import toInteger from '../_lib/toInteger/index.js'
import toDate from '../toDate/index.js'
import getWeek from '../getWeek/index.js'

/**
 * @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|String|Number} date - the date to be changed
 * @param {Number} week - the week of the new date
 * @param {Options} [options] - the object with options. See [Options]{@link https://date-fns.org/docs/Options}
 * @param {0|1|2} [options.additionalDigits=2] - passed to `toDate`. See [toDate]{@link https://date-fns.org/docs/toDate}
 * @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.additionalDigits` must be 0, 1 or 2
 * @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) {
  if (arguments.length < 2) {
    throw new TypeError(
      '2 arguments required, but only ' + arguments.length + ' present'
    )
  }

  var date = toDate(dirtyDate, dirtyOptions)
  var week = toInteger(dirtyWeek)
  var diff = getWeek(date, dirtyOptions) - week
  date.setDate(date.getDate() - diff * 7)
  return date
}
