dates.rb

def start_of_next_week(date)
  date + (7 - date.wday)
end

def date_of_next(day)
  date = Date.parse(day)
  delta = date > Date.today ? 0 : 7
  date + delta
end

def nth_day(day, now=Date.today)

  day.gsub!(/\b(in|on|of)\b/, '')

  day = day.split
  nth = day.shift.to_i
  first_day_name = day.first
  first_day_num = %w(su mo tu we th fr sa).index(first_day_name[0..1].downcase)
  month = %w(jan feb mar apr may jun jul aug sep oct nov dec).index(day.last[0..2].downcase) + 1

  first_day = Date.new(now.year, month)

  first_occurance = first_day + ((first_day_num - first_day.wday) % 7)

  nth == 1 ? first_occurance : first_occurance + (7 * (nth - 1))
end