Adding primary taxon field to product

app/models/enterprise.rb

@@ -15,6 +15,7 @@ class Enterprise < ActiveRecord::Base
   has_and_belongs_to_many :payment_methods, join_table: 'distributors_payment_methods', class_name: 'Spree::PaymentMethod', foreign_key: 'distributor_id'
   has_and_belongs_to_many :shipping_methods, join_table: 'distributors_shipping_methods', class_name: 'Spree::ShippingMethod', foreign_key: 'distributor_id'
 
+
   delegate :latitude, :longitude, :city, :state_name, :to => :address
 
   accepts_nested_attributes_for :address

app/models/spree/classification_decorator.rb

@@ -0,0 +1,10 @@
+Spree::Classification.class_eval do
+  before_destroy :dont_destroy_if_primary_taxon
+
+  def dont_destroy_if_primary_taxon
+    if product.primary_taxon == taxon
+      errors.add :base,  "Taxon #{taxon.name} is the primary taxon of #{product.name} and cannot be deleted"
+      return false
+    end
+  end
+end

app/models/spree/product_decorator.rb

@@ -6,6 +6,7 @@ Spree::Product.class_eval do
 
 
   belongs_to :supplier, :class_name => 'Enterprise'
+  belongs_to :primary_taxon, class_name: 'Spree::Taxon'
 
   has_many :product_distributions, :dependent => :destroy
   has_many :distributors, :through => :product_distributions
@@ -13,9 +14,10 @@ Spree::Product.class_eval do
   accepts_nested_attributes_for :product_distributions, :allow_destroy => true
   delegate_belongs_to :master, :unit_value, :unit_description
 
-  attr_accessible :supplier_id, :distributor_ids, :product_distributions_attributes, :group_buy, :group_buy_unit_size, :variant_unit, :variant_unit_scale, :variant_unit_name, :unit_value, :unit_description, :notes
+  attr_accessible :supplier_id, :primary_taxon_id, :distributor_ids, :product_distributions_attributes, :group_buy, :group_buy_unit_size, :variant_unit, :variant_unit_scale, :variant_unit_name, :unit_value, :unit_description, :notes
 
   validates_presence_of :supplier
+  validates_presence_of :primary_taxon
 
   validates_presence_of :variant_unit, if: :has_variants?
   validates_presence_of :variant_unit_scale,
@@ -25,6 +27,7 @@ Spree::Product.class_eval do
 
   after_initialize :set_available_on_to_now, :if => :new_record?
   after_save :update_units
+  before_save :add_primary_taxon_to_taxons
 
 
   # -- Joins
@@ -118,10 +121,6 @@ Spree::Product.class_eval do
     order_cycle.variants_distributed_by(distributor).where(product_id: self)
   end
 
-  def primary_taxon
-    self.taxons.order.first
-  end
-
   # Build a product distribution for each distributor
   def build_product_distributions_for_user user
     Enterprise.is_distributor.managed_by(user).each do |distributor|
@@ -157,6 +156,10 @@ Spree::Product.class_eval do
     end
   end
 
+  def add_primary_taxon_to_taxons
+    taxons << primary_taxon unless taxons.find_by_id(primary_taxon)
+  end
+
   def self.all_variant_unit_option_types
     Spree::OptionType.where('name LIKE ?', 'unit_%%')
   end

db/migrate/20140522044009_add_primary_taxon_to_products.rb

@@ -0,0 +1,5 @@
+class AddPrimaryTaxonToProducts < ActiveRecord::Migration
+  def change
+    add_column :spree_products, :primary_taxon_id, :integer
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20140522015012) do
+ActiveRecord::Schema.define(:version => 20140522044009) do
 
   create_table "adjustment_metadata", :force => true do |t|
     t.integer "adjustment_id"
@@ -681,6 +681,7 @@ ActiveRecord::Schema.define(:version => 20140522015012) do
     t.float    "variant_unit_scale"
     t.string   "variant_unit_name"
     t.text     "notes"
+    t.integer  "primary_taxon_id"
   end
 
   add_index "spree_products", ["available_on"], :name => "index_products_on_available_on"

spec/factories.rb

@@ -2,6 +2,9 @@ require 'ffaker'
 require 'spree/core/testing_support/factories'
 
 FactoryGirl.define do
+  factory :classification, class: Spree::Classification do
+  end
+
   factory :order_cycle, :parent => :simple_order_cycle do
     coordinator_fees { [create(:enterprise_fee, enterprise: coordinator)] }
 
@@ -150,6 +153,9 @@ end
 
 
 FactoryGirl.modify do
+  factory :product do
+    primary_taxon { Spree::Taxon.first || FactoryGirl.create(:taxon) }
+  end
   factory :simple_product do
     # Fix product factory name sequence with Kernel.rand so it is not interpreted as a Spree::Product method
     # Pull request: https://github.com/spree/spree/pull/1964
@@ -157,6 +163,7 @@ FactoryGirl.modify do
     sequence(:name) { |n| "Product ##{n} - #{Kernel.rand(9999)}" }
 
     supplier { Enterprise.is_primary_producer.first || FactoryGirl.create(:supplier_enterprise) }
+    primary_taxon { Spree::Taxon.first || FactoryGirl.create(:taxon) }
     on_hand 3
 
     variant_unit 'weight'

spec/models/spree/classification_spec.rb

@@ -0,0 +1,15 @@
+require 'spec_helper'
+
+module Spree
+  describe Classification do
+    let(:product) { create(:simple_product) }
+    let(:taxon) { create(:taxon) }
+    let(:classification) { create(:classification, taxon: taxon, product: product) }
+
+    it "won't destroy if classification is the primary taxon" do
+      product.primary_taxon = taxon
+      classification.destroy.should be_false
+      classification.errors.messages[:base].should == ["Taxon #{taxon.name} is the primary taxon of #{product.name} and cannot be deleted"]
+    end
+  end
+end

spec/models/spree/product_spec.rb

@@ -5,6 +5,7 @@ module Spree
 
     describe "associations" do
       it { should belong_to(:supplier) }
+      it { should belong_to(:primary_taxon) }
       it { should have_many(:product_distributions) }
     end
 
@@ -13,6 +14,12 @@ module Spree
         create(:product).should be_valid
       end
 
+      it "requires a primary taxon" do
+        product = create(:simple_product)
+        product.primary_taxon = nil
+        product.should_not be_valid
+      end
+
       it "requires a supplier" do
         product = create(:simple_product)
         product.supplier = nil
@@ -551,10 +558,10 @@ module Spree
     describe "Taxons" do
       let(:taxon1) { create(:taxon) }
       let(:taxon2) { create(:taxon) }
-      let(:product) { create(:simple_product, taxons: [taxon1, taxon2]) }
+      let(:product) { create(:simple_product) }
 
       it "returns the first taxon as the primary taxon" do
-        product.primary_taxon.should == taxon1
+        product.taxons.should == [product.primary_taxon]
       end
     end
   end