Use scope and class method to clean up implementation

app/models/email_address.rb

@@ -49,6 +49,11 @@ def mil_email?
     email.end_with?('.mil')
   end
 
+  def self.last_sign_in
+    order('last_sign_in_at DESC NULLS LAST').first
+  end
+
+
   class << self
     def find_with_email(email)
       return nil if !email.is_a?(String) || email.empty?

app/models/user.rb

@@ -65,15 +65,15 @@ class User < ApplicationRecord
   attr_accessor :asserted_attributes, :email
 
   def confirmed_email_addresses
-    email_addresses.where.not(confirmed_at: nil).order('last_sign_in_at DESC NULLS LAST')
+    email_addresses.confirmed
   end
 
   def fully_registered?
     !!registration_log&.registered_at
   end
 
   def confirmed?
-    email_addresses.where.not(confirmed_at: nil).any?
+    confirmed_email_addresses.any?
   end
 
   def has_fed_or_mil_email?
@@ -522,7 +522,7 @@ def reload(...)
   end
 
   def last_sign_in_email_address
-    confirmed_email_addresses.first
+    email_addresses.confirmed.last_sign_in
   end
 
   private

spec/models/user_spec.rb

@@ -1721,4 +1721,39 @@ def it_should_not_send_survey
       end
     end
   end
+
+  describe '#last_sign_in_email_address' do
+    let(:user) { create(:user) }
+
+    let!(:last_sign_in_email_address) do
+      create(
+        :email_address,
+        email: '[email protected]',
+        user: user,
+        last_sign_in_at: 1.minute.ago,
+      )
+    end
+
+    let!(:older_sign_in_email_address) do
+      create(
+        :email_address,
+        email: '[email protected]',
+        user: user,
+        last_sign_in_at: 1.hour.ago,
+      )
+    end
+
+    let!(:never_signed_in_email_address) do
+      create(
+        :email_address,
+        email: '[email protected]',
+        user: user,
+        last_sign_in_at: nil,
+      )
+    end
+
+    it 'returns the last signed in email address' do
+      expect(user.last_sign_in_email_address).to eq(last_sign_in_email_address)
+    end
+  end
 end