var parse = require('../parse/index.js')
var getDaysInMonth = require('../get_days_in_month/index.js')

/**
 * @category Month Helpers
 * @summary Set the month to the given date.
 *
 * @description
 * Set the month to the given date.
 *
 * @param {Date|String|Number} date - the date to be changed
 * @param {Number} month - the month of the new date
 * @returns {Date} the new date with the month setted
 *
 * @example
 * // Set February to 1 September 2014:
 * var result = setMonth(new Date(2014, 8, 1), 1)
 * //=> Sat Feb 01 2014 00:00:00
 */
function setMonth (dirtyDate, dirtyMonth) {
  var date = parse(dirtyDate)
  var month = Number(dirtyMonth)
  var year = date.getFullYear()
  var day = date.getDate()

  var dateWithDesiredMonth = new Date(0)
  dateWithDesiredMonth.setFullYear(year, month, 15)
  dateWithDesiredMonth.setHours(0, 0, 0, 0)
  var daysInMonth = getDaysInMonth(dateWithDesiredMonth)
  // Set the last day of the new month
  // if the original date was the last day of the longer month
  date.setMonth(month, Math.min(day, daysInMonth))
  return date
}

module.exports = setMonth