 - Sunday)
* @param {1|2|3|4|5|6|7} [options.firstWeekContainsDate=1] - the day of January, which is always in the first week of the year
* @returns {Date} the new date with the local week set
* @throws {TypeError} 2 arguments required
* @throws {RangeError} `options.weekStartsOn` must be between 0 and 6
* @throws {RangeError} `options.firstWeekContainsDate` must be between 1 and 7
*
* @example
* // Set the 1st week to 2 January 2005 with default options:
* var result = setWeek(new Date(2005, 0, 2), 1)
* //=> Sun Dec 26 2004 00:00:00
*
* @example
* // Set the 1st week to 2 January 2005,
* // if Monday is the first day of the week,
* // and the first week of the year always contains 4 January:
* var result = setWeek(new Date(2005, 0, 2), 1, {
* weekStartsOn: 1,
* firstWeekContainsDate: 4
* })
* //=> Sun Jan 4 2004 00:00:00
*/
export default function setWeek(dirtyDate, dirtyWeek, dirtyOptions) {
requiredArgs(2, arguments)
var date = toDate(dirtyDate)
var week = toInteger(dirtyWeek)
var diff = getWeek(date, dirtyOptions) - week
date.setDate(date.getDate() - diff * 7)
return date
}