Storing estimated prices for standing line items in the database

app/controllers/admin/standing_orders_controller.rb

@@ -9,7 +9,6 @@ module Admin
     respond_to :json
 
     def index
-
       respond_to do |format|
         format.html do
           @payment_methods = Spree::PaymentMethod.managed_by(spree_current_user)
@@ -25,7 +24,7 @@ module Admin
     end
 
     def create
-      form = StandingOrderForm.new(@standing_order, params[:standing_order])
+      form = StandingOrderForm.new(@standing_order, params[:standing_order], fee_calculator)
       if form.save
         render_as_json @standing_order, fee_calculator: fee_calculator
       else
@@ -34,7 +33,7 @@ module Admin
     end
 
     def update
-      form = StandingOrderForm.new(@standing_order, params[:standing_order])
+      form = StandingOrderForm.new(@standing_order, params[:standing_order], fee_calculator)
       if form.save
         render_as_json @standing_order, ams_prefix: params[:ams_prefix], fee_calculator: fee_calculator
       else

app/forms/standing_order_form.rb

@@ -3,20 +3,22 @@ class StandingOrderForm
   include ActiveModel::Conversion
   include ActiveModel::Validations
 
-  attr_accessor :standing_order, :params
+  attr_accessor :standing_order, :params, :fee_calculator
 
   delegate :orders, :order_cycles, :bill_address, :ship_address, :standing_line_items, to: :standing_order
   delegate :shop, :shop_id, :customer, :customer_id, :begins_at, :ends_at, :standing_order_orders, to: :standing_order
   delegate :shipping_method, :shipping_method_id, :payment_method, :payment_method_id, to: :standing_order
   delegate :shipping_method_id_changed?, :shipping_method_id_was, :payment_method_id_changed?, :payment_method_id_was, to: :standing_order
 
-  def initialize(standing_order, params={})
+  def initialize(standing_order, params={}, fee_calculator=nil)
     @standing_order = standing_order
     @params = params
+    @fee_calculator = fee_calculator
   end
 
   def save
     @standing_order.transaction do
+      validate_price_estimates
       @standing_order.assign_attributes(params)
 
       initialise_orders!
@@ -129,4 +131,25 @@ class StandingOrderForm
   def line_items_from_future_and_undated_orders(variant_id)
     Spree::LineItem.where(order_id: future_and_undated_orders, variant_id: variant_id)
   end
+
+  def validate_price_estimates
+    item_attributes = params[:standing_line_items_attributes]
+    return unless item_attributes.present?
+    if fee_calculator
+      item_attributes.each do |item_attrs|
+        if variant = Spree::Variant.find_by_id(item_attrs[:variant_id])
+          item_attrs[:price_estimate] = price_estimate_for(variant)
+        else
+          item_attrs.delete(:price_estimate)
+        end
+      end
+    else
+      item_attributes.each { |item_attrs| item_attrs.delete(:price_estimate) }
+    end
+  end
+
+  def price_estimate_for(variant)
+    fees = fee_calculator.indexed_fees_for(variant)
+    (variant.price + fees).to_d
+  end
 end

app/serializers/api/admin/standing_line_item_serializer.rb

@@ -6,7 +6,9 @@ class Api::Admin::StandingLineItemSerializer < ActiveModel::Serializer
   end
 
   def price_estimate
-    if options[:fee_calculator]
+    if object.price_estimate
+      object.price_estimate
+    elsif options[:fee_calculator]
       (object.variant.price + options[:fee_calculator].indexed_fees_for(object.variant)).to_f
     else
       "?"

db/migrate/20161130001339_add_price_estimate_to_standing_line_items.rb

@@ -0,0 +1,5 @@
+class AddPriceEstimateToStandingLineItems < ActiveRecord::Migration
+  def change
+    add_column :standing_line_items, :price_estimate, :decimal, :precision => 8,  :scale => 2
+  end
+end

db/schema.rb

@@ -1065,11 +1065,12 @@ ActiveRecord::Schema.define(:version => 20170921065259) do
   end
 
   create_table "standing_line_items", :force => true do |t|
-    t.integer  "standing_order_id", :null => false
-    t.integer  "variant_id",        :null => false
-    t.integer  "quantity",          :null => false
-    t.datetime "created_at",        :null => false
-    t.datetime "updated_at",        :null => false
+    t.integer  "standing_order_id",                               :null => false
+    t.integer  "variant_id",                                      :null => false
+    t.integer  "quantity",                                        :null => false
+    t.datetime "created_at",                                      :null => false
+    t.datetime "updated_at",                                      :null => false
+    t.decimal  "price_estimate",    :precision => 8, :scale => 2
   end
 
   add_index "standing_line_items", ["standing_order_id"], :name => "index_standing_line_items_on_standing_order_id"

spec/forms/standing_order_form_spec.rb

@@ -217,5 +217,57 @@ module OpenFoodNetwork
         expect(line_items.map(&:quantity)).to eq [4]
       end
     end
+
+    describe "validating price_estimates on standing line items" do
+      let(:params) { { } }
+      let(:form) { StandingOrderForm.new(nil, params) }
+
+      context "when line_item params are present" do
+        before { allow(form).to receive(:price_estimate_for) }
+
+        it "does nothing" do
+          form.send(:validate_price_estimates)
+          expect(form.params[:standing_line_items_attributes]).to be nil
+        end
+      end
+
+      context "when line_item params are present" do
+        before do
+          params[:standing_line_items_attributes] = [ { id: 1, price_estimate: 2.50 }, { id: 2, price_estimate: 3.50 }]
+        end
+
+        context "when no fee calculator is present" do
+          before { allow(form).to receive(:price_estimate_for) }
+
+          it "clears price estimates on all standing line item attributes" do
+            form.send(:validate_price_estimates)
+            attrs = form.params[:standing_line_items_attributes]
+            expect(attrs.first.keys).to_not include :price_estimate
+            expect(attrs.last.keys).to_not include :price_estimate
+            expect(form).to_not have_received(:price_estimate_for)
+          end
+        end
+
+        context "when a fee calculator is present" do
+          let(:variant) { create(:variant) }
+          let(:fee_calculator) { double(:fee_calculator) }
+
+          before do
+            allow(form).to receive(:fee_calculator) { fee_calculator }
+            allow(form).to receive(:price_estimate_for) { 5.30 }
+            params[:standing_line_items_attributes].first[:variant_id] = variant.id
+          end
+
+          it "clears price estimates on standing line item attributes without variant ids" do
+            form.send(:validate_price_estimates)
+            attrs = form.params[:standing_line_items_attributes]
+            expect(attrs.first.keys).to include :price_estimate
+            expect(attrs.last.keys).to_not include :price_estimate
+            expect(attrs.first[:price_estimate]).to eq 5.30
+            expect(form).to have_received(:price_estimate_for).with(variant)
+          end
+        end
+      end
+    end
   end
 end