'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = getWeekYear;

var _index = require('../_lib/toInteger/index.js');

var _index2 = _interopRequireDefault(_index);

var _index3 = require('../toDate/index.js');

var _index4 = _interopRequireDefault(_index3);

var _index5 = require('../startOfWeek/index.js');

var _index6 = _interopRequireDefault(_index5);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * @name getWeekYear
 * @category Week-Numbering Year Helpers
 * @summary Get the local week-numbering year of the given date.
 *
 * @description
 * Get the local week-numbering year of the given date.
 * 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 given 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 {Number} the local week-numbering year
 * @throws {TypeError} 1 argument 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
 * // Which week numbering year is 26 December 2004 with the default settings?
 * var result = getWeekYear(new Date(2004, 11, 26))
 * //=> 2005
 *
 * @example
 * // Which week numbering year is 26 December 2004 if week starts on Saturday?
 * var result = getWeekYear(new Date(2004, 11, 26), { weekStartsOn: 6 })
 * //=> 2004
 *
 * @example
 * // Which week numbering year is 26 December 2004 if the first week contains 4 January?
 * var result = getWeekYear(new Date(2004, 11, 26), { firstWeekContainsDate: 4 })
 * //=> 2004
 */
function getWeekYear(dirtyDate, dirtyOptions) {
  if (arguments.length < 1) {
    throw new TypeError('1 argument required, but only ' + arguments.length + ' present');
  }

  var date = (0, _index4.default)(dirtyDate, dirtyOptions);
  var year = date.getFullYear();

  var options = dirtyOptions || {};
  var locale = options.locale;
  var localeFirstWeekContainsDate = locale && locale.options && locale.options.firstWeekContainsDate;
  var defaultFirstWeekContainsDate = localeFirstWeekContainsDate == null ? 1 : (0, _index2.default)(localeFirstWeekContainsDate);
  var firstWeekContainsDate = options.firstWeekContainsDate == null ? defaultFirstWeekContainsDate : (0, _index2.default)(options.firstWeekContainsDate);

  // Test if weekStartsOn is between 1 and 7 _and_ is not NaN
  if (!(firstWeekContainsDate >= 1 && firstWeekContainsDate <= 7)) {
    throw new RangeError('firstWeekContainsDate must be between 1 and 7 inclusively');
  }

  var firstWeekOfNextYear = new Date(0);
  firstWeekOfNextYear.setFullYear(year + 1, 0, firstWeekContainsDate);
  firstWeekOfNextYear.setHours(0, 0, 0, 0);
  var startOfNextYear = (0, _index6.default)(firstWeekOfNextYear, dirtyOptions);

  var firstWeekOfThisYear = new Date(0);
  firstWeekOfThisYear.setFullYear(year, 0, firstWeekContainsDate);
  firstWeekOfThisYear.setHours(0, 0, 0, 0);
  var startOfThisYear = (0, _index6.default)(firstWeekOfThisYear, dirtyOptions);

  if (date.getTime() >= startOfNextYear.getTime()) {
    return year + 1;
  } else if (date.getTime() >= startOfThisYear.getTime()) {
    return year;
  } else {
    return year - 1;
  }
}
module.exports = exports['default'];