'use strict';

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

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

var _index2 = _interopRequireDefault(_index);

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

var _index4 = _interopRequireDefault(_index3);

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

// This function will be a part of public API when UTC function will be implemented.
// See issue: https://github.com/date-fns/date-fns/issues/376
function startOfUTCWeek(dirtyDate, dirtyOptions) {
  if (arguments.length < 1) {
    throw new TypeError('1 argument required, but only ' + arguments.length + ' present');
  }

  var options = dirtyOptions || {};
  var locale = options.locale;
  var localeWeekStartsOn = locale && locale.options && locale.options.weekStartsOn;
  var defaultWeekStartsOn = localeWeekStartsOn == null ? 0 : (0, _index2.default)(localeWeekStartsOn);
  var weekStartsOn = options.weekStartsOn == null ? defaultWeekStartsOn : (0, _index2.default)(options.weekStartsOn);

  // Test if weekStartsOn is between 0 and 6 _and_ is not NaN
  if (!(weekStartsOn >= 0 && weekStartsOn <= 6)) {
    throw new RangeError('weekStartsOn must be between 0 and 6 inclusively');
  }

  var date = (0, _index4.default)(dirtyDate, options);
  var day = date.getUTCDay();
  var diff = (day < weekStartsOn ? 7 : 0) + day - weekStartsOn;

  date.setUTCDate(date.getUTCDate() - diff);
  date.setUTCHours(0, 0, 0, 0);
  return date;
}
module.exports = exports['default'];