From 4f6ab69add7cdf5667dc569d7c7cb0ac7dba1d1d Mon Sep 17 00:00:00 2001
From: Mohamed ABDELLANI <abdellani@gmail.com>
Date: Tue, 11 Jul 2023 10:42:31 +0100
Subject: [PATCH] implement OrderInvoiceGenerator service

---
 .../spree/admin/invoices_controller.rb        | 21 +------
 app/services/order_invoice_generator.rb       | 34 +++++++++++
 spec/services/order_invoice_generator_spec.rb | 60 +++++++++++++++++++
 3 files changed, 95 insertions(+), 20 deletions(-)
 create mode 100644 app/services/order_invoice_generator.rb
 create mode 100644 spec/services/order_invoice_generator_spec.rb

diff --git a/app/controllers/spree/admin/invoices_controller.rb b/app/controllers/spree/admin/invoices_controller.rb
index c304a63697..397b1a050f 100644
--- a/app/controllers/spree/admin/invoices_controller.rb
+++ b/app/controllers/spree/admin/invoices_controller.rb
@@ -23,20 +23,7 @@ module Spree
       def generate
         @order = Order.find_by(number: params[:order_id])
         authorize! :invoice, @order
-
-        @comparator = OrderInvoiceComparator.new(@order)
-        if @comparator.can_generate_new_invoice?
-          @order.invoices.create!(
-            date: Time.zone.today,
-            number: @order.invoices.count + 1,
-            data: invoice_data
-          )
-        elsif @comparator.can_update_latest_invoice?
-          @order.invoices.last.update!(
-            date: Time.zone.today,
-            data: invoice_data
-          )
-        end
+        OrderInvoiceGenerator.new(@order).generate_or_update_latest_invoice
         redirect_back(fallback_location: spree.admin_dashboard_path)
       end
 
@@ -56,12 +43,6 @@ module Spree
           render json: { created: false }, status: :unprocessable_entity
         end
       end
-
-      protected
-
-      def invoice_data
-        @invoice_data ||= InvoiceDataGenerator.new(@order).generate
-      end
     end
   end
 end
diff --git a/app/services/order_invoice_generator.rb b/app/services/order_invoice_generator.rb
new file mode 100644
index 0000000000..4e02ccf487
--- /dev/null
+++ b/app/services/order_invoice_generator.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class OrderInvoiceGenerator
+  def initialize(order)
+    @order = order
+  end
+
+  def generate_or_update_latest_invoice
+    if comparator.can_generate_new_invoice?
+      order.invoices.create!(
+        date: Time.zone.today,
+        number: order.invoices.count + 1,
+        data: invoice_data
+      )
+    elsif comparator.can_update_latest_invoice?
+      order.invoices.last.update!(
+        date: Time.zone.today,
+        data: invoice_data
+      )
+    end
+  end
+
+  private
+
+  attr_reader :order
+
+  def comparator
+    @comparator ||= OrderInvoiceComparator.new(order)
+  end
+
+  def invoice_data
+    @invoice_data ||= InvoiceDataGenerator.new(order).generate
+  end
+end
diff --git a/spec/services/order_invoice_generator_spec.rb b/spec/services/order_invoice_generator_spec.rb
new file mode 100644
index 0000000000..852de2028a
--- /dev/null
+++ b/spec/services/order_invoice_generator_spec.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe OrderInvoiceGenerator do
+  let!(:order) { create(:completed_order_with_fees) }
+  let!(:invoice_data_generator){ InvoiceDataGenerator.new(order) }
+  let!(:latest_invoice){
+    create(:invoice,
+           order:,
+           data: invoice_data_generator.serialize_for_invoice)
+  }
+
+  let(:instance) { described_class.new(order) }
+  let(:comparator){ double("OrderInvoiceComparator") }
+
+  before do
+    allow(instance).to receive(:comparator).and_return(comparator)
+  end
+
+  describe "#generate_or_update_latest_invoice" do
+    let(:subject) { instance.generate_or_update_latest_invoice }
+    context "when can generate new invoice" do
+      before do
+        expect(comparator).to receive(:can_generate_new_invoice?).and_return(true)
+      end
+
+      it "should create a new invoice" do
+        expect(instance).to receive(:invoice_data)
+        expect{ subject }.to change{ order.invoices.count }.by(1)
+        expect(order.invoices.order('created_at desc').first.number).to eq(2)
+      end
+    end
+
+    context "can update latest invoice" do
+      before do
+        allow(comparator).to receive(:can_generate_new_invoice?).and_return(false)
+        allow(comparator).to receive(:can_update_latest_invoice?).and_return(true)
+        order.update!(note: "This is an updated note")
+      end
+
+      it "should update the latest invoice" do
+        expect{ subject }.to change{ latest_invoice.reload.data }
+          .and change{ order.invoices.count }.by(0)
+      end
+    end
+
+    context "when can't generate new invoice or update latest invoice" do
+      before do
+        allow(comparator).to receive(:can_generate_new_invoice?).and_return(false)
+        allow(comparator).to receive(:can_update_latest_invoice?).and_return(false)
+      end
+
+      it "should not create or update invoices" do
+        expect(instance).not_to receive(:invoice_data)
+        expect{ subject }.to change{ order.invoices.count }.by(0)
+      end
+    end
+  end
+end