Refactored code

app/models/concerns/registrar/book_keeping.rb

@@ -4,6 +4,15 @@ module Registrar::BookKeeping
   DOMAIN_TO_PRODUCT = { 'ee': '01EE', 'com.ee': '02COM', 'pri.ee': '03PRI',
                         'fie.ee': '04FIE', 'med.ee': '05MED' }.freeze
 
+  included do
+    scope :with_cash_accounts, (lambda do
+      joins(:accounts)
+      .where('accounts.account_type = ? AND test_registrar != ?',
+             Account::CASH,
+             true)
+    end)
+  end
+
   def monthly_summary(month:)
     activities = monthly_activites(month)
     return unless activities.any?

app/models/registrar.rb

@@ -56,9 +56,48 @@ class Registrar < ApplicationRecord
     end
   end
 
-  def issue_prepayment_invoice(amount, description = nil, payable: true)
-    vat_rate = ::Invoice::VatRateCalculator.new(registrar: self).calculate
+  # rubocop:disable Metrics/MethodLength
+  def init_monthly_invoice(summary)
+    Invoice.new(
+      issue_date: summary['date'].to_date,
+      due_date: summary['date'].to_date,
+      currency: 'EUR',
+      description: I18n.t('invoice.monthly_invoice_description'),
+      seller_name: Setting.registry_juridical_name,
+      seller_reg_no: Setting.registry_reg_no,
+      seller_iban: Setting.registry_iban,
+      seller_bank: Setting.registry_bank,
+      seller_swift: Setting.registry_swift,
+      seller_vat_no: Setting.registry_vat_no,
+      seller_country_code: Setting.registry_country_code,
+      seller_state: Setting.registry_state,
+      seller_street: Setting.registry_street,
+      seller_city: Setting.registry_city,
+      seller_zip: Setting.registry_zip,
+      seller_phone: Setting.registry_phone,
+      seller_url: Setting.registry_url,
+      seller_email: Setting.registry_email,
+      seller_contact_name: Setting.registry_invoice_contact,
+      buyer: self,
+      buyer_name: name,
+      buyer_reg_no: reg_no,
+      buyer_country_code: address_country_code,
+      buyer_state: address_state,
+      buyer_street: address_street,
+      buyer_city: address_city,
+      buyer_zip: address_zip,
+      buyer_phone: phone,
+      buyer_url: website,
+      buyer_email: email,
+      reference_no: reference_no,
+      vat_rate: calculate_vat_rate,
+      monthly_invoice: true,
+      metadata: { items: summary['invoice_lines'] },
+      total: 0
+    )
+  end
 
+  def issue_prepayment_invoice(amount, description = nil, payable: true)
     invoice = invoices.create!(
       issue_date: Time.zone.today,
       due_date: (Time.zone.now + Setting.days_to_keep_invoices_active.days).to_date,
@@ -91,7 +130,7 @@ class Registrar < ApplicationRecord
       buyer_url: website,
       buyer_email: email,
       reference_no: reference_no,
-      vat_rate: vat_rate,
+      vat_rate: calculate_vat_rate,
       items_attributes: [
         {
           description: 'prepayment',
@@ -124,6 +163,7 @@ class Registrar < ApplicationRecord
 
     invoice
   end
+  # rubocop:enable Metrics/MethodLength
 
   def cash_account
     accounts.find_by(account_type: Account::CASH)
@@ -265,4 +305,8 @@ class Registrar < ApplicationRecord
   def vat_liable_in_foreign_country?
     !vat_liable_locally?
   end
+
+  def calculate_vat_rate
+    ::Invoice::VatRateCalculator.new(registrar: self).calculate
+  end
 end