move model validation into pattern classes and link from recurring_todo model

app/models/recurring_todos/weekly_repeat_pattern.rb

@@ -6,6 +6,27 @@ module RecurringTodos
       super user
     end
 
+    def every_x_week
+      get :every_other1
+    end
+
+    { monday: 1, tuesday: 2, wednesday: 3, thursday: 4, friday: 5, saturday: 6, sunday: 0 }.each do |day, number|
+      define_method("on_#{day}") do
+        on_xday number
+      end
+    end
+
+    def on_xday(n)
+      get(:every_day) && get(:every_day)[n, 1] != ' '
+    end
+
+    def validate
+      super
+      errors[:base] << "Every other nth week may not be empty for weekly recurrence setting" if every_x_week.blank?
+      something_set = %w{sunday monday tuesday wednesday thursday friday saturday}.inject(false) { |set, day| set || self.send("on_#{day}") }
+      errors[:base] << "You must specify at least one day on which the todo recurs" unless something_set
+    end
+
   end
   
 end