Complex form issue

I'm designing an application that has products and suppliers. Single product has_many suppliers and each supplier has unique supplier code for each product.

The form would facilitate something like 1. Select supplier from the list --> 2. Type the supplier code related to supplier in the text field

The supplier codes can be added dynamically.

#Product model class Product < ActiveRecord::Base   has_many :supplier_codes   has_many :suppliers, :through => :supplier_codes end

#Supplier_code model class SupplierCode < ActiveRecord::Base    belongs_to :product    belongs_to :suppliers end

#Supplier model class Supplier < ActiveRecord::Base    has_many :supplier_codes    has_many :products, :through => :supplier_codes end

The supplier_code table has these columns product_id supplier_id code

I'm stuck with developing controller and form. trying out many things but no success so far. Any help welcome.