I have a Model Campaign.

A Campaign has many Events.

Each Event has an attribute :days.

A Campaign also has_many Contacts.

Each Contact as a :date_entered attribute.

The from_today(contact,event) method returns a number, which is the number of days from the contact's :date_entered till today minus the event's :days. In other words, a positive number shows the number of days from today till the :days of the event is elapsed. If it is negative, if means that the number of days that has elapsed since the :date_entered is greater than the :days attribute of an event. In other words, the event is overdue.

What I would like to be able to do is do campaign.overdue and this would result in a total number of contacts that have an overdue event. It shouldn't count multiple events for a single contact, just one contact.

How do I do that? It seems like I would need to cycle through all the events for every contact and keep a counter but I'm assuming that there is a better way.