Allow admin to remove VAT rate

ecommerce/taxes/lib/taxes.rb

@@ -11,6 +11,7 @@ def call(event_store, command_bus)
       command_bus.register(SetVatRate, SetVatRateHandler.new(event_store))
       command_bus.register(DetermineVatRate, DetermineVatRateHandler.new(event_store))
       command_bus.register(AddAvailableVatRate, AddAvailableVatRateHandler.new(event_store))
+      command_bus.register(RemoveAvailableVatRate, RemoveAvailableVatRateHandler.new(event_store))
     end
   end
 end

ecommerce/taxes/lib/taxes/commands.rb

@@ -13,4 +13,8 @@ class AddAvailableVatRate < Infra::Command
     attribute :available_vat_rate_id, Infra::Types::UUID
     attribute :vat_rate, Infra::Types::VatRate
   end
+
+  class RemoveAvailableVatRate < Infra::Command
+    attribute :vat_rate_code, Infra::Types::String
+  end
 end

ecommerce/taxes/lib/taxes/events.rb

@@ -14,4 +14,8 @@ class AvailableVatRateAdded < Infra::Event
     attribute :available_vat_rate_id, Infra::Types::UUID
     attribute :vat_rate, Infra::Types::VatRate
   end
+
+  class AvailableVatRateRemoved < Infra::Event
+    attribute :vat_rate_code, Infra::Types::String
+  end
 end

ecommerce/taxes/lib/taxes/services.rb

@@ -1,6 +1,7 @@
 module Taxes
   VatRateAlreadyExists = Class.new(StandardError)
   VatRateNotApplicable = Class.new(StandardError)
+  VatRateNotExists = Class.new(StandardError)
   class SetVatRateHandler
     def initialize(event_store)
       @repository = Infra::AggregateRootRepository.new(event_store)
@@ -69,4 +70,29 @@ def stream_name(cmd)
       "Taxes::AvailableVatRate$#{cmd.vat_rate.code}"
     end
   end
+
+  class RemoveAvailableVatRateHandler
+    def initialize(event_store)
+      @catalog = VatRateCatalog.new(event_store)
+      @event_store = event_store
+    end
+
+    def call(cmd)
+      raise VatRateNotExists unless catalog.vat_rate_by_code(cmd.vat_rate_code)
+
+      event_store.publish(available_vat_rate_removed_event(cmd), stream_name: stream_name(cmd))
+    end
+
+    private
+
+    attr_reader :event_store, :catalog
+
+    def available_vat_rate_removed_event(cmd)
+      AvailableVatRateRemoved.new(data: { vat_rate_code: cmd.vat_rate_code })
+    end
+
+    def stream_name(cmd)
+      "Taxes::AvailableVatRate$#{cmd.vat_rate_code}"
+    end
+  end
 end

ecommerce/taxes/lib/taxes/vat_rate_catalog.rb

@@ -16,13 +16,17 @@ def vat_rate_for(product_id)
     end
 
     def vat_rate_by_code(vat_rate_code)
-      @event_store
+      last_available_vat_rate_event = @event_store
         .read
         .stream("Taxes::AvailableVatRate$#{vat_rate_code}")
         .last
-        &.data
-        &.fetch(:vat_rate)
-        &.then { |vat_rate| Infra::Types::VatRate.new(vat_rate) }
+
+      if last_available_vat_rate_event.instance_of?(AvailableVatRateAdded)
+        last_available_vat_rate_event
+          .data
+          .fetch(:vat_rate)
+          .then { |vat_rate| Infra::Types::VatRate.new(vat_rate) }
+      end
     end
   end
 end

ecommerce/taxes/test/taxes_test.rb

@@ -59,6 +59,22 @@ def test_should_not_allow_for_double_registration
       end
     end
 
+    def test_removing_available_vat_rate
+      vat_rate = Infra::Types::VatRate.new(code: "50", rate: 50)
+      add_available_vat_rate(vat_rate)
+      available_vat_rate_removed = AvailableVatRateRemoved.new(data: { vat_rate_code: vat_rate.code })
+
+      assert_events("Taxes::AvailableVatRate$#{vat_rate.code}", available_vat_rate_removed) do
+        remove_available_vat_rate(vat_rate.code)
+      end
+    end
+
+    def test_cannot_remove_non_existing_vat_rate
+      assert_raises(VatRateNotExists) do
+        remove_available_vat_rate("50")
+      end
+    end
+
     private
 
     def set_vat_rate(product_id, vat_rate_code)
@@ -72,5 +88,9 @@ def determine_vat_rate(order_id, product_id, vat_rate)
     def add_available_vat_rate(vat_rate, available_vat_rate_id = SecureRandom.uuid)
       run_command(AddAvailableVatRate.new(available_vat_rate_id: available_vat_rate_id, vat_rate: vat_rate))
     end
+
+    def remove_available_vat_rate(vat_rate_code)
+      run_command(RemoveAvailableVatRate.new(vat_rate_code: vat_rate_code))
+    end
   end
 end

ecommerce/taxes/test/vat_rate_catalog_test.rb

@@ -15,6 +15,12 @@ def test_returns_available_vat_rate
       def test_returns_nil_when_vat_rate_is_not_available
         assert_nil catalog.vat_rate_by_code("60")
       end
+
+      def test_returns_nil_when_vat_rate_was_removed
+        run_command(RemoveAvailableVatRate.new(vat_rate_code: "50"))
+
+        assert_nil catalog.vat_rate_by_code("50")
+      end
     end
 
     private

rails_application/app/controllers/available_vat_rates_controller.rb

@@ -26,17 +26,24 @@ def create
     end
 
     add_available_vat_rate(available_vat_rate_form.code, available_vat_rate_form.rate, available_vat_rate_id)
-    rescue Taxes::VatRateAlreadyExists
-      flash.now[:notice] = "VAT rate already exists"
-      render "new", status: :unprocessable_entity
-    else
+  rescue Taxes::VatRateAlreadyExists
+    flash.now[:alert] = "VAT rate already exists"
+    render "new", status: :unprocessable_entity
+  else
     redirect_to available_vat_rates_path, notice: "VAT rate was successfully created"
   end
 
   def index
     @available_vat_rates = VatRates::AvailableVatRate.all
   end
 
+  def destroy
+    remove_available_vat_rate(params[:vat_rate_code])
+    redirect_to available_vat_rates_path, notice: "VAT rate was successfully removed"
+  rescue Taxes::VatRateNotExists
+    redirect_to available_vat_rates_path, alert: "VAT rate does not exist"
+  end
+
   private
 
   def add_available_vat_rate(code, rate, available_vat_rate_id)
@@ -50,6 +57,14 @@ def add_available_vat_rate_cmd(code, rate, available_vat_rate_id)
     )
   end
 
+  def remove_available_vat_rate(vat_rate_code)
+    command_bus.(remove_available_vat_rate_cmd(vat_rate_code))
+  end
+
+  def remove_available_vat_rate_cmd(vat_rate_code)
+    Taxes::RemoveAvailableVatRate.new(vat_rate_code: vat_rate_code)
+  end
+
   def available_vat_rate_params
     params.permit(:code, :rate)
   end

rails_application/app/read_models/vat_rates/configuration.rb

@@ -6,6 +6,7 @@ class AvailableVatRate < ApplicationRecord
   class Configuration
     def call(event_store)
       event_store.subscribe(AddAvailableVatRate, to: [Taxes::AvailableVatRateAdded])
+      event_store.subscribe(RemoveAvailableVatRate, to: [Taxes::AvailableVatRateRemoved])
     end
   end
 end

rails_application/app/read_models/vat_rates/remove_available_vat_rate.rb

@@ -0,0 +1,7 @@
+module VatRates
+  class RemoveAvailableVatRate
+    def call(event)
+      AvailableVatRate.destroy_by(code: event.data.fetch(:vat_rate_code))
+    end
+  end
+end

rails_application/app/views/available_vat_rates/index.html.erb

@@ -13,14 +13,20 @@
     <tr>
       <th class="text-left py-2">Code</th>
       <th class="text-right py-2">Rate</th>
+      <th class="text-right py-2"></th>
     </tr>
   </thead>
 
   <tbody>
   <% @available_vat_rates.each do |available_vat_rate| %>
     <tr class="border-t">
       <td class="py-2"><%= available_vat_rate.code %></td>
-      <td class="py-2 text-right"><%= available_vat_rate.rate %></td>
+      <td class="text-right py-2"><%= available_vat_rate.rate %></td>
+      <td class="text-right py-2">
+        <%= form_with url: available_vat_rates_path, method: :delete do |f| %>
+          <%= f.hidden_field :vat_rate_code, value: available_vat_rate.code %>
+          <%= f.submit 'Delete' %>
+        <% end %>
     </tr>
   <% end %>
   </tbody>

rails_application/config/routes.rb

@@ -47,6 +47,7 @@
   end
 
   resources :available_vat_rates, only: [:new, :create, :index]
+  delete "/available_vat_rates", to: "available_vat_rates#destroy"
 
   post :login, to: "client/clients#login"
   get :logout, to: "client/clients#logout"

rails_application/test/integration/available_vat_rates_test.rb

@@ -15,6 +15,14 @@ def test_happy_path
 
     assert_equal "VAT rate was successfully created", flash[:notice]
     assert_select "h1", "VAT Rates"
+
+    delete "/available_vat_rates",
+            params: {
+              "vat_rate_code" => "10.0"
+            }
+    follow_redirect!
+
+    assert_equal "VAT rate was successfully removed", flash[:notice]
   end
 
   def test_validation_blank_errors
@@ -58,6 +66,6 @@ def test_vat_rate_already_exists
         }
 
     assert_response :unprocessable_entity
-    assert_select "#notice", "VAT rate already exists"
+    assert_select "#alert", "VAT rate already exists"
   end
 end