class Pagy::Calendar::Month

def months_in(time)
  (time.year * 12) + time.month
end

def page_offset_at(time)
  months_in(time.beginning_of_month) - months_in(@initial)
end

def setup_unit_vars
  super
  @initial = @starting.beginning_of_month
  @final   = @ending.next_month.beginning_of_month
  @pages   = @last = (months_in(@final) - months_in(@initial))
  @from    = starting_time_for(@page)
  @to      = @from.next_month
end

def starting_time_for(page)
  @initial.months_since(time_offset_for(page))
end