How can I have a single helper work on different models passed to it?

Question

I am probably going to need to refactor in two steps since I'm still developing the project and learning the use-cases as I go along since it is to scratch my own itch. I have three models: Letters, Calls, Emails. They have some similarilty, but I anticipate they also will have some different attributes as you can tell from their description.

Ideally I could refactor them as Events, with a type as Letters, Calls, Emails, but didn't know how to extend subclasses.

My immediate need is this: I have a helper which checks on the status of whether an email (for example) was sent to a specific contact:

def show_email_status(contact, email)

  @contact_email = ContactEmail.find(:first,
     :conditions => {:contact_id => contact.id, :email_id => email.id })
  if ! @contact_email.nil?
    return @contact_email.status
  end
end

I realized that I, of course, want to know the status for whether a call was made to a contact as well, so I wrote:

def show_call_status(contact, call)

  @contact_call = ContactCall.find(:first, 
     :conditions => {:contact_id => contact.id, :call_id => call.id })
  if ! @contact_call.nil?
    return @contact_call.status
  end
end

I would love to be able to just have a single helper show_status where I can say show_status(contact,call) or show_status(contact,email) and it would know whether to look for the object @contact_call or @contact_email.

Yes, it would be easier if it were just @contact_event, but I want to do a small refactoring while I get the program up and running, and this would make the ability to do a history for a given contact much easier.

Thanks!

NOTE: Currently I have status as an attribute of contact_email, contact_call, etc. Contact_email only gets created when the email is sent, so there is not contact_email if an email hasn't been sent, and I need to know that the status is "unsent"...

Answer 1

Since you already have show_call_status and show_email_status, you can write a third show_letter_status.

Then use this:

def show_status(contact, call_or_email_or_letter)
  model_name = call_or_email_or_letter.class.name.tableize.singularize
  send "show_#{model_name}_status", contact, call_or_email_or_letter
end

Answer 2

You can move the helper to the Contact model.

class Contact < ActiveRecord::Base

  has_many :contact_emails
  has_many :contact_calls
  has_many :contact_letters

  def event_status event
    assoc_name = "Contact#{event.class.name}".pluralize.underscore
    foreign_key = "%s_id" % event.class.name.underscore
    ce = send(assoc_name).first(:conditions => {foreign_key => event.id})
    ce ? ce.status : nil
  end

end

Now you can get the status as follows:

contact.event_status(email1)
contact.event_status(letter2)
contact.event_status(call12)

This alleviates the need for different helpers. One method to address different events.

Answer 3

Assuming from the example, that your associations look like this:

class Contact
    has_many :emails, :through => :contact_emails
    has_many :calls, :through => :contact_calls
end

and status is an attribute on ContactEmail / ContactCall, but you need a status for Email / Call object, then (based on Kandada answer here):

class Contact 
  def event_status(event)
    event_type = event.class.name
    foreign_key = ("%s_id" % event_type.downcase).to_sym

    assoc = "Contact#{event_type}".tableize
    contact_event = send(:assoc).first(:conditions => {foreign_key => event.id})
    contact_event.try(:status) 
  end
end