setTimeForDate.swift

func setTimeForDate (date: NSDate, hour: Int, minute: Int, second: Int) -> NSDate {
  let unitFlags = [.Year, .Month, .Day, .Hour, .Minute, .Second] as NSCalendarUnit
  // calendar here is NSCalendar.currentCalendar()
  let dateComponents = calendar.components(unitFlags, fromDate: date)
  dateComponents.hour = hour
  dateComponents.minute = minute
  dateComponents.second = second
  let newDate = calendar.dateFromComponents(dateComponents)
  print(newDate)
  return newDate!
}