move recurrence text helpers into patterns. move next_date calculation into

respective models

app/models/recurring_todos/monthly_repeat_pattern.rb

@@ -75,6 +75,54 @@ module RecurringTodos
       end
     end
 
+    def get_next_date(previous)
+      start = determine_start(previous)
+      day = every_x_day
+      n = get(:every_other2)
+
+      case recurrence_selector
+      when 0 # specific day of the month
+        if (previous && start.mday >= day) || (previous.nil? && start.mday > day)
+          # there is no next day n in this month, search in next month
+          #
+          #  start += n.months
+          #
+          # The above seems to not work. Fiddle with timezone. Looks like we hit a
+          # bug in rails here where 2008-12-01 +0100 plus 1.month becomes
+          # 2008-12-31 +0100. For now, just calculate in UTC and convert back to
+          # local timezone.
+          #
+          #  TODO: recheck if future rails versions have this problem too
+          start = Time.utc(start.year, start.month, start.day)+n.months
+          start = Time.zone.local(start.year, start.month, start.day)
+
+          # go back to day
+        end
+        Time.zone.local(start.year, start.month, day)
+
+      when 1 # relative weekday of a month
+        the_next = get_xth_day_of_month(every_xth_day, day_of_week, start.month, start.year)
+        if the_next.nil? || the_next <= start
+          # the nth day is already passed in this month, go to next month and try
+          # again
+
+          # fiddle with timezone. Looks like we hit a bug in rails here where
+          # 2008-12-01 +0100 plus 1.month becomes 2008-12-31 +0100. For now, just
+          # calculate in UTC and convert back to local timezone.
+          #  TODO: recheck if future rails versions have this problem too
+          the_next = Time.utc(the_next.year, the_next.month, the_next.day)+n.months
+          the_next = Time.zone.local(the_next.year, the_next.month, the_next.day)
+
+          # TODO: if there is still no match, start will be set to nil. if we ever
+          # support 5th day of the month, we need to handle this case
+          the_next = get_xth_day_of_month(every_xth_day, day_of_week, the_next.month, the_next.year)
+        end
+        the_next
+      else
+        raise Exception.new, "unknown monthly recurrence selection (#{self.recurrence_selector})"
+      end
+    end
+
   end
   
 end