before validation do something, no method error - ruby-on-rails

Question

I have an model for notifications.
An notification can be posted by an User or an Contact.
and the notification can go to either a business or a notification_area.
people has to be filled, so when there is no user added it has to fill in the Contact that is logged in.
the notification_to has to be filled to so when there is no business added it has to take the latitude and the longitude and add the right area.
I have written the code but it won't work.
First I added it in the controller. But after looking around on google and this site I found I had to add it to the model.
But it still won't work.
What do I do wrong?
I get an error
class Notification < ActiveRecord::Base
belongs_to :people, :polymorphic => true
belongs_to :notification_to, :polymorphic => true
belongs_to :App_of_area
belongs_to :kind
before_validation :if_empty_add_the_other
#validates :photo, presence: true
validates :message, :status, :people_id, :people_type, :notification_to_id, :notification_to_type, :App_of_area_id, :kinds_id, presence: true
def if_empty_add_the_other
unless self.people_type.present?
self.people = current_contact
end
unless self.notification_to_id.present?
if self.longitude && self.latitude
#noa = NotificationArea.where( "latitude_A <= #{self.latitude} AND latitude_B >= #{self.latitude} AND longitude_A <= #{self.longitude} AND longitude_B >= #{self.longitude}")
self.notification_to = #noa.first
end
end
end
end
end

Answer 1

First thing first you should DRY up your code:
belongs_to :business
belongs_to :app_of_area
has_many :people, source_type: "Notification"
has_many :api_keys
before_validation :if_empty_add_the_other
has_secure_password
validates :name, :email, :rights, :password_confirmation, :app_of_area_id, :business_id, presence: true
validates_format_of :email, :with => /\A([^#\s]+)#((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
validates :email, uniqueness: true
validates :password, confirmation: true, length: { minimum: 6 }
:as is used for polymorphic associations, I believe you want to use :source_type as shown above. This would allow you to perform self.people << current_contact, but I address this more below.
Why was :App_of_area capitalized? Same with :App_of_area_id?
Your if_empty_add_the_other validation method has a lot wrong with it.
Use unless rather than if not.
Can the two if statements testing latitude and longitude be combined to if self.longitude && self.latitude?
You have to ask yourself, how is current_contact being passed to this function? Also, you're trying to set self.people equal to this phantom current_contact; self.people would contain multiple records, an array if you will, so setting an array equal to an object won't work, hence the self.people << current_contact above.