Adding/Removing items to refunds

ecommerce/ordering/lib/ordering.rb

@@ -6,13 +6,17 @@
 require_relative "ordering/events/order_submitted"
 require_relative "ordering/events/order_rejected"
 require_relative "ordering/events/draft_refund_created"
+require_relative "ordering/events/item_added_to_refund"
+require_relative "ordering/events/item_removed_from_refund"
 require_relative "ordering/commands/add_item_to_basket"
 require_relative "ordering/commands/remove_item_from_basket"
 require_relative "ordering/commands/submit_order"
 require_relative "ordering/commands/set_order_as_expired"
 require_relative "ordering/commands/accept_order"
 require_relative "ordering/commands/reject_order"
 require_relative "ordering/commands/create_draft_refund"
+require_relative "ordering/commands/add_item_to_refund"
+require_relative "ordering/commands/remove_item_from_refund"
 require_relative "ordering/fake_number_generator"
 require_relative "ordering/number_generator"
 require_relative "ordering/service"
@@ -36,6 +40,8 @@ def call(event_store, command_bus)
       command_bus.register(AcceptOrder, OnAcceptOrder.new(event_store))
       command_bus.register(RejectOrder, OnRejectOrder.new(event_store))
       command_bus.register(CreateDraftRefund, OnCreateDraftRefund.new(event_store))
+      command_bus.register(AddItemToRefund, OnAddItemToRefund.new(event_store))
+      command_bus.register(RemoveItemFromRefund, OnRemoveItemFromRefund.new(event_store))
     end
   end
 end

ecommerce/ordering/lib/ordering/commands/add_item_to_refund.rb

@@ -0,0 +1,9 @@
+module Ordering
+  class AddItemToRefund < Infra::Command
+    attribute :refund_id, Infra::Types::UUID
+    attribute :order_id, Infra::Types::UUID
+    attribute :product_id, Infra::Types::UUID
+
+    alias aggregate_id refund_id
+  end
+end

ecommerce/ordering/lib/ordering/commands/remove_item_from_refund.rb

@@ -0,0 +1,9 @@
+module Ordering
+  class RemoveItemFromRefund < Infra::Command
+    attribute :refund_id, Infra::Types::UUID
+    attribute :order_id, Infra::Types::UUID
+    attribute :product_id, Infra::Types::UUID
+
+    alias aggregate_id refund_id
+  end
+end

ecommerce/ordering/lib/ordering/events/item_added_to_refund.rb

@@ -0,0 +1,7 @@
+module Ordering
+  class ItemAddedToRefund < Infra::Event
+    attribute :refund_id,  Infra::Types::UUID
+    attribute :order_id,   Infra::Types::UUID
+    attribute :product_id, Infra::Types::UUID
+  end
+end

ecommerce/ordering/lib/ordering/events/item_removed_from_refund.rb

@@ -0,0 +1,7 @@
+module Ordering
+  class ItemRemovedFromRefund < Infra::Event
+    attribute :refund_id,  Infra::Types::UUID
+    attribute :order_id,   Infra::Types::UUID
+    attribute :product_id, Infra::Types::UUID
+  end
+end

ecommerce/ordering/lib/ordering/refund.rb

@@ -2,16 +2,57 @@ module Ordering
   class Refund
     include AggregateRoot
 
+    ProductNotFoundError = Class.new(StandardError)
+
     def initialize(id)
       @id = id
+      @refund_items = ItemsList.new
     end
 
     def create_draft(order_id)
       apply DraftRefundCreated.new(data: { refund_id: @id, order_id: order_id })
     end
 
+    def add_item(product_id)
+      apply ItemAddedToRefund.new(data: { refund_id: @id, order_id: @order_id, product_id: product_id })
+    end
+
+    def remove_item(product_id)
+      raise ProductNotFoundError unless @refund_items.quantity(product_id).positive?
+      apply ItemRemovedFromRefund.new(data: { refund_id: @id, order_id: @order_id, product_id: product_id })
+    end
+
     on DraftRefundCreated do |event|
       @order_id = event.data[:order_id]
     end
+
+    on ItemAddedToRefund do |event|
+      @refund_items.increase_quantity(event.data[:product_id])
+    end
+
+    on ItemRemovedFromRefund do |event|
+      @refund_items.decrease_quantity(event.data[:product_id])
+    end
+  end
+
+  class ItemsList
+    attr_reader :refund_items
+
+    def initialize
+      @refund_items = Hash.new(0)
+    end
+
+    def increase_quantity(product_id)
+      refund_items[product_id] = quantity(product_id) + 1
+    end
+
+    def decrease_quantity(product_id)
+      refund_items[product_id] -= 1
+      refund_items.delete(product_id) if refund_items.fetch(product_id).equal?(0)
+    end
+
+    def quantity(product_id)
+      refund_items[product_id]
+    end
   end
 end

ecommerce/ordering/lib/ordering/service.rb

@@ -84,4 +84,28 @@ def call(command)
       end
     end
   end
+
+  class OnAddItemToRefund
+    def initialize(event_store)
+      @repository = Infra::AggregateRootRepository.new(event_store)
+    end
+
+    def call(command)
+      @repository.with_aggregate(Refund, command.aggregate_id) do |refund|
+        refund.add_item(command.product_id)
+      end
+    end
+  end
+
+  class OnRemoveItemFromRefund
+    def initialize(event_store)
+      @repository = Infra::AggregateRootRepository.new(event_store)
+    end
+
+    def call(command)
+      @repository.with_aggregate(Refund, command.aggregate_id) do |refund|
+        refund.remove_item(command.product_id)
+      end
+    end
+  end
 end

ecommerce/ordering/test/add_item_to_refund_test.rb

@@ -0,0 +1,41 @@
+require_relative "test_helper"
+
+module Ordering
+  class AddItemToRefundTest < Test
+    cover "Ordering::OnAddItemToRefund*"
+
+    def test_add_item_to_refund
+      order_id = SecureRandom.uuid
+      aggregate_id = SecureRandom.uuid
+      product_id = SecureRandom.uuid
+      stream = "Ordering::Refund$#{aggregate_id}"
+
+      arrange(
+        CreateDraftRefund.new(
+          refund_id: aggregate_id,
+          order_id: order_id
+        )
+      )
+
+      expected_events = [
+        ItemAddedToRefund.new(
+          data: {
+            refund_id: aggregate_id,
+            order_id: order_id,
+            product_id: product_id
+          }
+        )
+      ]
+
+      assert_events(stream, *expected_events) do
+        act(
+          AddItemToRefund.new(
+            refund_id: aggregate_id,
+            order_id: order_id,
+            product_id: product_id
+          )
+        )
+      end
+    end
+  end
+end

ecommerce/ordering/test/remove_item_from_refund_test.rb

@@ -0,0 +1,69 @@
+require_relative "test_helper"
+
+module Ordering
+  class RemoveItemFromRefundTest < Test
+    cover "Ordering::OnRemoveItemFromRefund*"
+
+    def test_removing_items_from_refund
+      order_id = SecureRandom.uuid
+      aggregate_id = SecureRandom.uuid
+      product_id = SecureRandom.uuid
+      stream = "Ordering::Refund$#{aggregate_id}"
+
+      arrange(
+        CreateDraftRefund.new(
+          refund_id: aggregate_id,
+          order_id: order_id
+        ),
+        AddItemToRefund.new(
+          refund_id: aggregate_id,
+          order_id: order_id,
+          product_id: product_id
+        )
+      )
+
+      expected_events = [
+        ItemRemovedFromRefund.new(
+          data: {
+            refund_id: aggregate_id,
+            order_id: order_id,
+            product_id: product_id
+          }
+        )
+      ]
+
+      assert_events(stream, *expected_events) do
+        act(
+          RemoveItemFromRefund.new(
+            refund_id: aggregate_id,
+            order_id: order_id,
+            product_id: product_id
+          )
+        )
+      end
+    end
+
+    def test_can_remove_only_added_items
+      order_id = SecureRandom.uuid
+      aggregate_id = SecureRandom.uuid
+      product_id = SecureRandom.uuid
+
+      arrange(
+        CreateDraftRefund.new(
+          refund_id: aggregate_id,
+          order_id: order_id
+        )
+      )
+
+      assert_raises(Refund::ProductNotFoundError) do
+        act(
+          RemoveItemFromRefund.new(
+            refund_id: aggregate_id,
+            order_id: order_id,
+            product_id: product_id
+          )
+        )
+      end
+    end
+  end
+end

rails_application/app/controllers/refunds_controller.rb

@@ -12,6 +12,14 @@ def create
     redirect_to edit_order_refund_path(refund_id, order_id: params[:order_id])
   end
 
+  def add_item
+    add_item_to_refund
+  end
+
+  def remove_item
+    remove_item_from_refund
+  end
+
   private
 
   def create_draft_refund_cmd(refund_id)
@@ -21,4 +29,20 @@ def create_draft_refund_cmd(refund_id)
   def create_draft_refund(refund_id)
     command_bus.(create_draft_refund_cmd(refund_id))
   end
+
+  def add_item_to_refund_cmd
+    Ordering::AddItemToRefund.new(refund_id: params[:id], order_id: params[:order_id], product_id: params[:product_id])
+  end
+
+  def add_item_to_refund
+    command_bus.(add_item_to_refund_cmd)
+  end
+
+  def remove_item_from_refund_cmd
+    Ordering::RemoveItemFromRefund.new(refund_id: params[:id], order_id: params[:order_id], product_id: params[:product_id])
+  end
+
+  def remove_item_from_refund
+    command_bus.(remove_item_from_refund_cmd)
+  end
 end

rails_application/app/read_models/refunds/add_item_to_refund.rb

@@ -0,0 +1,40 @@
+module Refunds
+  class AddItemToRefund
+    def call(event)
+      refund_id = event.data.fetch(:refund_id)
+      Refund.find_or_create_by!(uid: refund_id)
+      product_id = event.data.fetch(:product_id)
+      item =
+        find(refund_id, product_id) ||
+          create(refund_id, product_id)
+      item.quantity += 1
+      item.save!
+    end
+
+    private
+
+    def event_store
+      Rails.configuration.event_store
+    end
+
+    def find(refund_id, product_id)
+      Refund
+        .find_by_uid(refund_id)
+        .refund_items
+        .where(product_uid: product_id)
+        .first
+    end
+
+    def create(refund_id, product_id)
+      product = Orders::Product.find_by_uid(product_id)
+      Refund
+        .find_by(uid: refund_id)
+        .refund_items
+        .create(
+          product_uid: product_id,
+          price: product.price,
+          quantity: 0
+        )
+    end
+  end
+end

rails_application/app/read_models/refunds/configuration.rb

@@ -4,7 +4,7 @@ class Refund < ApplicationRecord
 
     has_many :refund_items,
              class_name: "Refunds::RefundItem",
-             foreign_key: :order_uid,
+             foreign_key: :refund_uid,
              primary_key: :uid
   end
 
@@ -15,6 +15,8 @@ class RefundItem < ApplicationRecord
   class Configuration
     def call(event_store)
       event_store.subscribe(CreateDraftRefund.new, to: [Ordering::DraftRefundCreated])
+      event_store.subscribe(AddItemToRefund.new, to: [Ordering::ItemAddedToRefund])
+      event_store.subscribe(RemoveItemFromRefund.new, to: [Ordering::ItemRemovedFromRefund])
     end
   end
 end

rails_application/app/read_models/refunds/remove_item_from_refund.rb

@@ -0,0 +1,24 @@
+module Refunds
+  class RemoveItemFromRefund
+    def call(event)
+      refund_id = event.data.fetch(:refund_id)
+      product_id = event.data.fetch(:product_id)
+      item = find(refund_id, product_id)
+      item.quantity -= 1
+      item.quantity > 0 ? item.save! : item.destroy!
+    end
+
+    private
+    def find(order_uid, product_id)
+      Refund
+        .find_by_uid(order_uid)
+        .refund_items
+        .where(product_uid: product_id)
+        .first
+    end
+
+    def event_store
+      Rails.configuration.event_store
+    end
+  end
+end