Marketplace: DeliveryArea fees as a percentage (#2643)

- #2641

Todo:
- [x] A `DeliveryArea` may have a delivery fee as a percentage
- [x] `Orders` to a `DeliveryArea` with a Percentage Fee calculate the fee correctly.
- [x] `Shoppers` see a description of the Delivery Fee when building their Order.

April has adjusted her fee schedule, and catering orders are now 12% and regular orders are $10 flat. This simplifies things quite a bit; hooray! But alas, we had already built out stuff to support different fees for every vendor and across regions (i.e. SF it's $20, Oakland it's $10)

I think it's probably for the best to leave that flexibility in for now, and have updated it so we now have another attribute for how to calculate fees.

I've made the Executive Decision to treat these fees as cumulative (i.e. $10 plus 12%) if both the `DeliveryArea#price` and the `DeliveryArea#fee_as_percentage` are set; rather than trying to figure out how to break ties or validate only one is set or whatever. This may be a poor decision.

app/furniture/marketplace/cart/delivery_area_component.html.erb

@@ -9,6 +9,7 @@
           <%- if single_delivery_area? %>
             <div><small>Orders outside of this location will be subject to cancellation.</small></div>
           <% end %>
+          <div>Delivery Fee: <%= fee_description %></div>
         </div>
       </div>
       <div class="text-right">

app/furniture/marketplace/cart/delivery_area_component.rb

@@ -12,6 +12,24 @@ def dom_id
       super(cart, :delivery_area)
     end
 
+    def price
+      helpers.humanized_money_with_symbol(delivery_area.price)
+    end
+
+    def fee_as_percentage
+      "#{helpers.number_to_percentage(delivery_area.fee_as_percentage, precision: 0)} of subtotal"
+    end
+
+    def fee_description
+      if delivery_area.charges_fee_as_percentage? && delivery_area.charges_fee_as_price?
+        "#{price} plus #{fee_as_percentage}"
+      elsif !delivery_area.charges_fee_as_percentage? && delivery_area.charges_fee_as_price?
+        price
+      elsif delivery_area.charges_fee_as_percentage? && !delivery_area.charges_fee_as_price?
+        fee_as_percentage
+      end
+    end
+
     def single_delivery_area?
       cart.marketplace.delivery_areas.unarchived.size == 1
     end

app/furniture/marketplace/delivery.rb

@@ -5,6 +5,7 @@ class Delivery < Record
     belongs_to :marketplace
     belongs_to :shopper
     belongs_to :delivery_area
+    has_many :ordered_products, inverse_of: :order, foreign_key: :cart_id
 
     has_encrypted :delivery_address
     has_encrypted :contact_phone_number
@@ -16,7 +17,11 @@ def delivery_window
     alias_method :window, :delivery_window
 
     def fee
-      delivery_area&.price.presence || Money.new(0)
+      delivery_area&.delivery_fee(subtotal: product_total) || Money.new(0)
+    end
+
+    def product_total
+      ordered_products.sum(0, &:price_total)
     end
 
     def details_filled_in?

app/furniture/marketplace/delivery_area.rb

@@ -16,5 +16,27 @@ class DeliveryArea < Record
 
     attribute :delivery_window
     monetize :price_cents
+
+    def delivery_fee(subtotal: nil)
+      if charges_fee_as_price? && !charges_fee_as_percentage?
+        price
+      elsif charges_fee_as_price? && charges_fee_as_percentage? && subtotal.present?
+        price + fee_as_percentage_of(subtotal:)
+      elsif !charges_fee_as_price? && charges_fee_as_percentage? && subtotal.present?
+        fee_as_percentage_of(subtotal:)
+      end
+    end
+
+    def charges_fee_as_percentage?
+      fee_as_percentage.present? && fee_as_percentage.positive?
+    end
+
+    def charges_fee_as_price?
+      price.present? && price.positive?
+    end
+
+    def fee_as_percentage_of(subtotal:)
+      subtotal * (fee_as_percentage.to_f / 100)
+    end
   end
 end

app/furniture/marketplace/delivery_area_component.html.erb

@@ -16,7 +16,7 @@
     </div>
 
     <div class="text-right mt-3">
-      <%= price  %>
+      <%= fee_description  %>
     </div>
   </div>
 

app/furniture/marketplace/delivery_area_component.rb

@@ -13,6 +13,20 @@ def price
       helpers.humanized_money_with_symbol(delivery_area.price)
     end
 
+    def fee_as_percentage
+      "#{helpers.number_to_percentage(delivery_area.fee_as_percentage, precision: 0)} of subtotal"
+    end
+
+    def fee_description
+      if delivery_area.charges_fee_as_percentage? && delivery_area.charges_fee_as_price?
+        "#{price} plus #{fee_as_percentage}"
+      elsif !delivery_area.charges_fee_as_percentage? && delivery_area.charges_fee_as_price?
+        price
+      elsif delivery_area.charges_fee_as_percentage? && !delivery_area.charges_fee_as_price?
+        fee_as_percentage
+      end
+    end
+
     def example_cart
       delivery_area.marketplace.carts.new(delivery_area: delivery_area)
     end

app/furniture/marketplace/delivery_area_policy.rb

@@ -9,7 +9,7 @@ def create?
     alias_method :update?, :create?
 
     def permitted_attributes(_)
-      [:label, :price, :order_by, :delivery_window, :restore]
+      [:label, :price, :fee_as_percentage, :order_by, :delivery_window, :restore]
     end
 
     class Scope < ApplicationScope

app/furniture/marketplace/delivery_areas/_form.html.erb

@@ -1,7 +1,8 @@
 <%= render CardComponent.new(dom_id: dom_id(delivery_area), classes: "mt-3") do %>
   <%= form_with(model: delivery_area.location) do |delivery_area_form| %>
     <%= render "text_field", attribute: :label, form: delivery_area_form %>
-    <%= render "money_field", attribute: :price, form: delivery_area_form, required: true, step: 0.01, min: 0 %>
+    <%= render "money_field", attribute: :price, form: delivery_area_form, step: 0.01, min: 0 %>
+    <%= render "percentage_field", attribute: :fee_as_percentage, form: delivery_area_form, step: 1, min: 0, max: 100 %>
     <%= render "text_field", attribute: :order_by, form: delivery_area_form %>
     <%= render "text_field", attribute: :delivery_window, form: delivery_area_form %>
 

app/furniture/marketplace/order.rb

@@ -42,7 +42,7 @@ def delivery
     end
 
     def delivery_fee
-      delivery_area&.price
+      delivery_area&.delivery_fee(subtotal: product_total)
     end
     delegate :delivery_window, to: :delivery_area, allow_nil: true
 

app/views/application/_percentage_field.html.erb

@@ -0,0 +1,13 @@
+<% required = local_assigns[:required] || false %>
+<% min = local_assigns[:min] || 0 %>
+<% step = local_assigns[:step] || 0.01 %>
+<div>
+  <%= form.label attribute, class: "block font-medium text-gray-700"%>
+  <div class="relative mt-1 rounded-md shadow-sm">
+    <%= form.number_field attribute, class: "block w-full rounded-md border-gray-300 !pl-7 !pr-12 focus:border-indigo-500 focus:ring-indigo-500", step: step, min: min, required: required %>
+    <div class="pointer-events-none absolute bottom-0 right-0 flex items-center pt-3 pr-3">
+      <span class="text-gray-500">%</span>
+    </div>
+  </div>
+  <%= render partial: "error", locals: { model: form.object, attribute: attribute } %>
+</div>

db/migrate/20241010004915_marketplace_add_fee_as_percentage_to_delivery_areas.rb

@@ -0,0 +1,5 @@
+class MarketplaceAddFeeAsPercentageToDeliveryAreas < ActiveRecord::Migration[7.1]
+  def change
+    add_column :marketplace_delivery_areas, :fee_as_percentage, :integer
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2024_05_31_200256) do
+ActiveRecord::Schema[7.1].define(version: 2024_10_10_004915) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
@@ -159,6 +159,7 @@
     t.string "delivery_window"
     t.string "order_by"
     t.datetime "discarded_at"
+    t.integer "fee_as_percentage"
     t.index ["discarded_at"], name: "index_marketplace_delivery_areas_on_discarded_at"
     t.index ["marketplace_id"], name: "index_marketplace_delivery_areas_on_marketplace_id"
   end

spec/factories/furniture/marketplace/marketplace.rb

@@ -200,7 +200,6 @@
     marketplace
 
     label { Faker::Address.city }
-    price { Faker::Commerce.price }
     trait :archived do
       discarded_at { 1.hour.ago }
     end

spec/furniture/marketplace/delivery_area_component_spec.rb

@@ -9,11 +9,31 @@
   let(:delivery_area) { create(:marketplace_delivery_area) }
 
   it { is_expected.to have_content(delivery_area.label) }
-  it { is_expected.to have_content(vc_test_controller.view_context.humanized_money_with_symbol(delivery_area.price)) }
-
   it { is_expected.to have_css("a[href='#{polymorphic_path(delivery_area.location)}'][data-turbo-method=delete]") }
   it { is_expected.to have_link(I18n.t("archive.link_to", href: polymorphic_path(delivery_area.location))) }
 
+  context "when the delivery area has a fee as percentage" do
+    let(:delivery_area) { create(:marketplace_delivery_area, fee_as_percentage: 10) }
+
+    it { is_expected.to have_content("10% of subtotal") }
+  end
+
+  context "when the delivery area has a price" do
+    let(:delivery_area) { create(:marketplace_delivery_area, price: 10) }
+
+    it { is_expected.to have_content("$10.00") }
+  end
+
+  context "when the delivery are has a price and a fee as percentage" do
+    let(:delivery_area) { create(:marketplace_delivery_area, price: 10, fee_as_percentage: 10) }
+
+    it { is_expected.to have_content("$10.00 plus 10% of subtotal") }
+  end
+
+  context "when the delivery area has neither a price nor a percentage" do
+    it { is_expected.to have_no_content("of subtotal") }
+  end
+
   context "when the delivery area is Discarded" do
     let(:delivery_area) { create(:marketplace_delivery_area, :archived) }
 

spec/furniture/marketplace/delivery_areas_controller_request_spec.rb

@@ -26,9 +26,10 @@
 
     specify do
       perform_request
-      assert_select("form input", 5)
+      assert_select("form input", 6)
       assert_select("#delivery_area_label")
       assert_select("#delivery_area_price")
+      assert_select("#delivery_area_fee_as_percentage")
       assert_select("#delivery_area_order_by")
       assert_select("#delivery_area_delivery_window")
     end

spec/furniture/marketplace/delivery_areas_system_spec.rb

@@ -9,6 +9,21 @@
     sign_in(space.members.first, space)
   end
 
+  describe "Setting a Delivery Fee" do
+    it "allows Percentage-Based Delivery Fees" do
+      visit(polymorphic_path(marketplace.location(child: :delivery_areas)))
+      click_link("Add Delivery Area")
+      fill_in("Label", with: "Percentage Based Delivery Area")
+      fill_in("Fee as percentage", with: "10")
+
+      expect { click_button("Create") }.to change(marketplace.delivery_areas, :count).by(1)
+      expect(page).to have_content("Percentage Based Delivery Area")
+      within(marketplace.delivery_areas.order(created_at: :desc).first) do
+        expect(page).to have_content("10% of subtotal")
+      end
+    end
+  end
+
   describe "Restoring Delivery Areas" do
     let!(:delivery_area) do
       create(:marketplace_delivery_area, :archived, marketplace:,
@@ -18,7 +33,7 @@
     it "Makes the DeliveryArea selectable" do
       visit(polymorphic_path(marketplace.location(child: :delivery_areas)))
       click_link("Archived Delivery Areas")
-      within("##{dom_id(delivery_area)}") do
+      within(delivery_area) do
         click_link("Edit")
       end
 
@@ -40,7 +55,7 @@
         cart = create(:marketplace_cart, delivery_area:, marketplace:)
         visit(polymorphic_path(marketplace.location(child: :delivery_areas)))
         click_link("Archived Delivery Areas")
-        within("##{dom_id(delivery_area)}") do
+        within(delivery_area) do
           accept_confirm { click_link(I18n.t("destroy.link_to")) }
         end
 
@@ -56,10 +71,14 @@
         visit(polymorphic_path(marketplace.location(child: :delivery_areas)))
         click_link("Archived Delivery Areas")
 
-        within("##{dom_id(delivery_area)}") do
+        within(delivery_area) do
           expect(page).to have_no_content(I18n.t("destroy.link_to"))
         end
       end
     end
   end
+
+  def within(model, *, **, &block)
+    page.within("##{dom_id(model)}", *, **, &block)
+  end
 end

spec/furniture/marketplace/delivery_spec.rb

@@ -13,11 +13,31 @@
   describe "#fee" do
     subject(:fee) { delivery.fee }
 
-    context "when `price_cents` is nil" do
+    context "when `delivery_area#price_cents` is nil" do
       let(:delivery_area) { build(:marketplace_delivery_area, marketplace: marketplace, price_cents: nil) }
 
       it { is_expected.to be_zero }
     end
+
+    context "when `delivery_area#fee_as_percentage` is set" do
+      let(:delivery_area) { build(:marketplace_delivery_area, marketplace: marketplace, fee_as_percentage: 10) }
+
+      context "with no products" do
+        it { is_expected.to be_zero }
+      end
+
+      context "with products" do
+        let(:product_a) { create(:marketplace_product, marketplace:, price_cents: 10_00) }
+        let(:product_b) { create(:marketplace_product, marketplace:, price_cents: 5_00) }
+
+        before do
+          delivery.ordered_products.build(product: product_a, quantity: 1)
+          delivery.ordered_products.build(product: product_b, quantity: 2)
+        end
+
+        it { is_expected.to eql(Money.new(2_00)) }
+      end
+    end
   end
 
   describe "#window" do

spec/furniture/marketplace/order_spec.rb

@@ -23,7 +23,7 @@
     subject(:price_total) { order.price_total }
 
     let(:marketplace) { create(:marketplace) }
-    let(:delivery_area) { create(:marketplace_delivery_area, marketplace: marketplace, price_cents: 1200) }
+
     let(:order) { create(:marketplace_order, marketplace: marketplace, delivery_area: delivery_area) }
     let(:product_a) { create(:marketplace_product, marketplace: order.marketplace) }
     let(:product_b) { create(:marketplace_product, marketplace: order.marketplace, tax_rate_ids: [sales_tax.id]) }
@@ -34,7 +34,23 @@
       order.ordered_products.create!(product: product_b, quantity: 2)
     end
 
-    it { is_expected.to eql(product_a.price + product_b.price * 2 + delivery_area.price + (product_b.price * 2 * 0.05)) }
+    context "when the delivery area has a fee as a percentage" do
+      let(:delivery_area) { create(:marketplace_delivery_area, marketplace: marketplace, fee_as_percentage: 10) }
+
+      it { is_expected.to eql(product_a.price + product_b.price * 2 + delivery_area.delivery_fee(subtotal: order.product_total) + (product_b.price * 2 * 0.05)) }
+    end
+
+    context "when the delivery area has a flat fee" do
+      let(:delivery_area) { create(:marketplace_delivery_area, marketplace: marketplace, price_cents: 1200) }
+
+      it { is_expected.to eql(product_a.price + product_b.price * 2 + delivery_area.price + (product_b.price * 2 * 0.05)) }
+    end
+
+    context "when the delivery area has a flat fee and a percentage fee" do
+      let(:delivery_area) { create(:marketplace_delivery_area, marketplace: marketplace, price_cents: 1200, fee_as_percentage: 10) }
+
+      it { is_expected.to eql(product_a.price + product_b.price * 2 + delivery_area.price + delivery_area.fee_as_percentage_of(subtotal: order.product_total) + (product_b.price * 2 * 0.05)) }
+    end
   end
 
   describe "#product_total" do