Find producer properties of items sold by a shop

app/models/producer_property.rb

@@ -8,6 +8,15 @@ class ProducerProperty < ActiveRecord::Base
   after_destroy :refresh_products_cache_from_destroy
 
 
+  scope :sold_by, ->(shop) {
+    joins(producer: {supplied_products: {variants: {exchanges: :order_cycle}}}).
+      merge(Exchange.outgoing).
+      merge(Exchange.to_enterprise(shop)).
+      merge(OrderCycle.active).
+      select('DISTINCT producer_properties.*')
+  }
+
+
   def property_name
     property.name if property
   end

app/models/spree/property_decorator.rb

@@ -1,5 +1,7 @@
 module Spree
   Property.class_eval do
+    has_many :producer_properties
+
     scope :applied_by, ->(enterprise) {
       select('DISTINCT spree_properties.*').
         joins(:product_properties).
@@ -14,6 +16,7 @@ module Spree
         select('DISTINCT spree_properties.*')
     }
 
+
     after_save :refresh_products_cache
 
     # When a Property is destroyed, dependent-destroy will destroy all ProductProperties,

spec/models/producer_property_spec.rb

@@ -1,14 +1,70 @@
 require 'spec_helper'
 
 describe ProducerProperty do
-  describe "products caching" do
-    let(:producer) { create(:supplier_enterprise) }
-    let(:pp) { producer.producer_properties.first }
+  let(:producer) { create(:supplier_enterprise) }
+  let(:pp) { producer.producer_properties.first }
+
+  before do
+    producer.set_producer_property 'Organic Certified', 'NASAA 54321'
+  end
+
+  describe ".sold_by" do
+    let!(:shop) { create(:distributor_enterprise) }
+    let!(:oc) { create(:simple_order_cycle, distributors: [shop], variants: [product.variants.first]) }
+    let(:product) { create(:simple_product, supplier: producer) }
+    let(:producer_other) { create(:supplier_enterprise) }
+    let(:product_other) { create(:simple_product, supplier: producer_other) }
+    let(:pp_other) { producer_other.producer_properties.first }
 
     before do
-      producer.set_producer_property 'Organic Certified', 'NASAA 54321'
+      producer_other.set_producer_property 'Spiffy', 'Ya'
     end
 
+    describe "with an associated producer property" do
+      it "returns the producer property" do
+        expect(ProducerProperty.sold_by(shop)).to eq [pp]
+      end
+    end
+
+    describe "with a producer property for a producer not carried by that shop" do
+      let!(:exchange) { create(:exchange, order_cycle: oc, incoming: true, sender: producer_other, receiver: oc.coordinator) }
+
+      it "doesn't return the producer property" do
+        expect(ProducerProperty.sold_by(shop)).not_to include pp_other
+      end
+    end
+
+    describe "with a producer property for a product in a different shop" do
+      let(:shop_other) { create(:distributor_enterprise) }
+      let!(:oc) { create(:simple_order_cycle, distributors: [shop], variants: [product.variants.first]) }
+      let!(:exchange) { create(:exchange, order_cycle: oc, incoming: false, sender: oc.coordinator, receiver: shop_other, variants: [product_other.variants.first]) }
+
+      it "doesn't return the producer property" do
+        expect(ProducerProperty.sold_by(shop)).not_to include pp_other
+      end
+    end
+
+    describe "with a producer property for a product in a closed order cycle" do
+      before do
+        oc.update_attributes! orders_close_at: 1.week.ago
+      end
+
+      it "doesn't return the producer property" do
+        expect(ProducerProperty.sold_by(shop)).not_to include pp
+      end
+    end
+
+    describe "with a duplicate producer property" do
+      let(:product2) { create(:simple_product, supplier: producer) }
+      let!(:oc) { create(:simple_order_cycle, distributors: [shop], variants: [product.variants.first, product2.variants.first]) }
+
+      it "doesn't return duplicates" do
+        expect(ProducerProperty.sold_by(shop).to_a.count).to eq 1
+      end
+    end
+  end
+
+  describe "products caching" do
     it "refreshes the products cache on change" do
       expect(OpenFoodNetwork::ProductsCache).to receive(:producer_property_changed).with(pp)
       pp.value = 123