Add tax reverse charge mode

admin/app/components/solidus_admin/tax_categories/edit/component.html.erb

@@ -5,6 +5,13 @@
         <%= render component("ui/forms/field").text_field(f, :name) %>
         <%= render component("ui/forms/field").text_field(f, :tax_code) %>
         <%= render component("ui/forms/field").text_field(f, :description) %>
+        <% if Spree::Backend::Config.show_reverse_charge_fields %>
+          <%= render component("ui/forms/field").select(
+              f,
+              :tax_reverse_charge_mode,
+              Spree::TaxCategory.tax_reverse_charge_modes.keys.map { |key| [I18n.t("spree.tax_reverse_charge_modes.#{key}"), key] }
+            ) %>
+        <% end %>
         <label class="flex gap-2 items-center">
           <%= render component("ui/forms/checkbox").new(
               name: "#{f.object_name}[is_default]",

admin/app/components/solidus_admin/tax_categories/index/component.rb

@@ -46,7 +46,7 @@
   end
 
   def columns
-    [
+    columns = [
       {
         header: :name,
         data: ->(tax_category) do
@@ -82,5 +82,18 @@
         },
       },
     ]
+
+    if Spree::Backend::Config.show_reverse_charge_fields
+      columns << {
+        header: :tax_reverse_charge_mode,
+        data: ->(tax_category) do
+          link_to_if tax_category.tax_reverse_charge_mode, I18n.t("spree.tax_reverse_charge_modes.#{tax_category.tax_reverse_charge_mode}"), edit_path(tax_category),
+            data: { turbo_frame: :resource_modal },
+            class: 'body-link'
+        end
+      }
+    end
+
+    columns
   end
 end

admin/app/components/solidus_admin/tax_categories/new/component.html.erb

@@ -5,6 +5,13 @@
         <%= render component("ui/forms/field").text_field(f, :name) %>
         <%= render component("ui/forms/field").text_field(f, :tax_code) %>
         <%= render component("ui/forms/field").text_field(f, :description) %>
+        <% if Spree::Backend::Config.show_reverse_charge_fields %>
+          <%= render component("ui/forms/field").select(
+              f,
+              :tax_reverse_charge_mode,
+              Spree::TaxCategory.tax_reverse_charge_modes.keys.map { |key| [I18n.t("spree.tax_reverse_charge_modes.#{key}"), key] }
+            ) %>
+        <% end %>
         <label class="flex gap-2 items-center">
           <%= render component("ui/forms/checkbox").new(
               name: "#{f.object_name}[is_default]",

admin/app/controllers/solidus_admin/tax_categories_controller.rb

@@ -7,7 +7,7 @@ class TaxCategoriesController < SolidusAdmin::ResourcesController
     def resource_class = Spree::TaxCategory
 
     def permitted_resource_params
-      params.require(:tax_category).permit(:name, :description, :is_default, :tax_code)
+      params.require(:tax_category).permit(:name, :description, :is_default, :tax_code, :tax_reverse_charge_mode)
     end
   end
 end

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

@@ -29,4 +29,16 @@
       <%= f.text_area :description, class: 'fullwidth' %>
     <% end %>
   </div>
+
+  <% if Spree::Backend::Config.show_reverse_charge_fields %>
+    <div class="col-4">
+      <%= f.field_container :tax_reverse_charge_mode do %>
+        <%= f.label :tax_reverse_charge_mode %>
+        <%= f.select :tax_reverse_charge_mode,
+            Spree::TaxCategory.tax_reverse_charge_modes.keys.map { |key| [I18n.t("spree.tax_reverse_charge_modes.#{key}"), key] },
+            { include_blank: false },
+            { class: 'custom-select fullwidth' } %>
+      <% end %>
+    </div>
+  <% end %>
 </div>

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

@@ -19,14 +19,20 @@
   <colgroup>
     <col style="width: 20%">
     <col style="width: 10%">
+    <% if Spree::Backend::Config.show_reverse_charge_fields %>
+      <col style="width: 10%">
+    <% end %>
     <col style="width: 40%">
-    <col style="width: 15%">
-    <col style="width: 15%">
+    <col style="width: 10%">
+    <col style="width: 10%">
   </colgroup>
   <thead>
     <tr data-hook="tax_header">
       <th><%= Spree::TaxCategory.human_attribute_name(:name) %></th>
       <th><%= Spree::TaxCategory.human_attribute_name(:tax_code) %></th>
+      <% if Spree::Backend::Config.show_reverse_charge_fields %>
+        <th><%= Spree::TaxCategory.human_attribute_name(:tax_reverse_charge_mode) %></th>
+      <% end %>
       <th><%= Spree::TaxCategory.human_attribute_name(:description) %></th>
       <th><%= Spree::TaxCategory.human_attribute_name(:is_default) %></th>
       <th class="actions"></th>
@@ -41,6 +47,9 @@
       <tr id="<%= spree_dom_id tax_category %>" data-hook="tax_row">
         <td><%= tax_category.name %></td>
         <td><%= tax_category.tax_code %></td>
+        <% if Spree::Backend::Config.show_reverse_charge_fields %>
+          <td><%= I18n.t("spree.tax_reverse_charge_modes.#{tax_category.tax_reverse_charge_mode}") %></td>
+        <% end %>
         <td><%= tax_category.description %></td>
         <td><%= tax_category.is_default? ? t('spree.say_yes') : t('spree.say_no') %></td>
         <td class="actions">

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

@@ -20,9 +20,33 @@ def rates_for_item(item)
         tax_category_id = item.try(:variant_tax_category_id) || item.tax_category_id
 
         @rates_for_item.select do |rate|
+          tax_category = rate.tax_categories.find { |tax_cat| tax_cat.id == tax_category_id }
+          next unless tax_category && tax_applicable?(tax_category, item.order.tax_address)
+
           rate.active? && rate.tax_categories.map(&:id).include?(tax_category_id)
         end
       end
+
+      # Determine if tax is applicable based on tax category and address
+      #
+      # @param [Spree::TaxCategory] tax_category
+      #   the tax category to check tax_reverse_charge_mode
+      # @param [Spree::Address] address
+      #   the address to check reverse_charge_status
+      # @return [Boolean] true if tax is applicable, false otherwise
+      def tax_applicable?(tax_category, address)
+        case tax_category.tax_reverse_charge_mode
+          # Strict mode: Tax applies only if the address is NOT enabled (reverse charge)
+        when 'strict'
+          !address.reverse_charge_status_enabled?
+          # Loose mode: Tax applies only if the address is explicitly disabled
+        when 'loose'
+          address.reverse_charge_status_disabled?
+          # Tax always applies
+        when 'disabled'
+          true
+        end
+      end
     end
   end
 end

core/app/models/spree/tax_category.rb

@@ -10,6 +10,12 @@ class TaxCategory < Spree::Base
       self.tax_rate_tax_categories = []
     end
 
+    enum :tax_reverse_charge_mode, {
+      disabled: 0,
+      loose: 1,
+      strict: 2
+    }, prefix: true
+
     validates :name, presence: true
     validates_uniqueness_of :name, case_sensitive: true, unless: :deleted_at
 

core/config/locales/en.yml

@@ -392,6 +392,7 @@ en:
         is_default: Default
         name: Name
         tax_code: Tax Code
+        tax_reverse_charge_mode: Tax Reverse Charge Mode
       spree/tax_rate:
         amount: Rate
         expires_at: Expiration Date
@@ -2273,6 +2274,10 @@ en:
     tax_rate_amount_explanation: When using the "Default Tax" calculator, the amount is treated as a decimal amount to aid in calculations. (i.e. If the tax rate is 5% then enter 0.05) If using the "Flat Fee" calculator, the amount is used for the static fee.
     tax_rate_level: Tax Rate Level
     tax_rates: Tax Rates
+    tax_reverse_charge_modes:
+      disabled: Disabled
+      loose: Loose
+      strict: Strict
     taxon: Taxon
     taxon_attachment_removal_error: There was an error removing the attachment
     taxon_edit: Edit Taxon

core/db/migrate/20250226052907_add_tax_reverse_charge_mode_to_spree_tax_categories.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class AddTaxReverseChargeModeToSpreeTaxCategories < ActiveRecord::Migration[7.0]
+  def change
+    add_column :spree_tax_categories, :tax_reverse_charge_mode, :integer, default: 0, null: false,
+               comment: "Enum values: 0 = disabled, 1 = loose, 2 = strict"
+  end
+end

core/spec/models/spree/tax/tax_helpers_spec.rb

@@ -80,5 +80,106 @@ def valid_rates(item)
         end
       end
     end
+
+    context "when tax_reverse_charge_mode is strict and address is enabled" do
+      let(:tax_category) { create(:tax_category, tax_reverse_charge_mode: 'strict') }
+
+      before do
+        allow(tax_address).to receive(:reverse_charge_status_enabled?).and_return(true)
+      end
+
+      it "returns an empty array" do
+        expect(subject).to be_empty
+      end
+    end
+
+    context "when tax_reverse_charge_mode is strict and address is not enabled" do
+      let(:tax_category) { create(:tax_category, tax_reverse_charge_mode: 'strict') }
+
+      before do
+        allow(tax_address).to receive(:reverse_charge_status_enabled?).and_return(false)
+      end
+
+      it "returns the applicable tax rate" do
+        expect(subject).to contain_exactly(tax_rate)
+      end
+    end
+
+    context "when tax_reverse_charge_mode is loose and address is disabled" do
+      let(:tax_category) { create(:tax_category, tax_reverse_charge_mode: 'loose') }
+
+      before do
+        allow(tax_address).to receive(:reverse_charge_status_disabled?).and_return(true)
+      end
+
+      it "returns the applicable tax rate" do
+        expect(subject).to contain_exactly(tax_rate)
+      end
+    end
+
+    context "when tax_reverse_charge_mode is loose and address is not disabled" do
+      let(:tax_category) { create(:tax_category, tax_reverse_charge_mode: 'loose') }
+
+      before do
+        allow(tax_address).to receive(:reverse_charge_status_disabled?).and_return(false)
+      end
+
+      it "returns an empty array" do
+        expect(subject).to be_empty
+      end
+    end
+
+    context "when tax_reverse_charge_mode is disabled" do
+      let(:tax_category) { create(:tax_category, tax_reverse_charge_mode: 'disabled') }
+
+      it "returns the applicable tax rate" do
+        expect(subject).to contain_exactly(tax_rate)
+      end
+    end
+  end
+
+  describe '#tax_applicable?' do
+    let(:tax_category) { create(:tax_category, tax_reverse_charge_mode: tax_reverse_charge_mode) }
+    let(:address) { create(:address) }
+
+    subject { DummyClass.new.send(:tax_applicable?, tax_category, address) }
+
+    context 'when tax_reverse_charge_mode is strict' do
+      let(:tax_reverse_charge_mode) { 'strict' }
+
+      context 'when address is enabled' do
+        before { allow(address).to receive(:reverse_charge_status_enabled?).and_return(true) }
+
+        it { is_expected.to be_falsey }
+      end
+
+      context 'when address is not enabled' do
+        before { allow(address).to receive(:reverse_charge_status_enabled?).and_return(false) }
+
+        it { is_expected.to be_truthy }
+      end
+    end
+
+    context 'when tax_reverse_charge_mode is loose' do
+      let(:tax_reverse_charge_mode) { 'loose' }
+
+      context 'when address is disabled' do
+        before { allow(address).to receive(:reverse_charge_status_disabled?).and_return(true) }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when address is not disabled' do
+        before { allow(address).to receive(:reverse_charge_status_disabled?).and_return(false) }
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
+    context 'when tax_reverse_charge_mode is disabled' do
+      let(:tax_reverse_charge_mode) { 'disabled' }
+
+      it { is_expected.to be_truthy }
+    end
   end
 end

core/spec/models/spree/tax_category_spec.rb

@@ -47,4 +47,34 @@
       end
     end
   end
+
+  describe 'enum tax_reverse_charge_mode' do
+    it 'defines the expected enum values' do
+      expect(Spree::TaxCategory.tax_reverse_charge_modes).to eq({
+        'disabled' => 0,
+        'loose' => 1,
+        'strict' => 2
+      })
+    end
+
+    it 'allows valid values' do
+      tax_category = build(:tax_category)
+      # Updates the tax_reverse_charge_mode to "strict"
+      expect(tax_category).to be_valid
+      tax_category.tax_reverse_charge_mode_strict!
+
+      # Updates the tax_reverse_charge_mode to "loose"
+      expect(tax_category).to be_valid
+      tax_category.tax_reverse_charge_mode_loose!
+      expect(tax_category).to be_valid
+
+      # Updates the tax_reverse_charge_mode to "disabled"
+      tax_category.tax_reverse_charge_mode_disabled!
+      expect(tax_category).to be_valid
+    end
+
+    it 'raises an error for invalid values' do
+      expect { Spree::TaxCategory.new(tax_reverse_charge_mode: :invalid_status) }.to raise_error(ArgumentError)
+    end
+  end
 end