Match tax zones by address instead of by zone

backend/app/views/spree/admin/zones/_form.html.erb

@@ -12,11 +12,6 @@
       <%= zone_form.text_field :description, :class => 'fullwidth' %>
     <% end %>
 
-    <div data-hook="default" class="field">
-      <%= zone_form.check_box :default_tax %>
-      <%= zone_form.label :default_tax %>
-    </div>
-
     <div data-hook="type" class="field">
       <%= label_tag Spree.t(:type) %>
       <ul>

backend/app/views/spree/admin/zones/index.html.erb

@@ -28,7 +28,6 @@
         <th>
           <%= sort_link @search,:description, Spree::Zone.human_attribute_name(:description), {}, {:title => 'zones_order_by_description_title'} %>
         </th>
-        <th><%= Spree.t(:default_tax) %></th>
         <th class="actions"></th>
       </tr>
     </thead>
@@ -37,7 +36,6 @@
         <tr id="<%= spree_dom_id zone %>" data-hook="zones_row" class="<%= cycle('odd', 'even')%>">
           <td class="align-center"><%= zone.name %></td>
           <td><%= zone.description %></td>
-          <td class="align-center"><%= zone.default_tax? ? Spree.t(:say_yes) : Spree.t(:say_no) %></td>
           <td class="actions">
             <% if can?(:update, zone) %>
               <%= link_to_edit zone, :no_text => true %>

core/app/models/spree/app_configuration.rb

@@ -320,6 +320,19 @@ def stock
       @stock_configuration ||= Spree::Core::StockConfiguration.new
     end
 
+    # @!attribute [rw] default_tax_address
+    #   Default Address used for taxation when no tax address present on an order
+    #   Use this when you want the following behaviour: The order is tax-adjusted
+    #   even if you don't yet know its tax_address (see also the setting `tax_using_ship_address`).
+    #   If you do not wish your order to be taxed before knowing the customer's address,
+    #   leave it at `nil`.
+    # @example Use the default country for taxing orders in cart state
+    #   Spree.config do |config|
+    #     config.default_tax_address = Spree::Address.build_default.freeze
+    #   end
+    # @return [Spree::Address,nil] default tax address
+    attr_accessor :default_tax_address
+
     # all the following can be deprecated when store prefs are no longer supported
     # @private
     DEPRECATED_STORE_PREFERENCES = {

core/app/models/spree/calculator/default_tax.rb

@@ -37,7 +37,7 @@ def compute_shipment_or_line_item(item)
     def compute_shipping_rate(shipping_rate)
       if rate.included_in_price
         pre_tax_amount = shipping_rate.cost / (1 + rate.amount)
-        if rate.zone == shipping_rate.shipment.order.tax_zone
+        if Spree::TaxRate.for_address(shipping_rate.order.tax_address).include?(rate)
           deduced_total_by_rate(pre_tax_amount, rate)
         else
           deduced_total_by_rate(pre_tax_amount, rate) * - 1

core/app/models/spree/order.rb

@@ -203,12 +203,13 @@ def backordered?
     # Returns the relevant zone (if any) to be used for taxation purposes.
     # Uses default tax zone unless there is a specific match
     def tax_zone
-      @tax_zone ||= Zone.match(tax_address) || Zone.default_tax
+      @tax_zone ||= Zone.match(tax_address)
     end
 
     # Returns the address for taxation based on configuration
     def tax_address
-      Spree::Config[:tax_using_ship_address] ? ship_address : bill_address
+      (Spree::Config[:tax_using_ship_address] ? ship_address : bill_address) ||
+        Spree::Config.default_tax_address
     end
 
     def updater

core/app/models/spree/shipment.rb

@@ -35,6 +35,8 @@ class Shipment < Spree::Base
     scope :reverse_chronological, -> { order('coalesce(spree_shipments.shipped_at, spree_shipments.created_at) desc', id: :desc) }
     scope :by_store, ->(store) { joins(:order).merge(Spree::Order.by_store(store)) }
 
+    delegate :tax_category, to: :selected_shipping_rate
+
     # shipment state machine (see http://github.com/pluginaweek/state_machine/tree/master for details)
     state_machine initial: :pending, use_transactions: false do
       event :ready do
@@ -88,8 +90,8 @@ def can_transition_from_canceled_to_ready?
     end
 
     extend DisplayMoney
-    money_methods :cost, :discounted_cost, :final_price, :item_cost
-    alias display_amount display_cost
+    money_methods :cost, :amount, :discounted_cost, :final_price, :item_cost
+    alias_attribute :amount, :cost
 
     def add_shipping_method(shipping_method, selected = false)
       shipping_rates.create(shipping_method: shipping_method, selected: selected, cost: cost)
@@ -244,10 +246,6 @@ def shipping_method
       selected_shipping_rate.try(:shipping_method) || shipping_rates.first.try(:shipping_method)
     end
 
-    def tax_category
-      selected_shipping_rate.try(:tax_rate).try(:tax_category)
-    end
-
     # Only one of either included_tax_total or additional_tax_total is set
     # This method returns the total of the two. Saves having to check if
     # tax is included or additional.

core/app/models/spree/shipping_rate.rb

@@ -1,12 +1,14 @@
 module Spree
   class ShippingRate < Spree::Base
+    include Spree::Tax::TaxHelpers
+
     belongs_to :shipment, class_name: 'Spree::Shipment'
     belongs_to :shipping_method, -> { with_deleted }, class_name: 'Spree::ShippingMethod', inverse_of: :shipping_rates
-    belongs_to :tax_rate, -> { with_deleted }, class_name: 'Spree::TaxRate'
 
     delegate :order, :currency, to: :shipment
-    delegate :name, to: :shipping_method
+    delegate :name, :tax_category, to: :shipping_method
     delegate :code, to: :shipping_method, prefix: true
+    alias_attribute :amount, :cost
 
     def display_base_price
       Spree::Money.new(cost, currency: currency)
@@ -16,31 +18,48 @@ def calculate_tax_amount
       tax_rate.calculator.compute_shipping_rate(self)
     end
 
+    def tax_rates
+      applicable_rates.select { |rate| rate.applicable_for?(self) }
+    end
+
     def display_price
       price = display_base_price.to_s
-      if tax_rate
-        tax_amount = calculate_tax_amount
-        if tax_amount != 0
-          if tax_rate.included_in_price?
-            if tax_amount > 0
-              amount = "#{display_tax_amount(tax_amount)} #{tax_rate.name}"
-              price += " (#{Spree.t(:incl)} #{amount})"
-            else
-              amount = "#{display_tax_amount(tax_amount * -1)} #{tax_rate.name}"
-              price += " (#{Spree.t(:excl)} #{amount})"
-            end
-          else
-            amount = "#{display_tax_amount(tax_amount)} #{tax_rate.name}"
-            price += " (+ #{amount})"
-          end
-        end
-      end
-      price
+
+      return price if tax_rates.empty? || amount == 0
+
+      tax_explanations = tax_rates.map { |rate| tax_explain(rate) }.join(", ")
+
+      Spree.t :display_price_with_explanations,
+               scope: 'shipping_rate.display_price',
+               price: price,
+               explanations: tax_explanations
     end
     alias_method :display_cost, :display_price
 
     def display_tax_amount(tax_amount)
       Spree::Money.new(tax_amount, currency: currency)
     end
+
+    private
+
+    def tax_explain(rate)
+      amount = rate.calculator.compute_shipping_rate(self)
+      Spree.t translation_key(amount, rate),
+        scope: 'shipping_rate.display_price.tax_explanations',
+        tax_amount: display_tax_amount(amount.abs),
+        tax_rate_name: rate.name
+    end
+
+    def translation_key(amount, rate)
+      if rate.included_in_price?
+        if amount > 0
+           :vat
+         else
+           :vat_refund
+         end
+       else
+         :sales_tax
+      end
+    end
   end
 end

core/app/models/spree/stock/estimator.rb

@@ -35,22 +35,10 @@ def choose_default_shipping_rate(shipping_rates)
       def calculate_shipping_rates(package)
         shipping_methods(package).map do |shipping_method|
           cost = shipping_method.calculator.compute(package)
-          tax_category = shipping_method.tax_category
-          if tax_category
-            tax_rate = tax_category.tax_rates.detect do |rate|
-              # If the rate's zone matches the order's zone, a positive adjustment will be applied.
-              # If the rate is from the default tax zone, then a negative adjustment will be applied.
-              # See the tests in shipping_rate_spec.rb for an example of this.d
-              rate.zone == order.tax_zone || rate.zone.default_tax?
-            end
-          end
 
           if cost
-            rate = shipping_method.shipping_rates.new(cost: cost)
-            rate.tax_rate = tax_rate if tax_rate
+            shipping_method.shipping_rates.new(cost: cost)
           end
-
-          rate
         end.compact
       end
 

core/app/models/spree/tax/item_adjuster.rb

@@ -12,7 +12,8 @@ def initialize(item, options = {})
         @item = item
         @order = @item.order
         # set instance variable so `TaxRate.match` is only called when necessary
-        @rates_for_order_zone = options[:rates_for_order_zone]
+        @order_rates = options[:order_rates]
+        @default_vat_rates = options[:default_vat_rates]
       end
 
       # Deletes all existing tax adjustments and creates new adjustments for all
@@ -23,19 +24,19 @@ def initialize(item, options = {})
       #
       # @return [Array<Spree::Adjustment>] newly created adjustments
       def adjust!
-        return unless order_tax_zone
+        return unless order.tax_address
         # Using .destroy_all to make sure callbacks fire
         item.adjustments.tax.destroy_all
 
         TaxRate.store_pre_tax_amount(item, rates_for_item)
 
-        rates_for_item.map { |rate| rate.adjust(order_tax_zone, item) }
+        rates_for_item.map { |rate| rate.adjust(nil, item) }
       end
 
       private
 
       def rates_for_item
-        @rates_for_item ||= applicable_rates.select { |rate| rate.tax_category == item.tax_category }
+        @rates_for_item ||= applicable_rates.select { |rate| rate.applicable_for?(item) }
       end
     end
   end

core/app/models/spree/tax/order_adjuster.rb

@@ -14,12 +14,21 @@ def initialize(order)
       # Creates tax adjustments for all taxable items (shipments and line items)
       # in the given order.
       def adjust!
-        return unless order_tax_zone
+        return unless order.tax_address
 
         (order.line_items + order.shipments).each do |item|
-          ItemAdjuster.new(item, rates_for_order_zone: applicable_rates).adjust!
+          ItemAdjuster.new(item, order_wide_options).adjust!
         end
       end
+
+      private
+
+      def order_wide_options
+        {
+          order_rates: order_rates,
+          default_vat_rates: default_vat_rates
+        }
+      end
     end
   end
 end

core/app/models/spree/tax/tax_helpers.rb

@@ -17,24 +17,22 @@ module TaxHelpers
       #
       # For further discussion, see https://github.com/spree/spree/issues/4397 and https://github.com/spree/spree/issues/4327.
       def applicable_rates
-        order_zone_tax_categories = rates_for_order_zone.map(&:tax_category)
-        default_rates_with_unmatched_tax_category = rates_for_default_zone.to_a.delete_if do |default_rate|
+        order_zone_tax_categories = order_rates.map(&:tax_category)
+        default_rates_with_unmatched_tax_category = default_vat_rates.to_a.delete_if do |default_rate|
           order_zone_tax_categories.include?(default_rate.tax_category)
         end
 
-        (rates_for_order_zone + default_rates_with_unmatched_tax_category).uniq
+        (order_rates + default_rates_with_unmatched_tax_category).uniq
       end
 
-      def rates_for_order_zone
-        @rates_for_order_zone ||= Spree::TaxRate.for_zone(order_tax_zone)
+      def order_rates
+        @order_rates ||= Spree::TaxRate.for_address(order.tax_address)
       end
 
-      def rates_for_default_zone
-        @rates_for_default_zone ||= Spree::TaxRate.for_zone(Spree::Zone.default_tax)
-      end
-
-      def order_tax_zone
-        @order_tax_zone ||= order.tax_zone
+      def default_vat_rates
+        @default_vat_rates ||= Spree::TaxRate
+                                .included_in_price
+                                .for_address(Spree::Config.default_tax_address)
       end
     end
   end

core/app/models/spree/tax/tax_location.rb

@@ -0,0 +1,31 @@
+module Spree
+  module Tax
+    # A class exclusively used as a drop-in replacement for a default tax address.
+    # It responds to `:country_id` and `:state_id`.
+    #
+    # @attr_reader [Integer] country_id the ID of a Spree::Country object
+    # @attr_reader [Integer] state_id the ID of a Spree::State object
+    class TaxLocation
+      attr_reader :country_id, :state_id
+
+      # Create a new TaxLocation object
+      #
+      # @see Spree::Zone.for_address
+      #
+      # @param [Integer] country_id the ID of a Spree::Country object, default: nil
+      # @param [Integer] state_id the ID of a Spree::State object, default: nil
+      # @param [Spree::Country] country a Spree::Country object, default: nil
+      # @param [Spree::State] state a Spree::State object, default: nil
+      #
+      # @return [Spree::Tax::TaxLocation] a Spree::Tax::TaxLocation object
+      def initialize(country: nil, country_id: nil, state: nil, state_id: nil)
+        @country_id = country_id || country && country.id
+        @state_id = state_id || state && state.id
+      end
+
+      def ==(other)
+        state_id == other.state_id && country_id == other.country_id
+      end
+    end
+  end
+end